make a ball mill in 5 minutes : 4 steps - instructables
This is for all the pyro nuts that I came across on Instructables. This can be used to grind chemicals to a very fine grain or to polish rocks.Wiki says "A ball mill is a type of grinder used to grind materials into extremely fine powder for use in paints, pyrotechnics, and ceramics."Many instructables refer to United Nuclear Ball Mills. Their small ball mill cost between $70 and $80 dollars.For no more than $30 and in 5 minute you can build a ball mill of appreciable performance.Check out my other Instructables:MAKE A HIGH VOLTAGE SUPPLY IN 5 MINUTESHack The Spy Ear and Learn to Reverse Engineer a CircuitSuper Easy E-mail Encryption Using Gmail, Firefox and WindowsMake a Rechargeable Dual Voltage Power Supply for Electronic ProjectsMake a Voltage Controlled Resistor and Use ItSODA CAN HYDROGEN GENERATOR
1. A rugged container (You can use PVC pipes or big plastic bottles)
2. An electric screwdriver (these are fairly cheap, I got mine for $10)
3. A bolt, a nut and maybe a washer.
4. Epoxy putty.
5. Steel or lead balls which in my case I substituted with screwdriver bits that I got for $3.
6. A vise clamp to hold down your ball mill.
This is the most important step. The joint holding the the container and electric screwdriver should be strong and able to hold the weight of the assembly.
Put a little putty on the bolt first. Insert the bolt into the screwdriver's bit holder. Cover the whole joint with putty. The more putty the better the ball mill stays together.
Fill the container with the screwdriver bits or with steel balls or lead balls. Add the chemical you need to grind. Close the container and clamp the whole assembly to a table top.
I use a popsicle stick to hold the screwdriver button down. I jam it between the clam vise and electric screwdriver (see video). But that depends on your electric screwdriver.
Im interested in this mill to dispose of mercury by combining it with sulphur to make mercury sulphide (HgS).A test report done in EU says an hours milling is best so there is no elemental mercury left.And the mercury sulphide is insoluble and is the same substance that mercury is found in the Earth which is cinnabar.
I may well be able to find a power drill at a resale shop, or buy an inexpensive one for the purpose. Any feedback on how well a power drill motor will hold up to being run for 24 hours continuously? I plan to make paper machie. I want to make a very fine paper pulp. While I doubt this is flammable, I would like to hear any comments on this as well. Who'd a thought flour was explosive?
If you want fine paper pulp, you may wish to consider using a blender. Ball mills are typically only needed for moderately-to-very hard materials that need to be crushed to effectively split them, and which might damage a blender if used in it.
Instead of using an electric screw driver, you could use a drill and a drill bit. Just putty the drill bit (preferably an old one) to the bolt inside the container. Seems like it would be a more powerful ball mill. But I'm definitely going to try this idea. Seems like it would be cool to make some gun powder. There's some simple step-by-step instructions on Wiki How if you guys need some instructions.
I would stay away from lead if you are making gun powder. That smoke that surrounds black powder ignition is not good for you. Fine particles of lead suspended in that smoke would be hell on your lungs etc.. i use a tumbler to get crud off of coins taken from the sea. Beach sand won't work well with water to do the job. But the sand at the oceans edge which is coarse makes a great scrubbing agent. Maybe some aquarium gravel would work to reduce some objects in size. Commercial media is often hell to work with.
hmm... methinks you should support the container. lead balls are heavy and (I'm assuming most people will want to make gunpowder with this so they'll have to use only lead balls) the current setup is going to make the screwdriver wear a lot, and the bottom of the container isn't going to last very long... I like this idea though, I haven't found a suitable motor to drive my ball mill, they're all either too weak or they're way too fast.
I know this is quite literally 10 years late, but for other hobbyists, try supporting it with a screw on the other side like the design pictured. The back end's screw can go through a piece of wood, brick etc. at the same level as the screw driver, creating a healthy amount of support, for a vitamin bottle filled with lead Potassium Nitrate, Sulfur and Carbon.
OR, you could just attach a bolt into the cap like he did for the bottom. Make a triangular piece of wood. Drill a hole for the bolt to fit through. And find some way to support the piece of wood? Seems like it would work to me, could even make your own cradle to support everything for that matter :P I'd never use something like this so have no need to make one, but that would be my advice :D
christian pfeiffer wins slovenian ball mill project
Christian Pfeiffer has won the contract to build an efficient ball mill circuit for limestone milling for a Slovenian client.The centrepiece of the plant will be a 3.2m (diameter) air stream ball mill with drying compartment and a high performance DSL separator.The commissioning of the plant is scheduled for the end of 2021.
In all ore dressing and milling Operations, including flotation, cyanidation, gravity concentration, and amalgamation, the Working Principle is to crush and grind, often with rob mill & ball mills, the ore in order to liberate the minerals. In the chemical and process industries, grinding is an important step in preparing raw materials for subsequent treatment.In present day practice, ore is reduced to a size many times finer than can be obtained with crushers. Over a period of many years various fine grinding machines have been developed and used, but the ball mill has become standard due to its simplicity and low operating cost.
A ball millefficiently operated performs a wide variety of services. In small milling plants, where simplicity is most essential, it is not economical to use more than single stage crushing, because the Steel-Head Ball or Rod Mill will take up to 2 feed and grind it to the desired fineness. In larger plants where several stages of coarse and fine crushing are used, it is customary to crush from 1/2 to as fine as 8 mesh.
Many grinding circuits necessitate regrinding of concentrates or middling products to extremely fine sizes to liberate the closely associated minerals from each other. In these cases, the feed to the ball mill may be from 10 to 100 mesh or even finer.
Where the finished product does not have to be uniform, a ball mill may be operated in open circuit, but where the finished product must be uniform it is essential that the grinding mill be used in closed circuit with a screen, if a coarse product is desired, and with a classifier if a fine product is required. In most cases it is desirable to operate the grinding mill in closed circuit with a screen or classifier as higher efficiency and capacity are obtained. Often a mill using steel rods as the grinding medium is recommended, where the product must have the minimum amount of fines (rods give a more nearly uniform product).
Often a problem requires some study to determine the economic fineness to which a product can or should be ground. In this case the 911Equipment Company offers its complete testing service so that accurate grinding mill size may be determined.
Until recently many operators have believed that one particular type of grinding mill had greater efficiency and resulting capacity than some other type. However, it is now commonly agreed and accepted that the work done by any ballmill depends directly upon the power input; the maximum power input into any ball or rod mill depends upon weight of grinding charge, mill speed, and liner design.
The apparent difference in capacities between grinding mills (listed as being the same size) is due to the fact that there is no uniform method of designating the size of a mill, for example: a 5 x 5 Ball Mill has a working diameter of 5 inside the liners and has 20 per cent more capacity than all other ball mills designated as 5 x 5 where the shell is 5 inside diameter and the working diameter is only 48 with the liners in place.
Ball-Rod Mills, based on 4 liners and capacity varying as 2.6 power of mill diameter, on the 5 size give 20 per cent increased capacity; on the 4 size, 25 per cent; and on the 3 size, 28 per cent. This fact should be carefully kept in mind when determining the capacity of a Steel- Head Ball-Rod Mill, as this unit can carry a greater ball or rod charge and has potentially higher capacity in a given size when the full ball or rod charge is carried.
A mill shorter in length may be used if the grinding problem indicates a definite power input. This allows the alternative of greater capacity at a later date or a considerable saving in first cost with a shorter mill, if reserve capacity is not desired.
The capacities of Ball-Rod Mills are considerably higher than many other types because the diameters are measured inside the liners.
The correct grinding mill depends so much upon the particular ore being treated and the product desired, that a mill must have maximum flexibility in length, type of grinding medium, type of discharge, and speed.With the Ball-Rod Mill it is possible to build this unit in exact accordance with your requirements, as illustrated.
To best serve your needs, the Trunnion can be furnished with small (standard), medium, or large diameter opening for each type of discharge. The sketch shows diagrammatic arrangements of the four different types of discharge for each size of trunnion opening, and peripheral discharge is described later.
Ball-Rod Mills of the grate discharge type are made by adding the improved type of grates to a standard Ball-Rod Mill. These grates are bolted to the discharge head in much the same manner as the standard headliners.
The grates are of alloy steel and are cast integral with the lifter bars which are essential to the efficient operation of this type of ball or rod mill. These lifter bars have a similar action to a pump:i. e., in lifting the product so as to discharge quickly through the mill trunnion.
These Discharge Grates also incorporate as an integral part, a liner between the lifters and steel head of the ball mill to prevent wear of the mill head. By combining these parts into a single casting, repairs and maintenance are greatly simplified. The center of the grate discharge end of this mill is open to permit adding of balls or for adding water to the mill through the discharge end.
Instead of being constructed of bars cast into a frame, Grates are cast entire and have cored holes which widen toward the outside of the mill similar to the taper in grizzly bars. The grate type discharge is illustrated.
The peripheral discharge type of Ball-Rod Mill is a modification of the grate type, and is recommended where a free gravity discharge is desired. It is particularly applicable when production of too many fine particles is detrimental and a quick pass through the mill is desired, and for dry grinding.
The drawings show the arrangement of the peripheral discharge. The discharge consists of openings in the shell into which bushings with holes of the desired size are inserted. On the outside of the mill, flanges are used to attach a stationary discharge hopper to prevent pulp splash or too much dust.
The mill may be operated either as a peripheral discharge or a combination or peripheral and trunnion discharge unit, depending on the desired operating conditions. If at any time the peripheral discharge is undesirable, plugs inserted into the bushings will convert the mill to a trunnion discharge type mill.
Unless otherwise specified, a hard iron liner is furnished. This liner is made of the best grade white iron and is most serviceable for the smaller size mills where large balls are not used. Hard iron liners have a much lower first cost.
Electric steel, although more expensive than hard iron, has advantage of minimum breakage and allows final wear to thinner section. Steel liners are recommended when the mills are for export or where the source of liner replacement is at a considerable distance.
Molychrome steel has longer wearing qualities and greater strength than hard iron. Breakage is not so apt to occur during shipment, and any size ball can be charged into a mill equipped with molychrome liners.
Manganese liners for Ball-Rod Mills are the world famous AMSCO Brand, and are the best obtainable. The first cost is the highest, but in most cases the cost per ton of ore ground is the lowest. These liners contain 12 to 14% manganese.
The feed and discharge trunnions are provided with cast iron or white iron throat liners. As these parts are not subjected to impact and must only withstand abrasion, alloys are not commonly used but can be supplied.
Gears for Ball-Rod Mills drives are furnished as standard on the discharge end of the mill where they are out of the way of the classifier return, scoop feeder, or original feed. Due to convertible type construction the mills can be furnished with gears on the feed end. Gear drives are available in two alternative combinations, which are:
All pinions are properly bored, key-seated, and pressed onto the steel countershaft, which is oversize and properly keyseated for the pinion and drive pulleys or sheaves. The countershaft operates on high grade, heavy duty, nickel babbitt bearings.
Any type of drive can be furnished for Ball-Rod Mills in accordance with your requirements. Belt drives are available with pulleys either plain or equipped with friction clutch. Various V- Rope combinations can also be supplied.
The most economical drive to use up to 50 H. P., is a high starting torque motor connected to the pinion shaft by means of a flat or V-Rope drive. For larger size motors the wound rotor (slip ring) is recommended due to its low current requirement in starting up the ball mill.
Should you be operating your own power plant or have D. C. current, please specify so that there will be no confusion as to motor characteristics. If switches are to be supplied, exact voltage to be used should be given.
Even though many ores require fine grinding for maximum recovery, most ores liberate a large percentage of the minerals during the first pass through the grinding unit. Thus, if the free minerals can be immediately removed from the ball mill classifier circuit, there is little chance for overgrinding.
This is actually what has happened wherever Mineral Jigs or Unit Flotation Cells have been installed in the ball mill classifier circuit. With the installation of one or both of these machines between the ball mill and classifier, as high as 70 per cent of the free gold and sulphide minerals can be immediately removed, thus reducing grinding costs and improving over-all recovery.
The advantage of this method lies in the fact that heavy and usually valuable minerals, which otherwise would be ground finer because of their faster settling in the classifier and consequent return to the grinding mill, are removed from the circuit as soon as freed. This applies particularly to gold and lead ores.
Ball-Rod Mills have heavy rolled steel plate shells which are arc welded inside and outside to the steel heads or to rolled steel flanges, depending upon the type of mill. The double welding not only gives increased structural strength, but eliminates any possibility of leakage.
Where a single or double flanged shell is used, the faces are accurately machined and drilled to template to insure perfect fit and alignment with the holes in the head. These flanges are machined with male and female joints which take the shearing stresses off the bolts.
The Ball-Rod Mill Heads are oversize in section, heavily ribbed and are cast from electric furnace steel which has a strength of approximately four times that of cast iron. The head and trunnion bearings are designed to support a mill with length double its diameter. This extra strength, besides eliminating the possibility of head breakage or other structural failure (either while in transit or while in service), imparts to Ball-Rod Mills a flexibility heretofore lacking in grinding mills. Also, for instance, if you have a 5 x 5 mill, you can add another 5 shell length and thus get double the original capacity; or any length required up to a maximum of 12 total length.
On Type A mills the steel heads are double welded to the rolled steel shell. On type B and other flanged type mills the heads are machined with male and female joints to match the shell flanges, thus taking the shearing stresses from the heavy machine bolts which connect the shell flanges to the heads.
The manhole cover is protected from wear by heavy liners. An extended lip is provided for loosening the door with a crow-bar, and lifting handles are also provided. The manhole door is furnished with suitable gaskets to prevent leakage.
The mill trunnions are carried on heavy babbitt bearings which provide ample surface to insure low bearing pressure. If at any time the normal length is doubled to obtain increased capacity, these large trunnion bearings will easily support the additional load.
Trunnion bearings are of the rigid type, as the perfect alignment of the trunnion surface on Ball-Rod Mills eliminates any need for the more expensive self-aligning type of bearing.
The cap on the upper half of the trunnion bearing is provided with a shroud which extends over the drip flange of the trunnion and effectively prevents the entrance of dirt or grit. The bearing has a large space for wool waste and lubricant and this is easily accessible through a large opening which is covered to prevent dirt from getting into the bearing.Ball and socket bearings can be furnished.
Scoop Feeders for Ball-Rod Mills are made in various radius sizes. Standard scoops are made of cast iron and for the 3 size a 13 or 19 feeder is supplied, for the 4 size a 30 or 36, for the 5 a 36 or 42, and for the 6 a 42 or 48 feeder. Welded steel scoop feeders can, however, be supplied in any radius.
The correct size of feeder depends upon the size of the classifier, and the smallest feeder should be used which will permit gravity flow for closed circuit grinding between classifier and the ball or rod mill. All feeders are built with a removable wearing lip which can be easily replaced and are designed to give minimum scoop wear.
A combination drum and scoop feeder can be supplied if necessary. This feeder is made of heavy steel plate and strongly welded. These drum-scoop feeders are available in the same sizes as the cast iron feeders but can be built in any radius. Scoop liners can be furnished.
The trunnions on Ball-Rod Mills are flanged and carefully machined so that scoops are held in place by large machine bolts and not cap screws or stud bolts. The feed trunnion flange is machined with a shoulder for insuring a proper fit for the feed scoop, and the weight of the scoop is carried on this shoulder so that all strain is removed from the bolts which hold the scoop.
High carbon steel rods are recommended, hot rolled, hot sawed or sheared, to a length of 2 less than actual length of mill taken inside the liners.
The initial rod charge is generally a mixture ranging from 1.5 to 3 in diameter. During operation, rod make-up is generally the maximum size. The weights per lineal foot of rods of various diameters are approximately: 1.5 to 6 lbs.; 2-10.7 lbs.; 2.5-16.7 lbs.; and 3-24 lbs.
Forged from the best high carbon manganese steel, they are of the finest quality which can be produced and give long, satisfactory service.
Data on ball charges for Ball-Rod Mills are listed in Table 5. Further information regarding grinding balls is included in Table 6.
Rod Mills has a very define and narrow discharge product size range. Feeding a Rod Mill finer rocks will greatly impact its tonnage while not significantly affect its discharge product sizes. The 3.5 diameter rod of a mill, can only grind so fine.
Crushers are well understood by most. Rod and Ball Mills not so much however as their size reduction actions are hidden in the tube (mill). As for Rod Mills, the image above best expresses what is going on inside. As rocks is feed into the mill, they are crushed (pinched) by the weight of its 3.5 x 16 rods at one end while the smaller particles migrate towards the discharge end and get slightly abraded (as in a Ball Mill) on the way there.
We haveSmall Ball Mills for sale coming in at very good prices. These ball mills are relatively small, bearing mounted on a steel frame. All ball mills are sold with motor, gears, steel liners and optional grinding media charge/load.
Ball Mills or Rod Mills in a complete range of sizes up to 10 diameter x20 long, offer features of operation and convertibility to meet your exactneeds. They may be used for pulverizing and either wet or dry grindingsystems. Mills are available in both light-duty and heavy-duty constructionto meet your specific requirements.
All Mills feature electric cast steel heads and heavy rolled steelplate shells. Self-aligning main trunnion bearings on large mills are sealedand internally flood-lubricated. Replaceable mill trunnions. Pinion shaftbearings are self-aligning, roller bearing type, enclosed in dust-tightcarrier. Adjustable, single-unit soleplate under trunnion and drive pinionsfor perfect, permanent gear alignment.
Ball Mills can be supplied with either ceramic or rubber linings for wet or dry grinding, for continuous or batch type operation, in sizes from 15 x 21 to 8 x 12. High density ceramic linings of uniform hardness male possible thinner linings and greater and more effective grinding volume. Mills are shipped with liners installed.
Complete laboratory testing service, mill and air classifier engineering and proven equipment make possible a single source for your complete dry-grinding mill installation. Units available with air swept design and centrifugal classifiers or with elevators and mechanical type air classifiers. All sizes and capacities of units. Laboratory-size air classifier also available.
A special purpose batch mill designed especially for grinding and mixing involving acids and corrosive materials. No corners mean easy cleaning and choice of rubber or ceramic linings make it corrosion resistant. Shape of mill and ball segregation gives preferential grinding action for grinding and mixing of pigments and catalysts. Made in 2, 3 and 4 diameter grinding drums.
Nowadays grinding mills are almost extensively used for comminution of materials ranging from 5 mm to 40 mm (3/161 5/8) down to varying product sizes. They have vast applications within different branches of industry such as for example the ore dressing, cement, lime, porcelain and chemical industries and can be designed for continuous as well as batch grinding.
Ball mills can be used for coarse grinding as described for the rod mill. They will, however, in that application produce more fines and tramp oversize and will in any case necessitate installation of effective classification.If finer grinding is wanted two or three stage grinding is advisable as for instant primary rod mill with 75100 mm (34) rods, secondary ball mill with 2540 mm(11) balls and possibly tertiary ball mill with 20 mm () balls or cylpebs.To obtain a close size distribution in the fine range the specific surface of the grinding media should be as high as possible. Thus as small balls as possible should be used in each stage.
The principal field of rod mill usage is the preparation of products in the 5 mm0.4 mm (4 mesh to 35 mesh) range. It may sometimes be recommended also for finer grinding. Within these limits a rod mill is usually superior to and more efficient than a ball mill. The basic principle for rod grinding is reduction by line contact between rods extending the full length of the mill, resulting in selective grinding carried out on the largest particle sizes. This results in a minimum production of extreme fines or slimes and more effective grinding work as compared with a ball mill. One stage rod mill grinding is therefore suitable for preparation of feed to gravimetric ore dressing methods, certain flotation processes with slime problems and magnetic cobbing. Rod mills are frequently used as primary mills to produce suitable feed to the second grinding stage. Rod mills have usually a length/diameter ratio of at least 1.4.
Tube mills are in principle to be considered as ball mills, the basic difference being that the length/diameter ratio is greater (35). They are commonly used for surface cleaning or scrubbing action and fine grinding in open circuit.
In some cases it is suitable to use screened fractions of the material as grinding media. Such mills are usually called pebble mills, but the working principle is the same as for ball mills. As the power input is approximately directly proportional to the volume weight of the grinding media, the power input for pebble mills is correspondingly smaller than for a ball mill.
A dry process requires usually dry grinding. If the feed is wet and sticky, it is often necessary to lower the moisture content below 1 %. Grinding in front of wet processes can be done wet or dry. In dry grinding the energy consumption is higher, but the wear of linings and charge is less than for wet grinding, especially when treating highly abrasive and corrosive material. When comparing the economy of wet and dry grinding, the different costs for the entire process must be considered.
An increase in the mill speed will give a directly proportional increase in mill power but there seems to be a square proportional increase in the wear. Rod mills generally operate within the range of 6075 % of critical speed in order to avoid excessive wear and tangled rods. Ball and pebble mills are usually operated at 7085 % of critical speed. For dry grinding the speed is usually somewhat lower.
The mill lining can be made of rubber or different types of steel (manganese or Ni-hard) with liner types according to the customers requirements. For special applications we can also supply porcelain, basalt and other linings.
The mill power is approximately directly proportional to the charge volume within the normal range. When calculating a mill 40 % charge volume is generally used. In pebble and ball mills quite often charge volumes close to 50 % are used. In a pebble mill the pebble consumption ranges from 315 % and the charge has to be controlled automatically to maintain uniform power consumption.
In all cases the net energy consumption per ton (kWh/ton) must be known either from previous
experience or laboratory tests before mill size can be determined. The required mill net power P kW ( = ton/hX kWh/ton) is obtained from
Trunnions of S.G. iron or steel castings with machined flange and bearing seat incl. device for dismantling the bearings. For smaller mills the heads and trunnions are sometimes made in grey cast iron.
The mills can be used either for dry or wet, rod or ball grinding. By using a separate attachment the discharge end can be changed so that the mills can be used for peripheral instead of overflow discharge.
how i built a quick and easy home-made ball mill
Anyone who has looked through my web site can see that I am fascinated with glass. I like to melt it, cast it, fuse it and turn it into new things.
Eventually I got the idea of doing the ultimate glass hack and making my own glass from scratch. For that I needed a way of grinding and mixing
the chemicals that would make up a batch of glass into a very fine and homogeneously mixed powder. I needed a ball mill. So naturally I decided
to build my own. Here it is in all it's bodged together glory. It doesn't look like much, but it works great, and it cost almost nothing to build.
As a bonus, this ball mill can also be used as a rock tumbler, or a glass tumbler to make your own "sea glass" at home. To use the
mill as a rock tumbler, just leave out the steel balls, add rocks, tumbling grit and water, and let it spin.
Here is a video of my home-made ball mill in operation with a brief explanation of all the parts and how I put it together. For
detailed descriptions of all the parts, how I built it, and how I use it, read further down this page.
The drum I used for the ball mill was originally a plastic container that held abrasive grit used in vibratory tumblers. It is about two liters in size.
I had several empty containers of this type,
and decided to put them to use in this project. They work pretty well in this application. There are a few potential problems. The container lids
are not liquid-tight. So use as a rock tumbler would require adding a cork or rubber gasket. Also, a little bit of the plastic does get ground off
the inside surface and contaminates the batch being ground. This is not a problem for my application because anything organic will be vaporized out
of the mix long before it reaches melting temperature in my kiln. Contamination might be an issue for other uses. A steel drum would probably work
better if you can find one, or make one, but it would be a lot louder in use.
Here you can see an overview of the ball mill with the drum removed. Construction is super simple. Just three pieces of wood plank banged together
to make a platform for mounting all the parts. The platform is made from a 1X10 wooden plank 14 inches long. It sits on two pieces of 1X4 wood.
Four inexpensive fixed caster wheels were mounted on top of the platform for the drum to roll on. They were mounted about 2 inches in from
the edges of the platform, and 7.5 inches apart.
The drive motor was mounted on the underside of the platform, and the dive belt comes up through a slot in the platform.
Here is a close-up showing how two of the caster wheels are mounted. The slot in the middle of the platform for the belt to pass through is also
visible. The fixed caster wheels were quite inexpensive, and were one of the few items I actually had to buy to build this project.
Here is a close-up of the other side of the platform and the other two caster wheels. Also shown is a stop mounted on one side of the platform.
It was found early
on in using the mill that the drum tended to slowly walk toward one side and would eventually drop off the wheels. So I found a scrap piece of
aluminum and mounted it the end the drum walked toward to act as a stop. The drum riding against the smooth aluminum surface doesn't seem to
produce much friction.
The ball mill is powered by a fairly robust 12V DC motor salvaged from a junked printer. It had a pulley for a fine-toothed belt on it. It was left in place
and it seems to drive the heavy round rubber belt well without slipping. The motor was mounted using screws on only one side, which were deliberately left
loose. This allows the motor to pivot downward under its own weight to put tension on the belt.
A long, narrow slot was cut in the platform for the belt to pass through. I did it by marking out where I wanted it, drilling a hole
at each end, and then cutting out the material between the holes with a jigsaw.
This photo shows the makeshift end stop that prevents the drum from walking off the casters. It is just a random piece of aluminum
I found in my junk collection. It conveniently had some holes already drilled in it which made mounting easy. Just about anything
that the drum will ride against nearly frictionlessly will work for a stop.
One of the few things I had to buy for this project, aside from the casters, was the steel balls. I found these online. They were
quite inexpensive. I went with 5/8 inch diameter balls, which seem to work well in a mill this size.
I have been powering the ball mill with my bench variable power supply so I could fine tune the rotation speed. I wanted it to turn as fast
as possible to speed grinding, but not so fast that centrifugal force pins the balls to the wall of the drum preventing them from tumbling
over each other. With a little experimentation, the correct speed was found.
So far, this makeshift mill has worked well for me. It has been run for long periods with no problems. It does a good job of reducing
even fairly chunky material into a very fine powder, and thoroughly mixing everything. The only real problem I have faced is accidentally
over-filling the drum a few times. The drum should not be too full or the balls and material to be ground won't have enough free space
to tumble around.
After a milling run, the contents of the drum are dumped out into a sieve over a bowl. With a few shakes of the sieve, the powder drops
through the mesh into the bowl leaving the balls behind to be put back in the drum. The sieve also catches any bits that haven't been
sufficiently ground down.
I need to add a disclaimer here for anyone thinking of using this sort of ball mill for milling gunpowder or other
flammable or explosive powders. First of all, it is really not a good idea. You could cause a fire or explosion and
destroy your place, or maybe even get yourself hurt or killed. So don't do it, and if you do it, don't blame me if
something bad happens. I'll be saying I told you so.
Also do not to use steel, ceramic or glass balls to grind flammable or explosive materials because they can create sparks
as they bang against each other while they tumble.
Future improvements: The plastic container I am using is really thick-walled and sturdy, but using it in this application will eventually wear it out. I also get some plastic
contamination in the materials I grind in it. So in the future I would like to replace the plastic container with a piece of large diameter steel or iron pipe with end caps.
That should also help improve the grinding action as the steel balls bash against the hard walls of the pipe. If I switch to a steel or iron container, which would be heavier,
I might also have to beef up the motor driving the unit. We'll see,
Other applications: As I mentioned at the top of the page, and in the attached video, this setup could also be used as a rock tumbler. The plastic container would be ideal for
that. Another possible application for this unit is for grinding samples of gold ore, and maybe other metallic ores. One of my many hobbies is gold prospecting.
It's often necessary to grind an ore sample to release all the fine particles of gold it contains so they can be separated. This unit may get used for that in the future too.
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Copyright 2014-2018 Michael Davis, All rights reserved.
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ball mill, custom engineering & manufacturing near tollesboro, ky
"Shane Wallingford and his team have become valuable members of our industrial ecosystem. JSB Industrial Solutions has become the single source manufacturer for our hydraulic closing units, the foundation of safety systems when extracting hydrocarbons in the oil and gas industry."
"Shane Wallingford and his team have become our go to supplier for ball mills and ball mill lid replacements... They perform quality work in a timely manner and are always available for one on one conversations when questions or consultations are needed."
ball mill project - tools and tooling - apc forum
I journeyed down the path of a ball mill project this fall and am posting a bit about the fun n' games in this post. Thanks goes out to the many related threads/post regarding the topic that helped me with the ideas/calculations/thoughts on the matter. Hope this post helps others looking to strike out on a similar project.
Started by looking for a suitable TEFC motor to run the show. Came across a new old stock 1/2HP Marathon 56C34F544 (LINK). Specs: 1/2HP, TEFC rated enclosure, 115/208-230V, single phase, thermally protected.
I know enough of the 3D modeling program Solid Works to be just about dangerous. This was a fairly straight forward and fun project to model up, helps tremendously with visualizing how things go together, length/amount of material needed, where you run into clearance issues etc... The design was to be made with light square tubing, be wheeled around, stored leaning upright if needed. The above is what I came up with. May still make a blast shield enclosure for the top. If anyone wants the solid files to use as a starting point, PM or email me.
Just about finished being assembled. 1" Pillow block bearings, 1" OD steel intermediate and mill jar drive shafts, 1" heater hose over the drive shafts (I did have a friend mill in a key way for the pulleys on both shafts). The primary drive belt didn't need a tensioner, as you could get the belt plenty tight by pulling and tightening down the motor. Most pulleys were bought from MSC Industrial Supply. Belt length was determined by measuring the distance between the pulleys in Solid Works and using a belt length calculator with the known pulley diameters.
For media I went with brass cylinders of both 1/2" and 5/16" size, figure the cylinder would have more grinding contact surface at any one given point vs. a ball and might be more efficient (shrug). I can't recall the reason for the going with the mixed size media. I remember reading something beneficial here (possibly more efficient when grinding at the airfloat stage due?) and thought it would be worth trying.
Bought 72" lengths, sawed and taped them into bundles and cut them into pieces on the band saw. From the first jars of oxidizer, charcoal and comp through through the mill, the mixed media works very well, but I don't have anything other than observation to back it up at this point. Media weight was approximately 35lbs and filled about half of the almost 12" long 6" diameter jar (not including the reducer length).
Mill in action in the link below. I use a WiFi outlet switcher to turn the mill on/off. Set an alarm on your phone for the duration you want to mill, when the alarm goes off hit up the outlet switcher app to turn off the mill.
The calculations used that are specific to this mill are listed below (copy/pasted from my notes). When measuring the RPM of the spinning jar I came within a few RPMs of the target, so if there's a boo boo in the work below, it's at least close .
Being that the motor RPM was a bit high I had to use an intermediate shaft and secondary reduction pulley to get the final jar speed. In hindsight, if I were to do over, I would probably shoot for a slower 1750RPM (or about) commonly available motor to be able to skip the intermediate shaft and run direct drive from motor to the jar drive shaft. If the 3450 RPM motor were to be direct drive the reduction pulley diameter would be huge. At the time of discovering this I already bought the motor.
Milling Jar diameter 6.67*pi: 20.94
Rod diameter with rubber 1.25*pi: 3.92
20.94 / 3.92: 5.34 ratio between shaft and jar, every turn of the jar, the rod turns 5.34 times.
74 * 5.34 = 395RPM needed on the drive rod w/rubber
2.05 primary motor pulley
3450 / 395 = 8.73, so need the motor to spin 8.73 times to rotate the drive rod once
Pulley selection, current pulley set
Primary: 2.05 motor pulley to 7.25 pulley on an intermediate shaft, (7.25 / 2.05 = 3.54 ratio), 3450
RPM / 3.54 = 975 RPM
Secondary: 3.75 pulley on an intermediate shaft to a 8.25 mill drive shaft, (8.25 / 3.75 = 2.2 ratio), 975
RPM / 2.2 = 443 RPM
X RPM * 5.34 ratio = 443 RPM, X = 82 RPM
Ideal pulley selection for 74RPM (different/larger OD jar)
Primary: 2.05 motor pulley to 8.25 pulley on an intermediate shaft, (8.25 / 2.05 = 4.02 ratio), 3450
RPM / 4.02 = 858 RPM
Secondary: 3.75 pulley on an intermediate shaft to a 8.25 mill drive shaft, (8.25 / 3.75 = 2.2 ratio), 858
RPM / 2.2 = 390 RPM
X RPM * 5.34 ratio = 390 RPM, X = 73 RPM
That's a good call with the belt guard. The thought has crossed my mind, I'm having to make sure the puppies are in the house when running the mill outside. Hate to see a wagging tail near it when on.
what's the difference between sag mill and ball mill - jxsc machine
A mill is a grinder used to grind and blend solid or hard materials into smaller pieces by means of shear, impact and compression methods. Grinding mill machine is an essential part of many industrial processes, there are mainly five types of mills to cover more than 90% materials size-reduction applications.
Do you the difference between the ball mill, rod mills, SAG mill, tube mill, pebble mill? In the previous article, I made a comparison of ball mill and rod mill. Today, we will learn about the difference between SAG mill vs ball mill.
AG/SAG is short for autogenous mill and semi-autogenous mill, it combines with two functions of crushing and grinding, uses the ground material itself as the grinding media, through the mutual impact and grinding action to gradually reduce the material size. SAG mill is usually used to grind large pieces into small pieces, especially for the pre-processing of grinding circuits, thus also known as primary stage grinding machine. Based on the high throughput and coarse grind, AG mills produce coarse grinds often classify mill discharge with screens and trommel. SAG mills grinding media includes some large and hard rocks, filled rate of 9% 20%. SAG mill grind ores through impact, attrition, abrasion forces. In practice, for a given ore and equal processing conditions, the AG milling has a finer grind than SAG mills.
The working principle of the self-grinding machine is basically the same as the ball mill, the biggest difference is that the sag grinding machine uses the crushed material inside the cylinder as the grinding medium, the material constantly impacts and grinding to gradually pulverize. Sometimes, in order to improve the processing capacity of the mill, a small amount of steel balls be added appropriately, usually occupying 2-3% of the volume of the mill (that is semi-autogenous grinding).
High capacity Ability to grind multiple types of ore in various circuit configurations, reduces the complexity of maintenance and coordination. Compared with the traditional tumbling mill, the autogenous mill reduces the consumption of lining plates and grinding media, thus have a lower operation cost. The self-grinding machine can grind the material to 0.074mm in one time, and its content accounts for 20% ~ 50% of the total amount of the product. Grinding ratio can reach 4000 ~ 5000, more than ten times higher than ball, rod mill.
Ball mills are fine grinders, have horizontal ball mill and vertical ball mill, their cylinders are partially filled with steel balls, manganese balls, or ceramic balls. The material is ground to the required fineness by rotating the cylinder causing friction and impact. The internal machinery of the ball mill grinds the material into powder and continues to rotate if extremely high precision and precision is required.
The ball mill can be applied in the cement production plants, mineral processing plants and where the fine grinding of raw material is required. From the volume, the ball mill divide into industrial ball mill and laboratory use the small ball mill, sample grinding test. In addition, these mills also play an important role in cold welding, alloy production, and thermal power plant power production.
The biggest characteristic of the sag mill is that the crushing ratio is large. The particle size of the materials to be ground is 300 ~ 400mm, sometimes even larger, and the minimum particle size of the materials to be discharged can reach 0.1 mm. The calculation shows that the crushing ratio can reach 3000 ~ 4000, while the ball mills crushing ratio is smaller. The feed size is usually between 20-30mm and the product size is 0-3mm.
Both the autogenous grinding mill and the ball mill feed parts are welded with groove and embedded inner wear-resistant lining plate. As the sag mill does not contain grinding medium, the abrasion and impact on the equipment are relatively small.
The feed of the ball mill contains grinding balls. In order to effectively reduce the direct impact of materials on the ball mill feed bushing and improve the service life of the ball mill feed bushing, the feeding point of the groove in the feeding part of the ball mill must be as close to the side of the mill barrel as possible. And because the ball mill feed grain size is larger, ball mill feeding groove must have a larger slope and height, so that feed smooth.
Since the power of the autogenous tumbling mill is relatively small, it is appropriate to choose dynamic and static pressure bearing. The ball bearing liner is made of lead-based bearing alloy, and the back of the bearing is formed with a waist drum to form a contact centering structure, with the advantages of flexible movement. The bearing housing is lubricated by high pressure during start-up and stop-up, and the oil film is formed by static pressure. The journal is lifted up to prevent dry friction on the sliding surface, and the starting energy moment is reduced. The bearing lining is provided with a snake-shaped cooling water pipe, which can supply cooling water when necessary to reduce the temperature of the bearing bush. The cooling water pipe is made of red copper which has certain corrosion resistance.
Ball mill power is relatively large, the appropriate choice of hydrostatic sliding bearing. The main bearing bush is lined with babbitt alloy bush, each bush has two high-pressure oil chambers, high-pressure oil has been supplied to the oil chamber before and during the operation of the mill, the high-pressure oil enters the oil chamber through the shunting motor, and the static pressure oil film is compensated automatically to ensure the same oil film thickness To provide a continuous static pressure oil film for mill operation, to ensure that the journal and the bearing Bush are completely out of contact, thus greatly reducing the mill start-up load, and can reduce the impact on the mill transmission part, but also can avoid the abrasion of the bearing Bush, the service life of the bearing Bush is prolonged. The pressure indication of the high pressure oil circuit can be used to reflect the load of the mill indirectly. When the mill stops running, the high pressure oil will float the Journal, and the Journal will stop gradually in the bush, so that the Bush will not be abraded. Each main bearing is equipped with two temperature probe, dynamic monitoring of the bearing Bush temperature, when the temperature is greater than the specified temperature value, it can automatically alarm and stop grinding. In order to compensate for the change of the mill length due to temperature, there is a gap between the hollow journal at the feeding end and the bearing Bush width, which allows the journal to move axially on the bearing Bush. The two ends of the main bearing are sealed in an annular way and filled with grease through the lubricating oil pipe to prevent the leakage of the lubricating oil and the entry of dust.
The end cover of the autogenous mill is made of steel plate and welded into one body; the structure is simple, but the rigidity and strength are low; the liner of the autogenous mill is made of high manganese steel.
The end cover and the hollow shaft can be made into an integral or split type according to the actual situation of the project. No matter the integral or split type structure, the end cover and the hollow shaft are all made of Casting After rough machining, the key parts are detected by ultrasonic, and after finishing, the surface is detected by magnetic particle. The surface of the hollow shaft journal is Polished after machining. The end cover and the cylinder body are all connected by high-strength bolts. Strict process measures to control the machining accuracy of the joint surface stop, to ensure reliable connection and the concentricity of the two end journal after final assembly. According to the actual situation of the project, the cylinder can be made as a whole or divided, with a flanged connection and stop positioning. All welds are penetration welds, and all welds are inspected by ultrasonic nondestructive testing After welding, the whole Shell is returned to the furnace for tempering stress relief treatment, and after heat treatment, the shell surface is shot-peened. The lining plate of the ball mill is usually made of alloy material.
The transmission part comprises a gear and a gear, a gear housing, a gear housing and an accessory thereof. The big gear of the transmission part of the self-grinding machine fits on the hollow shaft of the discharge material, which is smaller in size, but the seal of the gear cover is not good, and the ore slurry easily enters the hollow shaft of the discharge material, causing the hollow shaft to wear.
The big gear of the ball mill fits on the mill shell, the size is bigger, the big gear is divided into half structure, the radial and axial run-out of the big gear are controlled within the national standard, the aging treatment is up to the standard, and the stress and deformation after processing are prevented. The big gear seal adopts the radial seal and the reinforced big gear shield. It is welded and manufactured in the workshop. The geometric size is controlled, the deformation is prevented and the sealing effect is ensured. The small gear transmission device adopts the cast iron base, the bearing base and the bearing cap are processed at the same time to reduce the vibration in operation. Large and small gear lubrication: The use of spray lubrication device timing quantitative forced spray lubrication, automatic control, no manual operation. The gear cover is welded by profile steel and high-quality steel plate. In order to enhance the stiffness of the gear cover, the finite element analysis is carried out, and the supporting structure is added in the weak part according to the analysis results.
The self-mill adopts the self-return device to realize the discharge of the mill. The self-returning device is located in the revolving part of the mill, and the material forms a self-circulation in the revolving part of the mill through the self-returning device, discharging the qualified material from the mill, leading the unqualified material back into the revolving part to participate in the grinding operation.
The ball mill adopts a discharge screen similar to the ball mill, and the function of blocking the internal medium of the overflow ball mill is accomplished inside the rotary part of the ball mill. The discharge screen is only responsible for forcing out a small amount of the medium that overflows into the discharge screen through the internal welding reverse spiral, to achieve forced discharge mill.
The slow drive consists of a brake motor, a coupling, a planetary reducer and a claw-type clutch. The device is connected to a pinion shaft and is used for mill maintenance and replacement of liners. In addition, after the mill is shut down for a long time, the slow-speed transmission device before starting the main motor can eliminate the eccentric load of the steel ball, loosen the consolidation of the steel ball and materials, ensure safe start, avoid overloading of the air clutch, and play a protective role. The slow-speed transmission device can realize the point-to-point reverse in the electronic control design. When connecting the main motor drive, the claw-type Clutch automatically disengages, the maintenance personnel should pay attention to the safety.
The slow drive device of the ball mill is provided with a rack and pinion structure, and the operating handle is moved to the side away from the cylinder body The utility model not only reduces the labor intensity but also ensures the safety of the operators.