dry ball mill
Xinhai mineral processing equipment mainly include: grinding equipment,
flotation equipment, dewatering equipment, magnetic separation equipment,
and so on. Some of the equipment is Xinhai independent research and
development, and has been awarded national patent.
Gold CIP Production Line adsorbs gold from cyaniding pulp by active carbon
including 7 steps: leaching pulp preparation, cyaniding leaching, carbon
adsorption, gold loaded carbon desorption, pregnant solution electrodeposit,
carbon acid regeneration, leaching pulp. View details
The materials are uniformly sent to the first chamber of dry ball mill by the feeding device through the feeding hollow shaft. The first chamber of dry ball mill contains stepped lining board or corrugated lining board, and steel balls of different specifications. The centrifugal force generated by the cylinder rotation will bring the steel balls to a certain height and then drop down, which will have a pounding and grinding effect on the materials. After the rough grinding is finished in the first chamber of dry ball mill, the materials will enter into the second chamber through the single-wall partition, which is lined with flat lining board and steel balls to further grind the materials. The powder material is discharged through discharge grates, then the grinding operation is completed.
A Gansu mineral processing plant wanted to choose a dry type ball mill manufacturer for its second construction plant. At the early stage, too high equipment failure rate seriously influenced the productivity of entire mineral processing plant. Through the friend introduction, the client knew Xinhai Mining, and bought two dry ball mills for the mineral processing plant. At present, the dry ball mill has been formally put into production without abnormalities, and the working efficiency of the dry ball mills was increased by 12%.
ball mills - metso outotec
With more than 100 years of experience in developing this technology. Metso Outotec has designed, manufactured and installed over 8,000 ball and pebble mills all over the world for a wide range of applications. Some of those applications are grate discharge, peripheral discharge, dry grinding, special length to diameter ratio, high temperature milling oprations and more.
All equipment adheres to the applicable standards set by ASTM, NEMA, AGMA, AWS, and ANSI. Reliable and effective grinding mills includes being safe throughout. When the mills are quoted we make sure to include any and all safety components needed.
Metso Outotec process engineers welcome the opportunity to assist you with circuit and circuit control design as well as start-up, operation, and optimization of the milling plant. Automatic operation saves power, grinding media, and liner wear, while increasing capacity.
To ensure top-of-the-line operation, software can be developed to suit the most complicated circuits and complex ores. Our engineers can specify or supply computer control systems for your sophisticated circuit needs. These controls are feasible for also smaller installations.
Three types of tests are available for mill power determinations. In most cases one of two bench scale tests is adequate. First, a Jar Mill grindability test requires a 5 lb. (2 kg) sample and produces a direct measured specific energy (net Hp-hr/t) to grind from the design feed size to the required product size. The second test, a Bond Work Index determination, results in a specific energy value (net Hp-hr/t) from an empirical formula.
If time permits and the user wishes, grinding circuits are set up and continuous tests are run to simulate plant operation. These tests require two or three days for each ore type and approximately 1,000 pounds of material for each day of testing. Variations in ore hardness or circuit design may require larger samples.
Metso Outotec Premier horizontal grinding mills are customized and optimized grinding solutions built on advanced simulation tools and unmatched expertise. A Metso Outotec Premier horizontal grinding mill is able to meet any projects needs, even if it means creating something novel and unseen before.
Metso Outotec Select horizontal grinding mills are a pre-engineered range of class-leading horizontal grinding mills that were selected by utilizing our industry leading experience and expertise. With developing a pre-engineered package, this eliminates a lot of the time and costs usually spent in the engineering and selection stages.
dry grinding ball load calculation
Selection of Volume of Ball Loads in Continuous Dry Open Circuit Grinding:The tests reported in tables 19 and 20 were made in cooperation with a large cement-manufacturing company that wished to obtain more grinding for the power expended. The ball load in its clinker- grinding mills was 18 percent of the mill volume and the company did not deem it consistent to increase the ball load because the mills, having been pebble mills originally, could not carry a heavier load; also, the ball loads already taxed the motors to their limit. The tests required investigating the ordinary overflow type of mill and the low pulp-level type. The tests shown in table 19 anticipated the overflow mill and those analyzed in table 20 were expected to illustrate the deportment of the low-pulp-level or quick-discharge mill. All were dry-feed tests. In table 19 the ball volume was from 18 to 45 percent, and the feed rate had to be regulated so that the subsieve sizes in the products were about the same.
No noteworthy difference in type of grind resulted. The recording of capacities is omitted because, obviously, capacity would be low when ball volume was low. The change in efficiency, however, is important. The efficiency of the overflow mill slumped badly when the ball volume was small. This is because the small ball volume left too much space for ore in storage. These variations are shown in the next to the last line in table 19, in which is given as nearly correct an estimation of the amount of ore in the mill as could be determined conveniently. The best work was done with 40- and 45-percent ball volumes, the discharge being 4 inches in diameter.
The last line in table 19 shows the ratio of weight of ore to weight of balls. This weight relationship is significant because it leads to the conclusion that when the ball volume is small too much power is spent tumbling the ore; with 18 percent ball volume more than one-third of the weight of the mixture was ore. Then, also, there is the question whether the action of balls would be orderly in such a large volume of orethat is, would not the mill be little more than a tumbling device to mix ore and balls? Probably disorderly tumbling would result.
The importance of a correct ratio of amount of ore to balls is borne out by examination of the results of a test, shown in table 20, in which the grinding had to be in batch so that the ratio of ore to balls could be kept the same for the different ball volumes. When ratios were correct, the 18-percent ball volume performed nicely, although, for reasons already given, it had failed in the open circuit. The type of grinding and the efficiencies were about the same in the two tests. The conclusion was reached that cement-grinding mills with 18 percent ball volume were doing poorly if they were of the overflow type. If they were of the low-pulp-level type, and the low-pulp-level devices keep the clinker charge low in accord with manufacturers claims, the efficiency was not impaired because of the small volume of balls.
wet grid ball mill
Grid ball mill is widely used in smashing all kinds of ores and other materials, ore dressing and national economic departments like building and chemical industries etc. The size of ore shall not exceed 65mm and the best feed size is under 6mm. The effect in this job is better than coarse grinding. Grid ball mill consists of the shell, feeding part, discharging part, main bearing, lubricating system, driving system and other parts. There is wearing a liner inside the shell, and both ends of the shell are provided with a flange. The end cover of the mill is connected with the flange plate. The feeding part consists of the head, trunnion and feeding device. The discharge part includes the grid plate, head, and discharge trunnion.
Wet Grid ball mill is mainly used for mixing and grinding materials in two types: dry grinding and wet grinding .It has advantages of fineness uniformity and power saving. The machine uses different types of liner to meet different customer needs. The grinding fineness of material can be controlled by grinding time. The electro-hydraulic machine is auto-coupled and decompressed to reduce the starting current, and its structure is divided into integral type and independent type.
Compared with similar products,Wet Grid ball mill has the characteristics of low investment, low energy consumption, novel structure, simple operation, stable and reliable performance. It is suitable for mixing and grinding ordinary and special materials. The users can choose the right type, liner and medium type by considering the specific gravity, hardness, yield and other factors. The grinding medium is Wet Grid ball.
1.The ball mill is composed of a horizontal cylinder, a hollow shaft for feeding and discharging, and a grinding head. The main body is a long cylinder made of steel. The cylinder is provided with an abrasive body, and the steel lining plate is fixed to the cylinder body. The grinding body is generally a steel ball and is loaded into the cylinder according to different diameters and a certain proportion, and the grinding body can also be used with a steel section.
2.According to the particle size of the grinding material, the material is loaded into the cylinder by the hollow shaft of the wet grid ball mill feeding end. When the ball mill cylinder rotates, the grinding body acts on the cylinder liner due to the action of inertia and centrifugal force and friction. It is carried away by the cylinder. When it is brought to a certain height, it is thrown off due to its own gravity. The falling abrasive body crushes the material in the cylinder like a projectile.
3.The material is uniformly fed into the first chamber of the mill by the feeding device through the hollow shaft of the feeding material. The chamber has a step liner or a corrugated liner, and various steel balls are loaded therein. The rotation of the cylinder generates centrifugal force to bring the steel ball to a certain extent. The height drops and then hits and grinds the material. After the material reaches the rough grinding in the first bin, it enters the second bin through the single-layer partition plate. The bin is embedded with a flat liner with steel balls inside to further grind the material. The powder is discharged through the discharge raft to complete the grinding operation.
The main function of the steel ball in the ball mill is to impact crush the material and also play a certain grinding effect. Therefore, the purpose of grading steel balls is to meet the requirements of these two aspects. The quality of the crushing effect directly affects the grinding efficiency, and ultimately affects the output of the ball mill. Whether the crushing requirement can be achieved depends on whether the grading of the steel ball is reasonable, mainly including the size of the steel ball, the number of ball diameters, and the ball of various specifications. Proportion and so on.
The ball mill is composed of the main part such as a feeding part, a discharging part, a turning part, a transmission part (a reduction gear, a small transmission gear, a motor, and electric control). The hollow shaft is made of cast steel, the inner lining can be replaced, the rotary large gear is processed by casting hobbing, and the barrel is embedded with wear-resistant lining, which has good wear resistance. The machine runs smoothly and works reliably.
an analysis of fine dry grinding in ball mills - sciencedirect
The kinetics of dry grinding of several cement clinkers and two coals were investigated in a laboratory tumbling ball mill. The kinetic process is first-order at first, but the rates of breakage decrease as fines accumulate in the bed. It was demonstrated that the slowing of the breakage rates applies to all sizes in the mill, indicating that the cushioning action of fines affects the whole breakage process, even though mill power remains constant. Tests on cleaning or non-cleaning the balls showed that the major factor was not the build-up of a coating on the balls. Radio-tracing tests showed that the effect was not due to pelletizing of fines into larger particles. The quantitative magnitude of the cushioning action was different for different materials. It is, therefore, postulated that cushioning is affected not only by air trapped in the bed of fine particles but also by the cohesive attraction of fine particles, which is a function of the material.