crushing and grinding wet & sticky ore
In the handling of wet, sticky ores such as encountered in tropical areas having distinct dry and rainy seasons, the crushing plant is a section of the mill which must be planned very carefully. Unless this is done, crushing becomes a constant source of trouble resulting in lost production and high milling cost. In some areas rainfall is high for prolonged periods. This seriously affects ore handling and continuity of operations not only in open pit but also underground mining.
A washing section is a must in all operations handling wet, sticky ore. This facilitates ore handling, crushing, and also affords a means for separation of primary slimes and increasing grinding capacity. These slimes usually contain the bulk of the soluble salts and in many cases this fraction should be treated separately or even discarded if values are low. Soluble values such as copper sulphate can often be separated from the slime in a thickener and the clear overflow water passed over scrap iron for precipitation of the copper.
In the flowsheet illustrated the basic steps are shown for the average mill. Primary slimes are treated separately, while the washed and crushed ore is ground, classified, and floated in the usual manner. This practice quite often results in better metallurgy with lower reagent cost in addition to greatly simplifying the crushing operation. In most cases it is possible to confine the crushing operation to one or two shifts per day.
It is highly desirable to use a heavy duty apron feeder under the coarse ore bin to regulate the flow of coarse wet ore. Wearing surfaces and rollers for the apron flights must be designed to stand up under the wet primary slimes without excessive maintenance. Good insurance at this point is to obtain the very best feeder on the market even though the price may be higher than for light duty units.
The ore from the feeder next passes over a roll or vibrating grizzly. For the small 150 to 200 ton per day mill this opening can be 2 inches. This will allow the wet sticky fines to pass through the grizzly. A high pressure water spray over the grizzly often aids in the subsequent jaw crusher operation.
The fines from the grizzly and the crusher discharge pass by gravity and/or conveyor to a Combination Scrubber and Trommel. Here, further scrubbing and washing takes place to separate the ore into two fractions, usually plus and minusinch. The coarse washed fraction is further reduced in a Secondary Cone Crusher without difficulty. Secondary crushing may be in open circuit or closed circuit depending on the physical characteristics of the ore and the degree of size reduction desired.
The minus fraction from the Combination Scrubber and Trommel is further separated into a sand and slime fraction in a Spiral or Rake Classifier. The slimes plus the water used for sprays in the washing and scrubbing operation overflows the classifier and are collected in a Thickener prior to further treatment. This thickening step permits reclamation and possible retreatment of the overflow water, and in addition stores the thickened solids for treatment at a uniform rate by flotation or other means. Crushing, therefore, can be confined to a one shift operation, and the accumulated slimes treated over a 24 hour period.
The sand product from the Spiral or Rake Classifier discharges on the same belt as the crushed ore and passes on to the fine ore bin. The classifier should be long enough to provide an adequate drainage deck for the sands so a minimum of moisture is entrained in the spiral or rake product. Slimes from conveyor spillage drain to Vertical Sand Pumps. This is an ideal pump for this service since it handles fluctuating feed and can be run with pump bowl dry without damage, or air locks.
For plants handling several hundred tons of ore per day the primary grizzly and crusher may be set to produce a minus 4 to 6 inch product. In such cases the Combination Scrubber and Trdmmel must be a heavy duty unit. This is necessary tohandle the coarser ore and thoroughly disintegrate any clay balls which would otherwise cause serious trouble in the subsequent secondary crushing steps. It may also be necessary to incorporate vibrating screens into the circuit to improve screening efficiency in removing the fines along with spray and wash water. SRL Pumps and Cyclones for treatment of the primary classifier overflow may also be necessary to make a finer sand-slime split, for example 90% 200 mesh. In some cases it is possible to eliminate the primary slime thickener as illustrated in the circuit as follows:
Grinding and classification of the minus washed and crushed ore is accomplished in the usual manner, and generally no problems are encountered. In some cases where this fraction of ore is low in fines it may be necessary to blend back some of the thickened primary slime. This aids in properly lubricating the ball charge and in giving fluidity to the pulp in the classifier for proper size separation.
Treating the primary slimes in a separate circuit may be highly desirable for a more efficient separation. Often this fraction can be treated at its natural acid pH and the washed, crushed, and ground ore treated in a neutral or alkaline pulp. Alkalinity reagent requirements are kept low under these conditions.
iron ore processing plants - iron ore wash plants - cde
Our iron ore wet processing plants are proven to successfully deal with silica and alumina contamination in the iron ore, resulting in an increase in the Fe value of the iron ore thereby increasing the efficiency of the steel production process.
Silica requires very high temperatures in the kiln, therefore, increasing energy costs when it is present in the feed to the kilns. Both alumina and silica build up in the kilns as a coating, reducing the efficiency of the kilns over time.
This requires that the kilns be shut down in order to facilitate the removal of this material build up. Our iron ore processing plants target these contaminants and ensure their effective removal from the feed to the kilns. This has the effect of increasing the Fe value of the iron ore allowing for a more efficient steel production process.
wet air scrubber iron ore dust control - multi-vortex wet air scrubber
Heavy iron ore dust is a result of iron ore mining. The iron ore contains high quantities of hematite or magnetite, but also other elements that are often present in trace amounts. Such elements include silicon, phosphorus, aluminum, and sulfur. The iron ore itself is not harmful, however, the dust that is produced during transportation of the ore, like iron ore discharge into railroad cars, has detrimental effects on human health, the environment, and the business activity. Iron ore dust control is an important task that iron ore manufacturers need to consider.
The most efficient way of solving these issues is an implementation of wet air scrubbers into the mining facility. Some air scrubbers may be installed directly above the conveyor belt to efficiently scrub the air at the source of iron ore dust. Wet air scrubbers possess multiple advantages that make them an ideal solution: they are highly effective at removing both gases and particulate matter, can handle high temperatures and moisture, can neutralize corrosive matter.
However, most conventional wet air scrubbers suffer from several drawbacks: corrosion problems, water pollution problems, high power requirements. Being a new type of wet air scrubber, Scroiler cleans air from gases, dust, vapors and other admixtures using water or other cleaning liquid.
rotary scrubbers | mclanahan
Rotary Scrubbers are used to wash crushed rock, ore, sand, gravel, construction aggregates and oil sands. They are high-capacity, high-retention machines that can accept large-sized feed material and are used primarily to remove water-soluble clays, deleterious materials and coatings providing a cleaner product
McLanahan has extensive experience in washing a wide range of materials that started in 1891 when S.C. McLanahan was granted a patent for an ore washing steel shafted machine he called the Log Washer. As a manufacturer having the widest range of washing equipment, McLanahan can offer the correct solution, not an option of only one or two machines others may offer. This combination of experience and choices along with our global staffs process application knowledge makes McLanahan a company you should be speaking with.
McLanahan offers washing equipment having capacities ranging from 20 to 8,000 tph. For most any ore, rock or sand washing problem you have, McLanahan has the solution that offers less downtime maintenance and more clean product for your highest profitability!
All McLanahan Rotary Scrubbers are machined to be perfectly concentric, eliminating any undue vibration or wobble. Concentricity ensures the scrubber runs quieter and smoother with reduced tire and bearing maintenance, ultimately leading to longer life and lower operating costs per ton of production.
McLanahan considers its customers process needs prior to design, meaning units can be used with an all-in or scalped feed. They can easily be designed to handle a wide variety of tonnages and product sizes all with the same piece of equipment. Several drive options that offer minimal maintenance requirements are available, including chain and sprocket, gear and pinion, hydraulic and friction types.
McLanahan Rotary Scrubbers are cylindrical drums with internal lifters, typically supported by trunnion rollers at either end. The continuous lifting and dropping action combined with water helps to abrade, scrub, and break down soluble contaminants. Optional trommel screen extensions can be added to provide rough product separation, screening and dewatering capabilities.
Capacities are normally determined by analyzing the type of feed material, percent and type of waste material to be removed, screen analysis of the feed, available water and if specified, retention time. Retention time in a Rotary Scrubber varies from application to application due to different types and varying amounts of wastes to be removed.
Rotary Scrubbers are designed primarily for the removal of loam and light clays and soft, soluble waste materials from aggregates, stone and ore. These units are not intended to replace Log Washers on applications where tough plastic clays are contaminating the material to be cleaned. When these tough clays are fed to a Scrubber, the clay particles may have a tendency to pelletise through the tumbling action of the material. For example, golf ball-sized pieces of plastic clay may not break down and could actually increase in size.
Rotary Scrubbers and Coarse Material Screw Washers are often selected to wash out similar contaminants from aggregate and various ores. The major difference is that Scrubbers can accept larger feed sizes, whereas Coarse Material Screw Washers must have a controlled top size. Since large diameter Scrubber Screens can handle feeds up to 300mm or 12, they are sometimes used as a primary washer before downstream crushing or screening systems.
McLanahan Rotary Scrubbers are high-capacity, high-retention machines that can accept large-sized feed material and are used primarily to remove water soluble clays, deleterious materials and coatings from a wide variety of hard rock and ore. McLanahan offers Solid Shell Scrubbers, Combination Scrubber Screens and Trommel Scrubbers, which are all machined to be perfectly concentric, ultimately leading to longer life and lower cost per ton of production.
scrubber washing plant for mineral processing | prominer (shanghai) mining technology co.,ltd
Prominer can provide heavy duty module rotary scrubber system that is cylindrical drums with internal lifters and supported by four trunnion rollers at both end as well as trust rollers. The continuous lifting and dropping action combined with water helps to abrade, scrub, and break down soluble contaminants. Our rotary scrubber ensures a perfect concentric body, eliminating any undue vibration or bounce. This ensures the scrubber runs quieter and smoother, reducing tire and bearing maintenance and ultimately leading to longer life.
Prominer has been devoted to mineral processing industry for decades and specializes in mineral upgrading and deep processing. With expertise in the fields of mineral project development, mining, test study, engineering, technological processing.