Potash feldspar ore dressing equipment is a typical non-metallic ore beneficiation equipment. The general selection of potash feldspar equipment includes: jaw crusher, ball mill, classifier, magnetic separator, mixing tank, flotation machine, high gradient magnetic Equipment, etc. Henan Xingyang Mining Machinery Factory as a professional mineral processing equipment manufacturers more than 30 years, according to customer needs and actual conditions, can provide ore petrochemical inspection, beneficiation experiment, process design, complete equipment manufacturing, equipment installation and follow-up Equipment operations and other EPC work for the entire K-feldspar mineral processing project.
Gaofu potash feldspar dewatering screen has less investment and energy consumption than filter press, which is convenient in operation and has a better effect than spiral classifier. It is the first choice of potash feldspar mineral separation and dehydration. Potash feldspar need to be graded after milling. The large particles back to the ball milling,the qualified particles is finished product through deferrization and dehydration.At present, most of the production of potash feldspar powder plant in the dehydration step use filter press or spiral classifier for dehydration treatment, but the filter press has a large investment and energy consumption, the finished product is in high water content after spiral classifier. In order to solve these problems, Gaofu company developed a new type of potash feldspar dehydration screen through cooperation, communication and practice with potash feldspar manufacturers. The dewatering screen is small investment, low energy consumption and convenient operation, is the first choice of the majority of potassium feldspar concentrator!
In the production of potassium feldspar powder in a potassium feldspar concentrator in Quanzhou, Fujian Province, the technology is that the slag and water are separated by the screw separator, but the water content ...
In a sand and stone factory in Yulin, Shaanxi Province, the sand washing equipment used in the past has invested millions of dollars, but there is no suitable equipment to select the sand, so the benefit cannot be produced ...
High spiral classifier operation: the grinded pulp is fed into a tank from the inlet in the middle of settlement region, and the slurry classification sedimentation area is under the inclined tank. The spiral with low-speed rotation stirs the slurry, so that the fine particles rise, and the coarse particles sink to the bottom of the tank. The overflow weir is above the bearing center which is under screw shaft, and is underneath overflow end.
The spiral classifier working principle: Fine ore pulps are fed into a water tank through feeding opening located in the center of settling zone. Beneath the inclined a water tank is the ore pulp classification zone where ore pulps are stirred by low-speed impellers. Fine ore particles are lifted up and then spilled out the overflow opening; coarse ore particles precipitate down to the tank bottom and are discharged via discharge opening.
In mineral processing proceeding, ores need to be ground into a certain size for the complete separation of fine grain size mineral production and gangue minerals, and over-grinding should be avoided at the same time in case of the effect of sliming. The production below standard should be sent to mill for circular grinding, while the qualified product should be separated to extraction period in time and avoid unnecessary grinding. Therefore, classification takes an important part in grinding operation from technology and economic aspects.
Now, common classifiers in mineral processing plant are mainly mechanical classifier and hydrocyclone. Among them, mechanical classifier can be divided into spiral classifier, rake classifier, tank classifier and other types. With the development of classification operation, rake classifier is already replaced by spiral classifier for complicated structure and weak classification effect. Tank classifier is gradually replaced by hydrocyclone for large place occupied and low classification efficiency. Although the rapid development of hydrocyclone let classifier lose its importance, with the change of mineral processing plant requirement, people found that spiral classifiers have their advantages.
1. Sand return automatically lifts to a certain height and then directly returns to the feeding end of the ball mill, eliminating the need for joint feeder and greatly saving equipment and civil construction investment.
According to the height of overflow weir, that is the relative position of spiral in tank and slurry surface, spiral classifier can be divided into high weir spiral classifier, low weir spiral classifier, and submerged spiral classifier.
In high weir spiral classifier, the position of overflow weir is usually higher than the bearing center at the lower end of the spiral shaft and lower than the upper edge of the spiral at the overflow end. The height of weir can also be adjusted within a certain range, that is, the area of settlement area can be slightly changed according to the grading requirements, so as to adjust the grading particle size.
The overflow weir of the low weir type spiral classifier is usually lower than the center of the bearing at the overflow end. Therefore, the settlement area is too small and the overflow production capacity is too low, and the screw agitation on the pulp surface is too large. Therefore, it is only used in the actual production to wash the sand and coarse particles with less mud, and it is rarely used in the ore grinding grading operation.
The overflow end of submersible spiral classifier is usually equipped with 4-5 spiral blades, all of which are immersed under the liquid level in the settling area, so the settling area is large and the grading pool is deep.
There are differences in structure between high weir spiral classifier and submerged spiral classifier, so they are different in classification application. The high weir classifier is more suitable for the coarse classification and the first classification with minerals grain size over 0.15mm. Due to its stable grading surface, high overflow yield and fine particle size, the submerged spiral classifier are more suitable for separating overflow products with particle size less than 0.15mm. It is often combined with the grinding mechanism in the second section of the mill.
According to the number of screw shift, the spiral classifier can be divided into single spiral classifier and double spiral classifier. The grading performance of the two is basically the same, but the double helix classifier in return sand treatment capacity, overflow treatment capacity, the same specification of screw diameter is significantly larger than the single helix classifier, and the price of the double helix classifier is far higher than the single helix classifier, so it is more suitable for the use of large grinding machine.
Mineral processing experts suggest that the single screw classifier should be selected as far as possible under the determined processing capacity. According to statistics, the working load of the double screw classifier is 0.6-0.75 times that of the single screw classifier, and the efficiency is relatively low. Therefore, when selecting the screw classifier, the appropriate screw speed and number must be determined according to the processing capacity.
All types of classified equipment mentioned above have their own advantages and have different effects on the efficiency of classified equipment. According to the current different classification requirements, different types of classification equipment have been optimized and improved to achieve a good classification effect. When selecting grading equipment, each selecting plant must clearly grasp its type characteristics and working principle, and consider the ideal process flow and equipment according to its own selecting plant production demand.
Beneficiation by Flotation of feldspar is well established. It is a simple matter by flotation to remove the contaminating impurities and keep the alumina (Al2O3) content at 19% even on low grade feldspar ores. Dry recovery methods are economically limited to about 17% Al2O3.
The problem in feldspar flotation is to recover slime free granular products, all minus 20 mesh, usually with not over 10% finer than 200 mesh. Flotation under these conditions is critical and pulps are abrasive as well as corrosive. Action of the feldspar pulp must be counteracted by proper selection of equipment to withstand these conditions.
Feldspar is the basic raw material in the manufacture of virtually all burned clay products. It is used in glass, ceramics, pottery, porcelain, enamels, and in securing powders as well as in binders for grinding wheels.
The flowsheet illustrated is typical for the average feldspar ore containing quartz, mica, garnet and other iron bearing silicates normally encountered in pegmatites or large dykes of alaskite-granite. Equipment requirements and flotation conditions should always be established by a comprehensive laboratory testing program.
Feldspar ore is generally quarried from an open pit deposit and transported to the mill by truck. The flowsheet shows a conventional two stage open circuit crushing system capable of reducing the ore to which is suitable for further reduction by rod milling. Closed circuit crushing is advisable in larger tonnage operations for maximum grinding efficiency and capacity.
The Rod Mill is standard for grinding feldspar ore, producing a granular product with a minimum of slime and fine size material. Grinding is always done to minus 20 mesh on account of market requirements. Feldspar this coarse will float very nicely and if liberation is obtained at this size no further grinding is necessary.
Classifying or sizing the rod mill discharge can be done quite efficiently with a Spiral Screen. By operating the rod mill at 25-35% solids partial classification is accomplished in the mill and only the finer fraction discharges onto the spiral screen. Normally the spiral screen oversize is discarded to waste as it will contain coarse pieces of mica and hard particles of quartz with very little feldspar. This waste product may only represent 3 to 5% of the mill tonnage.
Large tonnage operations may require sizing the rod mill discharge through a Dillon Vibrating Screen. In the case of grinds minus 48 mesh and finer a conventional rake or spiral classifier may be used.
Rod Mills with Standard Trunnion overflows and manganese steel grates have given very good service and capacity on feldspar. The grates permit carrying a larger rod charge and also discharge the ground product without excessive production of fines. Slime losses are usually under 10% of the initial mill feed.
The feldspar flotation concentrates are dewatered in a Classifier to approximately 20% moisture and further dewatered on a top feed or horizontal vacuum filter down to 7-9% moisture. The balance of the moisture is removed in a Standard Rotary Dryer. The dry product is elevated to storage silos and passed over a 20 mesh Dillon Vibrating Screen to remove possible tramp oversize and scale which finds its way into the feldspar flotation product.
The rod mill discharge is deslimed in a Rake Classifier producing a sand and a slime product. The product overflowing the classifier is further deslimed in a Hydroclassifier and its overflow, generally minus 325 mesh, goes to waste. The underflow from the hydroclassifier is metered back to the rake classifier just above the liquid level by a Diaphragm Pump.
This arrangement has worked out very well in plant practice without build-up of critical size material in the system. The Mineral Jig also has an application as a deslimer in this system where sand raking capacity is limited.
The sand product from the classifier is subjected to high density intense conditioning in a Duplex Heavy Duty Conditioner. This conditioner is the open type and both mechanisms are driven by one motor. The shaft and propeller are rubber covered and the tank is wood to resist the corrosive action of the acid reagents which are introduced into the circuit at this point for subsequent flotation of the mica and iron oxide impurities. Conditioning is normally carried out at 65-70% solids.
All flotation is carried out in acid circuits, either with sulphuric acid or hydrofluoric acid both of which are highly corrosive to metal parts. For this reason it is necessary to use flotation machines with wooden tanks, partitions, hoods and standpipes, and molded rubber impellers and wearing plates. Conical impellers give the best service in handling the coarse, abrasive, slime-free solids.
In the flowsheet shown, the first bank of Sub-A cells removes the impurities. However, in some cases it may be desirable and necessary to float the mica first and then float out the iron bearing impurities including garnets.
After removal of impurities the feldspar-quartz fraction discharging as a tailing product from the primary flotation step is deslimed through a Rake Classifier and the sands conditioned at high density to depress the silica. Feldspar is floated in the last flotation step which is also in an acid circuit with hydrofluoric acid.
Often the silica product, due to local conditions, is of commercial value as a by-product. In this case it may be transferred to a drainage bin or silo for storage and market. Mica recovered in the primary circuit, if of sufficient quantity and quality, may be processed further and also marketed as a by-product.
Reagents normally used in feldspar are sulphuric acid, hydrofluoric acid, kerosene, fuel oil, amine acetates such as ARMAC T (also C-CDT and TD amine acetates derived from coconut and tallow fatty acids respectively), and mahogany soap, a petroleum sulfonate. An alcohol frother such as B-23 or Methyl Isobutyl Carbinol may also be used to regulate the character and type of froth. Pine oil may also be used. The amounts and combination of these reagents varies depending upon the character and grade of ore but for average conditions reagent costs are about 75 cents per ton of ore treated. The big reagent item is the hydrofluoric acid which must be used to depress the silica and make it possible to float the feldspar with one of the amine salts at a pH of 2.5-3.0.
For certain market requirements, as in the case of pottery grade, it is necessary to cut the reagent film from the feldspar and thereby make it water wettable. This can be accomplished by conditioning the feldspar concentrate in a Super Agitator and Conditioner ahead of the dewatering classifier and filter. Clays such as Kaolinite or bentonite or a combination of the two have the property of absorbing the reagents condition. The clay with its absorbed reagent can then be washed out in the classifier overflow and discarded as waste. Usually 2 to 5 pounds of clay per ton of the concentrate added to the agitator is sufficient to de-reagentize the feldspar.
Standard classification of ground feldspar is set up through co-operation of the (U.S.) National Bureau of Standards, Division of Trade Standards. This classification is effected under Commercial Standard CS 23-30 which covers standard screen tests and standard methods of chemical analysis. There is a physical classification based on fineness of grinding and a chemical classification based on composition as it influences use.
Feldspar: Three 6-cell No. 18 Special Sub-A Acid Proof Flotation Machines with wood tanks and molded rubber parts are used to produce marketable feldspar concentrate in this mill in the southeastern United States.
For all the grades of feldspar, requirements are that the iron content be below 0.10 per cent Fe2O3 and that there be definite ratios of K2O and Na2O to silica. These requirements necessitate ore dressing preparation, and flotation is fast developing into the principal method used.
Stage flotation of de-slimed ground ore is advisable. Mica impurity is first floated with a combination of fuel oil and some amine acetate in a pulp made acid with H2SO4. Second-stage flotation may be preceded by washing and re-conditioning with one of the petroleum sulphonates in apulp made acid with sulphuric acid to remove additional iron. Third stage flotation with hydrofluoric acid and amine acetate floats the feldspar and leaves a highly siliceous tailing. The first and second stages may be combined if the mica is not to be recovered. Owing to the diversity in mineral content of feldspar deposits, a separate reagent combination needs to be developed for each. Here again, thorough desliming and high-density conditioning are most important for a good separation of feldspar from its impurities.
The overflow spiral blade is higher than overflow level, and the overflow spiral center is lower than overflow surface. The high wire spiral classifier is applied in the classification of ore with particle size 0.83-0.15mm
The grinded pulp is fed into tank from the inlet in the middle of settlement region, and the slurry classification sedimentation area is under the inclined tank. The spiral with low speed rotation stirs the slurry, so that the fine particles rise, and the coarse particles sinks to the bottom of tank. Overflow weir is above the bearing center which is under screw shaft, and is underneath overflow end.
Zenith FL spiral classifiers are widely used for separation plant They can be combined with ball mill to form a closed circuit for preliminary classification and check classification,sometimes they can be applied for ore washing, desliming and dewatering as well.