Experimental Research On Preparation Of Filter Aids By Diatomites Concentrate Of Beneficiation

The uses of diatomites are very extensive because of the several particular and excellent characters of it. In China, the diatomites with high grade which can be made directly for filter aids are not very much, especially that can be made for high grade filter aids are much less. Apparently, producing filter aids by the diatomites concentrate of beneficiation not only can provide enough raw materials for high grade filter aids, but also can ensure the quality and stability of the filter aids products, which is very important to the efficient using of the diatomites in China.The main chemical composition of diatomites concentrate after beneficiation getting from some LinJiang corporation is SiO285.54%、Al2O33.78%、Fe2O31.81%and6.41%loss on ignition. The mian mineral compositon of that is noncrystalloid opal. There are some entire skeletal diatomite with fine microscopic pores and some small mineral chippings. With the diatomites concentrate, the explored texts of experiment methods, the conditional tests of flux and calcination and mechanism research of calcination and filtration were carried out. The conclusions of the investigation are on the list.The explored texts of experiment methods shows that the mixing machine with high rev which can destory the skeletal diatomite should be forbidden in the processing. The best mixing way of diatomites and flux is dry method. Bigger ones in the filter aids can improve the speed of filtration while the quality of filtration is not reduced. After marinating for22hours in the water, the permeability of filter aids increased, but the quality of filtration reduced.The result of the conditional tests of flux shows that the additions of Na2CO3, NaCl, NaOH, KCl and KOH can improve the capability of filtration of diatomite filter aids. With the dosage of flux increased, the granularity of filter aids turns to bigger, the whiteness and the capability of filtration ascend firstly and then drop down. All the indexs are the best when the granularity of filter aids is7%. The granularity of filter aids getting with no milling Na2CO3is bigger then that getting with milling Na2C03.The result of the conditional tests of calcination shows that with the minishing of the granularity of diatomites prepared for calcination, the rate of filtration is decreased but the quality of filtration is improved. With the decrease of the rate of heating-up, the whiteness increase firstly and then reach a plateau. The permeability is not change almost. The higher temperature of the calcination can get bigger granularity of filter aids. When the temperature is lower than1000℃, the whiteness and permeability grow with the temperature increase. However, when the temperature is higher than1000℃, the whiteness and permeability decrease with the temperature increase. With the time of heat preservation increasing, the granularity of filter aids turns to bigger, the whiteness increase and the quality of filtration is improved. The filter aids with higher quality of filtration could get when calcining without oxygen. The filter aids get by suddenly cooling are coarser than that by gradually cooling and there are no obviously orderliness in other indexs.The investigation of mechanism research shows that the small mineral chippings fuse and turn to bigger ones when the diatomites are calcined with flux. Then the speed of filtration was improved. In the process of filtration with filter aids, the impurity grains in the soliquoid are trapped and absorbed because of the cellularity and high adsorbability of the diatomite filter aids.The conclusions in the paper are very important to the production of filter aids with diatomite.