Application Of Polyammonium Organic Filter Aid In Hydraulic Filtration Of Coal Slime

China is the largest producer and consumer of coal in the world.With the increasing of mining depth and the improvement of automation,the quality of coal becomes worse and fluctuates more and more.When the coal quality deteriorates,the fine particle coal slime increases sharply,resulting in the difficulty in settling the slime water and the difficulty in pressing and filtering,which seriously affects the processing capacity of the filter press and even deteriorates the sorting environment.Therefore,without changing the existing process equipment,adding filter aid to improve the filter pressure effect and improve the processing capacity has the advantages of low cost,convenient operation and quick effect.This thesis aimed at qidong well mine coal preparation plant in anhui coal slime Shui Nan filter problem,in the field based on the analysis of the pressure filter into the material,choose different types of filter aid,the laboratory leaching test,and analyzes the filter aid for the coal particles and the influence of the strength of the floc,research results used in industrial production,solves the problems of the slime Shui Nan filter.The properties of coal slime water were analyzed,and the influence of different types of filter AIDS on the filtration performance of coal slime water was investigated.The results showed that the concentration of slime water reached 500 g/L,and the particle size of-0.074 mm accounted for 60%.Both polyaluminum chloride and polyacrylamide have a certain filtering effect,but the effect is poor due to the large dosage of agents.The filtration effect of the three ammonium organic filter AIDS was significantly better than that of polyaluminum chloride and polyacrylamide.In particular,the filtration effect of ammonium organic filter AIDS B was better.When the dosage was about 600 g/t of dry coal slime,the filtration duration was shortened from 935 s of blank sample to 360 s,with a decrease of 61.50%,while the moisture content of the filter cake was only increased from 25.59% to 28.90%,with an increase of 3.31%.The effects of polyaluminum chloride,polyacrylamide and ammonium polycarbonate on the particle size and flocculation strength of coal slime were analyzed by using focused beam reflectance meter(FBRM).The results show that the flocculation capacity of polyaluminum chloride is weak,the average chord length of flocculation is not stable,fragile and the recovery capacity is weak.Polyacrylamide is easy to over flocculate,forming large flocculation,water inclusion is serious and not easy to dehydrate;The flocs formed by polyammonium organic filter aid B are of moderate size,have good stability and are not easily broken.Besides,the flocs have strong recovery capacity after being damaged by high strength shear.The filter cake that is easy to form in the process of press and filtration has good permeability.At the same time,when the amount of polyammonium organic filter aid B is less than 600 g/t of dry coal slime,the average chord length of floc gradually increases with the increase of the amount.When it is higher than 600 g/t of dry coal slime,the average chord length of floc basically does not change.The analysis data agree with the results of the filter aid test,indicating that the flocculation particle size has a significant influence on the filtration performance.An industrial experiment of coal slime water assisted filtration was carried out in anhui qidong coal preparation plant.Firstly,the preparation and transportation system of filter aid was optimized,and a set of idle dissolving equipment was used as the dissolving and transportation equipment of filter aid,and the dosing point was optimized.When the charging point is placed at the front of the bottom flow pump,the bottom flow pump will fully mix the chemicals with the coal slime,and the feeding time will be shortened from 1100 s to 650-800 s.Reducing the cost of chemicals by 0.41 yuan/ton of raw coal,saving 820,000 yuan of chemicals per year.It not only improves the processing capacity of filter press and solves the problem of insufficient filter capacity caused by short-term fluctuation of coal quality,but also improves the economic benefit of coal preparation plant.This paper has 32 figures,11 tables and 52 references.