Effect Of Abraum Salts On KC1 Flotation Process

KCl is widely used as an important raw material in industrial and agricultural fields. Flotation is the major method to produce KCl, which takes above 95% of total production. With the development of the KCl flotation technology, the KC1 production capacity of single set device increased rapidly from 30 million metric tons per year in 1996 to 100 million in 2000. However, the quality of the potash ores declines rapidly when the produced quantity increased year by year. The abraum salts affected the quality of KCl and KC1 recovery seriously in flotation process. Therefore, the actual capacity can not come up to the devices requirement and the production operation can not keep normal. The study on the effect of high concentration of NaCl and MgCl2 on the process of cold dissolve have been researched by many scholars, but the effect of abraum salts on KCl flotation process have not given reasonable explanation. So, It is useful to improve the effective utilization of potash ores.This paper choose miscellaneous salts from potassium mineral, such as NaCl, as research object, discussed the fine size NaCl in flotation particles and high concentration MgCl2 in flotation solution effect on KCl flotation efficiency. The flotation technological conditions could be optimization by regulating the flotation aeration ratio and solid-liquid ratio.(1) In accordance with the ratio of MgCl2/KCl and NaCl/KCl, The study divided the potash ores into three types, normal carnallite ores (MgCl2/KCl=1.40～1.80, NaCl/KCl＜1.8), high NaCl content potash ores(MgCl2/KCl=1.40～1.80, NaCl/KCl～1.8), high MgCl2 content potash ores (MgCl2/KCl≥1.8, NaCl/KCl<1.8). The composition of the elements and the crystal morphology of the three potash ores were analyzed by SEM and x-ray energy spectrum. In order to study the form of KC1 existence, the change of NaCl and MgCl2 content, the elements composition and crystal morphology of the three potash ores in different sizes, the high NaCl potash ores and high MgCl2 potash ores were divided into ten different sizes by screening. The results show that, KCl existed in the form of carnallite in ores mostly when the sizes were＞850μm, KC1 existed in the form of monomer in ores mostly when the sizes were＜75μm, and the change of NaCl and MgCl2 content was small in the two sizes. The MgCl2 content decreased and NaCl content increased when the size were 850μm～75μrn, with the decrease of particle size.(2) In the study of Mg2+ and Na+ effect on flotation, KCl-NaCl and KCl-NaCl-MgCl2 solutions were used as the flotation systems, and NaCl,MgCl2 and KCl solution as the reference systems. Effect of NaCl concentration on the viscosity of NaCl and KCl-NaCl solutions, and the effect of MgCl2 concentration on the viscosity of MgCl2, MgCl2-KCl and KCl-NaCl-MgCl2 solutions were determined. The research showed that, NaCl was the main reason that increased the viscosity of KCl-NaCl flotation system, and MgCl2 was the main reason that increased the viscosity of KCl-NaCl-MgCl2 flotation system. The water structure maker properties of Na+ and Mg2+ decreased the liquidity of water molecules in solution and increased the viscosity of solution by binding up the around water molecules.(3) The behavior of NaCl floated out with KCl in direct flotation process was studied systematically. First, the effect of NaCl content on KCl flotation efficiency was researched by microflotation method. Further, the effect of NaCl particle size on its sedimentation rate, recovery ratio and quality of KCl product were investigated in KCl-NaCl and KCl-NaCl-MgCl2 solutions for decreasing the content of NaCl in KCl product. The results show that, NaCl particle size was one of the main reason that decrease KCl flotation efficiency and the best size of NaCl particles was>125μm in KCl flotation. At last, optimizing aeration ratio as 40mL/min was the best conditaion for improving KCl flotation efficiency and decreasing fine particle size NaCl involved.(4) The effect of MgCl2 concentration on the morphology and size distribution of ODA-HCl was researched with CCD microscope camera, and the turbidity of the solution was determined. In addition, the effect of MgCl2 concentration on KCl flotation recovery was studied with microflotation test. The results show that, the effective concentration of collector decreased when the dispersion of ODA-HCl got worse; the flotation recovery efficiency of KCl reduced by 13.49% when MgCl2 concentration increased from 0 to 20%. The recovery of KCl increased by 10.30%, as the aeration ratio and solid-liquid ratio were adapted to 200mL/min and 3:100. At these condition, the adverse influence of MgCl2 concentration on the dispersion of ODA-HCl decreased and the KCl flotation recovery increased by optimizing the flotation aeration ratio and solid-fluid ratio. (5) Some factors influencing the flotation recovery of KCl were studied in this part, such as the flotation time, the pulp density in flotation process. In this part, the potash ores contented high abraum salts were used as the raw materials, MgCl2-KCl-NaCl solution contented 20% MgCl2 was used as the flotation system to simulate the conditions of KCl production technology in Qaidam Basin. The results show that, KCl flotation efficient improved, when the concentration of ODA≥8×10-5mol/L, the flotation time≥4min and the pulp density on 15%～20%. The washing recovery of filter cake of KCl could reach 93%, and the quality of washing production could come up to above 90.43%, when the amount of filter cake washing water was 1.0～1.1 times than theory value and washing time was about 8min.