| This article optional Yunnan Phosphate flotation tailings phosphorus as raw materials, First using sulfuric acid method discussed preparation of magnesium phosphate fertilizer process. Then using parathion mixed acid on the preparation of industrial-grade magnesium phosphate fertilizer process conditions, Flotation tailings phosphorus in sulphuric acid, parathion mixed acid dissolved in the dynamics of the paper is studied.In the process of research experiments of flotation tailings phosphorus, Using XRD and analysis of all chemical elements of the tailings know the main phase of CaMg (CO3)2, Ca5 (PO4)3F, SiO2. The content of MgO is 13.92%and P2O59.87%, the phosphate tailings had high reaction activity and low resistance to retardency with highly foaming ability. So, it needs to add the defoaming agent.Through the concentrated sulphuric acid method mainly on the temperature, stirring speed, the amount of sulfuric acid, sulfuric acid theory ratio, reaction time, moisture content, curing time and tailings powder fineness factors such as magnesium phosphate fertilizer products on the nature of the impact. On the basis of this to parathion mixed acid test, using single factor investigated parathion ratio, temperature, stirring speed and reaction time and other factors on industrial-grade magnesium phosphate fertilizer products nature of the impact, and by orthogonal test for the optimum conditions:temperature:80℃; stirring speed:400 r/min; parathion ratio:2.07:1; reaction time:45 min. And under optimum conditions by the industrial-grade magnesium phosphate fertilizer products containing P2O5 to 17.55 percent effective, water-soluble P2O5 accounted for 79.56%, to 7.53%effective MgO, the free acid (P2O5) to 1.53%., the rate of decomposition of phosphorus which more than 95 percent, the rate of decomposition of magnesium more than 96 percent. By XRD analysis, elemental analysis, thermal analysis, infrared spectral analysis method of magnesium phosphate fertilizer analysis, its composition, structure and of the same area were characterized.Flotation tailings were studied in sulfuric acid, mixed acid in parathion acidolysis kinetics. And the experimental results obtain the kinetics equation:1/t ln 100/100-Kp -βKp/t=k. It can be quite satisfactory to describe the flotation tailings in sulfuric acid, phosphoric acid and mixed acid solution of parathion in the acidolysis kinetics. Flotation tailings dissolved in sulfuric acid solution of the activation energy is very small, about 1.8～4.3KJ/mol, pre-exponential factor A for EXP (-12.7445)～EXP (-14.0426) (s-1). Flotation tailings in parathion mixed acid in acidolysis kinetics can also be used more than trapeang equation description, where the reaction rate constant with increasing sulfuric acid content decreased resistance coefficient changed little, the phenomenon and the formation of surface membrane. When other conditions remain unchanged, the flotation tailings of parathion mixed acid solution of the process of effective diffusion coefficient increased with the sulfuric acid content to reduce the use of the revised model Gioia Acidolysis parathion obtained mixed acid solution of the process of effective diffusion coefficient. The process is the proliferation of control, easier.Flotation tailings in sulfuric acid, mixed acid in parathion acidolysis kinetics for low-grade phosphate rock flotation tailings are studied. Above-mentioned researches provide the theoretical foundation for the comprehensive utilization and large-scale production to low and medium-grade phosphate rock tailings, and also explain rationally the phenomenon happened in the course of pilot scale. |
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