| The traditional sodium roasting and leaching extraction of vanadium needs to consume a large amount of energy and additives in the roasting process,and produces toxic and harmful gases such as HCl and Cl2,which seriously pollute the environment.At the same time,some improved vanadium extraction processes such as calcification roasting,double salt roasting and oxidation roasting,all of them have problems such as complex production processes,low metal recovery rates and slow reaction rates.Therefore,it is of great significance to develop a high efficiency and environmental protection technology for the comprehensive utilization of vanadium titanium magnetite resources in China.According to statistics,the production of 1t titanium dioxide will generate 8?10 t waste acid with mass fraction of about 20%,and the annual output of waste sulfuric acid in China's titanium dioxide industry reaches 600,000 tons,and direct emissions will cause serious environmental pollution.This topic is to use the METSIM process simulation software to simulate the process of direct pressurized acid leaching of vanadium and scandium without roasting,and then to simulate the model.The leaching rates of the simulated elements V,Fe,Mn,Cr,and other elements,the extraction rate and stripping rate of Sc and V are compared with the actual technical indicators,and the precipitation rate of vanadium is compared with the actual technical indicators.To verify the feasibility of using METSIM simulation in each process;After the verification is completed,based on the treatment amount of 100,000 tons/year of vanadium slag,METSIM is used to select the equipment for each process,and the output of the final vanadium product is calculated by simulation to provide reference data for the construction of the process.The main results are as follows:1)The process of extracting vanadium and Scandium by pressurized leaching of titanium dioxide waste acid was simulated based on METSIM software.The leaching rate,extraction rate or stripping rate of some compounds calculated in METSIM was compared with the experimental data.Among them,the relative error of vanadium leaching rate and actual data was 0,the relative error of iron leaching rate was 0.08%,the relative error of manganese leaching rate was 0.31%,the relative error of chromium leaching rate was 0.92%.The relative error of scandium extraction rate and stripping rate,vanadium extraction rate and stripping rate were all 0,and the relative error of vanadium precipitation rate was also 0.2)The selection of equipment was carried out in the process of scandium and vanadium extraction by pressurized leaching of titanium dioxide waste acid,and the data of the selection,size and output of vanadium products were obtained through simulation calculation,which provided effective data for the estimation of the cost of construction of the plant.In the leaching process,the volume of the six-stage series autoclave is 728.54m3,365.12 m3,365.12 m3,365.12 m3,365.12 m3,365.12 m3 and 365.12 m3 respectively.In the extraction process of scandium,the effective capacity of the mixing chamber in the mixed clarification tank was 3.31 m3,and the effective capacity of the clarification chamber was 7.43 m3;In the washing process,the effective capacity of the mixing chamber in the mixed clarification tank was 4.06 m3,and the effective capacity of the clarification chamber was 9.54 m3;In the stripping process,the effective capacity of the mixing chamber in the mixed clarification tank is 1.70 m3,and the effective capacity of the clearing chamber was 1.94 m3;In the oxidation process,the reactor has a diameter of 3.15 m and a height of 3.6 m.In the extraction process of vanadium,the effective capacity of the mixing chamber in the mixed clarification tank was 14 m3,and the effective capacity of the clarification chamber was 20.35 m3.In the stripping process,the effective capacity of the mixing chamber in the mixed clarification tank was 16.94 m3,and the effective capacity of the clarification chamber was 22.31 m3;The reactor for the vanadium precipitation process has s diameter of 3.1 m and a height of 3.6 m.3)For the annual process of treating 100000 tons of vanadium slag,It is necessary to input 800,000 tons of titanium dioxide waste acid,3294.36 tons of oxygen,34222.97 tons of extractant(10%P204+2%TBP+88%KERO),344079.44 tons of detergent(hydrochloric acid),34232.67 tons of stripping agent(2 mol/L OH+1 mol/L NaCl),790.35 tons of NaCl03,342044.76 tons of extractant(20%Mexal 973H+80%KERO),356026.63 tons of antiextractant(20%NaCO3 solution)and 3258.60 tons of ammonia into the system.Through the system operation,16.65 tons of Sc(OH)3 and 15931.17 tons of(NH4)2V12O31 are finally obtained. |
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