Indium Centrifugal Extraction From The Feeding Liquid With Indium And High Iron

To solve the problem of low extraction rate of indium and high cost of liquid volatilization in zinc smelter,method like the single factor test,response surface method,slope method,saturation capacity method and infrared spectroscopy were used to study the indium centrifugal extraction and the mechanism.The thesis focus on the optimal technological parameter,increasing extraction rate and providing guidance for the indium extraction process.The results of slope method,saturation capacity method and infrared spectroscopy showed that the composition of extraction complex is InA3·3HA.The structural formula of extraction complex and extraction chemical equation were also found.The experimental results for one-stage extraction of indium of simulated solution showed that the extraction rate of indium was 99.0%while iron and zinc were 2.42%and 2.52%,respectively,under the conditions including phase ratio(O/A)of 1:1,pH 2.0,P204 concentration of 15%,mixing time of 3 min and stirring intensity of 400 rpm.The optimum conditions were obtained by single factor test,and response surface method of indium single stage extraction.The optimum conditions for pH is 1.0,P204 concentration is 14.64%,phase ratio(O/A)is 1.18,stirring intensity is 397.27,mxing time is 2.98 min,the predicted rate of indium extraction is 98.96%,the measured rate is 98.79%.The rank of influence factors were:stirring intensity>phase ratio(O/A)>mixing time>P204 concentration.The extraction isotherm and McCabe-Thiele diagram of indium showed that indium could be extracted well under two-stage of continuous extraction.The results of centrifugal extraction for indium showed the extraction rate of indium was about 97.8%while iron and zinc were 1.31%and 2.11%,respectively,under the conditions including two-stage countercurrent extraction,phase ratio(O/A)of 1:5,pH 1.0,P204 concentration of 15%and the centrifugal speed of 6000 rpm.The stripping isotherm and McCabe-Thiele diagram of indium showed that indium could be extracted well under two-stage of continuous stripping.The results of centrifugal stripping for indium showed the stripping rate of indium was about 99.1%while iron and zinc were 10.3%and 40.5%,respectively,under the conditions including two-stage countercurrent stripping,phase ratio(O/A)of 5:1,HCl concentration of 3 mol/L and the centrifugal speed of 6000 rpm.At last,a closed circuit process of two-stage of continuous centrifugal extraction and stripping were designed.The above experiments show that the extraction rate of indium in the feeding liquid improved over 35%under the optimum conditions.The use of phase ratio(O/A)of 1:5 can effectively reduce the consumption of extractant and reduce the cost.