Extraction Of Tungsten And Enrichment Of Tin From High Arsenic Tungsten Tin Ore

The raw material of this subject is high arsenic tungsten tin ore produced by a factory in Inner Mongolia,which is mainly composed of tin dioxide,calcium tungstate,calcium iron garnet,iron arsenide,iron arsenate,etc.Using alkali pressure boiling process to decompose this kind of minerals has the disadvantages of large amount of alkali,large amount of slag and no enrichment of tin.In order to realize the enrichment and recovery of tin while extracting tungsten efficiently,this paper proposes to decompose the tungsten tin ore by acid process and purify the arsenic containing leaching solution by arsenic iron coprecipitation.The main results are as follows:1.The influence of main technological conditions on the decomposition effect of tungsten-tin ore under high acid and acid decomposition was investigated.The acid decomposition test results showed that the reaction temperature was 90℃,the concentration of hydrochloric acid was 7mol/L,and the liquid-solid ratio was 3:1.The reaction time of 3h is the best reaction condition.Under this condition,the decomposition rate of tungsten reaches 99.63%,the tungsten content is only 0.118%in the alkali solution slag,the WO₃ content in the leaching solution is 0.30g/L,the tungsten loss rate is 0.65%,the tin leaching rate is0.65%,and the tin content in alkali solution slag can be enriched to 60.15%,the enrichment ratio is 2.31 times.In the process of acid decomposition,arsenate is formed by the reaction of hydrochloric acid with smellite and enters into the leaching solution,while arsenopyrite and ferric arsenate are not involved in the reaction and remain in the residue.When the reaction temperature was 55℃,the ratio of liquid to solid was 1:1 and the amount of ammonia water was 4 times the theoretical amount,the dissolution rate of tungstic acid was 96.68%.2.The hydrochloric acid and arsenic acid coordination reaction kinetics of tungsten and tin ore,the results show that the apparent activation energy of the leaching process is 68.74 k J/mol,belongs to chemical reaction control.The results of coordination leaching test show that the decomposition rate of tungsten reaches 95%,the content of tungsten is1.65%,the content of tin is 48.3%,and the enrichment ratio is 1.87 times under the conditions of reaction temperature of 95℃,hydrochloric acid concentration of 2.5mol/L,the ratio of liquid to solid is 4:1,and the reaction time is 1h.D309 resin can effectively recover arsenic-tungsten-heteropoly acid from leaching solution.The adsorption process follows Langmuir isothermal equation and is monolayer adsorption.The control step of adsorption process is particle diffusion control.Under the conditions of25℃,4h reaction time and liquid-solid ratio of 2.5,the adsorption rate can reach 99.90%.Under the conditions of desorption temperature 55℃,reaction time 3h,ammonia concentration 210g/L and liquid to solid ratio1.25:1,the optimum desorption rate is 91.78%.3.The arsenic-iron co-precipitation method was used to purify the waste liquid containing arsenic,and the reaction p H was adjusted to 4 to obtain high arsenic slag.At this time,the concentration of As in the leaching solution was 20mg/L,and the arsenic removal rate could reach99.9%.Then adjust p H to 10 for deep impurity removal,and finally obtain iron slag and calcium chloride solution.