| In this dissertation,we focused on the pollution and remediation of titanium white waste acid produced by various manufacturers in Panzhihua.The physical and chemical properties of the waste acid,the content of the components,the treatment technology scheme,and the basic theory and test methods for recovery and utilization of the valuable components were studied.Basic research,at the same time,also carried out research on titanium dioxide waste acid using solar natural evaporation,concentrated freezing and separation of ferrous sulfate heptahydrate,titanium white waste acid extraction method to extract thorium in waste acid,through the above experimental methods,obtained separately high concentrations of sulfuric acid,ferrous sulfate heptahydrate,iron oxide powder,antimony trioxide products.The pre-treated waste acid was subjected to an extraction condition test.The extraction agent ratio of 15%P204+3%TBP+yellowing kerosene and the extraction rate of yttrium reached 86.8%.For the loaded organic phase containing titanium and niobium,eluent was used to directly elute titanium.Compared with the traditional methods such as titanium sulfate hydrous sulphide washing and acid-soluble hydrolyzed titanium,the loss of niobium during the elution of titanium was small and there was no influence of precipitation.After elution,the elution rate of titanium can reach86.2%.During the entire extraction and elution process,the mass ratio of niobium to titanium was enriched from 1/176.5 of the original solution to 5/1,and the separation effect of niobium and titanium was obvious.The loaded organic phase after the elution of titanium was back-extracted with sodium hydroxide.The single-stage stripping rate of rhenium could reach over 90%,and the rhodium ion concentration reached 1318.3 mg·L-1.The addition of eluent ethanol can effectively reduce the solubility of ferrous sulfate heptahydrate,and can effectively separate the ferrous ion and sulfuric acid solution.The removal rate of iron reaches 93.8%.Titanium dioxide waste acid volume after freezing reduced from 3L to 0.547L,therefore,concentrated5.48 times,concentrated sulfuric acid concentration of 9.96 mol·L-1,the mass fraction of 72.8%,to meet the acidity requirements of waste acid recovery.Recrystallisation method was used to remove ferrous sulfate.The crystallization temperature had little effect on the removal of impurities Ti and Al in ferrous sulfate.The removal rate of impurities Mn increased slightly with the increase of crystallization temperature.After two times of crystallization,metal ions such as Ti,Mn,and Al are substantially removed.By adjusting the pH,when the pH is 9.5,the iron hydroxide precipitates completely,and the iron sesquioxide product is preliminarily prepared by filtration and washing.Through the above research,the problem of environmental pollution of titanium white waste acid was successfully solved,and at the same time,the comprehensive recycling of sulfuric acid,antimony,and iron was realized,which was valuable in solving the waste acid contaminated titanium white waste acid in the production of titanium dioxide in the sulfuric acid process.The fact that resources cannot be reasonably used provides new ideas. |
PDF Full Text Request