| According to the chemical component characteristics of tin anode slurry, a new fine hydrometallurgy process was proposed for treating a typical tinny resource. This process not only can reclaim regenerative resources comprehensively, but also can produce some high value chemical products. Based on the analysis of existing literatures, This dissertation also were carried out some researches about the relative theories and technologies, gained some significant results.Firstly, according to the principles of simultaneous equilibrium and electronic charge neutrality, the thermodynamics in Sn(Ⅳ)-NH4+-Cl--H2O system and Sn(Ⅳ)-Sb(Ⅲ)-NH3-NH4Cl-H2O system at normal condition had been analysed. Relation between all sorts of Men+ concentration versus pH has been plotted. Based on thermodynamics analysis and calculation, some experiments were done to validate the calculation results. In the first system, the total concentration of ammonium and pH are the most important factors which determined whether (NH4)2SnCl6 or Sn(OH)4 existed in this system. Results further show when [HCl]≥ 6mol·l-1, Sn4+ in this system will be precipitated as the form of (NH4)2SnCl6:SnCli4-i+2NH4Cl=(NH4)2SnCl6↓+(i-4)Cl-The concentration of total stannic ions reached the max when pH is equal to 0.8; when pH<0.8, the concentration of total stannic ions declined sharply because of coming out of (NH4)2SnCl6(s). When pH>0.8, the concentration of total stannic ions also decrease sharply, for there comes out of Sn(OH)4(s). When pH<-l, this system is suited for preparing (NH4)2SnCl6, while pH>1.5, this system is suited for preparing Sn(OH)4.To the second system, based on the thermodynamics analysis results, was analysed the co-precipitation essential about this system. Results show that pH is the most important factor that determine the co-precipitation reaction direction and feasibility in this system. Results further show the ATO powders prepared by tradition process are actually the mixed compounds of Sn(OH)4 and Sb4O5Cl2.Then, a new hydrometallurgy process were deeply done for treatingtin anode slurry to recover tin, antimony and copper, etc, Which includes oxidation-leaching by hydrochloric acid, precipitation tin, refining (NH4)2SnCl6, reduction-precipitation copper, hydrolyzation of SbCl3, refining Sb^sC^ and complex-co-precipitation to fabricate ATO powders, gained the optimal experiment conditions: (1) oxidation-leaching by hydrochloric acid: concentration of hydrochloric acid is 6mol-L"1, rate of liquid to solid is 7:1, leaching time is 2 hours, leaching temperature is 70 centigrade. (2) The optimal conditions of tin precipitation process are 3.5 times of theory quantity of chloride ammonium, reaction temperature of 25 °C, reaction time of 30-40 min; (3) reduction-precipitation copper : reaction time is 45 min, reaction temperature is 75 °C, quantity of ammonium chloride is one time of its theory quantity; (4) hydrolization of SbC^: normal temperature, 8.5 times of original solution cubage.Gained a excellent technique-economy target: (1) tin leaching rate, antimony leaching rate and copper leaching rate are 98.91%, 94.98% and 97.72%, respectively, (counted by liquid leaching rate); (2) tin precipitation rate can be reached more than 99%; (3) precipitating copper rate was 95.1%; (4) precipitating antimony rate is 98%.A kind of process successfully has been developed to refine (NH4)2SnCl6 and Sb^tOsC^. The optimal condition and steps of refining (NH^SnCk are as: Firstly, being used 5% analysis purity ammonium chloride to wash (NH4)2SnCl6 for three times quickly, rate of liquid to solid being 1:1, Secondly, being used 5g/L tartaric acid to quickly wash (NH4)2SnCl6 for three times again, also keep rate of liquid to solid being 1:1; in the end, gained 99.99 percent (NH^SnCle, which can meet with the purity demand of the raw materials for producing ATO or ITO. SD4O5CI2 refining optimal conditions and method are as: being used a solution consisting of 80% citric acid plus 10% salicylic plus 10% hydrochloric acid to wash impure Sb4O5Cl2, rate of liquid to solid being 2:l(mg/g), stirs it at normal temperature for 3 hours, being washed it by distilled water, is gained 99.9% of SD4O5CI2 after dryness.In order to prepare completely-mixed ATO powders, the author firstly used (NH^SnC^ and Sb4O5Cl2 as raw materials, proposedcomplex-co-precipitation process to produce antimony doped tin oxide, and did deep research about this proposition, ascertained the optimal reaction conditions. Which are as: pH value of 3, reaction temperature of 60°C, antimony concentration of 3%, heat treating temperature of 600X:, wash times of 6, dispersant of c. Synthetical experiment results show that this process can prepare even, well-shape and dispersive nano-phase ATO powder. Complex-co-precipitation process can avoided these shortcomings: conglomeration, limited original material, expensive cost, wasting lots of acid and alkali; different hydrolyzing speed of tin and antimony; uneven doped rate et al.
|
PDF Full Text Request