The Recovery Of Germanium From The Pb And Zn Sulfide Concentrate

The paper covers the elaboration of the experiment and research of the extraction of Ge from hard zinc produced at a factory by the process of" Ge collection in vacuum furnace— roasting with ddition of Na₂CO₃—distilling by chlorination—hydrolysis of GeCl₄". The two processes of Ge collection in vacuum furnace and distilling by chlorination for manufacturing GeCl₄ are emphasized. The ways to treat the residual liquor,waste water and slag produced during distilling by chlorination to meet with the environmental requirements are also discussed in the paper. Only verification tests were made for the processes of roasting with addition of Na₂CO₃—hydrolysis of GeCl₄, which have been adopted by factories at home and abroad .The experiments of Ge collection in vacuum furnace were made at the vacuum 66-106 Pa . The effects of the distilling temperature and time on first-pass recovery and overall recovery of germanium were observed during the experiments . The experiment results show that Ge will be collected in the vacuum furnace slag if we keep the distilling temperature at 1010℃ for 40-100minutes and the total distillation time for 275 -445 minutes, thegermanium content of the vacuum furnace slag is 2.87-4.12% ,the first-pass recovery and overall recovery of germanium is 97.26-94.09% and nearly 100% respectively . The collection ratio of germanium is 10.63-15.26%. Meanwhile refined Zn and Pb can be obtained by treating the condensed alloy produced from the process . The solution of CaClz -HCl was used as distilling liquor during the process of distilling by chlorination , and the influence of acidity of distilling liquor on the first-pass recovery and overall recovery of germanium was investigated . The experiment results showed : the distilling solution was dosed at the proportion of l(kg):4(l):4(l) for the mineral, the solution of CaCl2 (at the concentration of 450g/l-500/l) and industrial chlorhydric acid , and was distilled for half an hour at constant temperature of 120 °c ; the output solution of GeCU contained 600g Ge /I and only 0.3g As /I. The first-pass recovery and overall recovery of germanium during the distilling process was 88.14% and 97.12% respectively, and the purity of the solution of GeCU obtained was more than 99.9%.Verification tests were made for the processes of roasting with addition of Na2COi—hydrolysis of GeCl4. The test results were identical with the technical parameters obtained in factories at home and abroad .The overall recovery and first-pass recovery of ermaniumduring the process of roasting with addition of Na2CO, was 98% and 96.8% respectively. The proportion of 1:6.5 for GeCl4 and distilled water was was used for the hydrolysis of GeCl4, the hydrolytic reaction lasted for 2 hours at 0"c , and GeO2 with purity of 98.0% or so was obtained . The first-pass recovery and overall recovery of germanium was 94.8% and 98.55% respectively during the process of hydrolysis of GeClA .This method was used to treat hard zinc produced in the factory . The first-pass recovery and overall recovery of germanium obtained during the whole process was 78.7% and 93.79% respectively , and the purity of GeO2 is more than 98% . Better economic indice were also obtained : the total cost for lkg GeO2 (calculated as germanium) was only RMB yuan 656.56 . The supply of raw material has no problem . Furthermore this method have the advantages of vacuum smelting by adopting vacuum furnace for collecting germanium : Firstly, the oxidation reaction of reactive metals such as Zn and As ect. can be avoided nearly completely because of the scare oxygen in the furnace . Secondly, low distillation temperature, material for making distilling equipments is easy to choose , lower energy consumption , the required volume of vacuum furnace is small , lower investment for equipments and capital construction, and less pollution ; comparedwith the traditional process , it is a great innovation that CaCl2 is introduced during the process of distillation by chlorination , making easier treatment of residual solution produced during the process , which was always regarded as a tough nut to crack . In conclusion, the process of " Ge collection in vacuum furnace— roasting with addition of Afa2C0, — distilling by chlorination — hydrolysis of GeClA" for recovering germanium in hard zinc is operational and practical, therefore it is worth generalizing .