从粉煤灰中回收锗的湿法工艺研究

Research on Hydrometallurgical Process of Germanium Recovery from Fly Ash

采用氟化铵硫酸浸出法提取粉煤灰中的锗:以氟化铵与硫酸反应生成的氟化氢作为破坏粉煤灰中二氧化硅和氧化钙的试剂,硫酸作为破坏氧化镁的试剂,并以氯酸钠作为氧化剂,使锗由二价态转变成四价态后被硫酸溶解进入浸出液,最后以丹宁酸沉淀锗。该工艺具有锗回收率高、成本低、对环境友好等优点,在最佳工艺条件下锗的回收率可高达80.12%,对应的锗精矿品位为4.69%。

Germanium was recovered from fly ash by ammonium fluoride-sulfuric acid leaching. In the process ,ammonium fluoride reacts with sulfuric acid to generate hydrogen fluoride as the destruction rea- gent of silica and calcium oxide in fly ash,sulfuric acid serves as the destruction reagent of magnesia,and sodium chlorate serves as the oxidant to oxidize Ge（ Ⅱ ） into Ge（Ig）,which can he dissolved into the leac- hing solution by sulfuric acid. Finally, germanium is precipitated with tannic acid. The above process has the advantages of high germanium recovery,low cost, low pollution and so on. Under the optimal technical conditions,the germanium recovery reaches 80.12% and the grade of resultant germanium concentrate is up to 4. 69%.