Study Of The New Process For Collecting And Extracting Gallium From The ISP Slag Produced At Shaoguan Smelter

150,000 tonnes of granulated slag is produced annually from the slag fuming furnace at Shaoguan Smelter , which contains about 30—40 tonnes of Ga and 40,000 tonnes of Fe . The total amount of granulated slag stored until now is approximately up to 2,000,000 tonnes , which contains about 400—500 tonnes of Ga . The value of Ga content is about more than a billion RMB Yuan based on present price . The researchers of the Scientific and Technical Development Department of Shaoguan Smelter and other scientific research institutes have done a lot of work on the recovery of Ga from the granulated slag produced at Shaoguan Smelter. The four main processes for recovering Ga are as following :Chlorination volatilization process at high temperature;Only hydro metallurgical process for recovering Ga ;Melting with alkali- leaching process;Reduction smelting - electrolysis process .If chlorination volatilization process at high temperature is used to recover Ga from granulated slag , Ga may be collected in the dust , gallium of 98 % will be collected in the dust. The process is easier , and its energy consumption is lower . But the chlorinates and the products produced during chlorinating are corrosive , requiring equipments with bettercorrosion-resistance . 20% of chlorinate reports to the waste gas in the form of HC1 and CI2 during operation , causing pollution if no extra treatment is added.If only hydro-metallurgic process is used to recover Ga , the process flow-sheet is easier , the leaching rate is up to 70—80% . But the total recovery of gallium for the whole flow-sheet is low , only 45—51% . The acid consumption is high , and the iron content of leachate is high . The separation of gallium and iron is difficult , requiring high treatment cost .It is difficult to treat a large quantity of ferro-sulfate produced from the separation of gallium and iron . Therefore the leaching process with sulfuric acid is not reasonable technically and economically .If melting with alkali - leaching process is used to recover Ga , the leaching rate of gallium is up to 90% . But the gallium content of the sludge is too low , leading to too low gallium content of the leachate— only 60 mg/1 . The extraction flow-sheet becomes more difficult .If reduction smelting - electrolysis process is used to recover Ga , gallium will be collected in iron produced by using the grain iron method ( a reduction smelting method for iron ) The non-magnetic material produced during operation may be sold directly as cement-making material , the galliumand iron alloy will be melted and cast into anode plate for electrolyzing . The purity of pure iron produced during electrolyzing is more than 99.5% . Pure iron may be sold directly as magnetic material. The anode slime will be leached with alkali and be treated by electrowinning . Electrolytic gallium will be washed by acid and metallic gallium of 99.9% will be obtained .The technical and economic indices of reduction smelting -electrolysis process are better .The project has been proved to be feasible by industrial experiment . The small-scale experiment and pilot experiment of the reduction smelting-electrolysis process and the results obtained are mainly introduced in the paper .