Study On The Gallium Recovery From Red Mud

The red mud is the waste residue from the productive process of alumina,a ton of alumina was produced and output 1-1.8 tons of the red mud.It requires a large area to pile,and causes serious environmental pollution.However,it contains to a large number of metallic elements and is the valuable secondary resource.At present,there are many researches about recovery iron,aluminum,titanium,scandium and other elements from red mud.But researches about recovery gallium are few.The essay analyzed the phase composition and chemical composition of red mud..The new process of recovery gallium from red mud was studied.It is the craft route of acid leaching-extraction?back-extraction?-electrolysis.For the purpose of recovery gallium from red mud,the research is as follows:?1?The best parameter of traditional sulfuric acid leaching process is: leaching temperature of 90?,the concentration of sulfuric acid is 7 mol/L,liquid-solid ratio is 5:1,leaching time of 3h,the leaching rate of gallium is 89%.The best parameter of curing the red mud with concentrated sulfuric acid process is: curing temperature of 200?,curing time of2 h,the concentration of sulfuric acid is 4 mol/L,liquid-solid ratio is 2:1.The best parameter of water leaching process is: leaching temperature of 70?,leaching time of 60 min,the dosage of water is 20 mL,the leaching rate of gallium is 93%.The best parameter of traditional hydrochloric acid leaching process is: leaching temperature of 100?,leaching time of 4h,the concentration of hydrochloric acid is 8 mol/L,liquid-solid ratio is 7:1,the leaching rate of gallium is 82.07%.The leaching rate in curing the red mud with concentrated sulfuric acid process is higher than regular sulfuric acid leaching,the viscosity of the leached residue is small,filter speed was increased.But,adding amount of fluoride can control theinfusion of more stringent.?2?The best parameter of microwave-assisted hydrochloric acid leaching process is:leaching time of 25 min,leaching temperature of 80?,liquid-solid ratio is 7:1,the concentration of hydrochloric acid is 7 mol/L,the leaching rate of gallium is 93.46%.The best parameter of ultrasonic-assisted hydrochloric acid leaching process is: the concentration of hydrochloric acid is 8 mol/L,leaching temperature of 80?,liquid-solid ratio is 7:1,leaching time of 15 min,the leaching rate of gallium is 90.09%.The leaching rate of microwave-assisted hydrochloric leaching was higher than that of ultrasonic-assisted leaching.?3?The extraction experiment was carried out after curing the red mud with concentrated sulfuric acid process.In sulfuric acid system,1-propanol as extraction agent,the phase separation extraction behavior of gallium with 1-propanol-ammonium sulphate system was investigated.The best parameter of extracting process is: the dosage of ammonium sulphate is4.5g,extraction time is 15 min,the dosage of 1-propanol is 30%,the exaction rate of gallium is 82%.?4?The extraction experiment was carried out after microwave-assisted hydrochloric acid leaching process.In hydrochloric acid system,TBP as extraction agent.The best parameter of extracting process is: extraction time is 30 min,the dosage of TBP is 30%,pH=5,the exaction rate of gallium is 86.34%.NH₄Cl as back-extraction agent,the best parameter of back-extraction process is: the concentration of NH₄Cl is 1.5mol/L,pH=5.5,back-phase ratio is 2:1,the back-extraction rate of gallium is 90.34%.?5?After acid-base neutralization,using the back-extraction solution for electrolysis.The experiment takes platinum piece as cathode,platinum wire as anode,when the current density value were 200³00A/m2,the tank voltage value were 1.5¹.9V,the best parameter of electrolysis process is: the concentration of NaOH is 130¹60 g/L,the temperature of electrolysis process is 40⁴5?,the electrolytic rate of gallium is 48.42%.?6?Experiments show that by this process recovery rate reaching 36% of gallium.It can conclude that craft route of acid leaching-extraction?back-extraction?-electrolysis was designed to be feasible.