Experimental Study On The Elimination And Absorption Of Chlorine Of Double Membrane And Three Compartment The Electrodeposited Cobalt

Chlorine how the deal electrowinning cobalt industry has been a serious problem,modern lines cobalt electrowinning cobalt Co Cl2 prepared using multi-industry system solutions, high cobalt which can be prepared quality, bright color, in line with the national standard. However, the electrowinning process will produce chlorine, resulting in high concentrations of chlorine plant, endangering the health of workers, but also reduces the quality of urban air. At the same time, with lye absorption of chlorine not only increases the cost of production of cobalt, the product after the absorption of NaClO, causing secondary pollution of the environment directly after discharge. At present, domestic and foreign multi only from the viewpoint of absorption of chlorine and chlorine produced not solve the problem fundamentally.This test is subtracted from the absorption of both chlorine and starting pilot study. The use of ion-exchange membrane electrowinning technology, three-compartment design double film cobalt electrowinning device, using the selection of the cation permeable membrane barrier Cl- into the anode compartment, to avoid the generation of chlorine gas from the root.Test with current efficiency, the quality of cobalt and chlorine reduction rate indicators, the current density, electrolyte temperature, electrolyte pH, electrolyte concentration, the circulation flow rate, single-factor test electrode spacing and hydrochloric acid initial acidity,and orthogonal allows to determine the optimum conditions for the test: 6h for a period of electrolysis, current density of 250 A / m2, electrode spacing 10 cm, the circulation flow rate of200 r / min, Co2 + concentration of about about 60 g / L, pH of the electrolyte 2, HCl and H2SO4 initial the mass fraction of 0.5% and 1.5%, in conditions of operating at a current efficiency of about 98% energy consumption by about 4450 kw.h / t, cobalt plate smooth color,no pitting, chlorine reduction rate of about 95%. Orthogonal experiment to determine the effect size of the current efficiency of factors: the current density> Temperature> Loop Flow>pole spacing, affect the rate of chlorine reduction factor size: electrolyte temperature> initial pH> pole spacing. Chlorine reduction rate of the US film about 95%, the rate of reduction of domestic films was about 90%, the US-made film about the film 10 times the price, taking into account economic factors, the demonstration project using the domestic film.Absorption of chlorine with water absorbs radio mode, absorbing solution compared lye and FeCl2 solution, considering determine FeCl2 solution as absorption liquid, FeCl2 solution to absorb the cost of chlorine per ton of 1,000 yuan, half of alkali absorption cost savings.Meanwhile, the final product can do for the polymerization ferric chloride coagulant water purification, can achieve closed loop, protecting the environment, economic value and safe operation.Demonstration projects 4000 t / demonstration production line in green membrane electrowinning new technology demonstration project run results show that the membraneelectrowinning technology to the average current efficiency of 91.3%, higher than the conventional electrowinning process current efficiency of 1.2 percentage points; membrane electrowinning chlorine reduction process was 99.13%; electric film deposition process can produce chlorine gas and hydrochloric acid chloride is converted to the full recycling,resource recovery rate of 97.28% hydrochloric acid; direct production costs of films electrowinning technology for saving electricity per tonne of cobalt 5000 yuan.Electrowinning test uses membrane technology to replace the traditional hydrometallurgical technology to effectively suppress the generation of chlorine, eliminates the conventional cobalt electrowinning chlorine leakage problems, to achieve zero emissions of chlorine, so that the concentration of chlorine in the workshop meet the national emission standards. At the same time can produce chlorine chloride ions into hydrochloric acid, used in all the back to the hydrometallurgical process system, refined cobalt product quality meet the national standard product level. In summary, the two-film triple rooms cobalt electrowinning process is a new type of electrowinning technology, and traditional compared to electrowinning technology has certain advantages.