| Zinc is widely used in construction,shipbuilding and other industries because of its excellent calendering,wear resistance and corrosion resistance.The chlorine in the zinc hydrometallurgy system mainly comes from the chloride in zinc concentrate and zinc dust.When the content of chlorine exceeds a certain concentration,it will affect the zinc electrowinning process.The anode plate and system equipment will cause corrosion,increase the production cost and reduce the quality of zinc.Therefore,in order to ensure the safety and stability of zinc smelting process,it is necessary to strictly control the chlorine content.Compared with other chlorine removal methods,the use of copper slag synergistic valence regulation technology to remove chloride ions in zinc smelting acidic solution,Cu（II）can be better controlled,with higher chloride ion removal efficiency and better process stability.In addition,it avoids the problem of reverse dissolution caused by adding additional oxidants,such as ferric iron or manganese dioxide,and realizes turning waste into treasure,which greatly saves cost and is more environmentally friendly.In this paper,the acidic solution produced by zinc smelting system of a lead-zinc smelting enterprise in Yunnan is taken as the research object.The process of copper slag combined dechlorination by copper slag synergistic valence regulation is proposed.The effects of conventional conditions and ultrasonic strengthening on the dechlorination effect are explored,and the dechlorination reaction mechanism is studied.The specific research contents are as follows:（1）In this paper,the combined dechlorination of conventional copper slag and valence control copper slag and the combined dechlorination of ultrasonic enhanced copper slag and valence control copper slag were determined.The optimized conditions for the conventional process dechlorination reaction are n（Cu）:n(Cu2+):n（Cl-）=6:5:1,the reaction temperature is 20°C,the reaction time is 60 min,the chloride ion concentration decreases from 1600 mg/L to 50 mg/L,the dechlorination rate is 96.88%.The optimum conditions for the dechlorination reaction of the ultrasonic enhanced process are as follows:the addition amount of copper slag and valence-controlled copper slag is n（Cu）:n(Cu2+):n（Cl-）=3:5:1,the reaction time is 40 min,the reaction temperature is 20°C,the ultrasonic power is 500 W,and the chloride ion concentration is reduced from 1600 mg/L to 46.56 mg/L.The chloride ion removal rate in the acidic solution of zinc smelting can reach 97.09%.Through comparison,it is found that the ultrasonic strengthening process has the advantages of small reagent addition,high chlorine removal efficiency and short reaction time.（2）The relationship betweenΔG and temperature T of each chemical reaction in the reaction system was studied by thermodynamic analysis,and the valence control temperature of copper slag was determined to determine the feasibility of chemical reactions in the dechlorination reaction system.The microstructure of chlorine-containing precipitates was analyzed by XRF,XRD,XPS and SEM.The transformation mode of Cl and Cu elements in acid solution of zinc smelting was explored,and the reaction mechanism of conventional process and ultrasonic strengthening process was revealed.（3）The kinetic experiments of conventional process and ultrasonic strengthening process were carried out.The experimental results of the two processes were fitted.The apparent activation energy Ea of the conventional process was 11.53 k J/mol,and the apparent activation energy Ea of the ultrasonic strengthening process was 8.26 k J/mol.Compared with the conventional process,the activation energy of the ultrasonic strengthening process is smaller,indicating that the ultrasonic can reduce the activation energy of the chemical reaction and accelerate the chemical reaction rate,which provides a basis for the industrial prospect. |
PDF Full Text Request