| Usually before electrolytic Zinc sulfate solution, dechlorination purification treatment has to be finished for electrolysis request. The common method for dechlorination is copper residue dechlorination method. The raw material for copper dechlorination method can be obtained easily and the production costs are low. Further more, simple process, high initial dechlorination rate and secondary dechlorination to electrolyte so electrolysis requirement can be achieved. At present, most hydrometallurgy of zinc smelter select the copper residue dechlorination method from the system. The copper residue dechlorination method in dechlorination fields has achieved some good results, but there is still no good way to deal with the outputting dechlorination copper residue.For CuCl residue, due to the chlorine mainly exists in the form of strong absorbing phase CuCl. and other ingredients of absorbing material is relatively weak, therefore, make full use of the microwave selective internal heating this feature, combined with oxygen, strengthen the impurity components-chlorine oxidation reaction, and then release the chlorine body, achieve the goal of removing and recycling chlorine. Under the condition of ventilation with oxygen and water vapor, can further speed up the dechlorination reaction, and then release the hydrogen chloride gas. The research details are as following:Firstly, This paper studied the physical basics of this new process mainly by analysis of the electromagnetic property of CuCl residues. A method of microwave cavity perturbation were used to measure the dielectric constant and loss factor of the roasting products and the raw materials with different density or particle size. With these dielectric data, the microwave penetration depths of the above materials were calculated. From these parameters, a set of optimized operation parameter of microwave roasting technology, granularity is between20mesh and100mesh, and its density is above2g/cm3were deduced.Secondly. The basics of microwave drying process of CuCl residue filter cake were studied. The effects of power levels and sample mass on drying characteristics of moisture content, drying rate, moisture ratio were studied, with microwave power ranging from250W to850W and sample mass from100g to300g. The moisture content and drying rates are found to be dramatically affected by microwave power density and samples mass. For all drying processes the prior microwave absorption of moisture produces all accelerating peak on the drying rate curves in the initial stage. The experimental results fit well to the Page model. And then by using response surface methodology(RSM), the optimal condition of microwave drying CuCl residue, microwave power801W, drying time400s, material mass151g, respectively, were obtained, obtained. The dry basis moisture content of microwave drying CuCl residue in this condition was4.41%.Thirdly. XRD results show that CuCl can be oxidized by O2into Cu2OCl2, then the Cu2OCl2translates into CuO and Cl2. SEM results showed the structure change of copper residue after microwave treatment.Fourthly, Using both on air and oxygen atmosphere of microwave roasting, comparative study of two different conditions to deal with the effect of CuCl slag dechlorination, and studied the roasting temperature, roasting time and oxygen flow rate on the microwave roasting chlorine effect of copper slag dechlorination.Under the condition of oxygen and water vapor, found that the time of dechlorination further shorten.Generally, this article system to study the microwave roasting chlorinated copper slag dechlorination of hydrometallurgical zinc smelting:dry. dielectric properties, roasting process. The significant values of this work are aiming to develop a new process for removing Cl from CuCl residue through the comparative study on two methods of oxygen and air roasting dechlorination effect. This study has opened up a new train of thought for chlorine material processing. |
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