Study On The High Value Utilization Of Low Value Raw Materials Generated From Non-ferrous Metals Metallurgical Industry By The All Wet Process

In china, amounts of solid waste, such as feigh and flue dusts, are generated from metallurgical processing of non-ferrous metals every year, which will cause baneful influence on environment. The clean and effective governance of these solid wastes should not be ignored. Meanwhile, there are many low-value intermediate goods due to the lower utilization oeffency of traditional crafts need for efficient utilization urgently. Facing to the seirous situation of continue accumulation of solid waste and low-end products, we selected two kinds of low value material in metallurgical processing of non-ferrous metals (flue dusts and secondary zinc oxide) as probe to study the all-wet treatment process of utilization these low value material, and then, to recycle them as the high value products through the clean production process. The main research contents include:(1) Successful designing a wet process to treat flue dust as follows:water leaching-magnetic-acid leaching-subsequent separation. It was found that zinc oxide and insoluble arsenate is the main existing form of zinc and arsenic element in this flue ash and water-soluble zinc, arsenic mainly in the form of zinc chloride and arsenic trioxide are leached out by water. After magnetic separation, the iron grade of magnetic substance reaches 36.8% which is mainly composed of Fe and Fe3O4. By comparing the single sulfuric acid, hydrochloric acid and mixed sulfuric acid-nitric acid, mixed hydrochloric acid-nitric acid leaching system, we found that the mixed sulfuric acid-nitric acid system is the best one. Under the optimum conditions:the amount of nitric acid 8mL/100g, reaction temperature 80℃, reaction time 2h, the leaching rates of Cu, Zn, As, Bi were 92.14%,92.34%,90.00% and 10.01%, respectively. There is no leaching of Pb.(2) The zinc arsenic separation process of water leaching solution was studyed deeply. Based on the single ferric sulfate or calcium oxide route, we firstly proposed a ferric sulfate-calcium oxide-zinc arsenic ammonia selective three-steps selectively separation new process. Under the optium reaction conditions, the removal rate of As is more than 98.9%, while that of Zn is less than 10%. A further mechanism study found:when the pH value changes between 2-3, the removal rate of As does not change obviously while that of Zn vary greatly. The reason for this result not only because the solubility product constant (ksp) the competitive adsorption of Fe3+, Ca2+ also play some role.(3) Determining preparation process of nano-zinc oxide from the second zinc oxide as follows:acid leaching-impurity-precursors preparation-calcination. We studied the influene of acid leaching process on the zinc sulfate solution by one-step method and two-step method; optimized the ZnO/copper sulfate-zinc/zinc impurity order and obtained the qualified zinc sulfate electrolyte.(4) By contrast ammonium bicarbonate, sodium carbonate, ammonia three kinds precipitation system, we firstly proposed a new technology of ultrasound-cationic surfactants coupled precipitation system and accessed the superior grade of zinc oxide sample with hexagonal structure and its BET value reaches as high as 46.99m2/g.