【作者】 张雪；

【导师】 王三反；

【作者基本信息】 兰州交通大学 ， 市政工程， 2016， 硕士

【摘要】 氯气怎么处理是电积钴行业一直亟待解决的问题,现代电积钴行多业采用Co Cl2溶液体系制备钴,该方法制备出的钴品质较高,色泽鲜亮,符合国家一级标准。但是,电积过程中会有氯气产生,导致车间内氯气浓度过高,危害职工身心健康,同时降低了城市的空气质量。而且,用碱液吸收氯气不仅增加了钴的生产成本,吸收后的产物为NaClO,直接排放后造成环境的二次污染。目前,国内外多只从氯气的吸收角度进行考虑,并没有从根本上解决氯气产生的问题。本试验从氯气的消减和吸收两方面出发进行试验研究。利用离子膜电积工艺,设计双膜三室电积钴装置,因为阳离子膜的选择透过性有效阻挡了Cl-进入阳极室,这从源头上消除了氯气的产生。试验以电流效率,钴品质及氯气消减率为指标,进行电流密度、电解液温度、电解液酸度、电解液浓度、循环流量、极间距及盐酸硫酸的初始酸度的单因素试验,并通过正交试验确定最佳允许条件为:电解6h为一个周期,电流密度为250A/m2,电极间距10cm,循环流量为200r/min,Co2+浓度约60g/L左右,电解液pH为2,HCl和H2SO4初始质量分数为0.5%和1.5%,在此条件运行下的电流效率为98%左右,能耗4450kw.h/t左右,钴板色泽光滑,无孔蚀,氯气消减率达到95%左右。正交试验确定影响电流效率的因素大小为:电流密度>温度>循环流量>极间距,影响氯气消减率的因素大小为:电解液温度>初始酸度>极间距。美国膜的氯气消减率在95%左右,国产膜的消减率在90%左右,美国膜约是国产膜价格的10倍,考虑到经济因素,示范工程中使用的是国产膜。氯气的吸收采用水射器吸收方式,吸收溶液进行了碱液和FeCl2溶液的对比,综合考虑确定FeCl2溶液为吸收液,FeCl2溶液吸收每吨氯气的费用为1000元,比碱液吸收成本节约一半。同时,最终产物为聚合氯化铁可做净水的混凝剂,可实现闭路循环,保护环境,具有经济价值,且操作安全。示范工程建设4000吨/年绿色膜法电积新工艺的示范生产线,示范工程运行结果表明,膜电积工艺平均电流效率为91.3%,比常规电积工艺电流效率高1.2个百分点;膜电积工艺的氯气消减率为99.13%;膜电积工艺可将产生氯气的氯离子转换为盐酸并全部回用,盐酸资源回收利用率97.28%;膜电积工艺节约的直接生产成本约为5000元/t。试验用离子膜电积技术替代传统的湿法冶炼技术,有效抑制了氯气的产生,消除了常规钴电积中氯气泄漏的问题,实现氯气零排放,使得车间内的氯气浓度符合国家排放标准。同时可将产生氯气的氯离子Cl-转化为盐酸,全部回用到湿法冶炼工艺系统中去,精炼钴产品质量达到国家一级品标准。综上所述,双膜三室电积钴工艺是一种新型的电积工艺,与传统电积工艺相比较具有一定的优越性。更多还原

【Abstract】 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.更多还原