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Study On The Ammonia Process To Produce Electrolysis Zinc And Effect Of Additive During Electrodeposition

Posted on:2008-03-10Degree:MasterType:Thesis
Country:ChinaCandidate:J ZhangFull Text:PDF
GTID:2121360218462572Subject:Chemical Process Equipment
Abstract/Summary:PDF Full Text Request
According to the question that it is difficult to treat zinc oxide ores whichcontain many kinds of impurities such as Fe, Cd, Cu by usual acid process, this thesisstudy theammonia process, decide the flow, optimize the parameters and discuss theireffect on the result.In this process, a solution of NH4C1 and NH3 is used as leaching agent whichreacts with zinc oxide, and the zinc is dissolved in the form of Zn(NH3)i2+. Firstdecide the concentration of leaching agents as following: NH4Cl 5mol/L, NH3·H2O2.5mol/L. Then study the effect of temperature, time, the ratio of liquid to solid,rotate speed on the ratio of zinc leaching by orthogonal test. The best leachingcondition is that the temperature is 40℃; the time is 3 hours; the ratio of liquid tosolid is 8:1 and the rotate speed is 730 r/min. Under this best condition the ratio ofzinc leaching can reach 74.2%. The orthogonal test also shows that effect of theratio of liquid to solid and time is significant and the former is the most significant,while rotate speed and temperature are not so.In the purification process, we use colloid to absorb the As and Sb, then use zincpowder to replace. Cu, Cd and so on which has higher electrode potential thanzinc.The best condition is that the temperature is normal temperature 25℃, the time is90 mins, the FeCl3 and H202 is 2.5g/L and 1.5ml/L and the zinc is 3g/L. The liquid after purification accord the electrolysis standard.In the electrolysis process, we choose the titanium plate coated with rutheniumas anode material and the pure aluminium plate as cathode material. The bestcondition is that the temperature is normal temperature, the distance between twoelectrodes is 37mm and the quantities of additives T-A glue, T-B andT-C are 0.1g/l,0.05g/1 and 0.1g/1. Under these, conditions, the smooth and compact zinc plate can begot.The study on the effect of additives and concentration of Zn2+ onelectrodeposition process shows that the quantity of T-A glue has great effect onelectrodeposition process; while the T-B and T-C's effect is less. The concentration ofZn2+ has great effect on electrodeposition process too, as the concentration of Zn2+reduce, the range of appropriate current density become narrow.The synthetical electrodeposition experiment shows that through this processwecan get zinc plate accord to industrial require. This process for treating zinc oxideores to produce electrolysis zinc has the advantages of simplified flow; many kindsof raw materials; high recovery rate of zinc; easy purification; operation at roomtemperature, low power consumption; little pollution and investment, and so on. Itmust be a new process that will develop well in future.
Keywords/Search Tags:zinc, ammonium leaching, electrolysis, additive
PDF Full Text Request
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