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Research On The Technology And Mechanism Of Treatment Process To JNMC Sponge Copper

Posted on:2005-04-10Degree:MasterType:Thesis
Country:ChinaCandidate:C J YangFull Text:PDF
GTID:2121360125451348Subject:Non-ferrous metallurgy
Abstract/Summary:PDF Full Text Request
The sponge copper is a kind of purring scraps which is produced in the nickel electrolyzing in Jinchuan Non-ferrous Metal Company(JNMC). Present on the application of nitric acid on metallurgy in recent years at home and abroad are reviewed on base of studying a lot of papers and books. A new hydrometallurgical process for conversion of the sponge copper derived copper and copper sulfide into bluestone crystal is provided basing on the previous experiments carried out by both JNMC and. Kunming University of Science and Technology. The process comprises: oxidation of copper, absorption of nitric oxide, refining of copper sulfate. Oxygen and nitric acid are used as oxidation and catalyst, respectively. During the leaching process,the pressure of vessel is less than 400mmHg. The results of the plant scale test are showed below: the leaching ratio of copper is 99.3-99.94%, nickel 94.73-99.85%; The contain of sulfur in the residue is 70.28%, and the result means most of sulfur in sulfide is oxygenated into elemental sulfur; The product of copper sulfate accords with the China top industrial standard; Oxygen is utilized to oxidize gaseous NOx to regenerate nitric acid, and more than 70% of nitric acid is recoverable. Economic analysis showed that the process had a lower operation cost ( 166.10 per ton copper sulfate), as compared to the Sulfuric Acid Roast Leaching processes ( 1302.17 per ton). Process and mechanism were been researched after the plant test. Oxidation of copper is researched by the rotating disk method. The oxidation of copper includes the passivation oxidation and the activation oxidation. The effects of oxidation time, temperature, agitation speed, concentration of nitric acid and sulfuric acid, chlorine ion, nitrous acid in the leaching solution are discussed. In addition, the mechanism of activation oxidation is suggested. The reaction rate is calculated, and the formula is accorded with the data of experiments. The oxidation of copper is a self-catalyzed reaction. The nitrous acid is active mid-product. All the phenomena occurring in the plant scale can be explained with the mechanism. The apparent activation energy for activation oxidation of copper is determined as 23.22KJ/mol at 300 rpm. It means a mixture controlling procedure. The optimal condition for oxidation of copper are: sulfuric acid 392g/l, nitric acid 1.5mol/l,temperature 80 C, agitation speed 300rpm. Absorption of nitric oxide is studied in a experimental device which simulates the reactor in the plant scale test. It is founded that high temperature is of advantage to form nitric acid, but that is disadvantageous to the oxidation of nitric oxide in dynamics. However, the latter is the determination step of the absorption process. So nitric oxide should be absorbed in low temperature. The higher the acidity of the absorption solution, the higher ratio of nitric acid forms. The concentration of nitric acid in absorption solution can reach 4.79mol/l, which is high enough to be reused as oxidant. Combining experiment of oxidation and absorption proves that the oxidation of copper and absorption of nitric oxide can be carried out at the same time effectively. The distribution of nitrate between oxidation and absorption reactor can be controlled by the circulating speed of gas. An excellent refining method for bluestone is given. It can save more water and energy than the traditional evaporation method. Through washing, re-dissolving, re-crystal, the removal rate of dissociation sulfuric acid is more than 98%. Quality of the product: CuSO4-5H2O 98%;H2SO4 0.1%; un-dissolved substance 0.1%, reaches the China top industrial standard. During the lab and plant scale test, a powerful and regenerable oxidant, nitric acid, is utilized to completely ( 99%) leach copper and nickel from the copper sponge. The result of this paper is significant not only to JNMC, but also to be utilized in some metallurgy processes using nitric acid.
Keywords/Search Tags:nitric acid, copper sulfate, oxidation absorption, nitric oxide
PDF Full Text Request
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