Xianxia YUAN
,
Yindong WANG
,
Feng ZHAN
材料科学技术（英文）
Effects of various Co species added by mechanically mixing with Ni(OH)(2) on the performance of Ni electrode were studied and the results were interpreted by means of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It was found that CoO, Co and CoO+Co all can improve the performance of Ni electrode to some extent and the effect of CoO was the most obvious. This could be attributed to several causes: all three forms of additives increased the reversibility of Ni(II)/Ni(III) redox reaction, enhanced the oxygen evolution polarization, improved the charging efficiency of Ni electrode, improved the lattice imperfection of Ni hydroxide and made it more beneficial to charge transfer and H+ diffusion processes.
关键词:
Transactions of Nonferrous Metals Society of China
A new process for the hydrometallurgy of refractory gold concentrates was presented. The process comprises grinding-leaching, intensified alkaline leaching (IAL), cyanidation and adsorption. In a stirring-type pulverizing-leaching tower mill, the concentrate is ground to <35. 6 μm of 95. 5 % while simultaneously leached by NaOH of 12 kg/t, then carried out intensified alkaline leaching for 48 h by NaOH of 108 kg/t in enhanced agitation tanks with the pulp concentration of 40% solids at the environmental temperature of 9. 5 &SIM; 13. 5 &DEG;C and the environmental pressure of 10(5) Pa. The oxidation rate of As is 94. 9%, and 47. 6% for S. The total consumption of NaOH is only 20% of that theoretically calculated under the conditions of full oxidation at the same oxidation rates of arsenic to arsenate and sulfur to sulfate. The gold leaching rate by NaCN in 24 h is increased from 9. 2% before pretreatment to 94. 2%. The consumption of NaCN is 7. 5 kg/t, which is one times less than that before pretreatment. The extraction cost of gold is about 422 Yuan/t.
关键词:
refractory gold concentrates;grinding-leaching;intensified alkaline;leaching (IAL);pretreatment;common temperature and pressure
