摘要
电化学实验的研究结果表明方铅矿在碳酸铵溶液中转化为碳酸铅及元素硫的反应是由若干单元反应串联而成的,反应速度由电化学步骤控制.导致方铅矿阳极钝化的原因是生成的碳酸铅及元素硫复盖了电极表面.电解液中 CO_3^(2-)及 NH_4^+离子浓度的增加都会使反应加速,其中 NH_4^+离子还明显地延缓了电极的钝化,增加了反应量.将电解液 pH 值提高到10.2左右或适当提高温度也可使反应速度增加.
Besed on our previous investigation,further studies of kinetics of conversion of galena to lead carbonate and elementary S in(NH_4)_2CO_3 solutions were conducted using eletrochemical techniques of linear sweep voltammetry and potential step experiments with galena as working electrode. The experimental results show that the conversion of galena consists of a series of ele- mentary reactions.It is inferred that the reaction rate is controlled by chemical reactions. The galena electrode passivation is attributed to the fact that the lead carbonate formed and elementary'S masks the reacting surface. Reaction mechanism was proposed based on the results of electrochmical experiments. Reaction rate is found to increase with the increase in either carbonate or ammonium concen- trations.The latter significantly delay passivation of the galena electrode and thus amount of the reaction increased.Moreover,the reaction proceeds faster at higher temperature.
出处
《化工冶金》
CSCD
北大核心
1992年第2期139-144,共6页
基金
国家自然科学基金资助
