(1. 中南大學(xué) 資源加工與生物工程學(xué)院，長沙 410083；2. 湖南辰州礦業(yè)股份有限公司，懷化 419607)
摘 要: 采用熱力學(xué)計(jì)算及交流阻抗和循環(huán)伏安等電化學(xué)方法研究石灰和氫氧化鈉對黃鐵礦浮選抑制行為的影響。單礦物浮選試驗(yàn)結(jié)果表明：當(dāng)pH值為7.0~11.5時，石灰對黃鐵礦的抑制作用強(qiáng)于氫氧化鈉；當(dāng)pH>11.5時，石灰和氫氧化鈉均對黃鐵礦表現(xiàn)出強(qiáng)烈的抑制作用。熱力學(xué)計(jì)算和電化學(xué)測試結(jié)果表明：黃鐵礦表面法拉第反應(yīng)電阻Rp隨pH值的升高而減小，利于黃鐵礦表面的電子傳遞，從而使得黃鐵礦表面更易于氧化，導(dǎo)致Fe(OH)3和SO42−等親水性物質(zhì)的生成；在堿性條件下，黃鐵礦表面電阻Rs增大，說明其表面覆蓋不良導(dǎo)電物質(zhì)；在石灰體系中，同時存在鈣膜的影響，使得Rs增加的幅度比在氫氧化鈉體系中的大，該結(jié)果與浮選試驗(yàn)結(jié)果一致。
關(guān)鍵字: 黃鐵礦；石灰；氫氧化鈉；浮選；交流阻抗；循環(huán)伏安
lime and sodium hydroxide as depressantors
（1. School of Resources Processing and Bioengineering, Central South University, Changsha 410083, China;
2. Hunan Chenzhou Mining Co., Ltd., Huaihua 419607, China）
Abstract:Thermodynamic calculations, alternating current impedance and cyclic voltammetry were adopted to study the flotation behaviors of lime and sodium hydroxide on the pyrite. Single mineral flotation test results show that lime depresses pyrite more strongly than sodium hydroxide when pH is in the range of 7.0−11.5; at pH> 11.5, lime and sodium hydroxide depress pyrite intensely. By thermodynamic calculations and electrochemical tests, the Faraday resistance Rp of pyrite surface is declined by increasing pH, which is helpful for the electron transfer and oxidation on the surface of pyrite, resulting in producing hydrophilic substance, such as Fe(OH)3 and SO42−. Under alkaline conditions, the surface resistance Rs of pyrite increases, and unconductive material appears on its surface. The increment of Rs in lime system is larger than that in sodium hydroxide system for the adsorption of calcium membrane on the surface of pyrite, which is the reason why lime has stronger depression effect on the pyrite flotation than sodium hydroxide.
Key words: pyrite; lime; sodium hydroxide; flotation; alternating current impedance; cyclic voltammetry
