(1. 中南大学 资源加工与生物工程学院，长沙 410083；2. 湖南辰州矿业股份有限公司，怀化 419607)
摘 要: 采用热力学计算及交流阻抗和循环伏安等电化学方法研究石灰和氢氧化钠对黄铁矿浮选抑制行为的影响。单矿物浮选试验结果表明：当pH值为7.0~11.5时，石灰对黄铁矿的抑制作用强于氢氧化钠；当pH>11.5时，石灰和氢氧化钠均对黄铁矿表现出强烈的抑制作用。热力学计算和电化学测试结果表明：黄铁矿表面法拉第反应电阻Rp随pH值的升高而减小，利于黄铁矿表面的电子传递，从而使得黄铁矿表面更易于氧化，导致Fe(OH)3和SO42−等亲水性物质的生成；在碱性条件下，黄铁矿表面电阻Rs增大，说明其表面覆盖不良导电物质；在石灰体系中，同时存在钙膜的影响，使得Rs增加的幅度比在氢氧化钠体系中的大，该结果与浮选试验结果一致。
关键字: 黄铁矿；石灰；氢氧化钠；浮选；交流阻抗；循环伏安
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
