铜矿浸出热力学分析

Thermodynamics and Electrochemistry Analysis of Copper Mineral Leaching

矿物浸出过程中的热力学研究,可以揭示浸出过程中反应热变化规律、反应进行的可行性以及反应自动进行的条件.针对铜矿主要矿物浸出过程中的基本反应,收集了反应中化合物的热力学数据,采用热力学焓变、反应吉布斯自由能以及电位E-pH方程,分别对氧化矿、硫化矿及其与不同氧化剂作用时的焓变值、反应吉布斯自由能进行计算,并着重分析了温度对焓变值、自由能的影响程度,最后绘制了各矿物电位E对比图.研究表明,硫化矿反应热较氧化矿的大,硫化矿在细菌直接作用下放出大量的热量,而在间接作用下甚至有吸热现象,但对温度变化比较敏感;同一种硫化矿物与O2作用时的自由能值较低,这说明硫化矿在细菌作用时起主导地位的是直接作用,但温度越高,反应的热力学趋势变小;当矿物与O2作用时,电位范围在201～366 mV之间,与Fe2(SO4)3作用时,电位范围在479～828 mV之间,用O2作为氧化剂要优于用Fe2(SO4)3.

In the paper, the thermodynamics of bioleaching of minerals were studied for elucidating the rules of reaction probability, feasibility and heat changing during bioleaching. Aimed at the primitive reactions in leaching process of principal minerals in copper ore, by collecting thermodynamics data of compounds in reactions, adopting the analyzing method about thermodynamics parameters, such as enthalpy, Gibbs free energy and E-pH chart, the reacting enthalpy, Gibbs free energy of oxide minerals and sulpfide minerals acting with different oxidant are calculated separately. Influence of temperature on these parameters are analyzed emphatically. The diagram of minerals electric potential is ploted finally. It is indicted that the quantity of reaction heat of sulpfide ores is higher than that of oxide ore, sulpfide ore emit more heat under bacterial direct action, but absorb heat and sense to temperature under bacterial indirect action. The Gibbs free energy of sulpfide mineral reacting with H2SO4 or O2 is lower. It shows that bacterial direct action plays dominant role in the reaction, The higher temperature, the smaller thermodynamics aptitude is. The electric potential is in the range of 201mV to 366 mV under the mineral reacting with H2SO4 or O2, and 479 to 828 mV reacting with Fe2 （SO4）3 ,so O2 is excellent oxidant over Fe2 （SO4）3.