Roasting Preprocessing Of High Arsenic High Sulfur Gold Concentrate And Thiourea-Leaching Processes Research

Along with the gold ore resources which easy to process dry up day after day, the development and utilization of the refractory gold ores with high-sulfur and high arsenic content by the world-wide attention. The development and utilization of this kind of gold mineral resources is of far-reaching significance in our country. Choice and application of pretreatment is the key to the development of such ores, the application of the leaching process will be directly related to the gold leaching rate, the production cost, the environmental protection and many other factors.The sample of this research choose from Jin Chiling gold mine, selects the roasting oxidation process as the pretreatment method,and the acidic thiourea leaching process conditions and mechanism of leaching gold studied.The experiment first inspected the different roasting way, the roasting temperature, the roasting time to the influence of As, S removing rate and the effects of silver and gold leaching rate, had determined the roasting pretreatment's best technological conditions are:Two section of roasting ways, the first section in 700℃under seals up the roasting, the second section in 750℃under ventilates the roasting, two section of roasting time are 45min;Then, the test also from grinding granularity, the amount of thiourea, leaching pH, leaching temperature, leaching time, the amount of ferric and whether to ventilate and other aspects of thiourea leaching of the factors, makes a comparative study of determined thiourea leaching process, the best processing parameters and trying to dissolve gold from thiourea thermodynamics and kinetics perspective thiourea leaching of gold and silver, principle and the stability of thiourea influence. Test the best gold leaching process were:roasting sand 20min fine grind to-400 mesh content above 99%, the amount of thiourea 2%, pH 0.5, leaching temperature 30℃, leaching time 4h, ferric addition amount 1%, ventilation mixing leaching.Leaching dregs the expensive fluid use the ICP-AES for element analysis. Calculated the leaching rate of gold and silver by determining the grade of gold and silver from leaching dregs. According to the best roasting and leaching process determine the leaching rate of gold and silver are 92.52% and 94.36%.