| In gold concentrates usually contain a lot of valuable associated elements,such as copper,lead,zinc and so on.In the traditional cyanide-based gold extraction process,in addition to gold and silver,only the copper element through the additional process has been recycled and the use of other associated elements with slag abandoned.This not only caused a waste of resources,and heavy metals in the slag will produce environmental pollution.In order to improve the comprehensive utilization of resources and the sustainable development of the environment,this paper focuses on the development of comprehensive recovery of hydrometallurgical processes for gold concentrates,which is green and efficient.In this paper,according to the actual situation of a gold concentrate in Jilin Province and in combination with the needs of enterprises,we proposed and determined the use of 3YL(the patent reagent of the research group)organic chlorination to leaching the gold,silver,copper,lead and zinc simultaneously,which shortens the original process of the enterprise.Aiming at the problem that silver and zinc leaching rate is not ideal,a secondary leaching process is proposed.The optimum process conditions were determined by experimental study,and the preliminary technical route of multi-metal comprehensive recovery was designed.In this paper,the effects of parameters on the extraction of gold,silver,copper,lead and zinc in the leaching process were studied,and the optimum conditions were determined.The key parameters are: the concentration of 3YL leaching agent 、hydrochloric acid and NaCl,solid-liquid ratio,leaching temperature,leaching time.The results showed that the concentration of 3YL and hydrochloric acid were the important factors affecting the leaching of gold.When 3YL concentration was 1.5 g/L and hydroelectric acid concentration was 1 mol/L,gold could achieve good leachingeffect.The leaching effect of silver is mainly affected by the concentration of 3YL and the temperature,and the increase of temperature can significantly improve the leaching rate of silver.The extraction of copper is greatly affected by the concentration of hydrochloric acid,and almost no leaching of copper at 10-3 mol/L and 10-2 mol/L.But when the concentration of hydrochloric acid increased to 1 mol/L,the copper extraction can reach more than 90%.Lead extraction is mainly affected by hydroelectric acid concentration,NaCl concentration,solid-liquid ratio,by changing the amount of chloride ions in the solution,lead can achieve a better leaching effect.3YL concentration,hydroelectric acid concentration and temperature have a great influence on the leaching effect of zinc.After more than 0.5 h,the leaching time did not significantly affect the leaching rate of each metal.Consider the cost of reagents and easy to operate,the optimum conditions were as follows: 3YL concentration 1.5g/L;hydrochloric acid concentration 1 mol/L;NaCl concentration 8%;solid-liquid ratio(W/V)1:6;leaching temperature was room temperature(25℃);leaching time0.5 h.The effects of 3YL concentration,solid-liquid ratio,NaCl concentration and leaching time on the leaching rate of each metal were investigated by using the first leaching residue as raw material to carry out the second leaching test.As a result of first leaching so that the grade of metal elements decreased,the impact of the parameters on the metal leaching rate was different with the first leaching.In the process of secondary leaching,only the leaching effect of copper was not affected by various factors,the leaching rate was about 50%.Other metal leaching effect was affected by the impact of various factors,especially the lead can still achieve a better leaching effect when the grade was decreased after one leaching.In order to realize the better leaching effect of the poly metal,considering the equipment operation and the cost,determining the secondary leaching conditions were as follows: 3YL concentration 1.5 g/L;solid-liquid ratio(W/V)1:4;NaCl concentration 4%;leaching time 2 h.After two cumulative leaching,the metal leaching rate has a certain increase,and the leaching rates of gold,silver,copper,lead and zinc were 97.36%,77.78%,90.58%,95.21% and 54.63% respectively under the best leaching conditions.The extraction of copper in the leaching solution was carried out by using M5640 as extractant.We explored the effects of the initial pH,extractant concentration,extraction time,extraction phase on copper extraction rate at room temperature.Through the test of following conditions: the initial pH was 2.0,the concentration of extractant was 12%,phase ratio(O/A)was 1:1 and contact time was6 min.Under these conditions,the extraction rate of copper was 98.60%.The effect of sulfuric acid concentration,stripping time and stripping phase on copper stripping rate was investigated with sulfuric acid as stripping agent at room temperature.The suitable conditions of stripping: the sulfuric acid concentration was 3.5 mol/L,the stripping time was 5 min and stripping phase(O/A)was 1:1.At this time,the stripping rate of copper was 96.25%. |
PDF Full Text Request