Abstract
The difficulties associated with the hydrometallurgical processing of refractory ores and some methods of their solution are discussed in the article. Difficulties associated with leaching of goldcopper ores are characterized. Gold and copper content is 0.5 ppm and 0.37 % respectively in the primary ores of the Malmyzh deposit. The ore is characterized as low grade. The geotechnology method of heap leaching is feasible for low grade ores processing. The characteristics of ore material favorable for heap leaching are listed in the paper. The current trends in ore preparation for heap leaching are briefly described. Hydrodynamic parameters of spraying are one of the important aspects influencing the process result. The hydrodynamic regimes implemented in the processes of heap leaching are listed and methods for determining the rational irrigation regime and the method of feeding the solution are given. Technological studies are required for any type of ore to assess the feasibility of heap leaching. Typically, technological studies begin with laboratory stage, then large-scale research are performed and the pilot-plant tests allows assessing the feasibility of the technology on the industrial scale. In this study, laboratory scale column leaching research were carried out. A method of activation chloride leaching with sulfuric acid-peroxide pre-oxidation was developed and tested. The leaching solutions were activated by the method of electro-photo-chemical activation with sequential electrolysis and ultraviolet irradiation. As a result of the experiment, 68-80% copper recovery was achieved.
Highlights
The technology for the extraction of precious metals from ores is based on the cyanide process; up to 90% of gold and a significant amount of silver are extracted by cyanide leaching
Laboratory column leaching of silver, gold and copper from the diorite-porphyrite type of primary ore of Malmyzh deposit was carried out on small-scale samples
The use of standard cyanide leaching of gold-copper ores is associated with a number of difficulties, including the high cyanide consumption for the formation of copper-cyanide complexes
Summary
The technology for the extraction of precious metals from ores is based on the cyanide process; up to 90% of gold and a significant amount of silver are extracted by cyanide leaching. Category of refractory ores is presented by ores not amenable for cyanidation; cyanidation is either ineffective or characterized by low rates of metal recovery [1]. Refractory ores contain the gold not amenable to simple cyanidation alone, and low recoveries have resulted from metallurgical testwork. Common occurence is where the surface ore body is well oxidized and non-refractory and frequently overlays large tonnages of non-oxidized refractory ore. In these cases, the initial metallurgical operation will be conventional, with an ‘add-on’ refractory treatment process at a later stage [2]. Roasting and pressure oxidation are the most commonly used types of preparation of refractory mineral raw materials for hydrometallurgical processing. In one of the leading research institutes of the Russian Federation, it is proposed to use ultrafine grinding to increase the efficiency of liberation of refractory geo-material [3]
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