Process for extracting gold by modified pressure oxidation-cyaniding

Abstract

The invention discloses a process for extracting gold by modified pressure oxidation-cyaniding. The pressure oxidation technology and alkali silicon dissolving technology are organically combined and a technological scheme of mixed medicament of NaOH and Na2CO3 is adopted to process Carlin dipped-type obstinate gold-containing ore, and the pressure oxidation process is adopted, thus sulphide mineral can be fully oxidized and decomposed and gold wrapped in the ore can be fully exposed and dissociated; under the conditions of higher temperature and higher pressure, NaOH reacts with SiO2 to effectively decompose gangue, thus gold wrapped in the ore is fully exposed and dissociated; wraps of the sulphide mineral and gangue are opened, and harmful elements enter into a liquid phase in a soluble salt form, thus secondary wrapping to gold is avoided; and most harmful substances such as sulphur and arsenic are oxidized and then enter into the liquid phase to be neutralized and recycled. By applying the process disclosed by the invention, the gold leaching rate is improved to 96.5% from 5% of the conventional process, thus the gold leaching rate is obviously improved; and the pollution to the environment is greatly reduced.

Description

technical field [0001] The invention relates to a gold extraction process for refractory gold-bearing ores, in particular to a modified pressure oxidation-cyanidation gold extraction process. Background technique [0002] With the rapid development of the gold industry, the easy-to-handle gold ore resources are decreasing and exhausted, and the difficult-to-handle gold ore resources have become the main raw materials for the gold industry in the future. The rational, efficient and environmentally friendly development of refractory gold resources has become the main technical problem currently faced by all gold-producing countries in the world. The development and utilization of refractory gold resources in foreign advanced countries has accounted for a considerable proportion, while my country is far behind. One of the important reasons is that the development and industrial application of refractory gold ore dressing and smelting technology is relatively low. [0003] The...

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Problems solved by technology

However, as countries pay more and more attention to environmental protection requirements, the use of traditional roasting technology to process this part of gold resources will inevitably produce harmful flue gases such as sulfur dioxide, arsenic oxide, and mercury vapor. The flue gas treatment and dust collection system Complex and high investment; at the same time, due to the need for high roasting temperature, some low-melting point oxides contained in the material will cause secondary wrapping of gold during the roasting process, reducing the recovery rate of gold, so its application range is limited; The biological oxidation pretreatment process has been applied rapidly in recent years. Due to the strict requirements of the bacteria species on their living environment, the reaction conditions need to be strictly controlled. At the same time, the production cycle of biological oxidation is long, and the total recovery rate of gold is relatively low. Popularization and application have been affected; the pressure oxidation method is one of the methods that were applied earlier and faster in foreign countries. It is the main production method for metals such as nickel, copper, cobalt and alumina, and is also used in gold production.

In the domestic gold production industry, due to the strict requirements of the pressure equipment used and the influence of large infrastructure investment and other conditions, there is no promotion and production application. Alkaline pressure oxidation-cyanide gold extraction process has not yet been adopted in gold production.

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