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Associated gold in polymetallic ores often contains minerals such as arsenic and carbon, which have a certain impact on the flotation of gold ores. The beneficiation methods include cyanide leaching, flotation separation, gravity separation and so on. In this article, we will answer three questions one by one: how to deal with gold-bearing sulfide ores, how to deal with arsenic-containing gold ores, and how to deal with organic carbon-bearing gold ores.
Use the table of contents below to navigate through the guide:
Flotation separation process is the main process for treating gold-bearing sulfide ores. The main feature of this type of gold ore is that it often contains gold, silver, lead, sulfur and other minerals. Metal minerals include pyrite, sphalerite, galena, chalcopyrite, etc. Gangue minerals are mainly quartz, and also include calcite, barite and other minerals. Gold minerals and sulfide minerals have similar flotation properties, especially similar to copper sulfide minerals, so the flotation process of gold ore is similar to that of copper sulfide.
Collectors used in gold ore flotation include xanthate, black powder, ammonium black powder, etc. Usually, there are two ways of using one type alone or combining several collectors. Commonly used foaming agents include pine alcohol oil, ten alcohol oil, 730 series foaming agents, etc. Inhibitors include lime, sodium sulfide, dichromate, etc. The composition of the agent is selected according to the specific properties of the ore.
Due to the complex distribution of such minerals, it is necessary to control the appropriate grinding fineness. In the process of determining the grinding fineness and chemical system, the beneficiation test is particularly important.
Arsenic not only has a great impact on the quality of gold concentrate, but also pollutes the environment. Arsenic in gold ore generally exists in the gangue mineral arsenopyrite, and most of them are closely embedded with gold minerals, so it is difficult to separate.
Among the methods for reducing the content of arsenic in concentrates, soda method, lime method, oxidation method and so on are commonly used. Oxidation method is one of the most effective and widely used methods. The main principle of this method is to use an oxidant to increase the free oxygen content in the aqueous solution to oxidize the surface of the arsenic minerals, thereby obtaining the effect of inhibiting the arsenic minerals.
On the basis of suppressing arsenic, the content of free oxygen in water can be increased and the buoyancy of arsenic minerals can be reduced by means of adjusting pH value and temperature, so that the arsenic content in gold concentrate can be reduced. Generally, arsenic minerals have better floatability under weakly acidic conditions, but under neutral and weakly alkaline conditions, the floatability of arsenic minerals decreases, and gold minerals still have better floatability under these conditions. Usually, the pH value is about 8 as the pH value condition for flotation of arsenic-containing gold ore.
For different arsenic-containing gold ores, the specific oxidant, pH value, and temperature range are different. It is a more scientific and reasonable method to determine the appropriate conditions and factors by using mineral processing tests.
Organic carbon minerals in gold ore not only have good buoyancy, but also have strong adsorption force, which not only affects the grade of gold concentrate, but also wastes a lot of flotation reagents. Therefore, it is necessary to reduce the impact of organic carbon on gold ore through decarbonization. The effect of flotation.
Decarburization can be achieved by roasting, adding chemicals and other methods. Roasting is mainly aimed at gold ores with high carbon content. For gold mines with relatively low carbon content, water glass, No. 2 oil, and kerosene can be used to select carbon first, and CMC can also be added to the slurry to inhibit the floatability of carbon. However, the method of adding inhibitors has a greater impact on the recovery rate of gold ore, so the method of carbon selection can be used to remove organic carbon in gold ore.
These are the common problems and solutions of polymetallic ore gold extraction. Polymetallic ore has a relatively complex ore composition, and the gold mining plant needs to adjust the parameter range determined by the beneficiation test, combined with the production needs of the concentrator, and determine the specific beneficiation schemes for different gold mines, so as to achieve the ideal recovery rate and gold concentrate grade.
