At present, according to the complexity of ore composition and the difficulty of beneficiation, gold ore can be roughly divided into lean sulfide ore, high sulfide gold ore, polymetallic sulfide gold ore, gold copper ore, telluride gold ore and gold-bearing oxide ores. Different types of gold ores have different beneficiation methods due to their different properties. Next, I will take you to understand the ore characteristics of various types of gold ore and the commonly used beneficiation methods.
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The material composition of this kind of ore is relatively simple, and most of them are quartz vein type or hydrothermal alteration type. Pyrite is the main sulfide but its content is small, and it is occasionally accompanied by minerals such as copper, lead, zinc, tungsten, aluminum, etc. Gold minerals are mainly natural gold, and other minerals have no recovery value or can only be recovered as by-products.
Lean sulfide ores can be sorted by simpler gold mineral processing techniques, such as coarse-grained gold recovered by gravity separation. Fine-grained gold is generally recovered by flotation, and the flotation concentrate is then treated by cyanidation. The extremely fine-grained lean ore is recovered by the full-slime cyanidation method.
This type of ore contains a lot of pyrite or arsenopyrite, and they are also recycled objects like gold. The grade of gold is on the low side with little change, and the natural gold particles are relatively small and mostly wrapped in pyrite. It is generally relatively simple to separate gold and sulfides by flotation; but to separate gold and sulfides requires a simple combined process of separation and smelting, otherwise the recovery index of gold is not high.
This type of ore is characterized by high sulfide content. Besides gold, the ore also contains copper, lead, zinc, silver, tungsten, antimony and other metal minerals, and the latter often has the value of separate mining and recovery. The variation range of gold particle size is large, and the distribution in the ore is particularly uneven. In addition to being closely related to pyrite, natural gold also closely coexists with minerals such as copper, lead, zinc, silver, tungsten, and antimony. There are many types of metal minerals that need to be comprehensively recovered.
For the selection of this type of gold-bearing ore, it is necessary to first determine its ore type. Then determine the specific beneficiation method according to the difference of its metal minerals and gangue minerals. For example, for gold-bearing copper-iron ores, the main metallic minerals are chalcopyrite and magnetite. Natural gold occurs in chalcopyrite in the form of fine particles, which can be separated by flotation-magnetic separation combined beneficiation process to obtain two products, namely gold-bearing copper concentrate and iron concentrate.
The difference between this type of ore and the gold-bearing copper sulfide ore in the polymetallic sulfide gold-bearing ore is that the grade of gold is lower, but gold is the main comprehensive recovery element. The particle size of gold minerals is medium, and the symbiosis relationship with copper minerals is complicated. Flotation + flotation concentrate fire treatment can be used for separation, that is, the copper-gold concentrate is first obtained by flotation, and then the copper-gold concentrate obtained by flotation is separated. The ore is sent to the smelter for smelting, and gold is recovered during the smelting process.
Gold-bearing minerals are still dominated by natural gold, but a considerable part of gold occurs in gold telluride. From the perspective of origin, these ores are mostly low-temperature hydrothermal deposits, and the gangue minerals mainly include quartz, chalcedony quartz and carbonate minerals.
Such gold-bearing ores are often recovered by flotation. Due to the brittleness of gold telluride minerals, it is easy to muddy in the grinding process, which brings difficulties to the flotation of gold telluride minerals. Therefore, when dealing with telluride-containing gold ores, the process of stage grinding and stage flotation is often used.
The main metal mineral of this kind of mineral is limonite, which contains no or little sulfide. However, it contains stable secondary minerals such as gold-bearing iron hydroxide or iron hydrous oxide and some quartz. This is the main feature of the mineral composition of this type of ore. Most of the gold occurs in the main gangue minerals and weathered metal oxide fissures. The particle size of gold varies greatly, and the mineral composition is relatively simple. The separation methods are mainly gravity separation and cyanidation.
For partially oxidized ores, gravity separation + cyanidation method is often used for separation. For all oxidized ores, coarse-grained gold is recovered by gravity separation, ore slime is separated by stirring cyanide, and ore sand is separated by percolation cyanide.
Gold ore resources are very precious. In order to select ores more reasonably, gold mineral processing techniques are very important. If you want to extract gold from gold ore in a more economical and environmentally friendly way, you should first conduct a beneficiation test, comprehensively analyze the properties of the ore, and obtain a scientific beneficiation test report to determine which gold mineral processing technique to use. After comprehensive consideration of the actual situation of the gold ore concentrator, investment and other factors, the beneficiation plan is determined to achieve an ideal return on investment.