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Five Easy Ways to Extract Gold from Gold Ore

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Different gold extraction processes are adopted for different gold ore types. Five simple methods for extracting gold from gold ore include gravity separation, flotation, heap leaching, cyanidation, amalgamation and gold extraction. Domestic gold dressing and smelting processes include single gravity separation, single flotation, gravity separation-flotation, amalgamation-flotation, all-slime cyanidation-zinc powder replacement, all-slime cyanide carbon slurry, all-slime cyanide resin Gold extraction process, flotation + cyanidation of gold concentrate, heap leaching process, etc. According to the needs, a combined process can be used, such as gravity separation-flotation, flotation-cyanidation (cyanidation of concentrate or tailings), cyanide-flotation and gravity separation (flotation)-carbon leaching process, etc. Applications in mines.

I. Gold ore extraction gold amalgamation method

The amalgamation method can be divided into internal amalgamation and external amalgamation according to its production method. In placer gold mines, amalgamation is commonly used to separate gold and heavy sand minerals; in vein gold mines, amalgamation is usually used as a part of the combined process to cooperate with flotation, gravity separation, cyanidation, etc., and is mainly used to promote the collection of coarse grains. body gold.

This method has its special features in recovering dissociated monomer natural gold (especially coarse-grained gold). It is based on the selective wetting of gold particles in the slurry by liquid metal, which separates them from other metal minerals and gangues, recovers them in the form of mercury and separates them by distillation to obtain gold. The advantage is that the gold extraction process is simple, the cost is low, and the loss of gold in the tailings can be reduced.

 

Internal amalgamation is carried out in the amalgamation cylinder or grinding machine, which can better control mercury pollution.

The main equipment for external amalgamation is the amalgamation plate, which consists of three parts: the bracket, the bed surface, and the amalgamation plate. Mercury plates are made of red copper plates, silver-plated copper plates, mercury plates, etc. Silver-plated copper plates have the best amalgamation effect. For the convenience of silver plating and production replacement, electrolytic copper plates are often cut into small pieces with a width of 400-600 mm and a length of 800-1,200 mm. The determination of the area of the mercury plate is related to the amount of ore to be processed, the nature of the ore and the role of the amalgamation operation in the gold beneficiation process. Usually, under the condition that the slurry flow depth on the mercury plate is 5-8 mm and the flow velocity is 0.5-0.7 m/s, the mercury plate area required to process one ton of ore is 0.05-0.5 square meters per ton•day. If the amalgamation is only for collecting large particles of free gold, and the tailings still need flotation, gravity separation and cyanidation, the official quota can be set at 0.1-0.2 square meters per ton. day.

1. Internal amalgamation method

The internal amalgamation method refers to the method in which the ore is crushed and the amalgamation is amalgamated to extract gold at the same time in the grinding equipment. Grinding equipment is usually a rolling machine, a pounding machine, a mixing drum or a special small ball mill, rod mill, etc.

The process of extracting gold by the internal amalgamation method is: when adding ore during the grinding process, mercury liquid is added, and the ore is mixed with mercury at the same time as the ore is ground, and the newly exposed gold particles will come into contact with mercury and be mercuryized. After internal amalgamation, the pulp and amalgam are discharged from the internal amalgamation equipment, and then the amalgam is separated by traps, chutes, and classifiers.

The main disadvantage of the internal amalgamation method is the pulverization of mercury. When the ore is crushed, the mercury is broken into fine particles. These particles are wrapped and covered by oxide films of base metals, lubricating oil films and slime particles, thus losing the ability to combine with each other and causing pulverization. Mercury fines are difficult to separate from the ore being processed and most of the mercury fines will be lost, along with some gold.

When the content of copper, lead and zinc minerals in the gold-bearing ore is very small, and does not contain sulfides that are easy to pulverize mercury in large quantities, and the particle size of the gold embedding is large, the internal amalgamation method is often used. Placer gold mines also use internal amalgamation to separate gold from other heavy minerals.

2. External amalgamation method

The external amalgamation method refers to the method of amalgamation and gold extraction carried out outside the grinding equipment.

Amalgamation plates are commonly used for gold extraction by external amalgamation. There are fixed type and vibrating type for amalgamation plates. The fixed amalgamation plate is divided into three types: flat type, stepped type and type with intermediate trapping ditch. At present, fixed plane amalgamation plates are mostly used in our country. The flat fixed amalgamation plate consists of three parts: the bracket, the bed surface and the mercury plate. The structure is shown in the figure below. The bracket and the bed surface can be made of wood or steel, and the bed surface must not leak the pulp. The mercury plates on the bed are silver-plated copper plates, 3-5 mm thick, 400-600 mm wide, and 800-1000 mm long. The mercury plates are connected to the bed one by one according to the inclination direction of the support.

The operation process of gold extraction by external amalgamation method is: the mercury solution is applied on the silver plated surface of the mercury plate, and the ore slurry flows through the plate surface, and then contacts with mercury. Mercury is then added to the slurry after the operation has started. After the amalgamation operation has been carried out for a period of time, a layer of amalgam paste is conveniently left on the mercury surface, which should be scraped off in time.

The external amalgamation method is suitable for processing gold-bearing polymetallic ores, and is mainly used to capture coarse-grained gold. In the gold beneficiation plant, the amalgamation plate is mostly installed at the ore discharge port of the ball mill to capture the coarse free gold in the grinding product.

II. Gold ore extraction gold gravity separation method

Gravity separation is an ancient method of extracting gold from gold ore, and it was used in gold beneficiation production earlier. It is a main gold beneficiation method. In placer gold ore, gold usually exists in the form of natural natural gold, and its density is generally different from that of gangue. Therefore, gravity separation is the main, effective and economical method for separating placer gold ore. But in vein gold beneficiation plant, gravity separation is seldom used alone, mostly as a part of the joint gold extraction process, generally in the grinding and grading circuit, using jig or spiral chute and shaking table to recover the decomposed gold in advance The separated coarse-grained monomer gold is beneficial to the subsequent flotation or cyanidation operation, and can obtain qualified gold concentrate. This method is more commonly used in small-scale gold mines and local group mining mines, such as Jinchanggouliang and Dashuiqing gold mines in Inner Mongolia. The main equipment for gravity separation of gold is various forms of chute, jig and shaker. In addition to conventional gravity separation equipment, according to the production characteristics of my country's gold mines, on the basis of digesting and absorbing foreign advanced equipment, my country has developed new gravity separation equipment such as belt chutes, Ross chutes, circular jigs, and placer gold centrifugal washing units. The equipment has achieved good results in gold production. For example, in the concentrator of Yinan Gold Mine in Shandong Province, a soft cladding (blanket) chute is installed in the grinding and grading circuit, and the recovery rate of gold can reach 70%. Soft-faced chutes are also used to treat flotation or amalgamated tailings to increase gold recovery.

III. Gold ore extraction gold flotation method

It is mainly used to process finer disseminated vein gold ore. Gold is often floated into copper and lead concentrates, and then gold is extracted from these concentrates. Therefore, it is more economical and reasonable for ores containing ferrous metals in raw materials. It can realize multi-metal comprehensive utilization, but the disadvantage is that the recovery rate of oxidized ore is low, and it is difficult to collect coarse gold particles.

About 80% of rock gold mines in my country use flotation to select gold, and the concentrates produced are mostly sent to non-ferrous smelters for processing. Due to the increasing development of gold extraction by cyanidation and the enterprises to improve economic efficiency and reduce the loss of concentrate transportation, they often adopt on-site treatment (of course, due to the contradiction between dressing and smelting and pricing issues, the mine is forced to deal with it on the spot) It promotes the greater development of flotation technology and occupies a very important position in gold production. There are usually two processes of priority flotation and mixed flotation. Due to new progress in technological process modification and reagent addition system, the flotation recovery rate has also been significantly improved. According to more than 40 gold dressing plants across the country, the survey results of flotation process indicators show that the recovery rate of sulfide ore flotation is 90%, and a few are as high as 95% to 97%; the recovery rate of oxidized ore is about 75%; 85%. In production practice, there are many innovations and scientific research achievements in flotation process, and the effect is obvious. Stage grinding and flotation process, heavy-float joint process, etc. are the main trends in the development of flotation technology in my country at present.

The main equipment of the gold ore flotation method is the flotation machine, and other supporting equipment such as ball mills, dryers, and spiral classifiers are also used. Each equipment has irreplaceable important functions and functions, and is respectively responsible for the selection of gold ore, Grinding, drying, grading and other work. The flotation machine is an indispensable piece of equipment in the flotation method of the gold ore concentrator. The operation investment of the equipment is relatively low, the separation accuracy is high, and there is an automatic electronic control device for the liquid level inside, and the degree of foam refinement is high, which greatly improves The flotation effect is improved, the power consumption is less, the wear is less, and the maintenance and repair are simple and convenient, the processing capacity is large, and the models and specifications are relatively complete. The common flotation machine models on the market mainly include: XJK flotation machine, SF flotation machine machine, JJF type flotation machine, etc.,

 

IV. gold ore extraction gold cyanidation method

The process of gold extraction by cyanidation was gradually perfected. It is to crush and grind the gold-bearing ore and then cyanide leaching. After the ore pulp is fully leached, the activated carbon produced by FKN company is added to absorb the gold. The carbon is desorbed, and the precious liquid is electrolyzed to produce gold powder, which is then smelted into gold ingots. After the desorption carbon is regenerated, it is proportioned to the new carbon and used repeatedly in the process.

 

Cyanide gold extraction method is currently the most widely used beneficiation method for gold ore beneficiation. Common cyanide gold extraction methods include carbon pulp gold extraction, carbon leaching gold extraction, and pool leaching gold extraction.

1. The carbon pulp extraction method (CIL), also known as the all-slime cyanidation method, is a method in which activated carbon is put into cyanide slurry to make the dissolved gold adsorb on the activated carbon, and then extract gold from the activated carbon. CIL is suitable for gold mines with low sulfur silver content and high mud content, and the recovery rate can reach more than 90%. The advantage of using the carbon slurry method to extract gold is that the leaching and adsorption are carried out at the same time, which overcomes the shortcomings of the carbon slurry method. And the area is small, the infrastructure investment is low, and the disadvantages that are difficult to overcome at present are that the consumption of gold-carrying carbon is high, and the amount of gold and silver lost by the wear and tear of gold-carrying carbon is relatively high. Among these four common cyanidation gold extraction processes, carbon The investment of slurry gold extraction method is higher.

2. The carbon leaching gold method (CIP) combines the process of adsorption and extraction on the basis of the carbon slurry method. It is dense before leaching, and carbon is added shortly after the leaching begins, so that leaching and adsorption can be carried out at the same time, and then the loaded gold is Carbon desorption electrolysis. CIP is suitable for ores that are deeply oxidized and do not contain copper, tin and carbonaceous substances. The recovery rate of ore dressing is comparable to that of CIL, and can also reach more than 90%. The cost is slightly lower than that of carbon pulp gold extraction. Carbon leaching The gold method has the advantages of simple technology, convenient operation, recyclable activated carbon, and low consumption. The disadvantages are: the leaching and adsorption processes are separated, so it occupies a large area and requires high infrastructure investment.

3. The pool leaching gold method is suitable for low-grade gold and silver ores and tailings, and gold ores with low clay content. The recovery rate of ore dressing can reach 50%~70%. The cost of the method is slightly lower, and it can improve low-grade gold mines with low economic benefits. It is simple to operate and low in personnel costs. However, the initial construction cost of the pool leaching gold extraction method is relatively high, and the leaching time is relatively long, because it is necessary to build a leaching tank and a barren solution pool to ensure that the pool is not leaky and basically dry. Prepare the leaching solution, pump the leaching solution into the leaching tank for leaching, and release the expensive solution after a period of time for replacement.

Cyanide method is the main method of gold ore dressing at home and abroad, but it takes a long time in the cyanide process, and cyanide is a highly toxic substance. Today, the demand for environmental protection is increasingly strong, and it will bring great benefits to enterprises in tailings cyanide treatment. Comes a huge cost burden.

More and more companies have begun to test and adopt the FKN environmental protection and non-toxic gold extraction agent developed and produced by our company for gold extraction. The environmental protection gold extraction agent produced by our company has the following characteristics:

a. Wide range of application: widely applicable to gold and silver ores, cyanide tailings, roasted gold concentrates, sulfuric acid slag, lead-zinc slag, anode mud, and other gold-containing materials

b.High extraction: up to 99%

c. Non-toxic; safe to use, transport and storage

d. Cost saving

e. High stability

 

V. Gold ore extraction gold heap leaching gold extraction

Gold extraction by heap leaching means that low-grade gold ore or flotation tailings are piled up on the bottom pad material, and the gold and silver in the ore are dissolved out by circulating and spraying sodium cyanide solution. Gold-containing precious liquid is recovered by activated carbon adsorption, zinc replacement precipitation or direct electrolytic deposition, and the tailings after gold extraction are discharged after disinfection.

Gold extraction by heap leaching has the characteristics of simple process, easy operation, less equipment, less power consumption, low investment, quick effect, and low production cost. Heap leaching is used to treat low-grade ore of 0.5-3g/t, and the recovery rate of gold is 50-80%, or even 90%. As a result, heap leaching has enabled the economic recovery of many small gold deposits, low-grade ores, tailings or waste rock that were previously considered to be of no economic value. In my country, the heap leaching method was widely used in industrial production in the 1980s.

The heap leaching gold extraction production process mainly consists of the construction of the heap leaching site, ore pretreatment (crushing or granulation), heap building, spray leaching, recovery of gold in the gold-bearing liquid, disinfection of the waste ore pile, and unloading. Partial composition.

Heap leaching is suitable for processing the following types of mineral resources:

1. Large-scale, low-grade gold and silver mines that were considered unusable in the past;

2. Low-grade gold-bearing "waste rock" stripped during mining;

3. Medium and low-grade gold-bearing ores excavated in geological pit exploration and mine excavation;

4. The grade of gold content is slightly higher, but the scale is small, so it is not suitable to build gold and silver mines with mechanized concentrators;

5. Adopt conventional cyanidation method to treat economically unfavorable gold mines;

6. Gold-bearing smelting slag, high-grade tailings and large gold-bearing waste rock yards.

Through the summary analysis of the above five simple methods of extracting gold from gold ore, major gold ore concentrators can find suitable methods in gold ore separation, realize high-energy separation of concentrates, and increase the recovery rate of ore dressing. As a professional manufacturer of FKN gold ore beneficiation agent and FKN gold extraction activated carbon, our company is committed to providing high-quality products to gold mine customers to ensure the maximum benefit of customers.