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Gold beneficiation guide

 

Gold mines refer to gold mines or gold ore. Gold mines refer to places where gold ore is obtained through mining operations, and gold ore refers to mineral aggregates that have a certain gold content and can be used by industry. The gold obtained by its selection is a rare, precious and stable metal, and it has always been a symbol of wealth and status.

Placer gold mines and rock gold mines are two types of gold mines that are often processed by concentrators. Among them, placer gold mines are pretreated, deslimed and washed, and then re-selected to obtain gold-bearing coarse gold mines, while rock gold mines are The gold particles are dissociated by crushing and grinding, and then sorting is achieved through a certain gold ore dressing process. The commonly used beneficiation processes in rock gold mines are: single amalgamation process, amalgamation-gravity combined process, gravity separation (mercury amalgamation)-cyanidation combined process, single flotation process, amalgamation-flotation combined process, all mud cyanide Chemical process, flotation-reselection combined process, heap leaching gold extraction, etc.

 

1.Gold beneficiation process

 

(1) Crushing and screening stage

Usually the gold ore content is low, the Khenpo has a fine particle size, and the composition is complex. The commonly used crushing and screening process in the industry is mainly a three-stage one closed-circuit process, that is, the minerals are crushed to the appropriate particle size through coarse crushing, medium crushing, fine crushing, and screening.

 

(2) Grinding stage

The grinding operation of rock gold mine usually adopts one-stage or grid-type ball mill + overflow-type ball mill for two-stage grinding. The second stage of grinding operation and spiral classifier or hydrocyclone form a closed loop to ensure the fineness of grinding. In view of the shortcomings of traditional mills such as fast wear and high energy consumption, large mining machine manufacturers such as Shishi have carried out a series of transformations on the ball mill, such as adopting new wear-resistant rubber liners, changing the rolling bearings to sliding bearings, and making the mill larger. , While improving the operation rate of the mill, it also extends the service life of the equipment and creates economic benefits for the enterprise.

 

(3) The beneficiation stage

The gold ore beneficiation stage is divided into two types, one is the beneficiation of placer gold ore and the other is the beneficiation of rock gold ore. Placer gold mines contain high content of gold concentrate and mostly exist in the form of sand particles. Therefore, the gravity separation process is often used in the separation. After pretreatment, desliming and washing, the gravity separation method can directly obtain coarse gold ore particles .

Rock gold mines mainly choose suitable gold separation processes according to the composition and composition of the ore. The three commonly used gold separation processes are: cyanidation gold separation technology, flotation gold technology, and gravity separation gold technology.

 

2.Gold beneficiation method

 

(1) Cyanide gold selection process

The cyanide gold separation process is one of the main methods for extracting gold from gold ore.

The cyanidation gold selection process can be divided into stirring cyanidation and percolation cyanidation. Stirring cyanidation is used to treat heavy separation and amalgamation of tailings and flotation gold-bearing concentrates, or for all slime cyanidation; and percolation cyanidation is used to treat flotation tailings and low-grade gold-bearing ore Heap leaching and so on.

Stirring cyanidation gold extraction process mainly includes two types of gold extraction process, one is the so-called cyanide-zinc replacement process (CCD method and CCF method) that recovers gold through continuous countercurrent washing and replacement of precipitation with zinc powder (wire); The other is a non-filtering cyanide carbon slurry process (CIP method and CIL method) that uses activated carbon to directly absorb and recover gold from cyanide pulp without filtering and washing.

 

(2) Gold selection process of carbon slurry

The gold selection process by carbon slurry method (CIP method and CIL method) is to put activated carbon into the cyanide slurry, adsorb the dissolved gold on the activated carbon, and then extract gold from the activated carbon, mainly including leaching raw material preparation, stirring leaching and countercurrent Carbon adsorption, gold-loaded carbon desorption, electrowinning electrolysis, smelting ingot making, carbon regeneration and other operations.

 

(3)Percolation cyanide gold separation process

The percolation cyanide method is also one of the cyanide leaching processes. It is based on the cyanide solution penetrating through the ore layer to leaching the gold from the gold-bearing ore. It is suitable for placers and loose porous materials.

The percolation cyanide leaching method has two processes: pool leaching and heap leaching. The cyanide leaching solution is percolated and then treated with activated carbon adsorption or zinc powder (silk) replacement.

 

1.Pool leaching gold selection process

The percolation leaching is generally carried out in the percolation leaching tank, and the leaching tank usually uses a wooden tank, an iron tank tank or a cement tank. The bottom of the pool is horizontal or slightly inclined, round, rectangular or square. The pool is equipped with a false bottom made of a perforated acid-resistant plate, and the false bottom is covered with a filter cloth, and the filter cloth is covered with a grid with wooden or corrosion-resistant metal strips. When leaching, the ore is loaded in the pool, the leaching agent is added to the top of the pool, and the leaching liquid flows out from the lower part of the false bottom. The false bottom is used to filter and support ore.

 

2.Heap leaching gold selection process

Heap leaching is mainly to transfer the mined ore to a pre-prepared storage yard for pile, or directly on the piled waste rock or low-grade ore, spray or infiltrate with the cyanide leaching solution, so that the solution is produced through the ore Infiltration and leaching, the leaching solution is repeatedly circulated, spraying the ore pile repeatedly, and then collecting the leaching solution, and then using activated carbon adsorption or zinc replacement, the lean solution is returned to the heap leaching operation for recycling.

 

(4) Gold beneficiation process with resin pulp

Ion exchange resin is used to adsorb gold from ore pulp. RIP is now mostly used, and RIL is immature. Use anion exchange resin.

Compared with the carbon paste method, the resin method has the advantages of large adsorption capacity, good resin abrasion resistance, no fear of organic contamination, loose desorption conditions, and simple regeneration.

 

(5) Gold flotation process

For the flotation of gold ore containing a single gold mineral, with a relatively uniform particle size and a relatively coarse particle size, a one-stage grinding and flotation process is usually used.

For gold ore with uneven distribution of coarse and fine grains, mercury plates are usually placed in the grinding and classification circuit before flotation or re-selection equipment is used to pre-recover particulate gold. The above two processes are mostly used in gold concentrators.

For gold mines with complex ore properties, the flotation process is also more complicated. For example, the stage grinding stage separation process and the mud sand separation process are all applied in practice.

For the flotation of gold-bearing polymetallic ore, the process is complex and diverse. Gold is usually enriched in a certain mineral concentrate, and gold is sold as an associated mineral.

 

(6) Re-election gold selection process

Gravity separation is one of the commonly used methods for gold ore beneficiation. It mainly uses different proportions of materials and different sedimentation speeds in the medium to carry out layer separation. In placer gold mines, gold mostly exists in the form of single natural gold, which has a large difference in density with gangue. The reselection method is both effective and economical.

There are many kinds of gravity separation methods, such as jig gravity separation, shaking table gravity separation, chute gravity separation, spiral gravity separation, centrifugal gravity separation and wind gravity separation. In gold ore beneficiation, the common gravity separation methods mainly include There are three methods of gold selection by jig, gold selection by shaker and gold selection by chute.

These three gold selection methods are only used for gold ore with monomer dissociation (placer gold ore). For vein gold minerals, the gravity separation process is rarely used alone, and it is generally combined with other processes to form a combined process, such as the heavy-float combined gold extraction process. The heavy selection is used to assist the extraction of gold, and the jigging machine, The spiral chute cooperates with the shaker to first recover the easily dissociated coarse particles of gold, creating better separation conditions for subsequent flotation and cyanidation processes, and ultimately can effectively improve the gold mine index and the total gold recovery rate.

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