Gold Mine Ore Processing Equipment Introduction
The current mainstream gold selection process: generally involves crushing with a crusher, followed by grinding in a ball mill, then extracting concentrate and tailings through gravity separation and flotation. The concentrate is then processed chemically, and finally, through smelting, the product becomes finished gold.
Gold selection process: Crushing and Grinding
We primarily use jaw crushers for coarse crushing, cone crushers for medium crushing, and short-head cone crushers and roll crushers for fine crushing. Most medium and small gold selection plants employ two-stage closed-circuit crushing, while large gold selection plants use a three-stage closed-circuit crushing process. To enhance production and equipment utilization rates, mining plants generally adhere to the principle of more crushing and less grinding, reducing the particle size of the ore fed into the mill.
Gold Selection Process Detailed Explanation
Gold ore flotation equipment
Pulse gold mines commonly use flotation for ore separation. Currently, in China, the most commonly used flotation machines in gold ore processing plants are domestically produced mechanical agitation flotation machines.
Flotation equipment primarily consists of flotation machines and other devices necessary for the flotation process. The pulp is agitated and aerated, causing mineral particles to adhere to bubbles under the influence of various flotation agents. As the bubbles rise, they form a mineralized foam layer, which is then scraped out or overflowed. This entire flotation process is carried out within the flotation machine. Flotation machines are typically made up of a series of interconnected compartments.
In most cases, flotation is used to process gold-bearing sulfide ores with high recoverability, yielding significant results. Not only can gold be maximally enriched in the sulfide concentrate, but also the tailings can be discarded, making the beneficiation cost low. Flotation is also employed for processing gold-bearing polymetallic ores, such as gold-copper, gold-lead, gold-antimony, and gold-copper-lead-zinc-sulfur ores. For these ores, the use of flotation effectively identifies and selects various gold sulfide concentrates, benefiting the comprehensive recovery of mineral resources. Additionally, for so-called "difficult-to-solve ores" that cannot be processed directly with amalgamation or cyanidation methods, a combined process including flotation is required. Of course, flotation has its limitations; for ores with coarse grain distribution and gold particles larger than 0.2 millimeters, or quartz-bearing gold ores without sulfides, it is difficult to obtain stable flotation froth after slurry preparation, making the application of flotation challenging.
Section 2: Gold Ore Dressing Equipment
The sand gold mine typically utilizes gravity separation for beneficiation. The main equipment for gravity separation of gold includes various forms of sluice boxes, shaking tables, and jigging machines.
1. Jigging gold separation method
The Jigging Gold Separation Method is a gold separation process using a jigging machine as the equipment. Jigging machines are commonly used gravity separation equipment, with many types available.
As the eccentric drive mechanism drives the diaphragm to reciprocate, the water in the jigging chamber passes through the screen to create a vertically alternating pulsating water flow. The selected material is delivered to the surface of the bed, forming a particle system with the bed ore and water. When the water flow rises, the particles are in a loose suspension state, at which point particles of different sizes and weights settle at different speeds; larger, denser coarse particles (bedstones) settle at the bottom. When the water flow descends, it generates an intake effect, allowing denser, smaller particle sizes to pass through the bed gaps and settle at the lower level.
2. Jigging gold extraction method
The Shaking Table Gold Separation Method is a gold separation process primarily using the shaking table as the main equipment. The shaking table is a mineral separation device operating in a horizontal medium flow, consisting of two parts: the bed surface and the drive mechanism (refer to the illustration below). The bed surface is driven to perform longitudinal reciprocating motion by the drive mechanism. The separation of minerals on the shaking table is gradually completed during the reciprocating motion of the bed surface. Factors promoting the movement of mineral particles, in addition to their own gravity, are mainly the flushing flow and the differential motion of the bed surface. The movement of mineral particles experiences stratification action perpendicular to the bed surface and separation action parallel to the bed surface. The results of these two actions lead to the discharge of different mineral particles from different intervals on the bed surface. Depending on the selected particle size of the ore, shaking tables can be categorized into three types: coarse sand beds (>0.5 mm), fine sand beds (0.5-0.074 mm), and mud beds (0.074-0.037 mm).
3. Sluice Box Gold Separation Method
The Sluice Box Method is an ancient and still-used gravity separation technique. The primary equipment for sluice box gold separation is the sluice box itself. A sluice box is a narrow, elongated inclined trough made of wood (or steel), with an inclination angle of 3° to 4° (not exceeding 14° to 16°). The gold industry can manufacture it locally. The separation principle is: after the pulp is fed into the sluice box at the head, under the combined forces of water flow, gravity of mineral particles (or centrifugal force), and friction between the mineral particles and the bottom of the trough, particles of different densities are loosely layered and separated. The denser particles settle at the bottom as concentrate, while the less dense ones become tailings. The sluice box operates intermittently; when the concentrate at the bottom accumulates to a certain height, mining is stopped, and the concentrate is cleared out.
Chute separators come in two types: coarse sand chutes and slurry chutes. The former is suitable for handling coarse-grained materials, while the latter is ideal for fine-grained materials.
Coarse grain溜槽 is the main equipment for gold sand ore beneficiation, widely used both on land and on gold mining vessels. The large溜槽 on land typically measures around 15 meters, while those on gold mining vessels usually range from 4 to 6 meters.
4. Spiral Concentrator Gold Separation Method
The Spiral Gravity Concentrator gold selection method is a gold recovery process utilizing the spiral concentrator as the main equipment. The spiral concentrator is a sloping chute type mineral separator that uses a combination of gravity, friction, centrifugal force, and water flow to separate ore particles based on specific gravity, particle size, and shape (as shown on the left in the figure below). Its characteristic is that the entire chute is curved into a spiral shape in the vertical direction. The separation process is as follows: the ore slurry fed from the top of the chute flows downward in a spiral line. During the flow, the ore particles are stratified. Large particles with low density are distributed at the outer edge of the spiral channel, while fine particles with high density are distributed at the inner edge of the spiral channel (as shown on the right in the figure below). After stratification, the heavy concentrate is discharged through the discharge outlet at the bottom of the inner slot by the cutter, and the light concentrate is discharged from the end of the spiral channel.
The spiral concentrator has a simple structure, is easy to manufacture, has no transmission mechanism, and does not require power; however, its disadvantage is that it performs poorly in separating materials above 6 mm and below 0.05 mm, as well as materials containing flat-vein stones. It is widely used internationally for separating sand gold ore.
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