Gravity Separation Method

Overview:
Gravity separation is a traditional method used for the treatment of various ores, particularly effective in dealing with gold dust, sand tin, tungsten, tin, and gold ore. It finds applications in the treatment of rare metals such as niobium, tantalum, titanium, and zirconium. Additionally, it is employed in the sorting of weak magnetic iron ore and manganese ore.

Application:
Gravity separation is suitable for ores with a large density difference between the ore and gangue minerals. It is effective for coarse-grained, medium-grained, and fine-grained ores. However, its efficiency decreases when dealing with fine mineral mud. Modern processing equipment can recycle particles down to 20-30 microns, and centrifugal concentrators can achieve 10-micron separation.

Non-Metallic Mineral Processing:
Gravity separation has been developed for non-metallic mineral processing, including asbestos, diamond, kaolin, apatite, pyrite, and others.

Combined Methods:
In copper, lead, zinc, antimony, and mercury sulfide ore flotation plants, gravity separation is often used in conjunction with other beneficiation processes. It is typically employed as a primary election method for the concentration of coarse-grained materials.

Medium and Process:
Gravity separation requires a certain fluid medium, commonly water, air, or heavy-medium (heavy liquid or dense medium). Minerals are stratified based on their density, size, and shape.

Gravity Separation Process Methods:

1. Classification
2. Heavy media beneficiation
3. Jig beneficiation
4. Shaker dressing
5. Ore chute
6. Spiral concentrator
7. Centrifugal dressing
8. Wind dressing
9. Washing

Basic Principles:

• Settlement of particles and particle swarm theory
• Particle group stratification based on density
• Particle group separation in slope flow

Theoretical Basis:
Gravity separation relies on the relationship between loose and layered particles, aiming to achieve density stratification. The process involves fluid loose particles, resulting in different density (or size) layers. Key principles include settlement theory, density stratification theory, and slope flow separation theory.

Historical Development:

• Jigging process
• Slope flow dressing in the thick layer of water
• Development of flow membrane dressing for sorting micro-fine particles
• Introduction of interlaminar shear repulsion theory in turbulent flow conditions

Exploring Four Gold Ore Gravity Separation Techniques and Equipment.

Gravity separation remains a prevalent method for gold ore beneficiation, offering diverse approaches like jig mineral processing, shaking table mineral processing, chute mineral processing, and spiral chute processing. The choice of mineral processing equipment significantly influences ore types and production costs, requiring adjustments based on ore characteristics to enhance recovery rates. Explore the following sections for an in-depth understanding of these gravity separation methods.

Jig Mineral Processing

Jig mineral processing involves sorting mineral particles by density in water flow. Water flow types include intermittent rising, intermittent falling, and alternating rising and falling, with the latter being the prevailing method. Jig gravity separation comprises moving screen and fixed screen types, the latter further categorized into diaphragm and piston types based on the medium agitation mechanism. Diaphragm jigs are commonly employed in gravity separation processes, especially for ore with unevenly distributed gold particles. Jigs offer advantages such as effective separation, high processing capacity, wide particle size range, compact equipment design, and ease of operation and maintenance.

Shaking Table Mineral Processing

Shaking table mineral processing utilizes horizontal medium flow for beneficiation on an inclined surface. The stratification effect, induced by water flow and shaker vibrations, separates minerals with different densities into layers, facilitating horizontal or vertical movement. Widely used for fine-grained materials, shaking tables boast a high enrichment ratio, directly yielding concentrates and tailings. Pre-classification is essential due to a feeding particle size below 3mm. Shaking tables play a vital role in gold ore beneficiation, refining coarse concentrates after separation by chute or jig, with a recovery rate exceeding 90%.

Chute Mineral Processing

Chute mineral separation relies on the varying movement states of mineral particles in an inclined medium flow. Raw ore, introduced at the chute head with water flow, moves downward along the chute bottom for sorting. This gravity separation method, suitable for ores with a significant density difference, is commonly applied to sort gold, platinum, tin, nickel, and other placers. Chute usage extends to low-grade placer gold ore sorting, with recovery rates reaching 60%-90%. However, labor-intensive sand cleaning in the chute has led to its gradual replacement by jigs and spiral concentrators.

Spiral Concentrator Processing

Spiral concentrators, a form of chute mineral processing equipment, leverage gravity, friction, centrifugal force, and water flow to separate mineral particles based on density, particle size, and shape. Comprising a spiral chute, bracket, interceptor, and water supply pipe, the spiral concentrator’s slurry flows in a spiral shape, facilitating particle stratification and discharge through different outlets. With greater processing capacity than traditional chutes and efficient separation, spiral concentrators find utility in the separation of placer gold ores.

In practical gold ore production, a combination of mineral processing technologies may be necessary, including flotation and cyanidation, to optimize recovery. Choosing the appropriate gold ore beneficiation technology requires careful consideration of ore characteristics and production requirements, ensuring efficient resource utilization and preventing economic losses from impractical beneficiation plans.