Crushing gold ore is a very important link in mineral processing, mainly for the following reasons:
1. Demineralization
Gold in many gold mines is often present in hard ores in the form of small inclusions or cleavage gold. It needs to be broken to release the gold from the ores and expose it on the surface to prepare for subsequent mineral processing.
2. Control appropriate granularity
Different mineral processing has different requirements for ore particle size. Different gravity separation equipment can handle different maximum particle sizes. For example, shaking table generally requires mineral particle size to be below 2mm, flotation treatment feed requires fine-grained materials, and direct leaching process has stricter particle size requirements. Therefore, it is necessary to control the appropriate feed particle size through crushing.
3. Increase mineralization
Crushing can increase the contact area between ore and mineral processing agents or leaching agents, thereby increasing the degree of mineralization and facilitating subsequent enrichment or leaching for gold extraction.
4. Reduce subsequent energy consumption
Proper crushing of ore can reduce the power consumption required for subsequent grinding and other energy-intensive links.
So under what circumstances do gold mines need crushing?
1. Do rock gold mines have to be crushed?
For rock gold mines, crushing is usually required.
Most of the gold in rock gold mines exists in hard ores such as quartzite and slate in the form of cleavage gold (free gold) and finely wrapped gold. Crushing releases the gold from the ore, exposing cleaved gold particles. At the same time, commonly used gravity separation, flotation and other equipment have certain requirements for the ore particle size, and the ore particle size needs to be within a reasonable range. Through crushing, the whole ore can be broken into smaller particles, increasing the surface area of minerals and ores, which is beneficial to the full mineralization and gold enrichment of the subsequent mineral processing process.
Usually it needs to go through several levels of crushing, including primary crushing, medium crushing, fine crushing, etc. Design a reasonable crushing method and target particle size according to the specific ore properties and mineral processing process to achieve the best results. Therefore, crushing is an important process for beneficiation of rock gold ores.
2. Under what circumstances does Alluvial gold need to be crushed?
For alluvial gold, whether it needs to be crushed mainly depends on the existence state of gold and the properties of the ore.
When the gold in alluvial gold exists as free individuals, it generally does not need to be broken, and a very good recycling effect can be obtained by simple re-selection.
If the occurrence state of alluvial gold is more complicated, for example, part of the gold is wrapped in hard rock particles, or is associated with hard pyrite, galena and other minerals, then the ore needs to be crushed first. Crushing can release gold from the rock, and also reduce the particle size of gold-associated minerals, exposing more free gold area to facilitate subsequent mineral processing.
Another situation is that there is a lot of slime in the ore. Sometimes there will be clay ore larger than 100mm. This part of the ore is not broken and will be discharged with the gravel during screening, reducing the gold recovery rate. At the same time, for small-grained ores, the slime will be tightly wrapped on the surface of gold particles or ores, interfering with the subsequent mineral processing process. Crushing can separate the slime from the ore particles, expose the gold particles, and create favorable conditions for mineral processing. Therefore, it is very necessary to appropriately crush clay-containing placer gold ores. At the same time, it is also necessary to reasonably select crushing equipment and process parameters to avoid grinding and losing fine gold particles. After crushing, it generally needs to go through processes such as washing and grading to remove the slime.
In general, the main purpose of gold ore crushing is to decompose ore, control particle size and increase the degree of mineralization to meet the needs of different mineral processing processes. Crushing is an indispensable and important process in the gold ore beneficiation process. It can fully prepare for subsequent beneficiation and help improve the recovery rate of gold and the efficiency of beneficiation. Reasonable design of the crushing process route is crucial to the comprehensive mining and utilization of gold mines.
Commonly used crushing equipment for gold ore crushing include:
Jaw crusher: suitable for primary and secondary crushing
Hammer crusher: suitable for medium and fine crushing
Cone crusher: suitable for fine crushing
Others: Roller crushing
