Recently, affected by the expectation of new tariff policies, market concerns about inflation and trade frictions have intensified. As a traditional safe-haven asset, gold has once again become the focus of capital pursuit, and its price has continuously refreshed historical highs. The continued rise in gold prices has driven the exploration and mining boom of gold mines around the world, especially in Africa, South America and parts of Asia. At the same time, the effective beneficiation and recovery technology of gold ore has become a key link for gold mining companies to improve their economic benefits. This article will give you an in-depth analysis of the types of gold ore and the current mainstream gold beneficiation technology and methods.
Main types of gold ore
Gold ore can be divided into the following categories according to its geological origin, mineral composition and occurrence state:
1. Quartz vein type gold ore
Gold is mainly found in quartz veins in the form of natural gold, often coexisting with pyrite. The particle size distribution of gold is wide, ranging from microscopic gold to coarse gold. This type of ore is generally of high grade and is the focus of current gold resource development.
2. Broken zone altered rock type gold ore
Gold is found in altered rocks affected by fractures and hydrothermal action. The ore structure is complex and is often accompanied by sulfides such as pyrite and chalcopyrite. Gold is closely combined with gangue minerals and is mostly embedded in a fine-grained state, making beneficiation relatively difficult.
3. Volcanic rock type gold ore
Originated in volcanic rocks and subvolcanic rocks, it contains a variety of metal minerals, such as sphalerite and galena. The types of surrounding rock alteration are rich, the ore grade is uneven, and it often contains complex mineral components that interfere with beneficiation.
4. Placer gold ore
It is a secondary deposit formed by weathering, transportation and sedimentation. Gold mainly exists in loose gravel such as rivers and beaches as coarse-grained or flaky natural gold. Recovery is relatively easy, but the resource distribution is scattered and the grade is unstable.
Common beneficiation methods for gold ore-cyanidation
Cyanidation method: suitable for processing fine-grained encapsulated gold ore.
Cyanidation is the most widely used and highest recovery method in gold extraction, especially for refractory ores with fine gold particles or closely associated with gangue.
1. Stirring cyanidation
After crushing the ore, mix it with cyanidation solution, react under stirring, and recover gold through carbon slurry adsorption or zinc powder replacement.
Advantages: Suitable for high-grade gold mines, high recovery rate, and stable process.
Key points for control: pH value is controlled at 10-11 to prevent cyanide hydrolysis.
2. Percolation cyanidation
Put the crushed ore into the percolation tank and treat it with gravity permeation solution. Suitable for medium-coarse particles and relatively clean ores.
Applicable conditions: low mud content, particles should not be too fine.
3. Heap leaching cyanidation
Suitable for low-grade, highly oxidizing ores, such as weathered oxidized gold ores. Spray cyanide solution through the ore pile to recover gold in the solution.
Economic advantages: low investment cost, suitable for open-pit mining and low-grade resource development.
4. Pressurized cyanidation
React under high temperature and high pressure conditions to accelerate the leaching of gold, suitable for difficult-to-treat gold mines (such as high-arsenic and high-sulfur gold mines).
Features: fast gold extraction rate, high recovery rate, and strong adaptability to complex ores.
5. Biocyanidation
Use microorganisms to decompose the surrounding rock sulfides of gold, expose the gold and then extract it by cyanidation.
Suitable objects: high-sulfur gold mines such as pyrite and arsenopyrite.
Advantages: low energy consumption, environmentally friendly, and high resource utilization.
There are various methods for beneficiation of gold ore, and different types of ores need to be equipped with targeted process flows. Whether it is traditional gravity separation, flotation, cyanidation, or emerging biological gold extraction and non-cyanidation technology, it is necessary to conduct sufficient beneficiation tests and process design based on the actual ore properties.
Henan Kaiyun Intelligent Equipment Co., Ltd. has been engaged in the field of gold beneficiation for many years and has rich on-site experience and technical reserves. We can tailor the optimal gold extraction solution according to the characteristics of the customer’s ore to help achieve the goal of efficient, green and high-recovery gold extraction.