Quartz Vein Gold Beneficiation Process

Introduction to Quartz Vein Gold Deposits

Quartz vein gold deposits are among the most significant gold resources globally, particularly in China, where they account for over 50% of gold deposits and reserves. These deposits are characterized by simple mineralogy, primarily consisting of quartz gangue (>60%) and native gold or electrum (gold-silver alloy).

Key Features

1. Gangue Composition:
   • Dominated by quartz (SiO₂), typically exceeding 60% of the vein material.
   • Minor constituents may include carbonates (calcite, dolomite) and sulfides (pyrite, arsenopyrite).
2. Gold Mineralization:
   • Native gold (free gold) is the most common form.
   • Electrum (Au-Ag alloy) occurs frequently, with silver content varying widely.
   • Gold grain size ranges from medium to fine, affecting extraction methods.
3. Ore Texture & Structure:
   • Vein-type deposits: Gold occurs within fractures or fissures filled with quartz.
   • Disseminated mineralization: Fine gold particles may be embedded in quartz or sulfides.

Quartz Vein Gold Beneficiation Methods

Quartz vein gold ore beneficiation methods mainly include gravity separation, amalgamation, flotation, cyanidation, and combination processes like gravity separation – flotation, gravity separation – cyanide, and flotation – cyanide.

Among them, the amalgamation method has been basically abandoned due to its environmental hazard.

The full mud cyanidation method has a high recovery rate, but the coarse gold will prolong the cyanide time, increase the amount of cyanide reagent, and reduce production efficiency. What’s more, due to the hazard of cyanide chemicals, its development is limited.

The single flotation process is simple, but the gold in the ore cannot be completely recovered. The coarse gold in the flotation tailings is lost. Therefore, the effective recovery of granular gold by gravity separation before flotation and cyanidation is of great significance to the efficient utilization of gold resources. The Knelson concentrator can effectively separate gold minerals and gangues, has a high enrichment ratio, environmental friendliness, and low production cost. It has been widely used in China’s quartz vein-type gold ore beneficiation process.

Knelson Concentrator

The Knelson concentrator is an enhanced gravity separation equipment based on the centrifugal principle. The enrichment cone produces a high-magnitude gravitational field at high speeds, and the difference in gravity between minerals of different densities is multiplied, making the separation between light and heavy minerals easier.

What is the best substitute for the Knelson concentrator?

Based on the traditional centrifugal concentrator equipment, the Knelson concentrator has successfully solved the problem of ore layer tight packing and low sorting efficiency. The gold beneficiation ratio is up to 1 000 – 5,000. 

The Knelson concentrator has the following advantages:
(1) Chemical-free, environmentally friendly.
(2) Good separating effect, high beneficiation ratio, high gold grade.
(3) Automation and stability.
(4) High processing capacity and high production efficiency.

Knelson Concentrator Flotation Beneficiation Process

The experimental results show that when the grinding fineness is -0.074 mm, 84%, the recovery rate of the combination process of gravity separation – flotation is 91.40%, which is 3.09% higher than that of the single flotation process.

The Knelson gold concentrator has great advantages in the gravity separation of quartz vein type gold ore and has been applied to the beneficiation process by more and more gold plants. Among them, the most widely used is the Knelson concentrator flotation beneficiation process. The use of a Knelson concentrator to recover the natural gold in the gold mine in advance effectively avoids the loss of coarse gold in the flotation tailings and increases the concentrate grade.

The process is environmentally friendly, has high recovery efficiency and good adaptability, and is suitable for most quartz vein-type gold mines.