Six Major Gold Extraction Processes and Their Applicable Scenarios

Rock gold ores come in a wide variety of types, with significant variations in grain size and associated minerals. Many mines face challenges such as low gold recovery rates and persistently high production costs due to the selection of inappropriate processing methods. In fact, different rock gold ores possess unique mineral characteristics; by matching them with dedicated separation processes, metal recovery efficiency can be significantly improved, thereby generating greater economic benefits for the mine. Currently, there are six main categories of ore processing methods for rock gold deposits in the industry, each suited to different ore conditions.

Gravity separation is a classic method for processing coarse-grained gold ore. It relies on differences in mineral density to achieve separation; the equipment is simple to operate and maintain, and there is no chemical contamination. It is specifically designed for the pre-enrichment of single-particle, coarse gold and is often used as a pre-treatment stage in combined ore processing, enabling the early recovery of large gold particles and reducing the processing load on subsequent equipment.

The amalgamation method is particularly effective at recovering free coarse-grained gold. It features a short separation process and low operational complexity, and is frequently used in the pre-treatment stage for ore containing visible gold, enabling the rapid extraction of exposed gold minerals. It is well-suited to rock gold ores with a high proportion of coarse-grained free gold.

The core advantage of flotation lies in its high-efficiency enrichment of gold-bearing sulphide minerals; it is particularly well-suited to fine-grained and encapsulated gold ores. By adjusting the surface floatability of minerals through the use of reagents, gold is concentrated in the flotation concentrate, significantly reducing the scale of subsequent smelting operations. It is the primary separation method for polymetallic gold-bearing ores.

The cyanidation process is suitable for a wide range of ores; it achieves high leaching recovery rates for both coarse-grained and fine-grained, encapsulated gold, and is highly compatible with various complex rock-type gold ores. It has long been the mainstream gold extraction process for difficult-to-process gold ores.

The carbon-in-pulp (CIP) process is an integrated leaching and adsorption process. It simultaneously leaches and adsorbs gold ions using activated carbon, thereby eliminating the need for complex solid-liquid separation steps, shortening the production process, and reducing chemical and energy consumption. It is well-suited to routine production at small and medium-sized gold mines.

Heap leaching focuses on a low-cost development approach, requiring no large-scale grinding infrastructure. It offers significant advantages for low-grade, small-scale rock gold deposits, substantially reducing initial equipment investment, and is the preferred solution for the development of marginal low-grade gold deposits.

It is worth noting that no single process is suitable for all rock gold deposits; each technology has its own limits of applicability. A single process often struggles to balance recovery rates and production costs; mines must therefore tailor combined beneficiation schemes based on the distribution characteristics of the ore, gold particle size and ore grade. Professional mineral processing service providers can utilise mineral analysis data to design suitable process flows, thereby enhancing gold recovery whilst reducing chemical and energy costs, and achieving the efficient and maximised utilisation of mineral resources.