Gold Leaching for Low-Grade Ores: Complete Beginner’s Guide

gold extraction plant with 500tpd

Extracting gold from low-grade ores can be a daunting task for beginners. Low-grade ores contain very small amounts of gold, making it essential to use efficient methods to maximize recovery. Gold leaching is one of the most effective ways to recover gold from these ores, even for small-scale operations.

This beginner’s guide will explain what gold leaching is, the best methods for low-grade ores, step-by-step processes, and tips to help beginners get started safely and efficiently.

Low-grade gold ores typically contain less than 1–2 grams of gold per ton of ore. These ores cannot be efficiently processed using simple gravity methods because most of the gold particles are too fine or locked within minerals. Leaching allows you to dissolve gold into a solution for easier extraction, making it ideal for low-grade ores.

Gold leaching involves using a chemical solution to dissolve gold from crushed and ground ore. The dissolved gold can then be recovered from the solution using adsorption, precipitation, or electrochemical methods.

Key factors for effective leaching include:

• Ore particle size

• Type and concentration of leaching chemical

• pH and temperature of the solution

• Contact time between ore and solution

1. Cyanide Leaching

Cyanidation is the most commonly used method in gold leaching. Cyanide reacts with gold to form a soluble complex that can later be recovered.

Pros:

High recovery rate (up to 95%)

Well-established method with plenty of guidance for beginners

Cons:

Highly toxic and requires careful handling

Needs proper disposal to prevent environmental damage

Tip: Small-scale setups can use low-concentration cyanide with strict safety measures.

2. Thiosulfate Leaching

Thiosulfate is a non-toxic alternative to cyanide, suitable for ores with copper or sulfides that are difficult to process.

Pros:

Safe for operators and the environment

Works on ores resistant to cyanide

Cons:

Slightly lower recovery than cyanide if not optimized

Requires additional reagents like copper salts and ammonia

Tip: Experiment with small batches to determine the right reagent ratios.

3. Gravity-Assisted Leaching

Before chemical leaching, gravity separation can remove coarse gold and reduce the volume of ore needing chemicals. Methods include sluice boxes, shaking tables, and jigs.

Pros:

Reduces chemical consumption and costs

Environmentally friendly and safe for beginners

Cons:

Not effective for very fine gold without subsequent chemical leaching

• Ore Preparation: Crush and grind the ore until gold particles are exposed.

• Pre-Concentration: Use gravity methods to remove heavy gold particles if possible.

• Leaching: Mix the ore with the chemical solution and agitate for the recommended time.

• Gold Recovery: Use zinc precipitation, activated carbon adsorption, or electro-winning to recover gold from the solution.

• Solution Recycling: Reuse the leaching solution to reduce costs and minimize waste.

Gold leaching involves chemicals that can be hazardous if mishandled. Beginners should always:

• Wear personal protective equipment (gloves, goggles, masks)

• Work in a well-ventilated area

• Follow proper storage and disposal protocols for chemicals

• Avoid direct contact with solutions and skin

Gold leaching is a practical and effective method for recovering gold from low-grade ores, even for beginners. By understanding the basics, choosing the right leaching method, and following safe practices, small-scale miners and hobbyists can efficiently extract gold without excessive costs or environmental damage.

Whether you choose cyanide for maximum recovery, thiosulfate for safety, or gravity-assisted methods to reduce chemical use, this guide provides the foundational knowledge to start leaching low-grade ores successfully.