7 Q&A about Sodium Cyanide Use in Gold Mining

Sodium cyanide is a leaching agent use in gold mining plants. This article will take you to understand the 7 Q&A of sodium cyanide to help you better understand mining sodium cyanide.

1. When start using sodium cyanide for gold mining?

In 1969, sodium cyanide was successfully used in the heap leaching project of the Carlin Gold Mine in the United States. With the development of the carbon slurry method, by the 1980s, it has been adopted by gold mine cyanidation plants all over the world.

2. Why sodium cyanide, not other cyanide agents?

Commonly used cyanide leaching agents in cyanidation process are NaCN, KCN, NH4CN, Ca(CN)2.

KCN is the earliest agent used in the production of gold extraction by cyanidation, but its ability to dissolve gold is lower than that of NaCN, and its price is more expensive than that of NaCN, so it is gradually replaced by NaCN.

The cheapest is Ca(CN)2. However, Ca(CN)2 is easy to produce side effects that are not conducive to gold leaching.

Therefore, considering factors such as the relative solubility of cyanide to gold, the stability, the influence of impurities on the process, the price and the reliability of supply, sodium cyanide has become the preferred agent in the production of cyanide gold extraction.

3. How to use sodium cyanide to extract gold?

Heap leaching method: accumulate low-grade oxidized ore on an impermeable site, and intermittently spray the ore heap with dilute alkaline sodium cyanide solution to dissolve the gold, and the pregnant percolates out of the ore heap. The gold is recovered from the gold-containing solution by the activated carbon adsorption method or the zinc replacement method, and the lean liquid is supplemented with sodium cyanide and returned to the spraying operation for recycling.

CIP/CIL method: add the prepared alkaline sodium cyanide solution and the prepared gold ore powder into the leaching stirring tank, the ore slurry is leached under continuous stirring conditions, and gold forms gold cyanide complexes in sodium cyanide solution. Then, gold is recovered by countercurrent adsorption, gold-loaded carbon desorption and electrolysis and other processes.

4. What is the price of sodium cyanide?

The price of sodium cyanide fluctuates all the time.

Sodium cyanide price reached USD 1656/t in November 2021.

The average price of sodium cyanide in 2021 is USD 1971/ton.

During the five-year period from 2016 to 2021, the historical high value of sodium cyanide price appeared in 2014, reaching USD 3138/ton, while the historical low value appeared in 2004, which was USD 1340/ton.

5. Who are the manufacturers of sodium cyanide?

The sodium cyanide market is a comprehensive market, and the top 10 companies occupy more than 60% of the market share in terms of production capacity.

• Anhui Shuguang Group
• Australian Gold Reagents Pty Ltd
• Changsha Hekang Chemical Co. Ltd
• The Chemours Company
• Cyanco International LLC
• CyPlus Idesa
• Hebei Chengxin Group Co. Ltd
• Orica Limited
• Sasol
• Taekwang Industrial Co. Ltd

6. What should be paid attention to when using sodium cyanide?

Cyanide is highly toxic, so precautions must be taken in production. The main preventive measures are:

• Strictly abide by the operation and safety regulations during the production process.
• Prevent solid cyanide dust pollution and prevent inhalation of dust from the mouth. Shower and change clothes promptly after work.
• The equipment and places that generate HCN should be sealed, and the air should be exhausted with an exhaust fan, and the exhausted air should be washed with dilute lye.
• The waste water and washing water containing cyanide shall be discharged after reaching the standard.
• Use mechanized or automated feeding to reduce direct human contact.

7. What are the alternatives to sodium cyanide?

In recent years, the best application effect is CNFREE environmentally friendly gold leaching reagent.

The main components of CNFREE are: carbonized sodium cyanurate, alkaline thiourea, alkaline polymerized iron, alkali and carbonate.

CNFREE is widely used in heap leaching, pool leaching and carbon slurry process for leaching materials like gold and silver oxide ores, primary ores, high-sulfur and high-arsenic ores, cyanide tailings, sulfuric acid residues, anode slimes, and concentrates.

Compared with sodium cyanide, CNFREE has low toxicity, stable properties, higher leaching rate and lower price. The scope of use of the agent is similar to that of cyanide, and in terms of process production, there is no need to increase or modify the original cyanide gold leaching production equipment. It can better meet the requirements of green and safe production.

To wrap up

These are the answers to the 7 major questions of sodium cyanide use in gold mining. When you use cyanidation to extract gold, you can choose sodium cyanide or CNFREE gold leaching agent. Manufacturers generally provide customers with free samples for leaching tests. You can confirm the cooperative manufacturers based on test data, chemical prices, and transportation costs.