How Eco-Friendly Are Eco-Friendly Gold Leaching Agents?

The term "eco-friendly" is mentioned repeatedly in the gold leaching agent industry, but just how eco-friendly are they? Is it conceptual marketing or a true technical breakthrough? For mining enterprises, this directly affects the identification of tailings attributes, environmental disposal costs, and compliance risks.

This article answers this question using a set of authentic data from authoritative third-party testing institutions.

The test data cited in this article comes from two institutions:

CAS Testing Technical Services (Guangzhou) Co., Ltd. is a comprehensive third-party testing, inspection, and certification institution under the Chinese Academy of Sciences Holdings Co., Ltd. (CAS Holdings). Its predecessor was the Analysis and Testing Center of the Guangzhou Institute of Chemistry, Chinese Academy of Sciences, established in 1958. It holds dual CMA and CNAS qualifications and is a designated testing unit recognized by the Guangdong Provincial Hazardous Chemicals Registration and Registration Office.

Henan Gold Industrial Technology Research Institute Co., Ltd., established in 2018 and located in Lingbao City, Sanmenxia, Henan Province, is a state-owned sole proprietorship primarily engaged in research and experimental development. In 2025, it was rated "Good" among the provincial-level new R&D institutions in Henan Province.

CAS Testing conducted a comparative test between tailings leached with Jinsheng eco-friendly gold leaching agent and tailings leached with sodium cyanide (simulating the traditional sodium cyanide process). The determination was based on the method in Appendix G of GB 5085.3-2007:

Testing Item: Cyanide Ion

Testing Method: GB 5085.3-2007 Appendix G

Unit: mg/kg

Traditional Sodium Cyanide Process Tailings:  2.96×10²mg/kg

Jinsheng Eco-friendly Leaching Agent Tailings: 42.77 mg/kg

The cyanide ion content in Jinsheng's tailings is only one-seventh of that in the traditional sodium cyanide process.

What does this mean? The less cyanide remains in the tailings, the lower the probability that the tailings will be identified as hazardous waste, and the lower the corresponding environmental disposal costs.

Also from the CAS Testing report, the solid waste leaching solution was prepared according to HJ/T 299-2007 and judged according to the standard limits in Table 1 of GB 5085.3-2007:

Testing Item: Cyanide (calculated as CN-)

Testing Method: GB 5085.3-2007 Appendix G

Unit: mg/L

Standard Limit: 5

Traditional Sodium Cyanide Process Leaching Solution: 1.32 mg/L

Jinsheng Eco-friendly Leaching Agent Leaching Solution: 0.12 mg/L

The cyanide concentration in Jinsheng's leaching solution is only one-eleventh of the traditional process and only one-fortieth of the GB 5085.3-2007 standard limit (5 mg/L).

This means that the leaching solution produced using the Jinsheng agent has a cyanide concentration far below the threshold for hazardous waste identification, providing a significant advantage in determining tailings attributes.

In July 2026, the Henan Gold Industrial Technology Research Institute conducted a side-by-side comparison test of three leaching agents: Jinsheng, Jinchen, and Jinzhibao. The test utilized Xinling gold ore (raw grade 2.18 g/t), grinding fineness of -0.074mm at 85%, pulp concentration of 40%, pH ≈ 11, and a dosage of 1.5 kg/t for all agents.

Cyanide Content Results in Leaching Solution:

At 24 Hours:

Jinsheng: 0.05 mg/L

Jinchen: 0.05–0.1 mg/L

Jinzhibao: 0.05 mg/L

At 48 Hours:

Jinsheng: 0.01 mg/L

Jinchen: 0.01–0.05 mg/L

Jinzhibao: 0.01–0.05 mg/L

Jinsheng's cyanide content in the 48-hour leaching solution was as low as 0.01 mg/L, the lowest among the three.

This data has two levels of significance: First, under identical test conditions, Jinsheng's environmental safety is superior to its two main competitors. Second, as the leaching time extends (from 24 to 48 hours), the cyanide content in Jinsheng's solution continues to drop to 0.01 mg/L, indicating a more thorough reaction and fewer residues.

For mining enterprises, the three sets of data above directly relate to three realistic issues:

First: Tailings Attribute Identification. According to GB 5085.3-2007, if the concentration of hazardous components in a solid waste leaching solution exceeds the standard limit, it is identified as hazardous waste with leaching toxicity. Jinsheng's concentration of 0.12 mg/L is far below the 5 mg/L limit, providing strong data support for identifying tailings as "General Industrial Solid Waste."

Second: Environmental Disposal Costs. Once tailings are identified as hazardous waste (Category HW33), they must be professionally treated by institutions with hazardous waste qualifications, with disposal prices rising annually. If tailings are classified as general industrial solid waste, disposal costs drop significantly. For a 10,000-ton scale mine, this alone can save millions of RMB in annual environmental disposal fees.

Third: Policy Compliance Trends. The "Implementation Plan for High-Quality Development of the Gold Industry (2025–2027)" jointly issued by nine departments, including the Ministry of Industry and Information Technology, explicitly supports technical modification demonstrations such as cyanide extraction process upgrades and harmless filling of cyanide residues. Whether the indicators of an eco-friendly leaching agent are robust directly determines whether a mine can smoothly complete process transformation and receive policy support during this window.

How eco-friendly are eco-friendly gold leaching agents? The data provides the answer:

Tailings Cyanide Content: 42.77 mg/kg (1/7th of traditional process)

Leaching Solution Cyanide Concentration: 0.12 mg/L (1/11th of traditional process, 1/40th of standard limit)

48h Leaching Solution Cyanide Content: 0.01 mg/L (Lower than the two main competitors)

These data come from a third-party testing institution under CAS Holdings and a provincial-level gold industrial technology research institute, standing up to cross-verification and repeated inspection.

For mining enterprises, choosing a leaching agent cannot be based on the leaching rate alone. Environmental compliance is a hard threshold-tailings identification, disposal costs, and policy risks are all directly linked to the agent's environmental indicators. Data does not lie; third-party testing reports are the most reliable evidence.