Copper in Gold-Bearing Ore: What to Consider in JinChan Testing

Why copper needs to be considered

Gold-bearing materials may simultaneously contain copper. When planning testwork, it is necessary to know the initial composition of the material being studied and to record significant differences between samples.

If copper is present in quantities that are important for the purpose of the study, its content should be included in the characteristics of the original sample. There is no universal value from which Cu is automatically considered “high” for JinChan.

The need for advanced control of Cu is determined by the material properties and the research objective, rather than by a universal threshold for JinChan.

Total Cu content is not a complete characteristic of the material

General chemical analysis answers the question of the amount of copper in the sample, but does not fully describe the mineralogical state of the material. If mineralogical data is available for a project, it should be considered in conjunction with chemical analysis and leaching test results.

Chemical analysis of the original ore does not, by itself, indicate what proportion of Cu will go into solution, how Cu will relate to Au recovery, whether JinChan consumption will change, or whether pretreatment will be required.

The same Cu content does not automatically mean the two ores will behave the same.

Direct published study of JinChan on Au–Cu materials

Deng, Schwehr, Yang, and Oraby examined three different gold-bearing materials: Au–Ag ore, Au–Cu ore, and Au–Cu flotation tailings. The program compared cyanide, JinChan and GlyCat™, and the recovery of metals, including Au and Cu, was monitored experimentally.

This is a direct published example of the application of JinChan to copper-bearing gold raw materials. The article confirms that the authors conducted such comparative tests and separate control of metals.

The results of each experiment relate only to the material studied and the conditions of the authors and do not establish the universal behavior of JinChan on all copper-bearing ores.

Why can't one published experiment be turned into a statement "JinChan does not dissolve Cu"

In published tests, Deng et al., Cu behaviour of Cu depended on the material and mode being studied. In individual experiments with JinChan, the authors observed very little or no Cu recovery, but this result is experiment specific.

In a published JinChan study on selected Au–Cu materials, low Cu extraction was observed under specific test conditions. This is not enough to confirm the universal selectivity of the reagent with respect to copper.

Why you need to measure more than just gold

If the purpose of the study is the behavior of copper-bearing gold ore, it is useful to consider the distribution of metals separately within a specific test.

The determination method and detection limits should be consistent with the laboratory program and expected concentrations.

What the official manufacturer JinChan says

Guangxi Senhe recommends conducting a beneficiation test, determining the optimal conditions for the material being tested and adjusting the regime taking into account the differences between ore grade and harmful component.

During application, the manufacturer recommends monitoring the gold content in the pregnant solution, pH and JinChan concentration.

The published instructions do not establish the maximum allowable Cu content, a separate JinChan consumption guideline for copper-bearing ores, a conversion factor for Cu consumption, or a mandatory method of copper removal.

Control of JinChan conditions when testing Cu-containing ore

Guangxi Senhe specifies maintaining an alkaline environment with a pH of 11–12 and recommends monitoring the pH, JinChan concentration and gold content of the pregnant solution.

pH 11–12 is the range of the official JinChan instructions, and not a special regime for copper-bearing ores.

A different pH, different concentration, special oxidizer, temperature or duration is not assigned to Cu-bearing ore without testwork.

Is copper related to JinChan consumption

Based on the selected sources, it is impossible to establish a universal relationship of the form “the more Cu, the greater the JinChan consumption.” The official instructions require taking into account the characteristics of the ore and harmful components, but does not publish the coefficient of dependence of consumption on Cu.

A study by Deng et al. provides direct experimental data for specific Au–Cu materials, but is not the basis for a general formula for JinChan consumption versus Cu content.

The effect of Cu on the actual consumption of JinChan must be established experimentally for a specific material.

Why is it impossible to automatically transfer knowledge about cyanidation?

It is known from the literature on cyanidation that Cu-containing ores can pose special technological problems for cyanide systems. An enterprise's historical experience with NaCN may therefore be useful background information, but not direct evidence of JinChan's behavior.

JinChan is a different reagent system, so the chemical dependencies, application rates, Cu limits and processing methods established for NaCN cannot be automatically passed off as characteristics of JinChan.

In this article, cyanide-specific coefficients, modes, thresholds and formulations are not used to select JinChan conditions.

Is it necessary to remove copper first?

The need for separate copper preparation or removal should be determined after raw material characterization and testwork. The total Cu value in the analysis alone is not a sufficient basis for selecting a specific process flow.

If an industrial project demonstrates that Cu is a technologically significant component, the need for a separate step should be investigated as a technological task in its own right.

What to check in the laboratory program

How to compare the two modes on copper ore

If the goal is to understand the effect of a change in regimen, tests should be as comparable as possible in their source material.

What can you tell the client before the test?

Practical conclusion

For gold-bearing copper ore, the correct starting point is not to attempt to assign a universal JinChan flow rate correction to Cu content, but to characterize the material and controlled laboratory testing. During testwork, it is necessary to evaluate gold, the actual behavior of JinChan and, when important for the research problem, the behavior of copper in solution and solid residue.