High carbon gold ores, as we all know, in the beneficiation process, often contains carbon substances which adversely affected the gold recovery rate. In this article, we will detail several effective treatment methods to improve gold recovery from gold ores with high carbon content.
Challenges of gold ores with high carbon content
Gold ores with high carbon content face many challenges in the beneficiation process. Carbonaceous materials tend to adsorb gold, resulting in lower gold recovery. In addition, carbonaceous materials can affect the chemical reaction in the cyanide leaching process and increase the consumption of chemicals. Therefore, special treatment methods must be adopted for gold ores with high carbon content.
Flotation method for treating gold ores with high carbon content
Flotation is a commonly used method for treating gold ores with high carbon content. Through the flotation method, the gold can be separated from the carbonaceous material, so as to improve the recovery rate of gold. The specific steps are as follows:
1. Ore crushing and grinding: the gold ore with high carbon content is crushed to appropriate particle size, and then grinding is carried out to make the ore reach the fineness required for flotation.
2. Selection of flotation chemicals: according to the specific nature of the ore, select the appropriate flotation chemicals, such as xanthate, dithiophosphate, etc., in order to improve the recovery rate of gold flotation.
3. flotation process: add the ore slurry after grinding into the flotation tank, through stirring and bubbling, make the gold separate from carbonaceous material, the gold attached to the bubbles floats out, forming gold concentrate.
Cyanidation processing of carbonaceous high gold ore
Cyanidation is another commonly used method to treat carbonaceous high gold ores. Cyanidation leaches the gold through a cyanide solution and then recovers the gold by adsorption or replacement. The specific steps are as follows:
1. Ore pre-treatment: The gold ore with high carbon content will be pre-treated, such as roasting, oxidation, etc., to remove carbonaceous materials and reduce the interference to the cyanidation process.
2. Cyanide leaching: The pretreated ore is added into the cyanide solution, and the gold is dissolved in the cyanide solution by stirring and percolation.
3. Gold recovery: Gold dissolved in the cyanide solution is recovered by activated carbon adsorption or zinc powder replacement.
Carbon slurry processing of carbonaceous high gold ore
Carbon slurry method (CIP method and CIL method) is an efficient method to treat carbonaceous high gold ores. The carbon slurry method extracts gold from activated carbon by adding it to the cyanide slurry so that the gold is adsorbed on the activated carbon. The specific steps are as follows:
1. leaching raw material preparation: the gold ore with high carbon content is crushed and milled to make the ore reach the fineness required by the carbon slurry method.
2. Stirring leaching and counter-current carbon adsorption: Add the milled slurry into the stirring tank, add cyanide solution and activated carbon, and make the gold dissolved and adsorbed on the activated carbon by stirring.
3. Gold-carrying carbon desorption and electrowinning electrolysis: Separate the gold-carrying carbon from the ore slurry, desorb the gold from the activated carbon by high temperature and high pressure desorption method, and then recover the gold by electrowinning electrolysis method.
4. Carbon regeneration: the desorbed activated carbon is regenerated to restore its adsorption performance and then recycled.
Thiourea processing of carbonaceous high gold ore
Thiourea method is an emerging low-toxicity gold extraction process suitable for treating gold ores with high carbon content. Thiourea method dissolves gold through thiourea acidic solution and then recovers gold. The specific steps are as follows:
1. Ore pre-treatment: The gold ore with high carbon content is pre-treated, such as roasting, oxidation, etc., in order to remove the carbonaceous material and reduce the interference to the thiourea leaching process.
2. Thiourea leaching: The pretreated ore is added into the acidic solution of thiourea, and the gold is dissolved in the thiourea solution by stirring and percolation.
3. Gold recovery: the gold dissolved in the thiourea solution is recovered by ion exchange resin or activated carbon adsorption.
Comprehensive treatment method
For gold ores with high carbon content, a single treatment method may not achieve the desired recovery effect. Therefore, comprehensive treatment methods, such as flotation-cyanidation combined process and flotation-thiourea combined process, can be used to improve the recovery of gold. The specific steps are as follows:
1. Flotation pretreatment: the gold ore with high carbon content is subjected to flotation treatment to remove carbonaceous material and obtain gold concentrate.
2. Cyanide or thiourea leaching: the gold concentrate after flotation is subjected to cyanide or thiourea leaching, so that the gold is dissolved in the leaching solution.
3. Gold recovery: gold dissolved in the leaching solution is recovered by activated carbon adsorption, ion exchange resin or zinc powder replacement.
Conclusion
To treat gold ores with high carbon content and to improve the recovery of gold, it is necessary to choose a suitable treatment method according to the specific properties of the ore. Flotation, cyanidation, carbon slurry and thiourea are all commonly used treatment methods, which can be used individually or in combination. Through scientific and reasonable beneficiation process, the gold recovery rate of carbonaceous high gold ores can be effectively improved to achieve a win-win situation in terms of economic and environmental benefits.
Reagents selection for high carbon gold ore flotation
Selective collectors: use collectors with high selectivity to gold minerals, such asxanthate type collectors, in order to improve the recovery of gold minerals in flotation.
For example, for the gold ore collectors, Y&X has launched a high-efficiency collectors YX01, which is mainly used in the flotation of difficult copper ore and gold ore, and can effectively improve the recovery rate of beneficiation. Meanwhile, the product is not easy to be adsorbed by clay, talc, chlorite and so on.
Use of depressants: Use depressants (such as water glass, copper sulfate, etc.) to inhibit the flotation activity of carbonaceous materials and reduce their adsorption of flotation chemicals.
For example, Y&X has developed a carbon depressant D486 for gold mine, which is mainly used to inhibit graphite, organic carbon and other fine-grained carbon minerals in gold ore, with superior effect, which can greatly improve the beneficiation index and increase the economic benefits of beneficiation.
In the following high carbon gold ore flotation experiment, we added the depressant D486, the metal colour in the foam is obvious, which shows that the carbon in the gold ore has been effectively inhibited.
Optimisation of frothers: Selection of suitable frothers (e.g. turpentine oil, etc.) improves the stability and selectivity of the flotation froth, which contributes to the flotation separation of gold minerals.
In addition, Y&X has also launched a number of high-efficiency frotherss, such as Q60, Q80, STQ33, etc. These frotherss have fast frothing rate and strong frothing ability, which are suitable for non-ferrous metal ores and rare precious metal ores beneficiation, especially for non-ferrous metal ores beneficiation where the ratio of target minerals is large and the content of muddy veinstone is high. It is an excellent substitute for Dow 250 and MIBC.
For more information, please feel free to contact Y&X team!