Method for Recovering Gold and Copper from Bioheap Leaching Tailings of Copper Ores

Medium Conversion：Medium conversion is carried out in sequence: The discarded bioheap leaching tailings of copper ores undergo three-stage medium conversion without unloading the heap. Mine-sourced alkaline wastewater supplemented with lime and sodium hydroxide solution is sprayed onto the heap, with the pH value of the effluent discharged from the heap bottom controlled to above 10.5, to obtain the discarded copper ore bioheap leaching tailings after medium conversion.

Cyanidation Spray Leaching：The medium-converted discarded copper ore bioheap leaching tailings are treated with four-stage cyanidation spray leaching using sodium cyanide solution to obtain the pregnant leach solution.

Copper Recovery via Oxidative Cyanide Destruction：A cyanide destruction agent is added for oxidative cyanide breakdown and copper removal. The slag slurry after cyanide destruction and copper removal is processed by thickening, sedimentation and solid-liquid separation to produce filtrate and copper concentrate as the finished product. The overflow and filtrate are mixed and then sent for activated carbon adsorption, yielding the barren adsorption solution and gold-loaded activated carbon as the finished product.

This method features low investment, short processing cycle and low cost. The gold content in the final tailings is less than 0.07 g/t, while the total copper recovery rate exceeds 35%. It can be scaled up into industrial production lines, with simple operation, strong adaptability and environmental friendliness, and is suitable for the comprehensive resource recovery of solid waste residues in the non-ferrous metallurgy industry.

Direct Electrolysis of Copper Sulfide Ore to Produce Electrolytic Copper

Direct electrolysis of various copper ores to produce electrolytic copper falls under the fields of chemistry and metallurgy. It is characterized by using the reduced solution in the anode region for electrochlorination leaching of copper ore, while simultaneously electrowinning first-grade electrolytic copper meeting the GB466-82 standard in the cathode region.

Fluidized electrolytic cells with special structures can handle single copper sulfide ores, complex copper ores, and polymetallic copper sulfide ores with high lead and zinc contents. This process boasts a simple production flow, low comprehensive energy consumption, no pollution, and ease of industrial implementation.

After crushing and screening of copper oxide ore, the oversize material undergoes conventional acid heap leaching operation, while the undersize material is subjected to concentration, slurry adjustment and granulation before heap construction and leaching. The leachate rich in copper ions is processed through solvent extraction, electrowinning and other procedures to obtain marketable cathode copper.

After concentrating the undersize material, a binder needs to be added for slurry adjustment. The adjusted slurry is mixed with pre-prepared acid-resistant crushed stones (particle size: 5mm-25mm) for granulation. During the granulated heap leaching process, the heap height ranges from 3 to 5 meters, the concentration of dilute sulfuric acid is 0.1 to 2 mol/L, and the leaching cycle lasts 1 to 2 months.

This process is particularly suitable for the development of refractory copper ore resources dominated by copper oxide ore in various regions of China, especially in the remote areas of the western plateau.

Flotation-Acid Leaching Technology for Treating High Carbonate Copper Oxide Ore：

The flotation-acid leaching technology for high carbonate copper oxide ore involves grinding the ore to a certain fineness, then conducting sulfidization flotation with a combined collector to remove acid-consuming carbonate gangue. The resulting rough concentrate is leached under specific conditions to obtain copper sulfate solution.

This technology can effectively eliminate acid-consuming carbonate gangue from raw ore, reducing acid consumption in hydrometallurgical leaching of high carbonate copper oxide ore by over 70% while ensuring an overall copper recovery rate of more than 85%. It lowers production costs and the investment scale of hydrometallurgical plants, features a flexible and easy-to-control process, and is suitable for large-scale industrial applications.

Flotation Method Of Gold Ores:

Flotation method is mainly used to treat vein gold ores with fine dissemination. Usually, the core equipment for gold ore flotation is the flotation machine. During the process, additional equipment such as ball mills, dryers, and spiral classifiers are also employed, which are responsible for sorting, grinding, drying, and classification.

The flotation machine is a key device in gold ore dressing plants. It features low investment and high separation precision. Its built-in automatic electronic control system can produce finer foam, effectively enhancing flotation efficiency while reducing power consumption. Moreover, it has minimal wear, easy maintenance, large processing capacity, and a complete range of models and specifications.

Cyanidation Method:Cyanidation method for gold ore extraction mainly involves crushing, grinding, and cyanide leaching of gold ore. After leaching, activated carbon is added to the pulp to adsorb gold. Finally, through refining and smelting, gold ingots are produced.

Method for Enhanced Extraction of Copper from High-Grade Chalcocite

The method for enhanced extraction of copper from high-grade chalcocite belongs to the field of hydrometallurgy of non-ferrous metals. The high-grade chalcocite ore is crushed and formed into heaps. After heap construction, circulating leaching operations are performed using bacteria-containing raffinate with high acid and high iron content. The leachate is periodically sampled to analyze copper concentration; when the copper concentration in the leachate exceeds 3.5 g/L, the leachate is extracted for solvent extraction, and the raffinate after extraction is returned for continuous leaching.

By combining biological heap leaching circulation with acid return from extraction, a leaching system with high acid and high iron content is established in the high-grade chalcocite heap leaching process. This enhances and accelerates the rapid leaching of chalcocite, thereby shortening the leaching cycle, enabling large-scale copper leaching, and improving the utilization rate of copper resources.

Method for Synergistic Chlorination-Oxidation Leaching of Gold from Refractory Gold Ore:

This method for synergistic chlorination-oxidation leaching of gold from refractory gold ore belongs to the field of hydrometallurgy.

First, crush the gold ore into ore powder; fully mix the ore powder, sodium hydroxide, sodium hypochlorite and water to obtain ore slurry; introduce air into the slurry, and perform ultrasonic-enhanced leaching under stirring conditions.

During the enhanced leaching process, hydrogen peroxide is added periodically. The synergistic effect of hydrogen peroxide and sodium hydroxide is utilized to carry out redox reactions—their combined oxidation effect far exceeds that of either agent alone. 

This not only shortens the reaction time but also improves gold leaching efficiency, saving reagent costs while boosting overall ore leaching performance. The leaching rate can reach over 98% using this method. Using sodium hypochlorite as the leaching agent does not impose environmental pressure; additionally, this invention adopts a one-step enhanced leaching process, simplifying the leaching workflow.

The gold extraction process from copper-bearing oxidized gold ore falls under hydrometallurgical technology. First, the copper-bearing oxidized gold ore undergoes crushing, grinding and classification, followed by alkaline treatment. Then, a certain proportion of chelating agent and sodium cyanide are added to inhibit copper leaching and realize selective gold leaching. Finally, gold is extracted from the leachate via conventional activated carbon adsorption.

This method boasts a simple process, uncomplicated equipment and ease of implementation, along with high gold leaching rate, low reagent consumption, minimal capital investment and low cost. It is a gold extraction approach that is easy to industrialize and delivers good economic benefits.

Hydrometallurgy is another method for extracting copper from chalcopyrite. Due to its lower operating cost, it can be applied to the hydrometallurgical leaching of copper from low-grade copper ores. Common leaching agents are acidic chloride media and acidic sulfate media.

In sulfate media, the leaching kinetics are generally slow, and complete copper leaching is difficult to achieve. This is because a passivation layer forms on the mineral surface; additionally, a complex purification and impurity removal process is required.

In acidic chloride media, salts have high solubility in chloride-containing solutions, and copper ions can be stabilized in concentrated chloride systems. Thus, the leaching rate in chloride media is faster than in sulfate media. However, acidic chloride media have drawbacks: strong corrosivity, difficulty in electrowinning high-quality copper from them, and the need for complex purification and impurity removal processes after leaching.