Tailings are components produced in mineral processing operations that have low content of useful components and cannot currently be economically used in industrial production. They are also the main component of industrial solid waste. With the continuous exploitation of gold mine resources and the advancement of mineral processing technology for refractory gold mines, the emissions of gold mine tailings are also increasing year by year, which inevitably brings about a series of problems and further stimulates the treatment of gold mine tailings. and the development of comprehensive utilization.

In addition to the increasing amount of gold mine tailings, gold ore beneficiation often uses cyanide to extract gold (for details, see: A summary of cyanidation leaching gold extraction methods) or flotation. Cyanide and flotation reagents must be added during the process. As a result, a certain amount of cyanide and flotation reagents will remain in the gold mine tailings. Therefore, gold mine tailings emissions often have the following problems:

1. Long-term stacking takes up a lot of land.

2. Pollution of the environment: Chemical agents must be added during the gold ore beneficiation process. These agent residues will remain in the tailings, and the heavy metals and toxic and harmful pollutants contained in the tailings will flow downstream or seep into the ground, even extremely fine particles. Tailings sand particles drift with the wind, causing harm to the surrounding environment.

3. Waste of resources: Restricted by the previous level of mineral processing technology, a large number of valuable resources remain in the tailings and have not been comprehensively utilized.

4. Safety hazards: There are safety hazards such as collapse and landslides in the tailings stockpile.

Based on the above problems, the treatment and comprehensive utilization of gold mine tailings are urgent. At present, the common gold mine tailings treatment methods and comprehensive utilization mainly include the following ways:

1. Gold mine tailings re-selection

The gold content in gold mine tailings is generally 0.2-0.6g/t. Due to the backwardness of mining and dressing technology in the past, some gold and silver were lost in the tailings. At the same time, most of China's gold ores are accompanied by elements such as copper, lead, zinc, iron, and sulfur. With the advancement of mineral processing technology, In addition to recovering gold and silver, gold mine tailings reprocessing can also comprehensively recover valuable elements based on the nature of the tailings. Therefore, tailings re-selection has become a major trend in gold mine tailings treatment.
Gold mine tailings flotation process

Take the recovery of lead-zinc ore from gold mine tailings as an example. The lead-zinc minerals in the gold concentrate have experienced fine grinding and long-term aeration and stirring during the cyanide leaching process, resulting in severe over-grinding and a "colloidal-like" state. The dispersed system makes flotation difficult. In addition, a large amount of argillaceous minerals and residual cyanide form a hydrophilic film on the surface of the mineral, causing the collector to lose its selectivity for collecting various minerals. At the same time, the film also hinders the adsorption of the collector to the surface of the mineral particles. Increases the difficulty of flotation separation.

① Ultra-fine particle flotation can be achieved through pretreatment, using combined collectors, controlling slurry potential and pH and other measures.

②Slurry pretreatment technologies such as strong oxidation of concentrated sulfuric acid and activated carbon adsorption can be used, and mixed flotation technology can be used in acidic media to improve the comprehensive utilization rate of lead and zinc mineral resources in cyanide tailings.

2. Dehydration of gold mine tailings dry discharge process
The tailings dry discharge process relieves the pressure on the storage capacity of the tailings reservoir and reduces the safety hazards of the tailings reservoir. The use of return water reduces the pressure on sewage treatment and saves mine production and operation costs. It is a requirement for the construction of green and environmentally friendly mines in the country.

Gold mine tailings filter press dehydration

For gold mine tailings that have been extracted using all-mud cyanidation, the tailings filtration process of a filter press can be used. Since the press filtrate is returned to the process flow, most of the cyanide ions, alkali and dissolved gold in the filtrate are recovered, thus saving the amount of mineral processing water, lime and cyanide, and reducing the discharge of cyanide-containing sewage.

3. Production of building materials
Recovering valuable elements from tailings can only achieve comprehensive recovery of a small amount of valuable elements in the tailings, but it cannot significantly reduce the amount of tailings, and it still cannot fundamentally solve the large land occupation, damage and impact of tailings stockpiles. Ecological environment issues.
Take my country's gold mines as an example. The types of deposits are complex and the surrounding rocks are diverse. Some deposits contain scarce metal minerals and relatively pure gangue minerals. Gold mine tailings can be directly used as important non-metallic raw materials or building materials, such as brick making. , Preparation of crystallized glass, production of aerated concrete, Portland cement, etc.

4. Mine filling
Using tailings to fill mine goafs is one of the most effective ways to directly utilize gold mine tailings. Especially for mining companies that have nowhere to set up gold mine tailings storage, using tailings to backfill goafs has greater benefits. environmental and economic significance.

As a good filling material, tailings can be obtained locally and used as waste, eliminating the costs of collecting, crushing, and transporting gravel to produce filling materials. For high-value gold ore bodies, tailings can improve pillar mining conditions and reduce dilution losses. An appropriate amount of cement or other cementing materials is often added to the filling material to condense the loose tailings into a whole with a certain strength. .

5. Reclamation and land reclamation
Reclamation is also an effective way to deal with gold mine tailings. Taking certain measures on gold mine tailings ponds and planting agricultural, forestry, animal husbandry, and crops with strong vitality can protect the soil and consolidate the embankments, which will have a positive effect on protecting the environment and preventing pollution.

The above are the common gold mine tailings treatment and comprehensive utilization methods. In the actual application of the mineral processing plant, it is recommended to comprehensively consider the nature of the gold mine tailings, the scale of the tailings, the return on investment, etc. to determine the appropriate gold mine tailings treatment and comprehensive utilization methods, and tailor-made reasonable gold mine tailings treatment equipment .