Chemical Beneficiation Process Operation

Overview of Chemical Beneficiation

Chemical beneficiation is a mineral processing method based on differences in the chemical properties of minerals and their components. It uses chemical reactions, dissolution, precipitation, ion exchange, solvent extraction, and other chemical techniques to alter the composition or chemical form of minerals, thereby separating and enriching valuable components.

For example, malachite-bearing copper ore can be leached with dilute sulfuric acid. During leaching, malachite is converted into a copper sulfate solution. Copper metal can then be recovered from the solution by cementation, in which iron filings replace copper ions to produce metallic copper, commonly known as sponge copper.

Chemical beneficiation is particularly effective for processing low-grade, fine-grained, complex, and refractory mineral resources that are difficult to treat using conventional physical beneficiation methods. It can improve resource utilization, recover valuable components from previously uneconomic materials, and contribute to the treatment and utilization of waste streams such as wastewater and waste residues.

A typical chemical beneficiation process consists of six major operations:

• Preparatory work
• Roasting
• Leaching
• Solid-liquid separation
• Purification
• Recovery of chemical concentrates

The specific process configuration depends on the mineral composition, the properties of the valuable components, and the required product quality.

 

Chemical Beneficiation Process

Chemical beneficiation has different operations according to different technological processes. A typical chemical beneficiation process generally includes the following six primary operations.

 

 

1. Preparatory Work

This operation is the same as the physical beneficiation method, including crushing and screening materials, grinding and grading, ingredient mixing, and other mechanical processing processes. The purpose is to grind the material to a specific particle size, prepare suitable fineness and concentration for the next operation, and sometimes use physical beneficiation to remove some harmful impurities or enrich the target minerals in advance so that the mineral raw materials and chemical reagents are mixed well. If the fire method is used, sometimes the material must be dried or sintered to create favorable conditions for the next operation.

2. Roasting Operation

The purpose of roasting is to change the chemical composition of the ore or remove harmful impurities so that we can transform the target mineral (component) into a form that is easy to leach or beneficial to physical beneficiation and prepare conditions for the next operation. The roasted products include calcined sand, dry dust, wet dust collection liquid, and mud, from which corresponding methods can recover functional components according to their composition and properties.

3. Leaching Operation

This operation is to selectively dissolve the functional components or impurity components in the leaching solvent according to the properties of the raw materials and the process requirements so that the valuable components are separated from the impurity components, or the functional components are separated, which is the next step. Create conditions for recovering useful components from leaching solution or leaching residue.

4. Solid-liquid Separation Operation

This is the same as the dehydration operation of physical beneficiation products, but the solid-liquid separation of chemical beneficiation leached pulp is more complicated. Generally, sedimentation, filtration, and classification are used to process leached ore pulp to obtain a clarified solution or contain a small number of fine mineral particles.

5. Purification Work

To obtain high-grade chemical concentrates, the leaching solution is often purified and separated by chemical precipitation, ion exchange, or solvent extraction to remove impurities and obtain a purified solution with a high content of valuable components.

6. Production of Chemical Concentrates

Chemical concentrates are obtained by extracting valuable metals (components) from the leaching solution. Generally, chemical precipitation, metal replacement, electrowinning, carbon adsorption, ion exchange, or solvent extraction can be used; in some cases, physical beneficiation can also be used. The principal process of typical chemical beneficiation is as follows.

 

 

It has successfully used chemical beneficiation to process many metallic minerals and non-metallic mineral raw materials such as iron, manganese, lead, copper, zinc, tungsten, aluminum, tin, gold, silver, tantalum, niobium, cobalt, nickel, uranium, thorium, rare earth, aluminum, phosphorus, graphite, diamond, kaolin, and other solid mineral raw materials. It can also extract valuable components from mine water, wastewater, and seawater.

The processing object of characteristic chemical beneficiation is the same as that of physical beneficiation. Still, the adaptability of the chemical beneficiation method is stronger than that of the physical beneficiation method, and its separation principle and product form are different from physical beneficiation. The separation principle of chemical beneficiation is similar to the traditional metallurgical process. Chemical beneficiation and the metallurgical process both use the basic principles of inorganic chemistry, organic chemistry, physical chemistry, and chemical processes to solve their respective process problems. Mineral dressing is widely used in developing various refractory ferrous metals, non-ferrous metals, precious metals, and non-metallic mineral resources.

Applying chemical beneficiation is an effective method to deal with poor, fine, miscellaneous, and other refractory mineral raw materials and recycle unused mineral resources. Its separation efficiency is higher than that of physical beneficiation. However, the chemical beneficiation process consumes a lot of chemicals, and the requirements for equipment materials and solid-liquid separation are higher than those of physical beneficiation. Therefore, under normal conditions, it should use existing physical beneficiation methods to process mineral raw materials as much as possible.

When to consider the use of a chemical beneficiation process?

• It cannot be processed by physical beneficiation alone.
• When the physical beneficiation method fails to obtain reasonable technical and economic indicators

 

When Should Chemical Beneficiation Be Considered?

Chemical beneficiation should generally be considered under the following conditions:
1. Physical Beneficiation Alone Is Ineffective
When valuable minerals are extremely fine-grained, closely associated with gangue, disseminated, or chemically similar to the surrounding minerals, conventional physical beneficiation may not achieve satisfactory separation.
2. Physical Beneficiation Cannot Achieve Reasonable Technical and Economic Indicators
If physical beneficiation cannot provide acceptable recovery, concentrate grade, or economic performance, chemical treatment may provide an alternative or supplementary solution.
3. Valuable Components Occur in Complex or Refractory Forms
Chemical beneficiation is particularly suitable when valuable components occur in forms that are difficult to recover through conventional gravity, magnetic, flotation, or other physical methods.

 

 

Precautions When Using The Chemical Beneficiation Process

• Use closed-loop processes as much as possible. Fully regenerate the medicament and recycle water to reduce medicament consumption and environmental pollution.
• The joint process of physical beneficiation and chemical beneficiation should be adopted as much as possible. Various beneficiation methods are used to process mineral raw materials to make the most economical and comprehensive utilization of mineral resources.

 

Conclusion

Chemical beneficiation is an important mineral processing technology for treating low-grade, fine-grained, complex, and refractory mineral resources. By utilizing differences in chemical properties and employing operations such as roasting, leaching, solid-liquid separation, purification, and valuable-component recovery, it can achieve separations that are difficult or impossible to accomplish through physical beneficiation alone.

However, chemical beneficiation generally requires greater consumption of chemical reagents and places higher demands on equipment, materials, solid-liquid separation, and environmental management. Therefore, it should not automatically replace physical beneficiation.

In practice, physical beneficiation should be used whenever it can provide satisfactory technical and economic results, while chemical beneficiation should be introduced where necessary and, whenever possible, integrated with physical beneficiation. The optimal process should maximize valuable-component recovery, minimize reagent and water consumption, promote closed-loop operation, reduce environmental impact, and achieve comprehensive and economical utilization of mineral resources.