​Progress in Wolframite Beneficiation Technology

Introduction

Wolframite, as a key ore for tungsten extraction, plays a pivotal role in modern industry. Tungsten, due to its high melting point, high strength, excellent wear resistance, and corrosion resistance, is widely used in many fields such as metallurgy, machinery manufacturing, electronics, aerospace, etc. The efficient extraction of tungsten concentrate from wolframite is inseparable from a scientific and reasonable mineral processing technology. This article will elaborate on the mineral processing technology of wolframite, including its process flow, the principles and operation key points of each stage, as well as the development trends of related technologies.

I. Characteristics of Wolframite

Wolframite, with the chemical formula (Fe,Mn)WO₄, belongs to the oxide mineral of the monoclinic system. Its color and streak vary with the content of iron and manganese. The higher the iron content, the darker the color, usually ranging from brown - red to black, with a streak from yellow - brown to black - brown, and it has a metallic to sub - metallic luster. Wolframite has a relatively large specific gravity, ranging from 7.2 - 7.5, a Mohs hardness between 4 - 4.5, and generally has weak magnetism. These characteristics provide important bases for the selection and design of its mineral processing technology.

II. Wolframite Mineral Processing Process Flow

(1) Hand - sorting Method

The hand - sorting method is a relatively primitive but simple and effective pre - enrichment method for wolframite. It is selected manually based on the differences in color, luster, and shape between wolframite and associated minerals. Hand - sorting can be divided into positive hand - sorting (selecting qualified wolframite) and negative hand - sorting (selecting waste rock). This method is easy to operate, has low equipment requirements, and relatively low costs. However, the hand - sorting method has high requirements for the quality of the ore, and is only suitable for ores with high grades and obvious mineral characteristics. Moreover, its production efficiency is low, the labor intensity is high, and it may also lead to a large amount of resource waste, so it has great limitations in large - scale industrial production.

(2) Grinding Stage

Grinding is one of the key links in wolframite mineral processing. Due to the brittleness and high specific gravity of tungsten, over - grinding and over - comminution are likely to occur during the grinding process, which will not only affect the subsequent separation effect but also cause resource losses. Therefore, appropriate processes and equipment need to be carefully selected in the grinding stage. Common grinding processes for wolframite include single - stage grinding, single - stage rod grinding + middling grinding, two - stage grinding, etc. In terms of equipment, rod mills are mostly used because rod mills can reduce over - comminution during the grinding process, better protect the particle size of minerals, and are conducive to subsequent separation operations.

(3) Gravity Separation Stage

Gravity separation is one of the important methods for wolframite mineral processing, mainly based on the significant difference in density between wolframite and gangue minerals for separation. In the gravity separation stage of wolframite, a process of multi - stage jigging, multi - stage shaking table, and middling re - grinding is generally adopted. The specific operation is as follows: The qualified ore after fine crushing is classified by a vibrating screen and then enters multi - stage jigging to produce jigging gravity - separated rough sand. The coarse - grained jigging tailings enter the rod mill for re - grinding to further dissociate the minerals; the fine - grained jigging tailings are classified by a hydraulic classifier and then enter the multi - stage shaking table for one - roughing and one - scavenging separation to produce shaking - table gravity - separated rough sand. The shaking - table tailings are discharged into the tailings pond, and the shaking - table middlings are returned for re - grinding and re - separation to improve the mineral recovery rate.

(4) Flotation Stage

Flotation usually adopts a combination of flotation - gravity separation or flotation - gravity separation - magnetic separation processes. During the flotation process, sulfide minerals are removed through coarse - and fine - grained table flotation and mechanical flotation. The sulfide minerals from table flotation and mechanical flotation are combined and enter the sulfide mineral flotation separation to recover valuable metals therein. The wolframite from table flotation and mechanical flotation is further processed by gravity separation to produce wolframite concentrate. If the wolframite concentrate contains scheelite or cassiterite, a combination of gravity separation - flotation or gravity separation - flotation - magnetic separation (electrostatic separation) processes is required to effectively separate wolframite concentrate, scheelite concentrate, and cassiterite concentrate.

(5) Slime Treatment

The slime (particle size of - 0.074mm fraction) generated during the wolframite mineral processing process needs to be treated separately. First, desulfurization is carried out to remove sulfide impurities in the slime. Then, according to the properties of the slime materials, separation processes such as gravity separation, flotation, magnetic separation, electrostatic separation, or a combination of several processes are selected to recover tungsten minerals. At the same time, attention is paid to the comprehensive recovery and utilization of associated metal minerals to improve the resource utilization rate.

III. Mineral Processing Principles at Each Stage

(1) Principle of Gravity Separation

The basic principle of gravity separation is to utilize the density difference between wolframite and gangue minerals. Under the action of force fields such as gravity, centrifugal force, and the dynamic force of the medium flow, they produce different movement trajectories and speeds, thereby achieving separation. For example, during the jigging process, through the up - and - down pulsation of the water flow, mineral particles of different densities are stratified according to density. The high - density wolframite particles sink to the lower layer, while the low - density gangue mineral particles float to the upper layer, thus realizing separation.

(2) Principle of Flotation

Flotation is based on the differences in the physical and chemical properties of the mineral surface, especially the wettability differences of the mineral surface for separation. During the flotation process, specific collectors, frothers, regulators, and other reagents are added to the pulp. The collector can selectively adsorb on the surface of wolframite, making its surface hydrophobic; the frother can generate a large number of stable bubbles; the regulator is used to adjust the pH value and other properties of the pulp to create conditions conducive to flotation. The hydrophobic wolframite particles attach to the bubbles, float to the surface of the pulp with the bubbles, and form a foam layer, thus separating from the gangue minerals.

(3) Principle of Magnetic Separation

Wolframite has certain weak magnetism, and magnetic separation is based on this characteristic. In a magnetic field, wolframite will be affected by magnetic force, while gangue minerals generally do not have magnetism or have extremely weak magnetism. By adjusting the magnetic field strength and other parameters, wolframite is adsorbed by the magnetic separation equipment, while the gangue minerals flow away with the pulp, thus achieving separation. For magnetic minerals coexisting with wolframite, such as ilmenite, they can also be separated by magnetic separation according to the differences in their magnetism.

IV. Optimization and Development Trends of Mineral Processing Technology

(1) Process Optimization

1.        Equipment Upgrading: Adopt new - type and high - efficiency mineral processing equipment, such as new - type jiggers, shaking tables, flotation machines, etc., to improve the processing capacity and separation efficiency of the equipment. For example, some new - type flotation machines can better realize the interaction between minerals and reagents and improve the flotation effect by optimizing the structure and aeration method.

2.        Process Optimization: Continuously optimize the mineral processing process according to the changes in ore properties, such as adopting a more reasonable grinding and classification process to improve the dissociation degree of minerals; optimize the parameters and sequence of each separation operation to maximize resource recovery.

3.        Reagent R & D: Develop new - type, high - efficiency, and environmentally friendly mineral processing reagents to improve the selectivity and collection ability of reagents, reduce reagent consumption and costs, and reduce the impact on the environment.

(2) Development Trends

1.        Intelligent Mineral Processing: Introduce automation control and artificial intelligence technologies to achieve real - time monitoring, intelligent regulation, and optimized management of the mineral processing process. For example, through sensors, parameters such as pulp concentration, particle size, and grade are monitored in real - time, and artificial intelligence algorithms are used to automatically adjust the operating parameters of the equipment to improve the stability and efficiency of the mineral processing process.

2.        Comprehensive Recovery and Resource Recycling: Pay attention to the comprehensive recovery of associated metal minerals and other useful components in wolframite to improve the resource utilization rate. At the same time, strengthen the treatment and recycling of tailings to achieve resource recycling and reduce the pressure on the environment.

3.        Green Mineral Processing: Develop and apply green and environmentally friendly mineral processing technologies and processes to reduce energy consumption, wastewater, waste gas, and waste residue emissions during the mineral processing process and achieve the sustainable development of the mineral processing industry.

V. Conclusion

The wolframite mineral processing technology is a complex and systematic project, involving the comprehensive application of multiple links and various technologies. From the preliminary enrichment of the hand - sorting method to the coordinated action of a series of processes such as grinding, gravity separation, flotation, and slime treatment, each stage has an important impact on the final mineral processing indicators and resource utilization rate. With the continuous progress of science and technology, the wolframite mineral processing technology is also constantly being optimized and innovated, developing towards the direction of intelligence, comprehensive recovery, and environmental protection. This not only helps to improve the utilization efficiency of tungsten ore resources, reduce production costs, but also reduces the impact on the environment and lays a solid foundation for the sustainable development of the tungsten ore industry.