Introduction of various tin ore dressing processes

Tin metal has the advantages of good plasticity, corrosion resistance, and non-toxicity. It is widely used in various industries. With the continuous development of science, the application of metallic tin has gradually expanded, resulting in the growing global demand for tin. However, with the reduction of easily beneficiated tin ores, improving the beneficiation level of fine and micro-fine tin ore resources is of great significance to the development of the tin mining industry. The following will introduce you to the types of tin ores and different types of tin ore beneficiation technology.

Types of tin ores

There are about 60 types of tin minerals in nature. The mineral resources used in the tin industry are mainly cassiterite sulfide ores and skarn-type tin ores.

Cassiterite sulfide ore: In this type of mineral, tin mainly exists in the form of cassiterite (SnO₂), and is accompanied by a variety of sulfide minerals, such as pyrite, chalcopyrite, galena and sphalerite. Its structure is often more complex, cassiterite and sulfide are closely coexisting, and the embedded grain size is uneven. Some cassiterite may be evenly dispersed in the sulfide mineral aggregate in fine particles, and some are wrapped with sulfide.

Skarn-type tin ore: It is formed by the contact metasomatism of magmatic hydrothermal fluid and surrounding rocks such as carbonate rocks. The ore mineral composition is complex. In addition to cassiterite, it often contains magnetite, hematite, chalcopyrite, calcite, garnet, diopside and other minerals. The embedded grain size of cassiterite varies greatly, ranging from coarse grains to fine grains. Its structure often has a typical skarn structure, and the degree of mineral crystallization is good.

Mineral processing methods for different types of tin ores

Due to the different types of tin deposits in various regions, the mineral properties are also different, which also leads to great differences in tin ore beneficiation technology. With the continuous advancement and development of tin ore beneficiation technology, the beneficiation effect and indicators have been improved to a certain extent. Common tin ore beneficiation processes include heavy medium pre-selection, cassiterite flotation, fine mud treatment, tailings re-selection, comprehensive recovery, etc.

1. Polymetallic tin sulfide ore beneficiation technology

The tin ore beneficiation method is mainly determined by its own characteristics. The density of cassiterite is generally greater than the density of paragenetic minerals, and gravity separation is an ideal method. Cassiterite polymetallic sulfide ores also contain other useful metal minerals and gangue minerals, so flotation, magnetic separation, electric separation and other auxiliary separation processes are also required. Generally, these auxiliary processes will form a joint beneficiation process with gravity separation to separate cassiterite, so that it can realize the transition from recovering a single tin concentrate product to comprehensive recovery of multiple useful concentrate products, thereby improving the utilization efficiency of the ore.

2. Iron-tin ore dressing technology

Iron-tin ore is a skarn tin ore. The iron minerals contained in the ore are mainly magnetite, limonite, hematite, etc. These iron minerals will have a great impact on the separation of tin minerals. In order to achieve the effective separation of cassiterite and iron minerals, it is necessary to remove iron before separation, and then re-select the iron-removed tailings on a shaking table to finally obtain tin concentrate. In iron-tin ore, cassiterite mineral particles are fine, present in an ionic state and distributed in minerals such as magnetite, which makes it difficult to separate iron and tin. Adding magnetic separation can effectively solve this problem. The treatment of magnetic separation tailings chooses re-selection to obtain tin concentrate.

3. Tin-containing tailings dressing technology

It refers to re-selection from tin-containing tailings to further recover tin valuable elements. Mainly because tin ore is brittle, a large amount of fine-grained cassiterite and tin ore mud are easily produced during grinding operations, which will be discharged together with the tailings. In order to recover tin ore to the maximum extent, the tailings need to be re-selected and recovered. The available methods include gravity separation and flotation. Among them, gravity separation uses the density difference between tin-containing minerals and other components in tailings to recover tin minerals through equipment such as shaking tables and spiral chutes. It is low-cost and environmentally friendly, but the recovery effect of fine-grained tin minerals is poor; flotation is to change the surface properties of minerals by adding flotation agents, so that tin minerals attached to bubbles float up and separate, which can process fine-grained tin minerals, but the selection and use of agents have high requirements; magnetic separation is for tin-containing tailings containing magnetic impurities, and magnetic minerals are separated by magnetic separators to improve the quality of tin concentrate, which is often used in combination with other technologies.

The above is an introduction to the types of tin ores and different cassiterite beneficiation methods. Through analysis, we understand that tin ore is difficult to beneficiate due to its complex composition. It is often necessary to adopt a combination of multiple beneficiation technologies to effectively obtain high-quality tin concentrate. These beneficiation process methods have their own advantages and disadvantages. In actual operation, the beneficiation plant needs to comprehensively select the appropriate process flow according to the properties of the ore, mining conditions and economic benefits to ensure the ideal beneficiation effect.