Introduction of mineral processing process

Processing is a preparatory work before smelting, after the mining of ore from the mine down, you first need to contain iron, copper, aluminum, manganese and other metal ore high selection element out to prepare for the next smelting activities. Mineral processing is generally divided into three parts: crushing, grinding, and sorting. Among them, the crushing is divided into: coarse broken, medium broken and fine broken; the different ways of sorting can also be divided into: magnetic separation, re-election, flotation and so on. This topic will tell you in detail about some specific process knowledge of mineral processing, as well as the general working principle of main mineral processing equipment, main control points and other knowledge.

The purpose of mineral processing: to improve the ore grade.

Mineral processing method

â—† Gravity beneficiation method. According to the different mineral density, the beneficiation medium has different sedimentation speeds for beneficiation.

â—† Magnetic beneficiation method. The magnetic beneficiation method utilizes the magnetic difference of minerals. In a non-uniform magnetic field, the magnetic minerals are attracted by the magnetic pole of the magnetic separator, while the non-magnetic minerals are rejected by the magnetic poles, thereby achieving the purpose of sorting.

â—†Floating mineral processing method. The floating ore dressing method utilizes the different hydrophilicity of the mineral surface to selectively float the hydrophobic mineral to the surface of the slurry with the foam, while the hydrophilic mineral remains in the slurry, thereby separating the different minerals from each other.

Mineralized products: concentrate, medium ore and tailings.

â—† Concentrate refers to products containing higher mineral content after mineral processing.

â—† China Mine is an intermediate product in the beneficiation process and needs further mineral processing. â—† Tailings are wastes left after ore dressing.

Mineral processing flow chart

Beneficiation process

(1) Ore crushing

China's concentrating plants generally use crushing, crushing and fine-breaking three-stage crushing process to break iron ore. The coarse crushing multi-purpose 1.2m or 1.5m rotary crusher is used in the 2.1m or 2.2m standard cone crusher, and the 2.1m or 2.2m short-head cone crusher is used for fine breaking. Through the coarse ore, the blockiness is not more than 1m, and then it is crushed by medium and fine, and sieved into the final product of the ore grain size less than 12mm.

(2) Grinding process

Most of China's iron ore grinding process uses two-stage grinding process, and small and medium-sized ore dressing plants use a grinding process. Due to the use of fine screening and re-grinding new processes, in recent years some concentrating plants have changed from two-stage grinding to three-stage grinding. The grinding equipment used is generally small, the largest ball mill is 3.6m×6m, the largest rod mill is 3.2m×4.5m, the largest self-grinding mill is 5.5m×1.8m, and the gravel mill is 2.7m×3.6m. The classification after grinding is basically a spiral classifier. In order to improve efficiency, some concentrators use hydrocyclones to replace the secondary spiral classifier.

(3) Sorting technology

Magnetite beneficiation

It is mainly used to select low-grade "Anshan-style" magnetite. Due to the strong magnetic properties of the ore and good grinding, the domestic magnetic separation plant adopts stage grinding and multi-stage grinding process. For the coarse-grained magnetite, the former (a section of grinding), fine-grained and fine-grained inlays are used. The magnetite uses the latter (two or three stages of grinding). The series of permanent magnetization developed by China has made the magnetic separator realize permanent magnetization. After the 1970s, fine screening was promoted in the national magnetite ore dressing plant.

Re-grinding new technology, the concentrate grade increased from 62% to about 66%, achieving the metallurgical industry's request for 65% concentrate grade.

Weak magnetic iron ore beneficiation

Mainly used to select hematite, limonite, mirror iron ore, siderite, imaginary hematite or mixed ore, also known as "red mine." This type of ore has a low grade, a fine grain size, a complex mineral composition, and difficulty in sorting. After the 1980s, the beneficiation technology has continuously improved the research on the process, equipment and new varieties of roasting magnetic separation, wet magnetic separation, weak magnetic flotation and re-election, so that the concentrate grade and metal recovery rate are continuously improved. For example, the Qishanshan Concentrator of Anshan Iron and Steel Co., Ltd. has adopted a new process of weak magnetic-strong magnetic-flotation, which has achieved encouraging results.

Polymetallic (concomitant) ore dressing

Such ore is complex in composition and various in type, so the methods, equipment and processes used are also different. For example, the Bayan Obo iron ore uses reverse flotation - multi-gradient magnetic separation, flocculation flotation, weak magnetic-reverse flotation - strong magnetic Different processes such as selection, weak magnetic-positive flotation, roasting magnetic separation, etc., to improve the recovery rate of iron and comprehensively recover rare earth oxides. The Panzhihua Iron Mine obtained about 53% of the ferro- vanadium concentrate of TFe by magnetic separation. The tailings after magnetic separation were obtained by weak magnetic sweep-strong magnetic separation-re-election-flotation-drying to obtain titanium concentrate and sulphur- cobalt concentrate. Mine, recycling titanium and cobalt. Daye Iron Mine uses weak magnetic-strong magnetic and flotation to comprehensively recover iron, copper, cobalt and sulfur.

Main equipment and introduction of mineral processing

(1) Ore crushing equipment

Jaw crusher

Jaw Crusher Working Principle: Jaw Crusher (Jaw Crusher) has the characteristics of large crushing ratio, uniform product size, simple structure, reliable work, easy maintenance and economical operation. [View the working principle of jaw crusher]

Common electrical equipment for jaw crusher: Soft starter low voltage electrical appliance (contactor, circuit breaker, etc.)

Hammer crusher

Working principle of hammer crusher: Hammer crusher is one of the main equipments for crushing limestone , coal or other brittle materials below medium hardness in metallurgy, building materials, chemical industry and hydropower industry. It has large crushing ratio and high production capacity. Uniform particle size and other characteristics. [View the working principle of hammer crusher]

Common electrical equipment for hammer crusher: Soft starter low voltage electrical appliance (contactor, circuit breaker, etc.) Electromagnetic coupler hydraulic coupler

(2) Grinding process equipment

Ball mill

The working principle of the ball mill: the material is smoothly inserted into the first chamber of the mill by the feeding device through the hollow shaft of the feed. The chamber has a step liner or a corrugated liner, which is filled with steel balls of different specifications, and the cylinder is conveyed to generate centrifugal force. The ball is dropped to a certain height and then falls, which causes heavy impact and grinding on the material. [See how the ball mill works]

Common electrical equipment for ball mill: Low-voltage electrical appliances (contactors, circuit breakers, etc.) Reducer high-voltage motor water resistance

Spiral classifier

Working principle of spiral classifier: The spiral classifier is based on the principle that the solid particle size is different and the specific gravity is different, so the sedimentation speed in the liquid is different. The fine ore particles float in the water and overflow, and the coarse ore particles sink to the bottom of the tank. [View the working principle of spiral classifier]

Common electrical equipment for spiral classifiers: Low-voltage electrical appliances (contactors, circuit breakers, etc.) Reducer motors

(3) Separation process equipment

Flotation machine

Working principle of flotation machine: When the flotation machine is working, the impeller rotates by the motor drive to generate centrifugal force to form negative pressure. On the one hand, the air is mixed with the slurry, on the one hand, the slurry is mixed with the drug, and the foam is refined. Above the mineral-bonded foam, float to the pulp surface to form a mineralized foam.

Common electrical equipment for flotation machines: Low-voltage electrical appliances (contactors, circuit breakers, etc.) Reducer motors

Magnetic separator

Working principle of magnetic separator: The magnetic separation process is sorted by the action of magnetic force and mechanical force on the ore particles in the magnetic field of the magnetic separator. [View the working principle of magnetic separator]

Common electrical equipment for magnetic separator: Low-voltage electrical appliances (contactors, circuit breakers, etc.) Reducer motor

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