Production method of extremely fine lean magnetite

Abstract

The invention relates to a production method of extremely fine lean magnetite. The production method is characterized by comprising the following steps that mineral aggregate with the particle size being not larger than 30mm is crushed to be 8-0mm through a high-pressure roller mill; water is added into the mineral aggregate with the particle size being 8-0 mm for size mixing till the solid mass concentration is 55%-60%, the mineral aggregate enters a wet screening machine with the screen mesh not exceeding 6 mm, the moisture of oversize return materials with the particle size larger than 6 mm is controlled to be within 8%, coarse-particle-size pre-selection tailing discarding is conducted on the mineral aggregate with the particle size smaller than 6 mm, and the magnetic field intensity is 4500 oersteds; the mineral aggregate with the particle size being smaller than or equal to 38 microns is mixed with water to form slurry; the 38-micron graded feeding mass concentration is controlled within 24.50%, and the graded product fineness P95 is equal to 38 microns; and the 25-micron graded feeding mass concentration is controlled within 20.00%, and the graded product fineness P95 is equal to 25 microns. According to the method, the ore grinding power index of the ore is greatly reduced, the ore grinding load and energy consumption are reduced, effective grading of superfine grinding narrow particle fractions is achieved, and metal loss is reduced.

Description

technical field [0001] The invention belongs to the technical field of metallurgy and mine engineering, and in particular relates to a production process of extremely fine lean magnetite. Background technique [0002] In the ferrous metallurgical mining industry, magnetite ore is an iron ore that is easier to produce and process in the past. Generally, the particle size of crushed ore does not need to be less than P80=45μm, and the dissociation degree of monomer can reach more than 80%. Usually, only weak magnetic separation method can be used. Produce iron ore concentrate powder with a total iron grade greater than 65%. And with the less and less easy-to-select ore resources, how to effectively process and utilize fine and extremely fine magnetite-poor ore has become a subject facing the industry. For about 55% of the extremely fine magnetite-poor ore with embedded particle size less than 19 μm, it is quite difficult to use conventional crushing process and horizontal ball...

AI Technical Summary

Problems solved by technology

[0009] 2. Crushing and sieving raises a lot of dust

Workers have a high chance of getting silicosis

However, the current dust suppression process requires large investment, high maintenance and operation costs, and low efficiency.

[0010] 3. Low pre-selection efficiency before grinding

The low tailing rate of pre-selection increases the load of the first stage of grinding, which leads to the increase of equipment selection and energy consumption

[0011] 4. The more economical grinding fineness of conventional horizontal mill grinding and grading is less than 0.045mm<85%. If this fineness is exceeded, the mill efficiency index—the mill utilization coefficient will be reduced by more than 15%, resulting in ball consumption. , power consumption and other energy consumption indicators increase

[0012] 5. It is difficult to classify ultra-fine grinding ore products with narrow particle size

At present, the grading equipment is mainly fine screen and cyclone. When the grinding fineness reaches less than 0.045mm ≥ 85%, the particle size of the grinding product becomes narrower, and when the mass concentration is greater than 30%, the viscosity of the slurry increases, and the coarser particle size The sedimentation velocity is reduced, the adsorption capacity of mineral particles is enhanced, the sieve holes are easily blocked by paste, and the classification of the cyclone is difficult

[0013] 6. Conventional permanent magnet wet magnetic separation has serious metal loss of ultra-fine ground magnetite

The main reason is that with the increase of magnetite particle size less than 50μm, its specific magnetic susceptibility drops sharply. The magnetic field of conventional wet magnetic separator is low and the magnetic pole spacing is large. It is difficult to capture ultra-fine magnetic minerals, which is easy to cause resource loss. At the same time, the number of magnetic reversals is small. , the adsorbed non-magnetic minerals cannot be flipped and removed, which is not conducive to the improvement of the concentrate grade