A raw ore powder-making process

Abstract

The present invention relates to the technical field of ore dressing, and specifically relates to a raw ore powder making process, which includes a grinding mill and a powder separator. The grinding mill is a bed grinding equipment, and the powder separator is a V-type powder separator, and / or a screening device; a selective crusher is arranged in front of the grinding mill for pretreatment of the raw ore; the raw ore includes laterite nickel ore, or smelting slag, or stone coal vanadium ore, or waste concrete, or alluvial gold ore; according to the strength difference between the target mineral and gangue, the rolling pressure of the grinding mill is adjusted; after the raw ore is rolled by the grinding mill, it is sorted by the powder separator, and according to the size of the material particle size, coarse particle tailing or fine particle tailing is selected; moreover, the material with intermediate particle size is returned to the grinding mill for rolling again; by applying this process, over-grinding can be eliminated during powder making, pre-selection enrichment can be realized, the ore grade can be improved, and finally the cost of smelting can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of ore dressing, and specifically, to a raw ore pulverization process. Background Art

[0002] Ore dressing is a process of separating useful minerals from gangue minerals according to the physical and chemical properties of different minerals in the ore. After the ore is crushed and ground, methods such as gravity separation, flotation, magnetic separation, and electrostatic separation are used to separate the useful minerals from the gangue minerals, and to separate various symbiotic (associated) useful minerals from each other as much as possible, removing or reducing harmful impurities to obtain raw materials required for smelting or other industries; Ore dressing can enrich the useful components in the minerals, reduce the consumption of fuel and transportation in the smelting or other processing processes, and enable low-grade ores to be economically utilized.

[0003] For some refractory ores, sometimes using only the ore dressing method often fails to achieve satisfactory results, or even fails to separate, so a combined ore dressing and metallurgy process needs to be used for treatment; The combined ore dressing and metallurgy process is a process flow that alternately uses ore dressing and metallurgy methods to treat ores.

[0004] Chinese Patent CN117120172A discloses a laterite nickel ore dressing equipment and process. The equipment includes: a cylindrical ore washer, a trough ore washer, a vibrating screen, a hydrocyclone connected to the trough ore washer and the vibrating screen, a first thickener connected to the hydrocyclone, a spiral chute connected to the hydrocyclone, a first ball mill connected to the spiral chute, and a second thickener connected to the first ball mill; The process includes: performing three-stage separation and gravity separation on the ore material in sequence, settling the ore material that meets the requirements after the three-stage separation and gravity separation, and crushing, grinding, and settling the ore material that meets the requirements. The ore is fully utilized, reducing the waste of ore and improving the nickel collection rate.

[0005] In the process of implementing the embodiments of the present invention, the inventors found that there are at least the following defects in the prior art: over-grinding is likely to occur during the grinding of raw ore.

[0006] The over-grinding phenomenon refers to the situation where the material that has reached the reasonable fineness requirement is continuously ground in the mill, resulting in the material being too fine. The inventors realized that: in the ore dressing industry, over-grinding usually manifests as follows: (1) If the gangue minerals that should not be ground fine are also ground fine, they will mix into the high-value target minerals, causing ore dilution and bringing difficulties to separation; (2) In addition, as the grinding time increases, the target mineral grains are easily over-ground. If the target minerals are also over-ground, the overly fine target minerals are likely to enter the tailings with the gangue minerals, commonly known as ore loss and tailing loss, resulting in a decrease in recovery rate and unnecessary energy consumption. Therefore, there is an urgent need to provide a raw ore pulverization process to solve the technical problem of easy over-grinding in the prior art, so as to improve production efficiency and reduce production costs. Summary of the Invention

[0007] In view of the above deficiencies in the prior art, the present invention provides a raw ore powder making process. In the powder making (grinding) stage, a material bed grinding device is selected as the grinding mill to replace the traditional tube mill. Moreover, the rolling pressure of the grinding mill is adjusted according to the strength difference between the target mineral and gangue, and tailing is discarded in a timely manner to enrich the target mineral through separation. The object of the present invention is achieved through the following technical solutions:

[0008] A raw ore powder making process includes a grinding mill and a powder separator, wherein:

[0009] The grinding mill is a material bed grinding device, including an external circulation vertical mill or a roller press. The external circulation vertical mill is a vertical mill without a separator;

[0010] The powder separator is a V-type powder separator and / or a screening device. The screening device includes a rotor type powder separator (32), or a cylindrical screen, or a grading screen;

[0011] According to the strength difference between the target mineral and gangue, the rolling pressure of the grinding mill is adjusted; after the raw ore is rolled by the grinding mill, it is separated by the powder separator. According to the particle size of the material, coarse particle tailing or fine particle tailing is selected; and the material with intermediate particle size returns to the grinding mill for rolling again; by applying this process, over-grinding can be eliminated during powder making, pre-selection enrichment can be achieved, and the ore grade can be improved.

[0012] In a specific feasible embodiment, a selective crusher is arranged in front of the grinding mill for pre-treatment of the raw ore; the selective crusher includes a drum sorting crusher.

[0013] In a specific feasible embodiment, a powder collecting device is arranged behind the powder separator. The powder collecting device includes a cyclone separator and / or a dust collector. The dust collector is a bag filter or an electrostatic precipitator; the powder collecting device is used for product collection and environmental protection; after the system waste gas is purified, it is led out by an exhaust fan connected to the powder collecting device and discharged into the atmosphere.

[0014] In a specific feasible embodiment, a regulating valve is arranged on the dust collection pipeline of the system. The dust collection pipeline includes a ventilation pipeline; the wind speed is regulated and controlled through the regulating valve, and then the product fineness is regulated.

[0015] In a specific feasible embodiment, the production waste heat is utilized or a hot blast stove is arranged; a hot air valve is arranged on the heat supply pipeline for regulating the hot air volume; and a cold air valve is arranged for regulating the temperature of the hot air; hot air is provided for raw ore powder making to achieve grinding and drying simultaneously.

[0016] In a specific feasible implementation, the raw ore includes laterite nickel ore, or smelting slag, or stone coal vanadium ore, or waste concrete, or alluvial gold ore.

[0017] In summary, the present invention has the following beneficial effects:

[0018] (1) The microstructure of minerals is closely related to the mineralization conditions. There are differences in the mechanical properties between minerals and gangue, and these differences are related to their respective microstructures. The mechanical strength of a material is a measure of its ability to resist external forces without being damaged. When the mechanical strength of a material is poor, it means that its resistance to external forces is weak. During mechanical processing such as grinding and cutting under external forces, materials with poor mechanical strength are more likely to deform or break. Due to the above reasons, during the grinding process, the weaker parts are more easily ground fine. Therefore, by adjusting the roller pressure, the soft ore is broken first, and the hard ore is kept as intact as possible, not all broken, thus eliminating over-grinding. For example, under normal circumstances, even the hardest mineral has a hardness not exceeding that of steel balls. The steel balls strike the materials indiscriminately, breaking both soft and hard ores, and those that don't need to be broken immediately are also broken, thus causing over-grinding. When using rollers to roll the clusters of mineral particles, the soft ore is always broken first, and then the soft ore particles hide in the space supported by the hard ore to avoid further extrusion. Therefore, over-grinding is eliminated.

[0019] (2) After the minerals are rolled, due to the difference in fineness between the soft ore and the hard ore, it is convenient to separate the two in advance. The present invention separates the fine powder (mostly soft ore) in time through sorting. Additionally, it can also reduce the over-grinding of the soft ore.

[0020] (3) In soft ore and hard ore, the content of the target mineral often varies. By separating the soft ore and the hard ore, it helps to enrich the concentrate and improve the grade of the ore, which is understandable.

[0021] In the prior art, over-grinding also causes low beneficiation efficiency. After eliminating over-grinding in the present invention, in addition to achieving the beneficial effect of energy conservation, it can also improve the beneficiation efficiency, and improving the beneficiation efficiency can be said to be an unexpected technical effect.

[0022] Then, why can't the prior art achieve the above beneficial effects? The inventor realizes that the reason lies in that the equipment and process of the prior art have defects. There are no separation measures during the grinding process, which easily causes over-grinding of the materials. Over-grinding leads to the impoverishment of the target mineral (doping, gangue mixing), making it more difficult to beneficiate the originally easy-to-beneficiate ore, increasing the subsequent separation burden. If there is flotation later, it will increase the dosage of reagents and result in high production costs. And / or, there is ore loss (loss of concentrate), causing waste of resources and a decrease in recovery rate.

[0023] In the process of powder making, the present invention adopts a new process and adds separation measures, which can eliminate over-grinding phenomenon during powder making and reduce energy consumption. At the same time, through pre-selection enrichment, the ore grade is improved, and discarding part of the tailings can greatly reduce the ore treatment volume in the subsequent sections. In short, during the production process, useful minerals are recovered in advance, tailings are discarded early, and tailings are discarded while moving forward, so as to go ahead lightly. Finally, the smelting cost is reduced.

[0024] Through the above comparative analysis, it can be found that the traditional ore dressing process is simply crushing, grinding, flotation, and pressure filtration. In the crushing and powder making stage, those skilled in the art often only consider monomer dissociation and grind the raw ore finely, without realizing the difference between the single-particle crushing principle and the bed crushing principle, nor realizing the influence of the mechanical property differences between minerals and gangue on crushing, ignoring the control of crushing intensity and the selection of separation timing, resulting in over-grinding of materials. For ordinary technicians in this field, it is obviously difficult to understand the above knowledge and make improvements, which is also the reason why the related technology cannot achieve this beneficial effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is the flow chart of Embodiment 1 of the present invention;

[0026] Figure 2 is the flow chart of Embodiment 2 of the present invention;

[0027] Figure 3 is the flow chart of Embodiment 3 of the present invention.

[0028] DESCRIPTION OF THE REFERENCE NUMERALS: 1 - drum crushing separator;

[0029] 21 - external circulation vertical mill; 22 - roller press;

[0030] 31 - V-type powder separator; 32 - rotor type powder separator; 33 - grading screen;

[0031] 4 - dust collector; 41 - regulating valve; 42 - exhaust fan;

[0032] 5 - hot blast stove; 51 - hot air valve; 52 - cold air valve. DETAILED DESCRIPTION OF THE INVENTION

[0033] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments; based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention. It should be noted that the present invention can be implemented in a variety of different ways as defined and covered by the claims. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other.

[0034] At present, laterite nickel ore is mainly smelted by pyrometallurgical or hydrometallurgical processes to produce high-grade nickel matte or nickel-cobalt hydroxide (MHP) intermediate products respectively; if pyrometallurgical process is adopted, during the smelting process, smelting slag (molten slag) is discharged from the slag outlet. Usually, the slag is subjected to water quenching, crushing and sorting for many times; that is, the raw materials need to be smelted repeatedly to be continuously enriched and high-grade nickel-iron alloy is obtained; the present invention is suitable for grinding and powdering laterite nickel ore or smelting slag (including roasted ore).

[0035] The present invention has a simple structure, reasonable design and convenient implementation; in the embodiments of the present invention, a variety of optional implementation methods are provided, which can be selected according to actual needs. No matter which method is adopted, the existing technology is no longer used for the powder making process of specific minerals, and the problems in the existing technology can be solved and the corresponding effects can be achieved; the following embodiments can be applied to the powder making of laterite nickel ore or stone coal vanadium ore, and can also be applied to the resource recycling of waste concrete, or the pre-selection of alluvial gold mines, etc. Therefore, the application of the present invention includes but is not limited to the powder making process of laterite nickel ore.

[0036] Embodiment 1:

[0037] In this embodiment, laterite nickel ore is ground into powder; as the finished product of the powder making stage, the powder is the raw material for smelting in the furnace, the free water content of the powder is about 1%, the crystal water content is 9% to 10%, and the residue on a 200-mesh sieve is 30%.

[0038] See also Figure 1 This embodiment provides a raw ore powder making process, including a grinding mill and a powder concentrator, wherein:

[0039] In this embodiment, a selective crusher is provided in front of the pulverizer. The selective crusher includes a drum sizing crusher 1 for the pretreatment of laterite nickel ore. The drum sizing crusher 1 is a horizontally rotating cylindrical barrel, driven by a motor to rotate, and is provided with sieve holes or sieve bars on the barrel wall. The laterite nickel ore is fed in from one end, where: the fine materials leak through the sieve holes in the middle of the equipment and enter the pulverizer; the lumpy materials are discharged from the other end to achieve preliminary tailing rejection. The "tailing rejection" refers to discarding low-grade lean ore and waste rock as tailings. The "tailing rejection" includes preliminary tailing rejection, and the advantage is to reduce the processing volume of subsequent grinding and separation operations.

[0040] The further explanation is as follows. In this embodiment, the purpose of using the selective crusher is that in laterite nickel ore, high-grade ores are fragile, while hard materials with significantly excessive strength are often surrounding rocks or gangues. According to this characteristic, by using a relatively small crushing force, the hard materials can be separated in advance. In this embodiment, with the help of the drum sizing crusher 1, the materials are repeatedly dropped during the moving process. In this way, by using a relatively small crushing force, the target minerals can be fragmented while the gangues remain intact, facilitating the separation of the two. After the preliminary tailing rejection, the primary selection of the raw ore is completed. Since the hardness of nickel ore varies greatly in different regions, a drop test of the nickel ore must be carried out before the selection of the equipment, and then the equipment specifications are determined according to the number of drops and the processing capacity of the nickel ore.

[0041] Similarly, in the coal mining industry, raw coal mined often contains coal gangue. The coal gangue is hard in texture and the raw coal is soft. If crushed improperly, the coal gangue will be fragmented into small pieces and mixed into the raw coal, reducing the quality of the raw coal and making it difficult to select. The drum sizing crusher 1 was once used for the crushing and screening of raw coal in coal preparation plants, replacing manual gangue picking with a selective crusher to realize the mechanization of gangue picking operations and reduce labor intensity.

[0042] In addition, in this embodiment, according to the actual situation, a media-free mill (autogenous mill) can also be selected as the selective crusher. The media-free mill is a grinding equipment that combines the functions of crushing and grinding. It uses the material itself as the medium and realizes crushing through mutual impact and grinding actions, thus getting its name. Its biggest feature is that the raw ore from the mining site or the ore after coarse crushing can be directly fed into the mill without passing through crushers, etc. The media-free mill can grind the materials to a content of -0.074mm accounting for 20% - 50% or more of the total product at one time. In the media-free mill, in fact, the hard part of the raw material is used as the grinding body, and the material hits the material. Always the soft raw material breaks first, so similar effects can be achieved.

[0043] The laterite nickel ore that has completed the primary selection is fed into the pulverizer. The pulverizer is a material bed grinding equipment, including an external circulation vertical mill 21 or a roller press 22. The external circulation vertical mill 21 is a vertical mill without a separator.

[0044] The main working components of a vertical mill are the grinding table and grinding rollers. The motor drives the grinding table to rotate through a speed reducer. The grinding rollers roll on the grinding table around their own axes. Materials pass through the air-lock feeding device and fall onto the center of the grinding table through the feeding chute. Due to the action of centrifugal force, a ring-shaped material bed is formed and is clamped into the gap between the grinding rollers and the grinding table, where it is crushed under the extrusion action. At the same time, due to relative sliding, a shearing force is generated, making the materials finely ground. The vertical mill uses the grinding rollers to extrude the materials on the grinding table and relies on the airflow to carry out the particles that meet the fineness requirements out of the mill. After being collected by the dust collector, they become finished products. Inside the vertical mill, the larger particles in the airflow fall back onto the grinding table for grinding under the action of gravity. This process needs to be carried out multiple times to make their fineness meet the requirements. The roller press consists of two extrusion rollers that rotate synchronously in opposite directions, one is a fixed roller and the other is a movable roller. Both the vertical mill and the roller press are bed grinding equipment.

[0045] For a long time in the beneficiation industry, tube mills are usually selected as grinding equipment. The tube mill includes a ball mill. A certain number of steel balls are loaded into the cylinder of the ball mill as grinding media. The main function of the steel balls in the ball mill is to impact and crush the materials, and at the same time, it also plays a certain grinding role. When processing limonite-type laterite nickel ore, its grinding and crushing processes will consume a large amount of energy. The existing technology often uses a ball mill, which has extremely low grinding efficiency and high energy consumption. According to the research and test measurements of grinding workers around the world, the grinding efficiency of the tube mill is only a few percent, and the rest is consumed by sound energy, the energy consumption of the wear of the grinding media and the lining plate, etc. The fundamental reason is that the tube mill usually adopts the single-particle crushing principle. In single-particle crushing, each particle is crushed by contacting the crushing equipment and being directly subjected to its pressure or shearing force, which is different from bed crushing.

[0046] Different from the single-particle crushing, the bed grinding equipment adopts the bed crushing (or layer crushing) principle. Only a small part of the particles are in direct contact with the crushing equipment. Under the action of pressure, the materials are crushed by mutual extrusion. The crushing efficiency of bed crushing is high. The materials are crushed during the mutual extrusion process without unnecessary energy waste, so it is energy-saving.

[0047] Furthermore, a vertical mill usually comes with a separator and can perform powder selection inside the mill. The present invention uses an external circulation vertical mill 21, which is a vertical mill without a separator. That is to say, the present invention transfers the powder selection function outside the mill. It can timely discharge the materials that meet the fineness requirements and do not need to be ground further at a certain stage from the mill, as long as it can meet the requirements of beneficiation. Therefore, the discharge of ore is timely and over-grinding will not occur.

[0048] In the materials fed into the mill, due to different mineral structures, their abilities to resist damage are different. The main function of the steel balls in the ball mill is to impact and crush the materials, and the impact force is the same. Parts that should not be crushed are often crushed more severely, thus easily causing over-grinding. As a layer grinding equipment, the external circulation vertical mill 21 can adjust the rolling pressure, that is, according to the strength difference between the target mineral and gangue, adjust the rolling pressure of the grinding mill. Therefore, the raw ore is rolled by the grinding mill. By taking advantage of the difference in the ability of different minerals to resist impact, step by step, the pressure is gradually increased, and tailing is carried out multiple times, further avoiding over-grinding.

[0049] For example, the chromite of the spinel type associated with laterite nickel ore has a strong abrasion effect on the anti-corrosion layer of wet equipment. Therefore, it is very necessary to carry out beneficiation and impurity removal of chromite. The essence of beneficiation and chromium removal in laterite nickel ore is the separation and enrichment of chromite and limonite. Regarding the differences between limonite and chromite, the existing technology believes that they mainly exist in aspects such as density and magnetism. However, not only that, the inventor realizes that abrasion occurs because some minerals are not easily broken, and the fact that minerals are not easily broken is determined by their mechanical properties. That is to say, among chromite and limonite, one is difficult to grind fine and the other is relatively easy to grind. Under the same grinding conditions, there will be a difference in fineness. By using the difference in particle size, the separation of chromite and limonite can be achieved.

[0050] Another example is that stone coal is a carbonaceous shale highly decayed in an oxygen-deficient environment. The humus it contains has complexing and adsorption effects. At the same time, due to the combined influence of the formation conditions of stone coal and hydrothermal impregnation during diagenesis, stone coal often associates or enriches more than 60 metal elements such as vanadium, molybdenum, nickel, and copper, and most of the metal elements exist in the form of sulfide ores. In some stone coal, one or several of these metal elements can often reach the cut-off grade of ore formation or the industrial grade for separate mining, making stone coal have independent mining value. For example, vanadium-bearing stone coal or stone coal vanadium ore is a very important one. Vanadium in stone coal mainly exists in the trivalent form and replaces aluminum (III) in the lattice of silicate minerals such as mica and garnet through isomorphous substitution. The occurrence state of vanadium in stone coal determines that the vanadium extraction process from stone coal should start from destroying silicate minerals containing vanadium such as vanadium mica and illite.

[0051] The microstructure determines the mechanical properties. Generally, island-structured silicate minerals have relatively high melting points and high hardness because the ions in their structures are closely arranged, making the mineral structures relatively stable. This structural feature endows island-structured silicate minerals with high thermal stability and mechanical strength. That is to say, the strength of island-structured silicate minerals is obviously higher than that of layered and framework silicates. Similarly, mica minerals are easily peeled off due to their layered structure, and their strength is not higher than that of framework-structured quartz sand. Under the same grinding force, mica minerals will definitely break first. By adjusting the rolling pressure of the mill, mica minerals (rich in vanadium) are broken first, while quartz sand (poor in vanadium) remains intact. After the two are separated, the quartz sand is discarded, which can improve the grade of vanadium in the ore. This is understandable. Similarly, by applying this embodiment, part of the gangue in laterite nickel ore, including chromite, can be removed to achieve nickel enrichment.

[0052] After being rolled by the external circulating vertical mill 21, the material is sorted by the separator. According to the particle size of the material, coarse particles are discarded, or fine particles are discarded. Moreover, the material with intermediate particle size returns to the mill for re-rolling.

[0053] In this embodiment, after the laterite nickel ore is pulverized, it is fed into the separator. The separator is a V-type separator 31, which is composed of baffle plates arranged in a trapezoidal shape. The baffle plates are similar to the grille at the outlet of an air conditioner and function to guide the flow and the material. The material is fed into the upper feed port and is dispersed by the stepped inclined baffle plates arranged on the inlet side and the outlet side to form a curtain of material. The material to be sorted forms a trapezoidal flow and falls on a set of steps. There is a sorting air flow passing through the steps. The incoming air flow passes through the curtain of material from the air inlet and comes into contact with the material. The material collides back and forth at the ends of the baffle plates on both sides, achieving the effects of breaking up the lumps of material, fully exposing the fine powder, and prolonging the residence time of the curtain of material.

[0054] This embodiment utilizes the production waste heat or sets up a hot blast stove 5 to provide hot air for the V-type separator 31. After the hot air is temperature-adjusted, it is the incoming air flow of the V-type separator 31. In this embodiment, a hot air valve 51 is arranged on the heat supply pipeline to adjust the amount of hot air; and a cold air valve 52 is used to adjust the temperature of the hot air, providing hot air for the raw ore pulverization to achieve both pulverization and drying.

[0055] In this embodiment, after the laterite nickel ore enters the V-type separator 31, the coarse particles in the material are separated from the material under the action of gravity and fall along the deflector for discharge. Under the same grinding conditions, this part of the material cannot be ground, which is equivalent to the grinding machinery performing screening passively. This indicates that the coarse particles are probably gangue minerals such as quartz, or chromite of the spinel type that is relatively difficult to grind, etc. Therefore, this embodiment selects the coarse particles for tailing discard, improving the grade of the ore.

[0056] Then, through the V-type powder separator 31, the airflow separates the fine materials from the materials and conveys them to the fine material outlet (i.e., the air outlet). The airflow carries the fine materials and discharges them from the air outlet and enters the screening device.

[0057] In this embodiment, the screening device includes a rotor-type powder separator 32. The rotor-type powder separator 32 generates a high-speed rotating airflow through the rotor. The materials enter the separation chamber of the rotor-type powder separator 32 along with the airflow. The coarse and heavy particles in the materials are thrown towards the inner wall surface of the separation chamber under the action of inertial centrifugal force. After collision, they lose kinetic energy and slide down along the wall surface and fall into the coarse powder collection cone. The remaining particles are carried away by the rotating upward airflow. When passing through the action area of the large wind blades, under the impact of the large wind blades, a part of the coarse and heavy particles are thrown towards the inner wall surface of the separation chamber again. After collision, they lose kinetic energy and slide down along the wall surface and enter the coarse powder collection cone. After passing through the large wind blades, the medium-coarse powder and the fine powder continue to rise and pass through the vertical guide vanes under the carrying of the upward airflow and enter the secondary separation area. Under the action of the strong and stable planar eddy current generated by the rotating cage-type rotor, the medium-coarse powder in the dusty airflow is thrown towards the vertical guide vanes under the action of centrifugal force. After collision, it loses kinetic energy and falls into the medium-coarse powder collection cone and is discharged through the medium-coarse powder pipe.

[0058] In this embodiment, the coarse and heavy particles (coarse powder) and the medium-coarse powder refer to the materials with intermediate particle sizes. Their particle sizes are unqualified, but they have the potential to become the target minerals. Therefore, they are returned to the grinding mill for rolling again.

[0059] By adjusting the rotation speed of the rotor, the particle size of the fine powder can be adjusted. The fine powder that meets the requirements is discharged along with the airflow through the cage-type rotor and is collected by the powder collection equipment to become the finished product.

[0060] In this embodiment, a powder collection equipment is arranged behind the powder separator. The powder collection equipment includes a cyclone separator and / or a dust collector 4. The dust collector 4 is a bag filter or an electrostatic precipitator, which is used for product collection and environmental protection. Among them, the cyclone separator is also called a cyclone tube or a cyclone dust collector. It is a dry gas-solid separation equipment that separates dust from the airflow by using the centrifugal force generated when the gas-solid mixture rotates at a high speed. Through the powder collection equipment, the system waste gas is purified and then led out by the exhaust fan 42 and discharged into the atmosphere. A regulating valve 41 is arranged on the dust collection pipeline of the system. The dust collection pipeline includes a ventilation pipeline. By adjusting and controlling the wind speed through the regulating valve 41, the product fineness can also be adjusted. To prevent abrasion, the regulating valve 41 should be installed in a place with a lower dust concentration or a part where the abrasion of dust particles is limited.

[0061] In summary, this embodiment can separate part of the gangue minerals such as calcite and quartz in advance when grinding the anthracite vanadium ore to achieve vanadium enrichment; or, when grinding the laterite nickel ore, at least part of the spinel-type chromite that is difficult to grind can be separated; it is worth mentioning that the definition of the target mineral and the gangue is only relative. For example, when refining nickel metal, chromite is the gangue; when refining chromium metal, only chromite is the high-value target mineral.

[0062] Embodiment 2:

[0063] This embodiment is suitable for extracting aggregate (crushed stone) and recycled sand powder from waste concrete; the stockpile of waste concrete accumulates year by year, and the waste concrete is essentially a man-made mineral. Rational use of its resources can alleviate environmental pressure and provide construction aggregate resources.

[0064] See also Figure 2 This embodiment also provides another raw ore powder making process, including a grinding mill and a powder separator, and a selective crusher is arranged in front of the grinding mill, and the selective crusher includes a drum crusher 1. Waste concrete often contains soil, which is fragile. In contrast to embodiment 1, the drum crusher 1 is used as a soil removal screen; this embodiment separates the soil from the waste concrete in advance and then discards the soil; that is, the pre-treated waste concrete is fed into the grinding mill; after the soil is removed by mechanical scrubbing, the product quality can be guaranteed.

[0065] The difference from Example 1 is that in this embodiment,

[0066] (1) The grinding mill is a roller press 22, and the roller press 22 includes a roller crusher; the roller crusher uses two rollers rotating in opposite directions to crush the material; the roller crusher is composed of a fixed roller, a movable roller, a bracket, a motor and a safety spring; the roller surface is mostly smooth, and the bearing of the movable roller can move along the frame and is supported by a strong safety spring. When a particularly hard object falls into it, the bearing automatically moves away and spits out the object.

[0067] (2) The crushed waste concrete is sent to the powder classifier, which includes a grading screen 33. The grading screen 33 is a bar vibrating screen, a drum screen, etc., which uses a screen to screen the material.

[0068] The pre-treated waste concrete often contains aggregates (crushed stones), bricks, masonry mortar, and plaster mortar, and their strengths decrease in turn; during rolling, by controlling the force of the roller crusher, the bricks and mortar can be broken first, so as to strip the crushed stones; when the rolling force is appropriate, the crushed stones will not crack and the quality is guaranteed. After screening, the materials passing through the sieve are used for sand making; finally, the remaining materials are returned and continue to be rolled until they become sand powder; the sand powder circulates in the system and acts as an abrasive. After the fineness meets the requirements, it can be collected by the dust collector 4 and discharged from the system. This embodiment can give priority to making waste concrete into crushed stones, and the remaining part into sand and sand powder. Among them, the value of sand and sand powder is far less than that of crushed stones. Therefore, this embodiment can maximize the resource recycling of solid waste.

[0069] Embodiment 3:

[0070] Alluvial gold ore is a sedimentary mineral containing gold formed by the long-term weathering of vein gold ore. It is a mineral with industrial mining value. In the deposit of the sedimentary gold ore, due to being washed during the formation process, the useful minerals with a large specific gravity are relatively concentrated. In addition to native gold, it usually also includes minerals such as platinum, cassiterite, magnetite, ilmenite, chromite, rutile, wolframite, scheelite, and rare earths; the gangue minerals usually include quartz, garnet, tourmaline, barite, mica, etc.; among them, the particle size of native gold is usually between 0.1 mm and 4 mm, and the shape is diverse. The deposit usually contains fine mud, and the fine mud is mainly composed of non-metallic minerals, including fine mud minerals such as kaolin, montmorillonite, and hydromica. Among them, montmorillonite is a layered mineral composed of extremely fine-grained hydrated aluminum silicate, also known as bentonite and microcrystalline kaolinite; and fine mud minerals such as calcite and feldspar, whose particle size is usually greater than 5 microns and the content is more than 3%. The fine mud wraps the gold particles, and as the mud content increases, the washing difficulty of the gold ore becomes greater and greater.

[0071] Refer to Figure 3 , this embodiment also provides another raw ore powder-making process, including a grinding mill and a powder separator, and a selective crusher is arranged in front of the grinding mill. The selective crusher includes a drum sorting machine 1; the drum sorting machine 1 is used to remove large pieces of gangue in the ore deposit, such as cobblestones, etc., and then send the remaining mud-sand mixture into the grinding mill for repeated rolling.

[0072] The difference from Embodiment 1 is that

[0073] (1) In this embodiment, the grinding mill is a roller press 22;

[0074] (2) Overly coarse materials (such as cobblestones) and overly fine materials (fine mud) are discarded, and the sand is repeatedly rolled as potential rich ore to separate out rough concentrate or concentrate;

[0075] (3) The fine marl is collected as tailings and then discarded.

[0076] In the prior art, the ore dressing preparation work for alluvial gold mines mainly includes the wet crushing, washing, and wet screening of placer gold. In this process, large - sized gangue and fine mud can be discarded, facilitating subsequent classification and gravity separation for gold recovery. However, the disadvantage is that the water consumption is extremely large. Applying the present invention to the pre - selection of alluvial gold mines can achieve dry separation, obtain the effect of saving water resources, and is applicable to arid regions.

[0077] In this embodiment, the medium - coarse powder (also known as the secondary - coarse powder) of the powder separator is collected as rough concentrate; the powder separator is a V - type powder separator 31. The coarse powder separated by the V - type powder separator 31 can be subjected to magnetic separation or electrostatic separation to obtain concentrate and middlings. The middlings are returned to the roller press 22 for re - rolling. Among them, the technology of magnetic separation utilizes the magnetic difference of minerals for separation, which is particularly suitable for gold ores containing magnetic minerals. This technology effectively separates magnetic minerals from non - magnetic minerals in gold ores through a high - gradient magnetic separator or a roller - type magnetic separator. In the process of gold ore dressing, the magnetic separation method is usually used to remove iron impurities that affect the subsequent purification process and improve the ore dressing efficiency.

[0078] The finally separated fine powder is collected by the dust collector 4 and discarded as lean ore. Or, in an additional embodiment, the fine powder is used as the finished product of the powder - making section. For example, using this process to grind silicate minerals into powder, the powder can be used in the building materials industry. Different from conventional oxide ores and sulfide ores, alluvial gold mines often have already completed monomer dissociation, with good ductility of gold, relatively difficult to be ground into powder, and a relatively large specific gravity. The ore deposits of alluvial gold mines are often river channels, which are rich in silicate minerals such as cobblestones and sand, and are also essential raw materials for the building materials industry. According to these characteristics of the raw materials, gold can be panned while making powder, achieving two goals with one action and obtaining unexpected effects.

[0079] Similarly, applying this process to the crushing and ore dressing of smelting slag, crushing the slag and recovering metals can obtain slag micro - powder while overcoming over - grinding and improving the metal recovery rate.

[0080] The above - mentioned are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A raw ore powder making process, characterized in that: It includes a grinding mill and a powder classifier, wherein: The grinding mill is a material bed grinding device, comprising an external circulation vertical mill (21) or a roller press (22), wherein the external circulation vertical mill (21) is a vertical mill without a separator; a selective crusher is arranged in front of the grinding mill for pre-processing the raw ore; The powder classifier is a V-type powder classifier (31), and / or a screening device, wherein the screening device comprises a rotor-type powder classifier (32), a cylindrical screen, or a grading screen (33); According to the strength difference between the target mineral and the gangue, the grinding force of the grinding mill is adjusted; the soft ore is crushed first, and the hard ore is kept intact as much as possible; and after the raw ore is ground by the grinding mill, it is sorted by the powder concentrator, and the coarse particles or fine particles are discarded according to the particle size of the material; and the material with the intermediate particle size is returned to the grinding mill and ground again; A powder collecting device is arranged after the powder classifier, and the powder collecting device is used for product collection and environmental protection; after the system exhaust gas is purified, it is led out by an exhaust fan (42) connected to the powder collecting device and discharged into the atmosphere; The raw ore includes laterite nickel ore, or smelting slag, or stone coal vanadium ore, or alluvial gold ore; By applying this process, over-grinding can be eliminated during powder making, pre-selection enrichment can be achieved, and the ore grade can be improved.

2. The ore powder making process according to claim 1, characterized in that: The selective crusher comprises a drum crusher (1) or a medium-free mill.

3. A raw ore powder making process according to claim 1 or 2, characterized in that: The powder collection equipment comprises a cyclone separator and / or a dust collector (4), and the dust collector (4) is a bag dust collector or an electric dust collector.

4. The ore powder making process according to claim 3 is characterized in that: A regulating valve (41) is provided on the dust collection pipeline of the system, and the dust collection pipeline comprises a ventilation pipeline; the wind speed is regulated and controlled by the regulating valve (41), thereby adjusting the fineness of the product.

5. A raw ore powder making process according to claim 1 or 2, characterized in that: Utilize waste heat from production or set up a hot air furnace (5); set up a hot air valve (51) on the heating pipeline to adjust the hot air volume; and a cold air valve (52) to adjust the temperature of the hot air; provide hot air for raw ore powder making to achieve powder grinding and drying.

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