Green and efficient dry cleaning method for ores difficult to clean

Abstract

The invention discloses a green and efficient dry cleaning method for ores difficult to clean. Aiming at the problems of high water consumption, low cleaning efficiency and need of subsequent water treatment when a traditional ore washing method is adopted for ore which is particularly difficult to clean, a dry type sand blasting method is innovatively introduced into the field of mining production, air is used as a medium, water is not needed, and cementing viscous substances on the surface of the ore are efficiently removed through material spraying; spraying materials and sludge are separated through magnetic differences, and the spraying materials are recycled. The sand blasting method is good in cleaning effect, iron sand is adopted as a blasting material, loss is small, recycling is achieved, compressed air is adopted as power, energy consumption is low, green and pollution-free are achieved, the ore cleaning efficiency can be improved, and the production cost is reduced. And high-quality raw materials are provided for subsequent ore photoelectric separation, flotation and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of mining engineering, and in particular relates to a green and efficient dry cleaning method for hard-to-clean ores. Background Art

[0002] With economic development, the demand and mining volume of mineral resources are increasing, high-quality ore resources are gradually depleted, and research on the utilization of low-grade and difficult-to-clean ore resources is imperative. Ore pretreatment can not only improve the ore grade, but also reduce subsequent operating costs.

[0003] For ores with high degree of mudification and strong sludge adhesion, surface sludge is difficult to clean and difficult to utilize. Ore washing is an important pretreatment method to remove sludge clay attached to the surface of mineral raw materials, improve the grade and utilization rate of selected ore, reduce the interference and difficulty of subsequent mineral sorting operations, and increase the economic benefits of the enterprise.

[0004] Conventional ore washing technology is wet ore washing, and the equipment includes vibrating screen, drum ore washer, trough ore washer, etc. It has low cleaning efficiency for difficult-to-clean ores, is complex to operate, and is prone to clogging, and consumes a lot of water (2~3m 3 / t ore or more) and requires water treatment, which has a high overall cost. Wet ore washing is even more difficult to apply in areas with scarce water resources, which brings great challenges to mining production.

[0005] In order to improve the cleaning efficiency, the research and development of cleaning methods for difficult-to-clean ores that use less or no water as a medium is becoming more and more urgent. Traditional dry ore washing mostly uses gravity difference or vibration to clean the ore surface. Common dry ore washing methods include vibration screening. Compared with wet ore washing, it does not use water but has poor cleaning effect. For ores with high mud content such as phosphate, iron, manganese, and tin, both traditional dry and wet ore washing methods are difficult to meet the subsequent production cleaning requirements.

[0006] The present invention is inspired by the dry sandblasting process of wind-powered ore dressing and rust removal, and innovatively introduces the dry sandblasting process into the cleaning of difficult-to-clean ores. The sandblasting process can be adjusted according to the properties of the ore, with high cleaning efficiency. The air-powered dry method does not require water, and iron sand is used as the spraying material. The iron sand can be separated from the sludge according to magnetism, and the spraying iron sand can be recycled with little iron sand loss. The entire dry sandblasting process is green and pollution-free, with a simple process, low energy consumption, and greatly reduced costs.

[0007] In recent years, artificial intelligence technology has developed rapidly, and artificial intelligence has great potential for application in intelligent sorting in mining. Intelligent sorting is to use the optical, magnetic, conductive and other property differences of the selected materials, and use photoelectric scanning projection and image recognition technology for sorting. It is an extension and development of manual sorting. However, intelligent sorting has high requirements for the cleanliness of the mineral surface. The greener and more efficient dry sandblasting technology has great advantages in providing high-quality raw materials for intelligent sorting. In addition, both intelligent sorting and dry sandblasting use compressed air as power, which can save production land and reduce the number of production equipment, improve corporate competitiveness, and help build smart mines. Summary of the invention

[0008] This patent invents a green and efficient dry cleaning method for difficult-to-clean ores. It uses compressed air from a dry sandblasting gun as power to make the spray collide with the ore surface at high speed, thereby removing difficult-to-clean sludge and solving the problem that the cleaning effects of the commonly used dry and wet ore washing methods are difficult to meet production needs.

[0009] The present invention attempts for the first time to utilize the synergistic effect of spraying and airflow to achieve efficient cleaning of cemented sticky substances on the surface of ore in a dry implementation environment.

[0010] This invention is the first to develop a green and efficient dry cleaning method for difficult-to-clean ores: The dry sandblasting system is designed to treat hard-to-clean ores, with compressed air as the power. The high-pressure air drives the spray material, and the spray material collides with the ore surface to achieve efficient removal of cemented sticky substances on the ore surface; the sandblasting pressure is 3~7.5bar, and the sandblasting angle of the sandblasting gun is 5~20°. The amount of spray material is the mass of the hard-to-clean ore raw material × A × B, where A is the selectivity coefficient and B is the protection coefficient. Generally speaking, the value of A is 0.4~0.8, preferably 0.6; the value of B is 1.2~1.4, preferably 1.3.

[0011] The present invention uses a sandblasting device to perform sandblasting treatment on the ore to be cleaned, uses compressed air as a power to push the spray material, and the spray material collides with the ore surface at high speed to remove the difficult-to-clean cemented and sticky substances on the ore surface, and finally realizes dry cleaning of the difficult-to-clean ore; the ore and the spray material sludge are screened and separated, and the clean ore product on the screen directly enters the subsequent production, and the spray material sludge is screened off; according to the magnetic difference, the spray material iron sand is separated from the sludge, and the spray material is recovered to realize the recycling of the spray material.

[0012] The sandblasting intensity and angle of the sandblasting equipment of the present invention can be adjusted to optimize the dry sandblasting cleaning capability.

[0013] The blasting air pressure is controlled within the range of 3-7.5 bar according to the target ore type, and the blasting angle of the blasting gun is set within the range of 5-20°, and more preferably 14-16°.

[0014] In the present invention, according to the ore conditions, the sandblasting air pressure is set, the air pressure control range is 3~7.5bar, preferably 5~7.5bar, and the sandblasting angle of the sandblasting gun is set, the angle control range is 5~20°, preferably 14~20°; the upward force generated by sandblasting in the cleaning chamber adjusts the air posture of the ore, slows down the ore falling speed, prolongs the ore cleaning time, and improves the cleaning efficiency. Of course, at this time, the coordination of the sandblasting cleaning chamber size, the number of spray guns, and the corresponding parameters of the sandblasting gun sandblasting is required to improve the cleaning effect to the best state.

[0015] The main equipment of dry sandblasting system includes sandblasting, screening and magnetic separation.

[0016] The above-mentioned sandblasting equipment is mainly composed of a sandblasting gas storage tank, a storage bin, a sandblasting gun, and a cleaning bin.

[0017] Furthermore, the sandblasting cleaning chamber is a cylinder with a diameter and length ratio of less than or equal to 1, and a small hole is provided on the side wall, and the sandblasting gun penetrates into the cylinder through the small hole; a feed port is provided at the top of the cylinder, and a discharge port is provided at the bottom. When applied in industry, a cylinder with a diameter of A meters, a value of A of 0.3 to 1, and a length of 2A-5A can be selected according to the processing volume, and at least 3 layers of circular holes are provided on the side wall of the cylinder, and the number of circular holes on each layer is greater than or equal to 6 (preferably greater than or equal to 8), and each layer of circular holes is horizontally distributed in the same plane. Each circular hole is provided with a steel pipe for fixing the sandblasting gun, and the sandblasting gun muzzle is inclined upward.

[0018] As a preferred solution, the bottom of the sandblasting cleaning chamber is funnel-shaped, and the clean ore, sludge and spray material go down from here into the screening equipment, and the sandblasting cleaning product is produced. The cleaning chamber is designed as a relatively closed space to reduce dust spillage and reduce the dust concentration of the sandblasting system.

[0019] Furthermore, in order to protect the cleaning bin cylinder from direct impact and friction and to increase the life of the cleaning bin, a lining is added to the inner wall of the cleaning bin. The lining material is one of high manganese steel, alloy white cast iron, wear-resistant ceramic lining, and rubber lining.

[0020] Furthermore, the sandblasting gun is installed in the hole left by the sandblasting cleaning wall, and the sandblasting gun is fixed. At least 3 layers of sandblasting guns are set on the cleaning chamber wall, and each layer is 0.5m apart. At least 8 sandblasting guns are set on each layer, and the sandblasting direction of the sandblasting gun can be adjusted, and the sandblasting angle is adjusted according to the type and nature of the ore.

[0021] Furthermore, the storage bin stores the spray material, receives the magnetic separation to recover the spray material, and controls the amount of the spray material.

[0022] Furthermore, the material of the spraying material is selected to be a wear-resistant high-strength iron-containing material, which is one of iron sand shot, chromium iron sand, nickel iron sand, and manganese iron sand, and the spraying particle size is 1~4mm.

[0023] Furthermore, the amount of blasting material is determined according to the difficulty of ore cleaning and the amount of ore. Generally, the ratio of ore mass to blasting material mass is 0.4~0.8 (i.e., the value of A is 0.4~0.8), preferably 0.55~0.8, and more preferably 0.6~0.8; determine the total mass of the ore to be cleaned; total blasting material mass = mass of ore to be cleaned × ratio; the total amount of sandblasting material takes into account the safety factor to deal with issues such as sandblasting efficiency and material loss. It can usually be increased by 20% to 40% (i.e., the value of protection factor B is 1.2~1.4).

[0024] The screening equipment is connected to the sandblasting cleaning chamber, where the cleaned ore and the blasting sludge are separated. The clean ore products on the screen directly enter the subsequent production, and the products below the screen are the blasting sludge.

[0025] The belt conveys the blasting sludge to the magnetic separation equipment. Due to the magnetic difference, the magnetic separator separates the blasting material and the sludge. The blasting material is recovered by the belt and conveyed to the blasting bin for recycling. The sludge enters the dumping yard. In actual application, the ore and iron sand sludge are separated by screening. The iron sand sludge enters the magnetic separation. The iron sand is separated from the sludge by magnetic difference. The blasting sand is recovered and recycled. The sludge enters the dumping yard.

[0026] Dry sandblasting system As for the sandblasting room, the sandblasting room is equipped with a bag dust removal system.

[0027] The iron sand produced by injection molding is recovered by magnetic separation and returned to the injection molding bin for continued use.

[0028] The calculation method of sludge removal rate of the present invention is: (m 目的 -m 清洁 ) / (m 目的 -m 净重 )*100%; Where m 目的 Mass of ore to be cleaned, m 清洁 is the mass of ore after cleaning, m 净重 Net weight of ore.

[0029] Principle of the present invention: The present invention applies the dry sandblasting process in industrial rust removal to the cleaning of the ore surface, uses the sandblasting equipment to use compressed air as the power to push the spray material, and the spray material collides with the ore surface at high speed to remove the sludge on the ore surface, thereby achieving the purpose of dry cleaning of difficult-to-clean ores. The spray material is made of iron-containing materials and can be recycled and reused through magnetic separation. The air pressure, sandblasting angle, and spray material specifications and models are selected according to the properties of the ore.

[0030] The beneficial effects of the present invention include at least: 1. The ore to be cleaned is sandblasted, and the compressed air is used to push the material. The material collides with the surface of the ore at high speed to remove the cemented and sticky substances on the surface of the ore, and the cleaning effect is good.

[0031] 2. Due to the difference in magnetic properties, the spray sludge is separated by magnetic separation, and the wear-resistant and high-strength iron-containing spray is recovered to achieve the recycling of the spray, reduce loss and reduce cleaning costs.

[0032] 3. Dry sandblasting cleans ore, saves water resources, reduces the restrictions of water on ore cleaning, and improves the efficiency of processes such as intelligent sorting that require dry ore as raw materials.

[0033] 4. The dry sandblasting process has a wider range of applications and is more suitable for application in the western region where water resources are scarce. It is a green, efficient and clean way to utilize difficult-to-clean ores such as phosphate, iron, manganese and tin. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a physical picture of ores No. 1-5 in Example 1; Figure 2 Flow chart of green and efficient cleaning technology for difficult-to-clean ores; Figure 3 Schematic diagram of dry sandblasting cleaning chamber; Figure 4 This is a comparison chart of the cleaning effects of dry sandblasting and high-frequency vibrating screen in Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0035] The technical solution of the present invention will be fully described in detail below in conjunction with embodiments.

[0036] In the embodiment of the present invention, The main equipment of dry sandblasting system includes sandblasting, screening and magnetic separation.

[0037] The above-mentioned sandblasting equipment is mainly composed of a sandblasting gas storage tank, a storage bin, a sandblasting gun, and a cleaning bin.

[0038] The sandblasting cleaning chamber is set as a cylinder with a diameter of one meter and a length of two meters. The outer wall is composed of a cylindrical steel cylinder and the upper part is open. The target ore enters here. The sandblasting cleaning chamber has 24 round holes, which are evenly distributed in groups of 8 on the same plane, with a total of 3 groups. Each group of round holes is horizontally distributed on the same plane. Each round hole is provided with a steel pipe for fixing the sandblasting gun, and the sandblasting gun muzzle is inclined upward; the bottom is funnel-shaped, and the clean ore, sludge and spray material go down from here to enter the screening equipment, and the sandblasting cleaning product is produced. The cleaning chamber is designed as a relatively closed space to reduce dust spillage and reduce the dust concentration of the sandblasting system.

[0039] In order to protect the cylinder of the cleaning bin from direct impact and friction and to increase the service life of the cleaning bin, a lining plate is added to the inner wall of the cleaning bin. The lining plate material is high manganese steel.

[0040] The sandblasting gun is installed in the hole left by the sandblasting cleaning wall. The sandblasting gun is fixed. Three groups of sandblasting guns are set on the cleaning chamber wall, and each group is 0.5m apart. There are 8 sandblasting guns in each group. The direction of sandblasting of the sandblasting gun can be adjusted, and the sandblasting angle can be adjusted according to the type and nature of the ore.

[0041] The blasting air pressure of the sandblasting equipment is controlled in the range of 3-7.5 bar, the blasting angle of the sandblasting gun is set, the angle control range is 5-20°, and the iron sand sprayed is one of iron sand shot, chrome iron sand, nickel iron sand, and manganese iron sand. Preferably, the sprayed material in this embodiment is iron sand shot, and the particle size is controlled at 1-4 mm.

[0042] Five ores of the same material, different shapes, and increasing particle sizes were randomly selected as research objects, and each ore was numbered in order from small to large particle size. Figure 1 As shown; the sizes of ore No. 1-5 are shown in Figure 1 .

[0043] The ore was cleaned and dried. The ore weight, particle size and other parameters are shown in Table 1.

[0044]

[0045] Embodiment 1: Mix clay and water in a mass ratio of 5:1 to make sludge, and use the sludge to completely cover the surface of the ore. The mass ratio of sludge to ore is about 3:5. Simulate the state of ore with a high degree of muddiness when it is mined, obtain the ore to be cleaned, and record the weight of each ore after being covered with sludge; The clay-covered ore sample to be cleaned was placed in a sandblasting dry cleaning device, and the sandblasting air pressure was set at 5.5 bar, the sandblasting angle of the sandblasting gun was set at 15°, the iron sand used was iron sand shot with a particle size of 2 mm, and the amount of iron sand shot was 405 g (approximately the mass of the ore to be cleaned × 0.6 (proportional range) × 1.3 (protection factor)) to remove the sludge on the surface of the ore; the mass of the ore sample after cleaning was recorded, and the removal rate of the sandblasting cleaning process was calculated. The specific data are shown in Table 2.

[0046] Comparative Example 1: The dry sandblasting equipment in Example 1 was replaced with a high-frequency vibrating screen with a vibration frequency of 50 Hz and an amplitude of 3 mm. Other conditions remained unchanged, and the single-factor variable experimental method was used. The difference in the mass of sludge covering the surface of the same number of ores in each group of experiments was controlled within 1 g; the action time of the high-frequency vibrating screen was consistent with that of the sandblasting equipment, and the mass of the ore after cleaning was compared with the net weight of the ore to obtain the cleaning effect of the sandblasting cleaning equipment.

[0047] Exploration Case 1-1 The other conditions were the same as those in Example 1, except that the blasting air pressure was set at 3 bar and the blasting angle of the blasting gun was set at 5°.

[0048] Exploration Case 1-2 The other conditions were the same as those in Example 1, except that the blasting air pressure was set at 3 bar and the blasting angle of the blasting gun was set at 15°.

[0049] Exploring Cases 1-3 The other conditions were the same as those in Example 1, except that the blasting air pressure was set at 3 bar and the blasting angle of the blasting gun was set at 20°.

[0050] Exploring Cases 1-4 The other conditions were the same as those in Example 1, except that the blasting air pressure was set at 7.5 bar and the blasting angle of the blasting gun was set at 5°.

[0051] Exploration Case 1-5 The other conditions were the same as those in Example 1, except that the blasting air pressure was set at 7.5 bar and the blasting angle of the blasting gun was set at 15°.

[0052] Exploration Case 1-6 The other conditions were the same as those in Example 1, except that the blasting air pressure was set at 7.5 bar and the blasting angle of the blasting gun was set at 20°.

[0053] Exploration Case 1-7 The other conditions were the same as those in Example 1, except that the amount of sandblasting was 270 g (which was different from the sandblasting in Example 1 and was the minimum value in the protection range).

[0054] Exploration Case 1-8 The other conditions are the same as those in Example 1, except that the amount of sandblasting is 540 g (which is different from the sandblasting in Example 1 and is the maximum value in the protection range). The experimental results are shown in Table 2.

[0055]

[0056] Experiments show that when clay is attached to the surface of the ore, dry sandblasting has a stronger cleaning ability on the ore surface than conventional high-frequency vibrating screen ore. Appropriate sandblasting angle, sandblasting intensity and amount of blasting material can increase the sludge removal rate.

[0057] Example 2

[0058] The ore to be cleaned was prepared under the same conditions as in Example 1, and the difference in sludge mass on the surface of the ore with the same number was controlled within 1 g; The ore to be cleaned was placed in an oven and dried at 65°C for 2 hours to obtain the ore to be cleaned with semi-dry sludge on the surface. The weight of each piece of ore after being covered with sludge was recorded.

[0059] The ore cleaning process conditions were the same as those in Example 1. The mass of the ore sample after cleaning was recorded, and the removal rate of the dry sandblasting cleaning process was calculated, as shown in Table 3.

[0060] Comparative Example 2: The dry sandblasting equipment in Example 2 was replaced with a high-frequency vibrating screen. The difference in the mass of sludge covering the surface of the same number of ores in each group of experiments was controlled within 1g. The action time of the high-frequency vibrating screen was consistent with that of the sandblasting equipment. The mass of the ore after cleaning was compared with the net weight of the ore to obtain the cleaning effect of the sandblasting cleaning equipment.

[0061] Exploration Case 2-1 The other conditions were the same as those in Example 2, except that the blasting air pressure was set at 3 bar and the blasting angle of the blasting gun was set at 5°.

[0062] Exploration Case 2-2 The other conditions were the same as those in Example 2, except that the blasting air pressure was set at 3 bar and the blasting angle of the blasting gun was set at 15°.

[0063] Exploration Case 2-3 The other conditions were the same as those in Example 2, except that the blasting air pressure was set at 3 bar and the blasting angle of the blasting gun was set at 20°.

[0064] Exploration Case 2-4 Other conditions were the same as those in Example 2, except that the blasting air pressure was set at 7.5 bar and the blasting angle of the blasting gun was set at 5°.

[0065] Exploration Case 2-5 The other conditions were the same as those in Example 2, except that the blasting air pressure was set at 7.5 bar and the blasting angle of the blasting gun was set at 15°.

[0066] Exploration Case 2-6 The other conditions were the same as those in Example 2, except that the blasting air pressure was set at 7.5 bar and the blasting angle of the blasting gun was set at 20°.

[0067] Exploration Case 2-7 The other conditions are the same as those in Example 2, except that the amount of sandblasting is 270 g (which is different from the sandblasting in Example 2, and the amount is the minimum value in the protection range).

[0068] Exploration Case 2-8 The other conditions are the same as those in Example 2, except that the amount of sandblasting is 540 g (which is different from the sandblasting in Example 2, and the amount is the maximum value in the protection range). The experimental results are shown in Table 3.

[0069]

[0070] Experiments show that when the ore surface is semi-dry sludge, dry sandblasting has a stronger cleaning ability on the ore surface than conventional high-frequency vibrating screen ore.

[0071] Example 3

[0072] Prepare the ore to be cleaned, the same conditions as in Example 1, the sludge mass difference on the surface of the ore with the same number is controlled within 1g; The ore to be cleaned is placed in an oven and dried at 65°C for 24 hours to obtain the ore to be cleaned with dry sludge on the surface. The weight of each piece of ore after being covered with sludge is recorded for subsequent calculation.

[0073] The ore cleaning process conditions were the same as those in Example 1. The mass of the ore sample after cleaning was recorded and the removal rate of the dry sandblasting cleaning process was calculated.

[0074] Comparative Example 3: The dry sandblasting equipment in Example 3 was replaced with a high-frequency vibrating screen. The difference in sludge mass covering the surface of the same number of ores in each group of experiments was controlled within 1g. The vibration cleaning time of the sandblasting equipment was consistent with that of the sandblasting equipment. The mass of the ore after cleaning was compared with the net weight of the ore to obtain the cleaning effect of the sandblasting cleaning equipment.

[0075] Exploration Case 3-1 The other conditions were the same as those in Example 3, except that the blasting air pressure was set at 3 bar and the blasting angle of the blasting gun was set at 5°.

[0076] Exploration Case 3-2 The other conditions were the same as those in Example 3, except that the blasting air pressure was set at 3 bar and the blasting angle of the blasting gun was set at 15°.

[0077] Exploration Case 3-3 The other conditions were the same as those in Example 3, except that the blasting air pressure was set at 3 bar and the blasting angle of the blasting gun was set at 20°.

[0078] Exploration Case 3-4 The other conditions were the same as those in Example 3, except that the blasting air pressure was set at 7.5 bar and the blasting angle of the blasting gun was set at 5°.

[0079] Exploration Case 3-5 The other conditions were the same as those in Example 3, except that the blasting air pressure was set at 7.5 bar, and the blasting angle of the blasting gun was set at 15°.

[0080] Exploration Case 3-6 The other conditions were the same as those in Example 3, except that the blasting air pressure was set at 7.5 bar and the blasting angle of the blasting gun was set at 20°.

[0081] Exploration Case 3-7 The other conditions are the same as those in Example 3, except that the amount of sandblasting is 270 g (which is different from the sandblasting in Example 3, and the amount is the minimum value in the protection range).

[0082] Exploration Case 3-8 The other conditions are the same as those in Example 3, except that the amount of sandblasting is 540 g (which is different from the sandblasting in Example 3, and the amount is the maximum value in the protection range). The experimental results are shown in Table 4.

[0083]

[0084] Experiments show that when dry sludge adheres to the surface of the ore, dry sandblasting has a stronger cleaning ability on the ore surface than conventional high-frequency vibrating screens.

[0085] Comparative Example 4 Other conditions are the same as those in Example 1, except that: The clay-covered ore sample to be cleaned was placed in the sandblasting dry cleaning equipment, and the sandblasting air pressure was set at 5.5 bar, the sandblasting angle of the sandblasting gun was set at 15°, and no spray material was added. The sludge on the surface of the ore was removed; the mass of the ore sample after cleaning was recorded, and the removal rate of the sandblasting cleaning process was calculated. The experimental results are shown in Table 5.

[0086]

[0087] The results in Tables 2, 3, 4 and 5 show that under the same conditions of dry and wet sludge on the ore surface, the cleaning effect of dry sandblasting is significantly better than that of high-frequency vibrating screen. Sandblasting equipment equipped with spraying material has the ability to efficiently clean the ore, and the spraying material particle size can be adjusted according to the specific cleaning situation, which can further improve the removal rate.

Claims

1. A green and efficient dry cleaning method for hard-to-clean ores, characterized by: The dry sandblasting system is used to treat hard-to-clean ores. Compressed air is used as the power. The high-pressure air drives the spray material, which collides with the ore surface to achieve efficient removal of cemented and sticky substances on the ore surface. The blasting air pressure is 3-7.5 bar, and the blasting angle of the sandblasting gun is 5-20°; the amount of the blasting material is the mass of the hard-to-clean ore raw material × A × B, the value of A is 0.4-0.8, preferably 0.6; the value of B is 1.2-1.4, preferably 1.

3.

2. The green and efficient dry cleaning method for hard-to-clean ores according to claim 1 is characterized in that: The sandblasting air pressure control range is 5~7.5bar, and the sandblasting angle of the sandblasting gun is set, and the angle control range is 5~20°.

3. The green and efficient dry cleaning method for difficult-to-clean ores according to claim 1 is characterized in that: The sandblasting angle is preferably 14~16°.

4. The green and efficient dry cleaning method for hard-to-clean ores according to claim 1 is characterized in that: Dry sandblasting system equipment includes sandblasting equipment, screening equipment and magnetic separation equipment; Sandblasting equipment includes sandblasting gas tank, storage bin, sandblasting gun, and cleaning bin; The sandblasting cleaning chamber is a cylinder with a diameter and length ratio less than or equal to 1. A fixing hole is provided on the side wall to fix the sandblasting gun, and the spray material penetrates into the cylinder through the hole; a feed port is provided at the top of the cylinder and a discharge port is provided at the bottom.

5. The green and efficient dry cleaning method for hard-to-clean ores according to claim 4, characterized in that: The sandblasting cleaning chamber is cylindrical, with a diameter of A meters, A value of 0.3~1, and a height of 2A-5A. There are at least 3 layers of circular holes on the side wall of the cylinder, the number of circular holes on each layer is greater than or equal to 6, and each layer of circular holes is horizontally distributed in the same plane; each circular hole is provided with a steel pipe for fixing the sandblasting gun, and the sandblasting gun muzzle is inclined upward.

6. The green and efficient dry cleaning method for hard-to-clean ores according to claim 4, characterized in that: The bottom of the sandblasting cleaning chamber is funnel-shaped, through which the clean ore, sludge and blasting material go down into the screening equipment, where the ore and blasting sludge are screened and separated. The clean ore products on the screen go directly into subsequent production, while the blasting sludge is screened off.

7. The green and efficient dry cleaning method for hard-to-clean ores according to claim 4, characterized in that: A lining plate is added to the inner wall of the cleaning chamber, and the lining plate material is one of high manganese steel, alloy white cast iron, wear-resistant ceramic lining plate and rubber lining plate.

8. The green and efficient dry cleaning method for hard-to-clean ores according to claim 4, characterized in that: The sandblasting gun is installed in the hole left by the sandblasting cleaning wall, and the sandblasting gun is fixed. At least 3 layers of sandblasting guns are set on the cleaning chamber wall, and each layer is 0.5m apart. At least 8 sandblasting guns are set on each layer. The sandblasting direction of the sandblasting gun can be adjusted, and the sandblasting angle can be adjusted according to the type and nature of the ore.

9. The green and efficient dry cleaning method for hard-to-clean ores according to claim 4, characterized in that: The spraying material is selected from at least one of iron sand shot, chromium iron sand, nickel iron sand and manganese iron sand, and the spraying material particle size is 1-4 mm.

10. The green and efficient dry cleaning method for hard-to-clean ores according to claim 9, characterized in that: The spraying sludge is screened out, and the spraying iron sand is recovered by magnetic separation according to the magnetic difference, and returned to the spraying bin for continued use, thus realizing the recycling of spraying materials.

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