A green and efficient dry cleaning method for difficult-to-clean ores

Abstract

The present invention discloses a green and efficient dry cleaning method for difficult-to-clean ores. In order to solve the problem that the traditional ore washing method for ores that are particularly difficult to clean consumes a lot of water, has low cleaning efficiency and requires subsequent water treatment, the present invention innovatively introduces dry sandblasting into the field of mining production. Air is used as the medium and no water is needed. The spray material efficiently removes the adhesive substances on the surface of the ore, and the magnetic difference is used to separate the spray material from the sludge, and the spray material is recycled. The sandblasting method not only has a good cleaning effect, but the spray material is iron sand with low loss and can be recycled, and the compressed air is low in power energy consumption, is green and pollution-free, can improve the ore cleaning efficiency, and reduce production costs. It provides high-quality raw materials for subsequent ore photoelectric sorting, flotation, etc.

Description

Technical Field

[0001] This invention belongs to the field of mining engineering technology, specifically a green and efficient dry cleaning method for difficult-to-clean ores. Background Technology

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

[0003] For ores with high mudification and strong sludge adhesion, surface sludge cleaning is difficult and utilization is challenging. Mineral washing is an important pretreatment method to remove sludge and clay adhering to the surface of mineral raw materials, improve the grade and utilization rate of the ore to be processed, reduce interference and difficulty in subsequent mineral sorting operations, and increase the economic benefits of enterprises.

[0004] Conventional ore washing technology is wet washing, using equipment such as vibrating screens, cylindrical washing machines, and trough washing machines. However, it has low cleaning efficiency for difficult-to-clean ores, is complex to operate, prone to clogging, and consumes a large amount of water (2-3 cubic meters per second). 3 Wet ore washing (containing ore per ton or more) requires water treatment, resulting in high overall costs. In water-scarce regions, wet ore washing is even more difficult to apply, posing a significant challenge to mining production.

[0005] To improve cleaning efficiency, research and development of cleaning methods for difficult-to-clean ores using little or no water are becoming increasingly urgent. Traditional dry washing methods often use gravity differences or vibration to clean the ore surface. Common dry washing methods include vibrating screening, which, compared to wet washing, does not use water but has poor cleaning effect. For ores with high mud content, such as phosphate, iron, manganese, and tin ores, both traditional dry and wet washing methods struggle to meet the cleaning requirements for subsequent production.

[0006] Inspired by the dry sandblasting process for wind-powered mineral processing and rust removal, this invention innovatively introduces dry sandblasting into the cleaning of difficult-to-clean ores. The sandblasting process can be adjusted according to the properties of the ore, resulting in high cleaning efficiency. Powered by air, the dry process requires no water. Iron sand is used as the abrasive material, which can be separated from the sludge by magnetic properties. The iron sand abrasive material can be recycled, and the iron sand loss is minimal. The entire dry sandblasting process is green and pollution-free, with simple technology, low energy consumption, and significantly reduced costs.

[0007] In recent years, artificial intelligence (AI) technology has developed rapidly, and its application potential in intelligent sorting in the mining industry is enormous. Intelligent sorting utilizes the differences in the optical, magnetic, and electrical properties of the materials being sorted, employing photoelectric scanning projection and image recognition technologies for separation. It is an extension and development of manual sorting. However, intelligent sorting requires a high degree of cleanliness of the mineral surface. The greener and more efficient dry sandblasting technology has significant advantages in providing high-quality raw materials for intelligent sorting. Furthermore, both intelligent sorting and dry sandblasting use compressed air as power, which can save production land and reduce the number of production equipment, improve enterprise competitiveness, and contribute to the construction of smart mines. Summary of the Invention

[0008] This patent invention provides a green and efficient dry cleaning method for difficult-to-clean ores. It utilizes compressed air from a dry sandblasting gun to drive the abrasive material to collide with the surface of the ore at high speed, thereby removing difficult-to-clean sludge and solving the problem that the cleaning effect of commonly used dry and wet ore washing methods is insufficient to meet production needs.

[0009] This invention is the first attempt to utilize the synergistic effect of spray and airflow to achieve efficient cleaning of adhesive substances adhering to the surface of ore in a dry environment.

[0010] This invention is the first to develop a green and efficient dry cleaning method for difficult-to-clean ores:

[0011] A dry blasting system is designed to treat difficult-to-clean ores. Powered by compressed air, the high-pressure air drives the abrasive material, which impacts the ore surface to efficiently remove adhesive substances. The blasting air pressure is 3~7.5 bar, and the blasting gun angle is 5~20°. The abrasive material usage is calculated as the mass of the difficult-to-clean ore raw material × A × B, where A is the selection factor and B is the protection factor. Generally, A is 0.4~0.8, preferably 0.6; B is 1.2~1.4, preferably 1.3.

[0012] This invention involves sandblasting the ore to be cleaned using a sandblasting device. Compressed air powers the abrasive material, which collides at high speed with the ore surface, removing stubborn, adhesive substances that are difficult to clean. This achieves dry cleaning of difficult-to-clean ore. The ore and the abrasive sludge are then separated by screening. The cleaned ore product on the screen is directly used in subsequent production, while the abrasive sludge on the underside is separated by screening. Based on magnetic differences, the iron sand and sludge are separated, and the abrasive material is recycled, achieving material recycling.

[0013] The sandblasting intensity and angle of the sandblasting equipment of this invention can be adjusted to optimize the dry sandblasting cleaning capability.

[0014] Depending on the type of ore, the sandblasting air pressure is controlled within the range of 3 to 7.5 bar, and the sandblasting angle of the sandblasting gun is set within the range of 5 to 20°, and more preferably 14 to 16°.

[0015] In this invention, the sandblasting air pressure is set according to the ore condition, with a control range of 3~7.5 bar, preferably 5~7.5 bar. The sandblasting angle of the sandblasting gun is also set, with a control range of 5~20°, preferably 14~20°. Sandblasting in the cleaning chamber generates an upward force to adjust the ore's aerial posture, slowing its descent and extending the cleaning time, thus improving cleaning efficiency. Of course, this requires coordination between the size of the sandblasting cleaning chamber, the number of spray guns, and the corresponding sandblasting parameters to achieve the optimal cleaning effect.

[0016] The main equipment of a dry sandblasting system includes sandblasting, screening, and magnetic separation.

[0017] The aforementioned sandblasting equipment mainly consists of a sandblasting air tank, a material storage silo, a sandblasting gun, and a cleaning chamber.

[0018] Furthermore, the sandblasting cleaning chamber is a cylinder with a diameter-to-length ratio of less than or equal to 1, and small holes are provided on its side walls. The sandblasting gun penetrates into the cylinder through these holes. The top of the cylinder has a feed inlet, and the bottom has a discharge outlet. In industrial applications, a cylinder with a diameter of A meters (where A ranges from 0.3 to 1) and a length of 2A-5A can be selected based on the processing capacity. The side walls of the cylinder have at least three layers of circular holes, with each layer containing at least six (preferably at least eight) circular holes, all horizontally distributed on the same plane. Each circular hole is fitted with a steel pipe for fixing the sandblasting gun, with the gun nozzle angled upwards.

[0019] As a preferred design, the bottom of the sandblasting cleaning chamber is funnel-shaped, through which the ore, sludge, and blasting material flow into the screening equipment, and the sandblasting cleaning products are separated. The cleaning chamber is designed as a relatively enclosed space to reduce dust overflow and lower the dust concentration in the sandblasting system.

[0020] Furthermore, in order to protect the cleaning chamber cylinder from direct impact and friction and improve the service life of the cleaning chamber, a lining plate is added to the inner wall of the cleaning chamber. The lining plate material is one of high manganese steel, alloy white cast iron, wear-resistant ceramic lining plate, and rubber lining plate.

[0021] Furthermore, the sandblasting gun device is installed in the holes left in the sandblasting cleaning wall to fix the sandblasting gun. At least three layers of sandblasting guns are set on the cleaning chamber wall, with each layer spaced 0.5m apart. Each layer has at least eight sandblasting guns, and the direction of sandblasting is adjustable, with the sandblasting angle adjusted according to the type and properties of the ore.

[0022] Furthermore, the storage silo stores the sprayed material, accepts magnetic separation to recover the sprayed material, and controls the amount of sprayed material used.

[0023] Furthermore, the abrasive material is selected as a wear-resistant, high-strength iron-containing material, which is one of iron shot, chromium iron shot, nickel iron shot, or manganese iron shot, with a particle size of 1~4mm.

[0024] Furthermore, the amount of blasting material used is determined based on the difficulty of ore cleaning and the quantity of ore. Generally, the ratio of ore mass to blasting material mass is 0.4~0.8 (i.e., A is 0.4~0.8), preferably 0.55~0.8, and even more preferably 0.6~0.8. The total mass of ore to be cleaned is determined; total blasting material mass = ore mass to be cleaned × ratio. The total amount of blasting material used considers a safety factor to address issues such as blasting efficiency and material loss. Typically, this can be increased by 20% to 40% (i.e., the protection factor B is 1.2~1.4).

[0025] The screening equipment is connected to the sandblasting cleaning chamber, where the cleaned ore and the blasting sludge are separated. The cleaned ore product on the screen goes directly into subsequent production, while the blasting sludge is left on the screen.

[0026] A belt conveyor transports the sprayed sludge to a magnetic separator. Due to magnetic differences, the magnetic separator separates the sprayed material and sludge. The sprayed material is then recovered and transported back to the sprayed material bin for recycling, while the sludge is disposed of in a waste disposal area. In practical applications, ore and iron sand sludge are screened and separated. The iron sand sludge then enters the magnetic separator, where the iron sand is separated from the sludge by magnetic differences. The sprayed sludge is then recovered and recycled, while the sludge is disposed of in a waste disposal area.

[0027] The dry sandblasting system is located in the sandblasting room, which is equipped with a bag filter dust collection system.

[0028] Magnetic separation is used to recover the iron sand from the blasting material and return it to the blasting hopper for continued use.

[0029] The method for calculating the sludge removal rate in this invention is as follows: (m 目的 -m 清洁 ) / (m 目的 -m 净重 ) * 100%;

[0030] Where m 目的 For the quality of the ore to be cleaned, m 清洁 For the quality of the cleaned ore, m 净重 This is the net weight of the ore.

[0031] The principle of this invention:

[0032] This invention applies the dry sandblasting process used in industrial rust removal to the cleaning of ore surfaces. Using compressed air, the sandblasting equipment propels the abrasive material at high speed, colliding with the ore surface to remove sludge and achieve the goal of dry cleaning of difficult-to-clean ores. The abrasive material is made of iron-containing materials and can be recycled through magnetic separation. The air pressure, sandblasting angle, and abrasive material specifications are selected according to the properties of the ore.

[0033] The beneficial effects of the present invention include at least the following:

[0034] 1. The ore to be cleaned is sandblasted by compressed air, which propels the abrasive material to collide with the ore surface at high speed, removing the adhesive substances adhering to the ore surface, resulting in a good cleaning effect.

[0035] 2. Due to differences in magnetic properties, the sprayed sludge is separated by magnetic separation, and the wear-resistant, high-strength iron-containing sprayed material is recycled, realizing the recycling of sprayed material, reducing losses and lowering cleaning costs.

[0036] 3. Dry sandblasting cleans ores, saving water resources, reducing water limitations in ore cleaning, and improving the efficiency of intelligent sorting and other processes that require dry ores as raw materials.

[0037] 4. Dry sandblasting technology has a wider range of applications and is more suitable for use in water-scarce western regions. It enables the green, efficient and clean utilization of difficult-to-clean ores such as phosphate, iron, manganese and tin. Attached Figure Description

[0038] Figure 1 These are actual images of ores 1-5 from Example 1;

[0039] Figure 2 Flowchart of green and efficient cleaning technology for difficult-to-clean ores;

[0040] Figure 3 Schematic diagram of a dry sandblasting cleaning chamber;

[0041] Figure 4 The image shows a comparison of the cleaning effects of dry sandblasting and high-frequency vibrating screen in Example 1 and Comparative Example 1. Detailed Implementation

[0042] The technical solution of the present invention will be described in detail below with reference to the embodiments.

[0043] In this embodiment of the invention,

[0044] The main equipment of a dry sandblasting system includes sandblasting, screening, and magnetic separation.

[0045] The aforementioned sandblasting equipment mainly consists of a sandblasting air tank, a material storage silo, a sandblasting gun, and a cleaning chamber.

[0046] The sandblasting cleaning chamber is a cylinder with a diameter of one meter and a length of two meters. The outer wall is composed of a cylindrical steel tube, with an opening at the top where the target ore enters. The chamber has 24 circular holes, evenly distributed in groups of eight on the same plane, for a total of three groups. Each group of holes is horizontally distributed on the same plane, and each hole is fitted with a steel pipe for fixing the sandblasting gun, with the gun nozzle angled upwards. The bottom is funnel-shaped, through which the cleaned ore, sludge, and blasting material flow into the screening equipment, and the sandblasting cleaning products are collected. The cleaning chamber is designed as a relatively enclosed space to reduce dust overflow and lower the dust concentration in the sandblasting system.

[0047] To protect the cleaning chamber from direct impact and friction, and to extend its service life, a lining plate is installed on the inner wall of the cleaning chamber. The lining plate is made of high manganese steel.

[0048] The sandblasting gun device is installed through holes left in the sandblasting cleaning wall. Three sets of sandblasting guns are installed on the cleaning chamber wall, spaced 0.5m apart. Each set contains eight sandblasting guns. The direction of the sandblasting is adjustable, and the spray angle can be adjusted according to the type and properties of the ore.

[0049] The sandblasting air pressure of the sandblasting equipment is controlled within the range of 3-7.5 bar. The sandblasting angle of the sandblasting gun is set within the range of 5-20°. The abrasive material is one of iron shot, chromium iron shot, nickel iron shot, and manganese iron shot. Preferably, in this embodiment, the abrasive material is iron shot, and the particle size is controlled within 1-4 mm.

[0050] Five pieces of ore of the same material but different shapes, with increasing grain size, were randomly selected as the research subjects. Each piece of ore was numbered sequentially according to its grain size, from smallest to largest. The experimental ore samples are shown below. Figure 1 As shown; the dimensions of ores 1-5 are shown in the figure. Figure 1 .

[0051] The ore was cleaned and dried. The ore weight, particle size and other parameters are shown in Table 1.

[0052]

[0053] Example 1:

[0054] Sludge was prepared by mixing clay and water in a mass ratio of 5:1. The sludge was used to completely cover the surface of the ore. The mass ratio of sludge to ore was about 3:5. This simulated the state of ore with a high degree of mudification when it was mined. The resulting ore was cleaned, and the weight of each piece of ore after being covered with sludge was recorded.

[0055] The clay-covered ore sample was placed in a dry sandblasting cleaning device. The sandblasting air pressure was set to 5.5 bar, the sandblasting gun angle was set to 15°, the abrasive material was iron shot with a particle size of 2 mm, and the amount of iron shot was 405 g (approximately the mass of the ore to be cleaned × 0.6 (proportion range) × 1.3 (protection coefficient)). 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 specific data are shown in Table 2.

[0056] Comparative Example 1:

[0057] 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. A single-factor variable experimental method was used, with the mass difference of sludge covering the surface of the same numbered ore in each group controlled within 1 g. The action time of the high-frequency vibrating screen was the same as that of the sandblasting equipment. The mass of the cleaned ore was compared with its net weight to determine the cleaning effect of the sandblasting equipment.

[0058] Exploring Case 1-1

[0059] Other conditions are the same as in Example 1, except that the sandblasting air pressure is set to 3 bar and the sandblasting gun angle is set to 5°.

[0060] Explore Case 1-2

[0061] Other conditions are the same as in Example 1, except that the sandblasting air pressure is set to 3 bar and the sandblasting gun angle is set to 15°.

[0062] Explore Case 1-3

[0063] Other conditions are the same as in Example 1, except that the sandblasting air pressure is set to 3 bar and the sandblasting gun angle is set to 20°.

[0064] Explore Cases 1-4

[0065] The other conditions are the same as in Example 1, except that the sandblasting air pressure is set to 7.5 bar and the sandblasting gun angle is set to 5°.

[0066] Explore Cases 1-5

[0067] The other conditions are the same as in Example 1, except that the sandblasting air pressure is set to 7.5 bar and the sandblasting gun angle is set to 15°.

[0068] Explore Cases 1-6

[0069] The other conditions are the same as in Example 1, except that the sandblasting air pressure is set to 7.5 bar and the sandblasting gun angle is set to 20°.

[0070] Explore Cases 1-7

[0071] The other conditions are the same as in Example 1, except that the amount of sandblasting is 270g (unlike the sandblasting in Example 1, the amount is the minimum value in the protection range).

[0072] Explore Cases 1-8

[0073] Other conditions were the same as in Example 1, except that the amount of sandblasting was 540g (unlike the sandblasting in Example 1, this amount was the maximum value within the protection range). The experimental results are shown in Table 2.

[0074]

[0075] Experiments show that when clay adheres to the surface of ore, dry sandblasting has a stronger cleaning ability than conventional high-frequency vibrating screen. Appropriate sandblasting angle, sandblasting force and amount of spray material can increase the sludge removal rate.

[0076] Example 2

[0077] Prepare the ore to be cleaned under the same conditions as in Example 1, and control the difference in sludge mass on the surface of the same numbered ore to within 1g.

[0078] Place the ore to be cleaned into an oven and dry it at 65°C for 2 hours to obtain ore with semi-dry sludge on the surface. Record the weight of each piece of ore after it is covered with sludge.

[0079] The cleaning process conditions for the ore were the same as in Example 1. The mass of the cleaned ore sample was recorded, and the removal rate of the dry sandblasting cleaning process was calculated, as shown in Table 3.

[0080] Comparative Example 2:

[0081] In Example 2, the dry sandblasting equipment was replaced with a high-frequency vibrating screen. The mass difference of sludge covering the surface of the same numbered ore in each group of experiments was controlled within 1g. The action time of the high-frequency vibrating screen was the same as 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.

[0082] Explore Case 2-1

[0083] The other conditions are the same as in Example 2, except that the sandblasting air pressure is set to 3 bar and the sandblasting gun angle is set to 5°.

[0084] Explore Case 2-2

[0085] The other conditions are the same as in Example 2, except that the sandblasting air pressure is set to 3 bar and the sandblasting gun angle is set to 15°.

[0086] Explore Case 2-3

[0087] The other conditions are the same as in Example 2, except that the sandblasting air pressure is set to 3 bar and the sandblasting gun angle is set to 20°.

[0088] Explore Case 2-4

[0089] The other conditions are the same as in Example 2, except that the sandblasting air pressure is set to 7.5 bar and the sandblasting gun angle is set to 5°.

[0090] Explore Case 2-5

[0091] The other conditions are the same as in Example 2, except that the sandblasting air pressure is set to 7.5 bar and the sandblasting gun angle is set to 15°.

[0092] Explore Case 2-6

[0093] The other conditions are the same as in Example 2, except that the sandblasting air pressure is set to 7.5 bar and the sandblasting gun angle is set to 20°.

[0094] Explore Case 2-7

[0095] The other conditions are the same as in Example 2, except that the amount of sandblasting is 270g (unlike the sandblasting in Example 2, the amount is the minimum value in the protection range).

[0096] Explore Case 2-8

[0097] Other conditions were the same as in Example 2, except that the amount of sandblasting was 540g (unlike the sandblasting in Example 2, this amount was the maximum value within the protection range). The experimental results are shown in Table 3.

[0098]

[0099] Experiments show that when the ore surface is semi-dry sludge, dry sandblasting has a stronger ore surface cleaning ability than conventional high-frequency vibrating screen.

[0100] Example 3

[0101] Prepare the ore to be cleaned under the same conditions as in Example 1, ensuring that the difference in sludge mass on the surface of ore with the same number is controlled within 1g;

[0102] The ore to be cleaned was placed in an oven and dried at 65°C for 24 hours to obtain ore with a dry sludge surface. The weight of each piece of ore after being covered with sludge was recorded for subsequent calculations.

[0103] The cleaning process conditions for the ore were the same as in Example 1. The mass of the cleaned ore sample was recorded, and the removal rate of the dry sandblasting cleaning process was calculated.

[0104] Comparative Example 3:

[0105] The dry sandblasting equipment in Example 3 was replaced with a high-frequency vibrating screen. The mass difference of sludge covering the surface of the same numbered ore in each group of experiments was controlled within 1g. The vibration cleaning time of the sandblasting equipment was the same as 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.

[0106] Explore Case 3-1

[0107] The other conditions are the same as in Example 3, except that the sandblasting air pressure is set to 3 bar and the sandblasting gun angle is set to 5°.

[0108] Explore Case 3-2

[0109] The other conditions are the same as in Example 3, except that the sandblasting air pressure is set to 3 bar and the sandblasting gun angle is set to 15°.

[0110] Explore Case 3-3

[0111] The other conditions are the same as in Example 3, except that the sandblasting air pressure is set to 3 bar and the sandblasting gun angle is set to 20°.

[0112] Explore Case 3-4

[0113] The other conditions are the same as in Example 3, except that the sandblasting air pressure is set to 7.5 bar and the sandblasting gun angle is set to 5°.

[0114] Explore Case 3-5

[0115] The other conditions are the same as in Example 3, except that the sandblasting air pressure is set to 7.5 bar and the sandblasting gun angle is set to 15°.

[0116] Explore Case 3-6

[0117] The other conditions are the same as in Example 3, except that the sandblasting air pressure is set to 7.5 bar and the sandblasting gun angle is set to 20°.

[0118] Explore Case 3-7

[0119] The other conditions are the same as in Example 3, except that the amount of sandblasting is 270g (unlike the sandblasting in Example 3, the amount is the minimum value in the protection range).

[0120] Explore Case 3-8

[0121] The other conditions were the same as in Example 3, except that the amount of sandblasting was 540g (unlike the sandblasting in Example 3, the amount used was the maximum value within the protection range). The experimental results are shown in Table 4.

[0122]

[0123] Experiments show that when dry sludge adheres to the surface of ore, dry sandblasting has a stronger ore cleaning ability than conventional high-frequency vibrating screen.

[0124] Comparative Example 4

[0125] All other conditions are the same as in Example 1, except that:

[0126] The ore sample to be cleaned was covered with clay and placed in a dry sandblasting cleaning device. The sandblasting air pressure was set to 5.5 bar, the sandblasting gun angle was set to 15°, and no abrasive material was added. The sludge on the ore surface was removed; the mass of the cleaned ore sample was recorded, and the removal rate of the sandblasting cleaning process was calculated. The experimental results are shown in Table 5.

[0127]

[0128] The results in Tables 2, 3, 4, and 5 show that, under the same conditions of dry and wet sludge on the ore surface, dry sandblasting is significantly better than high-frequency vibrating screen in cleaning. Only when the sandblasting equipment is equipped with sprayed material can it have the ability to clean ore efficiently. Furthermore, the particle size of the sprayed material 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 difficult-to-clean ores, characterized in that: A dry sandblasting system is used to treat difficult-to-clean ores. Compressed air is used as the power source, and high-pressure air drives the abrasive material. The abrasive material collides with the surface of the ore to achieve efficient removal of adhesive substances adhering to the surface of the ore. The sandblasting air pressure is 3~7.5 bar, and the sandblasting gun spray angle is 5~20°; the amount of abrasive is the mass of the difficult-to-clean ore raw material × A × B, where A is 0.4~0.8 and B is 1.2~1.

4. Dry sandblasting system equipment includes sandblasting equipment, screening equipment, and magnetic separation equipment; Sandblasting equipment includes a sandblasting air tank, a material storage silo, a sandblasting gun, and a cleaning chamber; The sandblasting cleaning chamber is a cylinder with a diameter-to-length ratio of less than or equal to 1. It has fixing holes on its side wall to fix the sandblasting gun, and the abrasive material penetrates into the cylinder through the holes. The top of the cylinder has a feed inlet and the bottom has a discharge outlet. The abrasive is selected from at least one of iron shot, chromium iron shot, nickel iron shot, and manganese iron shot, with a particle size of 1-4 mm. The undersized abrasive sludge is magnetically separated to recover the iron shot based on magnetic differences and returned to the abrasive silo for continued use. Achieve material recycling.

2. The green and efficient dry cleaning method for difficult-to-clean ores according to claim 1, characterized in that: The amount of spray material used is calculated as the mass of the difficult-to-clean ore raw material × A × B, where A is 0.6 and B is 1.

3.

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

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

5. A green and efficient dry cleaning method for difficult-to-clean ores according to claim 1, characterized in that: The sandblasting cleaning chamber is cylindrical with a diameter of A1 meters, where A1 is 0.3 to 1, and a height of 2A1 to 5A1. The side wall of the cylinder has at least 3 layers of circular holes, with each layer having 6 or more circular holes, and each layer of circular holes is horizontally distributed on the same plane. Each circular hole is equipped with a steel pipe for fixing the sandblasting gun, with the sandblasting gun nozzle angled upwards.

6. The green and efficient dry cleaning method for difficult-to-clean ores according to claim 1, characterized in that: The bottom of the sandblasting cleaning chamber is funnel-shaped, through which the cleaned ore, sludge, and blasting material enter the screening equipment. The ore and blasting material / sludge are screened and separated. The cleaned ore product on the screen goes directly into subsequent production, while the blasting material / sludge on the screen goes under.

7. A green and efficient dry cleaning method for difficult-to-clean ores according to claim 4, characterized in that: The inner wall of the cleaning chamber is lined with a lining plate, which is made of one of the following materials: high manganese steel, alloy white cast iron, wear-resistant ceramic lining plate, or rubber lining plate.

8. A green and efficient dry cleaning method for difficult-to-clean ores according to claim 4, characterized in that: The sandblasting gun device is installed in the hole left in the sandblasting cleaning wall, and the sandblasting gun is fixed. At least 3 layers of sandblasting guns are set on the cleaning chamber wall, with each layer spaced 0.5m apart; each layer has at least 8 sandblasting guns. The direction of sandblasting is adjustable, and the sandblasting angle is adjusted according to the type and properties of the ore.

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