Equipment for crushing and grading magnesium oxide

Abstract

Equipment for crushing and grading magnesium oxide comprises a composite grading machine, a striking crushing and stripping machine, a spiral feeding machine, a circulating fan, a cyclone separator, a bag-type dust collector and an air compressor, and is characterized in that a crushing and grading unit is upgraded and grafted on the magnesium oxide crushing and grading equipment by utilizing the air flow advantage of closed-loop circulating air; on the basis of ensuring that the content of MgO is not reduced due to the influence of moisture and CO2 in air in the crushing and grading process, heavy MgCO3 fine powder and coarse MgO powder in raw powder are separated and graded to the maximum extent, and a low-grade magnesium oxide product containing a small amount of MgCO3 is obtained through an outlet of a 1 # air-lock valve of a composite grading machine; a high-grade magnesium oxide fine powder main product is obtained through an outlet of a second air-lock valve of the cyclone separator, and a high-grade magnesium oxide superfine powder product is obtained through an outlet of a third air-lock valve of the bag-type dust collector. By adopting a simple mode of coarse particle stripping shell shrinkage crushing instead of coarse particle grinding, the non-calcined magnesite powder is prevented from entering the fine powder, and the amount of the magnesium oxide fine powder is also increased. Operation is simple and easy to control, productivity efficiency is high, production is safe and environmentally friendly, and market application prospects are wide.

Description

Technical Field

[0001] The invention relates to the technical field of material crushing and grading, in particular to equipment for crushing and grading magnesium oxide. Background Art

[0002] my country holds the largest global share of magnesite production, producing a vast quantity of calcined magnesium oxide (commonly known as light-burned powder). This calcination is typically performed using Raymond mills or vertical mills. Due to the limited performance of these mills, the resulting magnesium oxide specifications can only be determined based on the grade and processing fineness of the magnesite ore. As high-quality magnesite ore resources decrease, this simple, single-processing method can no longer meet market demand for magnesium oxide products with high physical and chemical properties, chemical activity, and fine particle size.

[0003] To obtain high-quality magnesium oxide products, in recent years, the practice of first grinding magnesite into a fine powder, removing silicon and calcium through flotation to improve the quality of the ore powder, and then rapidly calcining it in a suspension kiln to obtain higher-grade magnesium oxide raw powder has begun to emerge. This higher-grade magnesium oxide raw powder is then crushed and graded to produce a higher-quality, finer, and more active advanced magnesium oxide product. This product is widely used as a chemical raw material, increasing its added value and possessing promising market prospects. While this method of pre-purifying the raw ore and then rapidly calcining it in a suspension kiln can produce higher-quality magnesium oxide products to a certain extent, it also has some major drawbacks that have not been addressed. First, the suspension rapid calcination does not completely calcine the coarse-grained magnesite powder. After the crushing and calcination, the magnesium oxide contains a portion of the raw ore powder in the form of MgCO3, resulting in a high loss on ignition. In addition to reducing the magnesium oxide content, its chemical inertness becomes an impurity, affecting its application effect. Second, increasing the calcination temperature in the suspension kiln can achieve complete calcination, but the activity of the produced magnesium oxide is reduced. Third, the selected Raymond mill, vertical mill, or air flow mill and its matching classification equipment also have high power consumption and low efficiency, resulting in high cost pressure. Fourth, the characteristics of existing crushing and classification equipment determine that it is difficult to prevent the magnesium oxide content from decreasing due to the absorption of moisture and CO2 by the material during the crushing and classification process. The main problem that leads to the reduction of magnesium oxide content is that when the relative humidity of the air is greater than 50%, the crushing and classification process will cause the magnesium oxide content after crushing and classification to decrease by more than 2%. It is precisely because of the existence of these major problems that the quality of the produced magnesium oxide is unstable.

[0004] Obviously, it is imperative for the industry to develop suitable special crushing and grading equipment for magnesium oxide, break through the effective separation of residual MgCO3 ore powder during the crushing and grading process of magnesium oxide, reduce processing power consumption, improve crushing and grading efficiency, improve the quality of high-end magnesium oxide products, and provide a complete set of magnesium oxide crushing and grading equipment.

[0005] The applicant has conducted in-depth research and experiments on the ultrafine grinding and classification preparation of magnesium oxide currently used in China, and combined with the physical and chemical properties of dolomite powder suspended calcined light-burned powder, has developed a set of special grinding and classification equipment that can meet the production quality requirements of light-burned magnesium oxide, has low power consumption, good classification effect, high product quality, and has high promotion value. Summary of the Invention

[0006] The purpose of the present invention is to provide an equipment for crushing and classifying magnesium oxide, which adopts a fast and efficient peeling partial crushing method, separates the magnesium carbonate mixed in the magnesium oxide to the maximum extent through gravity separation and centrifugal separation under the premise of closed air circulation, and obtains a graded magnesium oxide product without being affected by moisture and CO2 in the air.

[0007] In order to achieve the above-mentioned purpose of the invention, the present invention provides an equipment for crushing and classifying magnesium oxide, which comprises a composite classifier, a flash crushing and stripping machine, a screw feeder, a circulating fan, a cyclone separator, a bag dust collector and an air compressor.

[0008] The composite classifier includes a crushed material inlet, a # Air lock outlet, light and fine powder outlet;

[0009] The flash crushing and stripping machine includes a raw powder feed inlet and a crushed material outlet;

[0010] The screw feeder includes a hopper and a raw powder discharge port;

[0011] The circulating fan includes an air inlet and an air outlet;

[0012] The cyclone separator includes a light fine powder inlet, a No. 2 air lock outlet and an air flow outlet;

[0013] The bag dust collector includes an air flow inlet, a 3# air lock outlet, a clean air outlet and a pulse air inlet;

[0014] The air compressor includes a clean air inlet and a compressed air outlet;

[0015] Its characteristics are:

[0016] The crushed material inlet of the composite classifier is connected to the crushed material outlet of the flash crushing and stripping machine through a closed-air pipeline, the light fine powder outlet of the composite classifier is connected to the light fine powder inlet of the cyclone separator through a closed-air pipeline, the raw powder feed port of the flash crushing and stripping machine is connected to the raw powder discharge port of the spiral feeder through a closed-air pipeline, the raw powder feed port of the flash crushing and stripping machine is also connected to the air outlet of the circulating fan through a closed-air pipeline, the air flow outlet of the cyclone separator is connected to the air flow inlet of the bag dust collector through a closed-air pipeline, the clean air outlet of the bag dust collector is respectively connected to the air inlet of the circulating fan and the air inlet pipeline of the air compressor, the compressed air outlet of the air compressor is connected to the pulse air inlet of the bag dust collector through a closed-air pipeline, forming an integrally closed-air-connected magnesium oxide crushing and grading equipment, and through 1 of the composite classifier # The low-grade magnesium oxide product containing a small amount of MgCO3 is obtained at the outlet of the air lock and is passed through the cyclone separator. # The main product of high-grade magnesium oxide fine powder is obtained at the outlet of the air lock, and is passed through the bag dust collector. # The export of air lockers produces high-grade magnesium oxide ultrafine powder products;

[0017] The compound classifier further comprises a first-stage gravity separator and a second-stage centrifugal separator. The first-stage gravity separator is located in the middle of the compound classifier, and the second-stage centrifugal separator is located at the top of the compound classifier.

[0018] The first-stage gravity separator is an umbrella-shaped baffle, which forms an annular gap with the inner wall of the compound classifier. The second-stage centrifugal separator is an impeller-shaped assembly connected to the motor shaft of the compound classifier in a concentric manner.

[0019] When the equipment is running, the calcined magnesium oxide powder or magnesium oxide raw powder is fed into the screw feeder including the hopper, and is fed into the raw powder feeding port of the flash crushing stripping machine from the raw powder discharge port of the screw feeder. The high-speed rotation of the flash crushing stripping machine drives the impeller blades to selectively flash crush the magnesium oxide, so that the lighter MgO and the heavier MgCO3 are peeled off and driven by the circulating fan airflow to go up into the first-stage gravity separator of the composite classifier. The heavier MgCO3 falls by inertia, and the lighter MgO rises with the airflow and enters the second-stage centrifugal separator of the composite classifier. The heavier MgCO3 fine powder and the coarser MgO powder are centrifugally separated and classified with the finer MgO powder. The fineness can be controlled by adjusting the speed of the second-stage centrifugal separator of the composite classifier. The heavier MgCO3 and the coarser MgO particles are thrown to the inner wall of the composite classifier by the centrifugal blades of the second-stage centrifugal separator and fall and mix with the MgCO3 particles separated by the first-stage gravity classifier. #The MgO powder is discharged from the air lock. Because it is enriched with a small amount of MgCO3 and has a low magnesium oxide content, it can be used as low-grade magnesium oxide and used as a refractory material or raw material for fused magnesia. The lighter MgO powder is driven by the air flow through the secondary centrifugal separator and enters the cyclone separator with the rising air flow. After cyclone separation, it enters the 2 # The airflow after separation of high-grade magnesium oxide fine powder contains a small amount of ultrafine MgO powder and is sent to the bag dust collector for gas-solid separation by the pulser. The separated high-grade magnesium oxide ultrafine powder is passed through 3 # The air is discharged from the air lock into the packaging bag, resulting in high-grade ultrafine magnesium oxide. A portion of the separated clean air enters the circulating fan and is sent to the inlet of the flash crushing and stripping machine. The remaining separated clean air is sucked in by the air compressor, pressurized, and sent to the pulse generator of the bag dust collector for dust removal. This circulating air flow pulverization and classification can pulverize and grade the light-burned magnesium oxide raw powder, while avoiding the use of new air, which would reduce the magnesium oxide content.

[0020] Compared with the prior art, the beneficial effects of the present invention are embodied in:

[0021] The present invention provides equipment for pulverizing and classifying magnesium oxide. This equipment utilizes a closed-circuit circulating air pulverizing and classifying system. This system effectively overcomes the key issue of reduced magnesium oxide product content caused by absorption of moisture and CO₂ from air during the existing pulverizing and classifying process of raw magnesium oxide powder. Furthermore, a primary gravity separator and a secondary centrifugal separator within a composite classifier are employed to maximize separation and classification of heavier MgCO₃ fine powder and coarser MgO powder from the raw powder. Furthermore, the equipment utilizes the advantages of closed-circuit circulating airflow to combine the advantages of optimal magnesium oxide pulverization and classification units within a single device. Furthermore, a simple, efficient, and energy-efficient shell-shrinking pulverization method, which removes coarse particles without grinding them, is employed to prevent the incorporation of uncalcined magnesite powder into the fine magnesium oxide powder. This method also increases the amount of magnesium oxide fine powder, resulting in a high-grade magnesium oxide fine powder main product, a small amount of high-grade ultrafine magnesium oxide product, and a small amount of low-grade magnesium oxide product. The equipment features a rational design, simple and easy-to-control operation, high efficiency, and low energy consumption. In particular, the closed-circuit circulating air operation eliminates exhaust gas emissions, resulting in safe and environmentally friendly production and broad market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A schematic diagram of equipment for crushing and classifying magnesium oxide provided by the present invention.

[0024] In the attached figure:

[0025] 1-compound classifier, 2-flash crushing and stripping machine, 3-screw feeder, 4-screw feeder, 5-cyclone separator, 6-bag dust collector, 7-air compressor, DETAILED DESCRIPTION

[0026] Example 1: Figure 1 The present invention provides an equipment for crushing and classifying magnesium oxide, which comprises a composite classifier (1), a flash crushing and stripping machine (2), a screw feeder (3), a circulating fan (4), a cyclone separator (5), a bag dust collector (6) and an air compressor (7).

[0027] The composite classifier (1) comprises a crushed material inlet, a No. 1 air lock outlet, and a light and fine powder outlet;

[0028] The flash crushing and stripping machine (2) comprises a raw powder feed inlet and a crushed material outlet;

[0029] The screw feeder (3) comprises a hopper and a raw powder discharge port;

[0030] The circulating fan (4) comprises an air inlet and an air outlet;

[0031] The cyclone separator (5) comprises a light fine powder inlet, a No. 2 air lock outlet and an air flow outlet;

[0032] The bag dust collector (6) includes an air flow inlet, a 3# air lock outlet, a clean air outlet and a pulse air inlet;

[0033] The air compressor (7) comprises a clean air inlet and a compressed air outlet;

[0034] The crushed material inlet of the composite classifier (1) is connected to the crushed material outlet of the flash crushing stripping machine (2) through a closed air pipeline, the light fine powder outlet of the composite classifier (1) is connected to the light fine powder inlet of the cyclone separator (5) through a closed air pipeline, the raw powder feed port of the flash crushing stripping machine (2) is connected to the raw powder discharge port of the spiral feeder (3) through a closed air pipeline, the raw powder feed port of the flash crushing stripping machine (2) is also connected to the air outlet of the circulating fan (4) through a closed air pipeline, the air flow outlet of the cyclone separator (5) is connected to the air flow inlet of the bag dust collector (6) through a closed air pipeline, and the bag dust collector (6) is connected to the air flow outlet of the cyclone separator (5). The clean air outlet of the dust collector (6) is airtightly connected to the air inlet of the circulating fan (4) and the air inlet duct of the air compressor (7), respectively. The compressed air outlet of the air compressor (7) is airtightly connected to the pulse air inlet of the bag dust collector (6) through the duct, forming an integral airtightly connected magnesium oxide crushing and grading equipment, and a low-grade magnesium oxide product containing a small amount of MgCO3 is obtained through the outlet of the No. 1 airtight device of the composite classifier (1), a high-grade magnesium oxide fine powder main product is obtained through the outlet of the No. 2 airtight device of the cyclone separator (5), and a high-grade magnesium oxide ultrafine powder product is obtained through the outlet of the No. 3 airtight device of the bag dust collector (6);

[0035] The compound classifier (1) further comprises a first-stage gravity separator and a second-stage centrifugal separator, wherein the first-stage gravity separator is located in the middle of the compound classifier and the second-stage centrifugal separator is located in the upper part of the compound classifier;

[0036] The first-stage gravity separator is an umbrella-shaped baffle, which forms an annular gap with the inner wall of the composite classifier (1); the second-stage centrifugal separator is an impeller-shaped assembly connected to the motor shaft of the composite classifier (1) in a concentric manner.

Claims

1. An equipment for crushing and classifying magnesium oxide, comprising a composite classifier (1), a flash crushing and stripping machine (2), a screw feeder (3), a circulating fan (4), a cyclone separator (5), a bag dust collector (6) and an air compressor (7). The composite classifier (1) comprises a crushed material inlet, a No. 1 air lock outlet, and a light and fine powder outlet; The flash crushing and stripping machine (2) comprises a raw powder feed inlet and a crushed material outlet; The screw feeder (3) comprises a hopper and a raw powder discharge port; The circulating fan (4) comprises an air inlet and an air outlet; The cyclone separator (5) comprises a light fine powder inlet, a No. 2 air lock outlet and an air flow outlet; The bag dust collector (6) includes an air flow inlet, a 3# air lock outlet, a clean air outlet and a pulse air inlet; The air compressor (7) comprises a clean air inlet and a compressed air outlet; Its characteristics are: The crushed material inlet of the composite classifier (1) is connected to the crushed material outlet of the flash crushing stripping machine (2) through a closed air pipeline, the light fine powder outlet of the composite classifier (1) is connected to the light fine powder inlet of the cyclone separator (5) through a closed air pipeline, the raw powder feed port of the flash crushing stripping machine (2) is connected to the raw powder discharge port of the spiral feeder (3) through a closed air pipeline, the raw powder feed port of the flash crushing stripping machine (2) is also connected to the air outlet of the circulating fan (4) through a closed air pipeline, the air flow outlet of the cyclone separator (5) is connected to the air flow inlet of the bag dust collector (6) through a closed air pipeline, and the bag dust collector (6) is connected to the air flow outlet of the cyclone separator (5). The clean air outlet of the dust collector (6) is airtightly connected to the air inlet of the circulating fan (4) and the air inlet duct of the air compressor (7), respectively. The compressed air outlet of the air compressor (7) is airtightly connected to the pulse air inlet of the bag dust collector (6) through the duct, forming an integral airtightly connected magnesium oxide crushing and grading equipment. A low-grade magnesium oxide product containing a small amount of MgCO3 is obtained through the outlet of the 1# airtight device of the composite classifier (1), a high-grade magnesium oxide fine powder main product is obtained through the outlet of the 2# airtight device of the cyclone separator (5), and a high-grade magnesium oxide ultrafine powder product is obtained through the outlet of the 3# airtight device of the bag dust collector (6).

2. The equipment for crushing and classifying magnesium oxide according to claim 1, characterized in that: The compound classifier (1) further comprises a primary gravity separator and a secondary centrifugal separator. The primary gravity separator is located in the middle of the compound classifier, and the secondary centrifugal separator is located at the top of the compound classifier.

3. The equipment for crushing and classifying magnesium oxide according to claim 2, characterized in that: The first-stage gravity separator is an umbrella-shaped baffle, which forms an annular gap with the inner wall of the composite classifier (1); the second-stage centrifugal separator is an impeller-shaped assembly connected to the motor shaft of the composite classifier (1) in a concentric manner.

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