Method and device for preparing active magnesium oxide and co-producing high-purity magnesium oxide

Abstract

The invention relates to the technical field of magnesium oxide preparation, in particular to a method and a device for preparing active magnesium oxide and co-producing high-purity magnesium oxide, which are characterized in that a light active magnesium oxide component with a small particle size and a heavy high-purity magnesium oxide component with a large particle size generated in a calcining process are separated by blowing air into a calcining kiln; the purpose of graded production of active magnesium oxide and high-purity magnesium oxide is achieved by utilizing the dust removal effect of the dust removal assembly; meanwhile, the calcining temperature and the calcining time are strictly controlled, so that the activity of the prepared active magnesium oxide is guaranteed, and the grading capability of the active magnesium oxide and the high-purity magnesium oxide is improved.

Description

Technical Field

[0001] The invention relates to the technical field of magnesium oxide preparation, and in particular to a method and device for preparing active magnesium oxide and co-producing high-purity magnesium oxide. Background Art

[0002] Magnesium oxide is widely used in the production of refractory materials, electrical engineering, papermaking, construction, rubber, adhesives and other fields. For example, magnesium oxide is used as a filler in the production of rubber, adhesives, adhesives, plastic materials, polymers, etc.; another example: magnesium oxide is used as a stabilizer in the production of chloroprene rubber; another example: magnesium oxide is used as a curing agent for organic solvents, etc.

[0003] Magnesium oxide is usually prepared by calcining magnesium-containing raw materials, for example, raw materials such as magnesium carbonate, basic magnesium carbonate, magnesium hydroxide, and magnesium chloride are prepared by calcining and thermally decomposing. Moreover, it is known that according to the calcination temperature of the raw materials, slight calcination, hard burning, dead burning, and melting can be presented. Therefore, during the calcination process of magnesium oxide production, high-activity magnesium oxide and high-purity magnesium oxide can be formed.

[0004] One of the most important indicators of activated magnesium oxide is its high reactivity, which is usually described by characteristics such as specific surface area, iodine adsorption value, and citric acid activity.

[0005] At present, there are a large number of active magnesium oxide production processes and high-purity magnesium oxide production processes in the prior art, for example: Patent No. 201980061345.9 discloses active high-purity magnesium oxide and its production method, which is a method for producing active high-purity magnesium oxide by calcining magnesium hydroxide produced by the interaction of an aqueous solution of a magnesium salt and an alkaline agent. The active high-purity magnesium oxide may be surface-treated, and magnesium hydroxide crystals are produced in separate and isolated areas by a continuous method: a seed treatment area, a magnesium hydroxide crystal formation and growth area, and a crystal increase and aggregation area. In addition, a pre-purified aqueous solution of magnesium chloride and a magnesium hydroxide seed suspension are fed into the seed treatment area in an amount of 1 to 80% of the total mass of the initial reagent fed in the presence of a liquid petroleum product, and the treated magnesium hydroxide crystal suspension from the previous area is mixed with an alkaline reagent sodium hydroxide aqueous solution at an ionic molar ratio of the alkaline reagent to the magnesium chloride: OH. – Mg 2+ (1.9-2.1): 1 is fed into the crystal formation and growth zone, the suspension in the previous zone is fed into the crystal increase and aggregation zone, and the temperature in all zones is maintained at not less than 40°C, the residence time of the magnesium hydroxide crystal suspension in each isolated zone is not less than 20 minutes, and the washed magnesium hydroxide crystals are calcined in a calcining furnace at a temperature of 300 to 700°C to obtain a specific surface area of ​​70-200m 2 / g, the iodine activity (iodine absorption value) is 70-200mg, the citric acid activity is no more than 40s, and the impurity content in the obtained magnesium oxide is low.

[0006] Another example: Patent No. 201911293798.2 discloses active magnesium oxide and its preparation method and application. After mixing light-burned magnesium powder, magnesium chloride and water, a hydrothermal reaction is carried out to obtain magnesium hydroxide precipitate and calcium chloride solution; the magnesium hydroxide precipitate is immersed in an aqueous ammonium chloride solution for leaching to obtain a magnesium chloride solution, ammonia and leached residue; the magnesium chloride solution, ammonia and carbon dioxide are mixed for magnesium precipitation reaction to obtain a basic magnesium carbonate precipitate; the basic magnesium carbonate precipitate is dried and calcined in turn to obtain active magnesium oxide. By decalcifying magnesium chloride and leaching magnesium with ammonium chloride, insoluble impurities such as silicon and calcium are retained in the ammonium chloride leached residue, which is beneficial to improve the purity and activity of the final product. The magnesium oxide obtained by the method provided by the present invention has high purity and activity, and the mass content of MgO in the active magnesium oxide is ≥98%, and the activity is >95%.

[0007] Another example: Patent No. 201911059054.4 discloses a process and system for producing sintered magnesia using magnesium hydroxide as raw material, including a filter cake storage bin, a variable combined feeding unit, a rapid drying device, a shaftless screw conveyor, a bucket elevator 1, a suspended roasting device, a high-temperature and high-pressure ball pressing system, a bucket elevator 2, a vertical kiln feeding bin and a high-temperature vertical kiln; the magnesium hydroxide filter cake made from seawater or brine is used as raw material, fed by a variable combined feeding unit, and sent to a rapid drying device for drying, and the dried magnesium hydroxide powder is transported to a suspended roasting device by a shaftless screw conveyor for roasting to obtain high-activity magnesium oxide powder.

[0008] It can be seen that the existing technology mainly focuses on how to obtain a magnesium oxide product with higher activity and higher purity after processing the magnesium-containing raw materials (magnesium hydroxide, magnesium chloride, etc.). However, according to common sense known to those skilled in the art, different degrees of calcination conditions may be presented as the calcination temperature of the magnesium-containing raw materials is different, and different degrees of calcination conditions will be one of the key factors affecting the activity and purity of the calcined magnesium oxide, which has formed a technical problem that it is difficult to ensure that the activity and purity of the magnesium oxide are taken into account.

[0009] In view of this, the research team of the present invention, based on the previous research on enriching phosphate concentrate using medium and low-grade phosphate ore or phosphate tailings while recovering calcium carbonate and magnesium hydroxide (patent announcement number CN109264686B), and in the process of industrializing and promoting the corresponding research results, launched a project research on the process of producing magnesium oxide using the produced magnesium hydroxide product as a raw material, improved the production process of activated magnesium oxide and high-purity magnesium oxide, and provided new ideas for the production of activated magnesium oxide and high-purity magnesium oxide. Summary of the invention

[0010] Based on the above technical problems, the present invention provides a method and device for preparing activated magnesium oxide and co-producing high-purity magnesium oxide, based on the promotion and application of the technology of enriching phosphate concentrate from medium and low-grade phosphate ore or phosphate tailings while recovering calcium carbonate and magnesium hydroxide, and the obtained magnesium hydroxide product is subjected to high value-added utilization supporting process research to form a co-production process of activated magnesium oxide and high-purity magnesium oxide, which not only shortens the cycle of producing activated magnesium oxide and high-purity magnesium oxide using magnesium hydroxide as raw material, but also simplifies the production process, helps to reduce costs, realizes the graded production of activated magnesium oxide and high-purity magnesium oxide, and improves the high value-added utilization rate of magnesium hydroxide.

[0011] The specific technical solution is:

[0012] One of the purposes of the present invention is to provide a method for preparing active magnesium oxide and co-producing high-purity magnesium oxide, comprising the following steps:

[0013] S1: washing magnesium hydroxide with deionized water and drying for later use;

[0014] S2: The magnesium hydroxide in step S1 is sent to a calcining kiln for calcination, and hot air is introduced at the same time, so that small-sized particles are introduced into the dust removal component through the air outlet through the air outlet pipe with the hot air to obtain active magnesium oxide; and large-sized particles are discharged from the discharge port as the calcining kiln rotates to obtain high-purity magnesium oxide.

[0015] By blowing air into the calcining kiln, the lighter active magnesium oxide components with smaller particle sizes and the heavier high-purity magnesium oxide components with larger particle sizes produced during the calcining process can be separated, and the dust removal function of the dust removal component can be used to achieve the purpose of graded production of active magnesium oxide and high-purity magnesium oxide; at the same time, combined with strict control of the calcination temperature and calcination time, the activity of the prepared active magnesium oxide is guaranteed, thereby improving the graded capacity of active magnesium oxide and high-purity magnesium oxide.

[0016] In order to significantly improve the activity of active magnesium oxide and high-purity magnesium oxide during the production process, and to ensure and improve the purity of high-purity magnesium oxide, preferably, the calcination temperature is 500-800°C and the calcination time is 10-90min. In a more excellent embodiment, the calcination temperature is 550°C and the calcination time is 30-90min, so that the iodine absorption value of the active magnesium oxide reaches more than 115mg, the purity reaches more than 92%, and the purity of the high-purity magnesium oxide reaches more than 98%. In a more excellent embodiment, the calcination temperature is 550°C and the calcination time is 60min or 90min, so that the iodine absorption value of the active magnesium oxide reaches more than 146mg, the purity reaches more than 92%, and the purity of the high-purity magnesium oxide reaches more than 98%.

[0017] The magnesium hydroxide used in the invention is obtained by enriching phosphate concentrate from medium- and low-grade phosphate ore or phosphate tailings and recovering magnesium, and the particle size of the magnesium hydroxide is between 2 and 35 μm.

[0018] The second purpose of the invention is to provide a device for preparing activated magnesium oxide and co-producing high-purity magnesium oxide, including an air supply and feeding assembly, a support assembly, a calcination assembly, a separation assembly and a dust removal assembly; the calcination assembly and the air supply and feeding assembly are both installed on the support assembly, and the air supply and feeding assembly is installed at the left end of the calcination assembly; the separation assembly is installed between the calcination assembly and the dust removal assembly, and the left end of the separation assembly is connected to the right end of the calcination assembly, and the right end of the separation assembly is connected to the side wall of the dust removal assembly near the top.

[0019] By connecting and installing the air supply and feeding components, calcination components and dust removal components, it is possible to simultaneously obtain active magnesium oxide products and high-purity magnesium oxide products during the production of magnesium oxide by calcining magnesium hydroxide, so that magnesium oxide products of different qualities can be obtained in the same calcination process, and the efficiency of enriching phosphate concentrate from medium and low-grade phosphate ore or phosphate tailings to recover magnesium and produce magnesium products with higher added value is improved, which helps to reduce the difficulty of balancing activity and purity in the production process of magnesium oxide and reduces the cost of resource utilization of magnesium hydroxide.

[0020] In order to meet the needs of continuous processing of magnesium hydroxide to produce active magnesium oxide and high-purity magnesium oxide and improve processing efficiency, it is preferred that the calcining assembly includes a calcining kiln installed on a support assembly and a power source installed on the support assembly, and the power source can drive the calcining kiln to rotate; the air supply and feeding assembly includes a feed end cover installed on the support assembly, the right end of the feed end cover is connected to the left end of the calcining kiln, and a feed hopper and an air inlet assembly are provided on the feed end cover, the feed hopper can feed magnesium hydroxide material into the calcining kiln, and the air inlet assembly can blow air into the calcining kiln; the The separation component includes a discharge end cover, the left end of which is connected to the calcining kiln, the left end of which is provided with an air outlet, the air outlet is provided with an air outlet pipe, and the bottom end of the discharge end cover is provided with a discharge port; the top of the dust removal component is provided with an opening, the top of the opening is provided with a collecting cover, the bottom of the opening is provided with a filter bag, the bottom of the filter bag is closed, the top of the filter bag is connected to the collecting cover, the bottom of the dust removal component is provided with a discharge port, the side wall of the dust removal component close to the top is provided with a connecting port, the air outlet pipe is connected to the connecting port; the top of the collecting cover is provided with an exhaust pipe.

[0021] More preferably, the calcining assembly further comprises a calcining furnace, the calcining furnace is provided with an exhaust gas outlet, and a fuel inlet is provided on a side wall of the calcining furnace; the calcining kiln runs through the left and right ends of the calcining furnace, and a rolling assembly is provided between the calcining kiln and the calcining furnace.

[0022] More preferably, the calcining kiln is provided with a driven toothed belt, the power source is provided with a driving toothed belt, and the driven toothed belt and the driving toothed belt are meshed with each other.

[0023] In order to improve the utilization rate of heat energy recovery, preferably, the outer layer of the outlet pipe is provided with an insulation pipe, the top of the insulation pipe is emptied or connected to an exhaust gas treatment component; the bottom of the insulation pipe is provided with an exhaust gas inlet, and a connecting pipe is provided between the exhaust gas inlet and the exhaust gas outlet.

[0024] Preferably, the air inlet assembly includes a blast pipe connected to the left end of the feed end cover and a blower installed on the blast pipe.

[0025] In order to improve the stability of the filter bag, preferably, a plurality of support rods are provided on the inner wall of the dust removal assembly, and the support rods are connected to the filter bag.

[0026] In order to realize timely recovery and storage of active magnesium oxide, preferably, a storage reservoir is provided at the bottom of the dust removal component, the top of the storage reservoir is connected to the discharge port, and a material taking door is provided on the storage reservoir.

[0027] In order to realize the recycling of the hot air blown out of the active magnesium oxide, preferably, the exhaust pipe is cyclically connected to the air inlet assembly.

[0028] Compared with the prior art, the technical effects created by the present invention are embodied in:

[0029] The invention adopts the process of introducing hot air into the calcining kiln, and combines the hot air blowing and the dust reduction effect in the dust removal component to realize the collection of lightweight magnesium oxide components (active magnesium oxide), so that the production and preparation of active magnesium oxide and high-purity magnesium oxide are met in the same calcining process, and combined with the control of calcining temperature and calcining time, it can be suitable for magnesium hydroxide raw materials prepared by precipitation method from magnesium associated with phosphate ore.

[0030] The invention adopts a rotating calcination kiln to calcine, thereby realizing rotation control of the sliding speed of magnesium hydroxide in the calcination kiln, and then controlling the calcination time of magnesium hydroxide in the calcination kiln, realizing conversion of the calcination time into the rotation speed control of the calcination kiln, reducing the difficulty of calcination time control, and then realizing the purpose of continuously processing magnesium hydroxide to prepare active magnesium oxide and high-purity magnesium oxide.

[0031] The device created by the invention has a simple structure and can be improved on the basis of existing rotary kiln equipment. It can realize product classification of magnesium oxide products produced by calcining magnesium hydroxide while reducing equipment improvement costs and is easy to promote and implement industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention is convenient for those skilled in the art to fully understand the technical solution of the present invention. In combination with the content of the technical solution and the provided drawings, the following description is made for the provided drawings. The directional words described in the present invention, such as: up, down, front, back, left, right, etc., are all descriptions made in combination with and facing the following drawings for easy understanding, and are not limitations on the technical solution of the present invention.

[0033] Figure 1 The overall process flow diagram is created for the present invention.

[0034] Figure 2 The present invention is a schematic diagram of the device structure.

[0035] Figure 3 for Figure 2 Another schematic diagram of the structure of the embodiment.

[0036] 1-blower 2-blast pipe 3-feed end cover 4-feed hopper 5-calcining kiln 6-calcining furnace 7-exhaust outlet 8-discharge end cover 9-discharge port 10-rolling assembly 11-driven toothed belt 12-driving toothed belt 13-power source 14-air outlet 15-air outlet pipe 16-dust removal assembly 17-support rod 18-filter bag 19-emptying pipe 20-discharge port 21-storage 22-feeding door 23-collection hood 24-connecting pipe 25-insulation pipe. DETAILED DESCRIPTION

[0037] In order to facilitate those skilled in the art to correctly understand the present invention and enable those skilled in the art to fully understand the technical content of the present invention, the technical solution of the present invention is further explained below in conjunction with specific implementation methods and drawings. However, this explanation does not limit the scope of protection required for the present invention. The scope of protection of the present invention by those skilled in the art cannot be limited to the following explanations. Any equivalent substitutions or changes made by any those skilled in the art or persons familiar with the technology in the art based on the present invention and the technical solution and inventive concept thereof should be covered within the scope of protection of the present invention.

[0038] like Figure 1 and Figure 2 As shown, in certain embodiments, a method for preparing active magnesium oxide and co-producing high-purity magnesium oxide comprises the following steps:

[0039] S1: washing magnesium hydroxide with deionized water and drying for later use;

[0040] S2: The magnesium hydroxide in step S1 is sent to the calcining kiln 5 for calcination, and hot air is introduced at the same time, so that small-sized particles are introduced into the dust removal component 16 through the air outlet 14 and the air outlet pipe 15 with the hot air to obtain active magnesium oxide; and large-sized particles are discharged from the discharge port 9 as the calcining kiln 5 rotates to obtain high-purity magnesium oxide.

[0041] By feeding magnesium hydroxide into the calcining kiln 5 for calcination, the magnesium hydroxide material fed from the feed end cover 3 at the left end of the calcining kiln 5 continuously slides into the discharge end cover 8 during the rotation of the calcining kiln 5, and then the calcination time of the magnesium hydroxide in the calcining kiln 5 can be controlled by controlling the rotation rate of the calcining kiln 5, so that the calcination temperature and time are controlled, and hot air is introduced so that the hot air is blown from the left end to the right end of the calcining kiln 5, so that the magnesium oxide component with higher activity enters the dust removal component 16 along with the hot air, and the active magnesium oxide component is collected by dust reduction; and the inert magnesium oxide enters the discharge end cover 8 along with the rotation of the calcining kiln 5 and is discharged from the discharge port 9 to obtain high-purity magnesium oxide, thereby achieving the purpose of graded production of active magnesium oxide and high-purity magnesium oxide in the same calcining kiln 5.

[0042] In some embodiments, the calcination temperature is 500-800°C, for example: 500°C, 550°C, 600°C, 700°C, 750°C, 800°C, etc., and the calcination time is 10-90min, for example: 10min, 20min, 30min, 40min, 50min, 60min, 70min, 80min, 90min, etc. Through proper temperature control, it can help to improve the activity of activated magnesium oxide, improve the purity of high-purity magnesium oxide, and realize the production of high-value-added activated magnesium oxide with magnesium hydroxide produced by enriching magnesium concentrate from phosphate ore in patent announcement number CN109264686B as a raw material, and obtain high-purity magnesium oxide at the same time, further improve the utilization value of low-grade phosphate ore, shorten the production cycle of activated magnesium oxide and high-purity magnesium oxide, reduce the difficulty of satisfying the technical problems that need to be overcome in the production process of magnesium oxide with both activity and purity, and reduce the cost of producing activated magnesium oxide and high-purity magnesium oxide.

[0043] The magnesium hydroxide raw material used in the invention is magnesium hydroxide produced by recovering magnesium resources from phosphate concentrate enrichment in accordance with patent announcement number CN109264686B, and its particle size is between 2-35 μm. Active magnesium oxide and high-purity magnesium oxide can be obtained by calcining at 500-800°C for 10-90 minutes, realizing the production of two magnesium oxide products with one process and one set of equipment.

[0044] like Figure 2 and Figure 3As shown, in certain embodiments, a device for preparing active magnesium oxide and co-producing high-purity magnesium oxide includes an air supply and feeding assembly, a support assembly, a calcination assembly, a separation assembly and a dust removal assembly 16; the calcination assembly and the air supply and feeding assembly are both installed on the support assembly, and the air supply and feeding assembly is installed at the left end of the calcination assembly; the separation assembly is installed between the calcination assembly and the dust removal assembly 16, and the left end of the separation assembly is connected to the right end of the calcination assembly, and the right end of the separation assembly is connected to the side wall of the dust removal assembly near the top.

[0045] When in use, the magnesium hydroxide raw material is fed into the air supply and feeding assembly so that it enters the calcination assembly. As the calcination assembly calcines and works, the calcined material is discharged from the right end of the calcination assembly. Moreover, under the air supply action of the air supply and feeding assembly, the light component (active magnesium oxide) formed by calcination in the calcination assembly is separated from the heavy component (high-purity magnesium oxide) in the separation assembly by the wind, and the light component enters the dust removal assembly 16 for dust removal, thereby realizing the separation of active magnesium oxide and high-purity magnesium oxide, thereby achieving the purpose of graded preparation of magnesium oxide products.

[0046] In certain embodiments, Figure 2 and Figure 3 As shown, the calcining assembly includes a calcining kiln 5 installed on a supporting assembly and a power source 13 installed on the supporting assembly, such as a motor, and the power source 13 can drive the calcining kiln 5 to rotate; the air supply and feeding assembly includes a feed end cover 3 installed on the supporting assembly, the right end of the feed end cover 3 is connected to the left end of the calcining kiln 5, and the feed end cover 3 is provided with a feed hopper 4 and an air intake assembly, the feed hopper 4 can feed magnesium hydroxide material into the calcining kiln 5, and the air intake assembly can blow air into the calcining kiln 5; the separation assembly includes a discharge end cover 8, the left end of the discharge end cover 8 is connected to the calcining kiln The kiln 5 is connected, the left end of the discharge end cover 8 is provided with an air outlet 14, the air outlet 14 is provided with an air outlet pipe 15, and the bottom end of the discharge end cover 8 is provided with a discharge port 9; the top of the dust removal component 16 is provided with an opening, the top of the opening is provided with a collection cover 23, the bottom of the opening is provided with a filter bag 18, the bottom of the filter bag 18 is closed, the top of the filter bag 18 is connected with the collection cover 23, the bottom of the dust removal component 16 is provided with a discharge port 20, the side wall of the dust removal component 16 close to the top is provided with a communication port, the air outlet pipe 15 is connected with the communication port; the top of the collection cover 23 is provided with an exhaust pipe 19. When applied, according to the following Figure 1 The production process shown in the figure is used for production, which realizes the graded preparation of magnesium oxide products and reduces the difficulty and cost of preparing active magnesium oxide and high-purity magnesium oxide separately in the same process.

[0047] like Figure 2 and Figure 3As shown, in some embodiments, the calcining assembly further comprises a calcining furnace 6, the calcining furnace 6 is provided with an exhaust outlet 7, and a fuel inlet is provided on the side wall of the calcining furnace 6; the calcining kiln 5 passes through the left and right ends of the calcining furnace 6, and a rolling assembly 10 is provided between the calcining kiln 5 and the calcining furnace 6. In some embodiments, the calcining kiln 5 is provided with a driven toothed belt 11, and the power source 13 is provided with a driving toothed belt 12, and the driven toothed belt 11 and the driving toothed belt 12 are meshed with each other.

[0048] like Figure 3 As shown, in some embodiments, the outer layer of the outlet pipe 15 is provided with an insulation pipe 25, the top of the insulation pipe 25 is emptied or connected to an exhaust gas treatment component; the bottom of the insulation pipe 25 is provided with an exhaust gas inlet, and a connecting pipe 24 is provided between the exhaust gas inlet and the exhaust gas outlet 7. The waste heat of the exhaust gas discharged by burning fuel is utilized, and the hot air entering the dust removal component 16 is continuously heated and preheated, ensuring that the waste heat can be recycled after the hot air is collected by the collection cover 23.

[0049] like Figure 2 and Figure 3 As shown, in some embodiments, the air inlet assembly includes a blast pipe 2 connected to the left end of the feed end cover 3 and a blower 1 installed on the blast pipe 2. Blast air is introduced to grade the magnesium oxide.

[0050] like Figure 2 and Figure 3 As shown, in some embodiments, the inner wall of the dust removal assembly 16 is provided with a plurality of support rods 17, and the support rods 17 are connected to the filter bag 18 to enhance stability; Figure 2 and Figure 3 As shown, in some embodiments, a storage reservoir 21 is provided at the bottom of the dust removal component 16, the top of the storage reservoir 21 is connected to the feed port 20, and a material taking door 22 is provided on the storage reservoir 21 to prevent the lighter magnesium oxide component from being emitted; Figure 2 and Figure 3 As shown, in some embodiments, the exhaust pipe 19 is cyclically connected to the air inlet assembly, thereby realizing the recycling of waste heat and reducing energy consumption.

[0051] In order to verify the technical effect of the technical solution created by the present invention, the researchers of the present invention calcined magnesium hydroxide at different temperatures and different calcination times, and sampled and analyzed the active magnesium oxide and high-purity magnesium oxide components obtained by hot air blowing and classification, and obtained the results as shown in Table 1 below:

[0052] Table 1

[0053]

[0054] Note: The above test data are obtained by taking the average value after three tests, and are graded according to the "HG-T3928-2012" standard.

[0055] As can be seen from the data in Table 1, the invention creates a process of calcining magnesium hydroxide by using a rotating calcining kiln 5, and using blast wind during the calcining process, so that the wind blows the light components (active magnesium oxide) during the calcining process into the dust removal component 16 for dust reduction treatment to obtain active magnesium oxide, and at the same time, the heavier components during the calcining process are discharged from the discharge port 9 as the calcining kiln 5 rotates, and high-purity magnesium oxide is obtained. In combination with strict control of the calcining temperature and time, the activity and purity of the active magnesium oxide and the activity and purity of the high-purity magnesium oxide will change, and then the active magnesium oxide and the high-purity magnesium oxide will be obtained by classification. In the invention, in a more optimal process, the calcining temperature is controlled to 550°C, and the calcination is performed for 30-90min, so that the magnesium oxide content in the active magnesium oxide can reach more than 92%, and the iodine absorption value can reach more than 115mg, and the citric acid activity is less than 11s; at the same time, the magnesium oxide content in the high-purity magnesium oxide reaches more than 98.4%. The graded preparation of active magnesium oxide and high-purity magnesium oxide is realized. Furthermore, the invention controls the calcination temperature to 550° C. and calcines for 60 min or 90 min, which can make the iodine absorption value of the active magnesium oxide reach more than 146 mg and the citric acid activity less than 9 s.

[0056] The invention creates other matters not covered by the invention, which can be realized by referring to the prior art or common knowledge known to those skilled in the art, and conventional technical means, for example, how to prepare magnesium hydroxide products using medium and low-grade phosphate ore, and refer to the technical solution disclosed in patent announcement number CN109264686B for production and preparation. Another example: how to install a power source 13 such as an electric motor, etc., can be completed according to common knowledge or conventional technical means known to those skilled in the art.

Claims

1. A method for preparing active magnesium oxide and co-producing high-purity magnesium oxide, characterized in that: The following steps are involved: S1: washing magnesium hydroxide with deionized water and drying for later use; S2: The magnesium hydroxide in step S1 is fed into a calcining kiln (5) for calcination, and hot air is introduced at the same time, so that small-sized particles are discharged from the air outlet (14) through the air outlet pipe (15) to the dust removal component (16) for dust reduction along with the hot air, thereby obtaining active magnesium oxide; and large-sized particles are discharged from the discharge port (9) as the calcining kiln (5) rotates, thereby obtaining high-purity magnesium oxide.

2. The method for preparing activated magnesium oxide and co-producing high-purity magnesium oxide according to claim 1, characterized in that: The calcination temperature is 500-800° C., and the calcination time is 10-90 minutes.

3. The method for preparing activated magnesium oxide and co-producing high-purity magnesium oxide according to claim 1, characterized in that: The particle size of the magnesium hydroxide is 2-35 μm.

4. A device for preparing active magnesium oxide and co-producing high-purity magnesium oxide, characterized in that: It comprises an air supply and feeding assembly, a support assembly, a calcining assembly, a separation assembly and a dust removal assembly (16); the calcining assembly and the air supply and feeding assembly are both mounted on the support assembly, and the air supply and feeding assembly is mounted at the left end of the calcining assembly; the separation assembly is mounted between the calcining assembly and the dust removal assembly (16), and the left end of the separation assembly is connected to the right end of the calcining assembly, and the right end of the separation assembly is connected to the side wall of the dust removal assembly near the top.

5. The device for preparing activated magnesium oxide and co-producing high-purity magnesium oxide as claimed in claim 4, characterized in that: The calcining assembly comprises a calcining kiln (5) mounted on a supporting assembly and a power source (13) mounted on the supporting assembly, wherein the power source (13) is capable of driving the calcining kiln (5) to rotate; the air supply and feeding assembly comprises a feed end cover (3) mounted on the supporting assembly, wherein the right end of the feed end cover (3) is connected to the left end of the calcining kiln (5), and a feed hopper (4) and an air supply assembly are provided on the feed end cover (3), wherein the feed hopper (4) is capable of feeding magnesium hydroxide material into the calcining kiln (5), and the air supply assembly is capable of blowing air into the calcining kiln (5); the separation assembly comprises a discharge end cover (8), wherein the left end of the discharge end cover (8) is connected to the calcining kiln (5), and the discharge end cover (8) is capable of feeding magnesium hydroxide material into the calcining kiln (5). An air outlet (14) is provided at the left end of the material end cover (8), an air outlet pipe (15) is provided on the air outlet (14), and a material outlet (9) is provided at the bottom end of the material outlet end cover (8); an opening is provided at the top of the dust removal component (16), a collecting cover (23) is provided at the top of the opening, a filter bag (18) is provided at the bottom of the opening, the bottom of the filter bag (18) is closed, the top of the filter bag (18) is connected to the collecting cover (23), a material discharge port (20) is provided at the bottom of the dust removal component (16), a connecting port is provided on the side wall of the dust removal component (16) close to the top, and the air outlet pipe (15) is connected to the connecting port; an exhaust pipe (19) is provided at the top of the collecting cover (23).

6. The device for preparing activated magnesium oxide and co-producing high-purity magnesium oxide as claimed in claim 5, characterized in that: The calcining assembly also includes a calcining furnace (6), the calcining furnace (6) is provided with an exhaust gas outlet (7), and the side wall of the calcining furnace (6) is provided with a fuel inlet; the calcining kiln (5) passes through the left and right ends of the calcining furnace (6), and a rolling assembly (10) is provided between the calcining kiln (5) and the calcining furnace (6).

7. The device for preparing active magnesium oxide and co-producing high-purity magnesium oxide as claimed in claim 6, characterized in that: The calcining kiln (5) is provided with a driven toothed belt (11), and the power source (13) is provided with a driving toothed belt (12), and the driven toothed belt (11) and the driving toothed belt (12) are meshed with each other.

8. The device for preparing active magnesium oxide and co-producing high-purity magnesium oxide as claimed in claim 6, characterized in that: The outer layer of the air outlet pipe (15) is provided with an insulation pipe (25), the top of the insulation pipe (25) is emptied or connected to an exhaust gas treatment component; the bottom of the insulation pipe (25) is provided with an exhaust gas inlet, and a connecting pipe (24) is provided between the exhaust gas inlet and the exhaust gas outlet (7).

9. The device for preparing activated magnesium oxide and co-producing high-purity magnesium oxide as claimed in claim 5, characterized in that: The air inlet assembly comprises an air blast pipe (2) connected to the left end of the feed end cover (3) and a blower (1) mounted on the air blast pipe (2).

10. The device for preparing active magnesium oxide and co-producing high-purity magnesium oxide as claimed in claim 5, characterized in that: The inner wall of the dust removal component (16) is provided with a plurality of support rods (17), and the support rods (17) are connected to the filter bag (18); and / or the bottom of the dust removal component (16) is provided with a storage reservoir (21), the top of the storage reservoir (21) is connected to the discharge port (20), and the storage reservoir (21) is provided with a material taking door (22); and / or the exhaust pipe (19) is cyclically connected to the air inlet component.

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