CN112094106A - Preparation method of large-crystal magnesia with low silicon dioxide content - Google Patents
Preparation method of large-crystal magnesia with low silicon dioxide content Download PDFInfo
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- C04B35/04—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on magnesium oxide, calcium oxide or oxide mixtures derived from dolomite based on magnesium oxide
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Abstract
The invention discloses a preparation method of large-crystal magnesite with low silicon dioxide content, belonging to the technical field of mineral resource processing. It comprises the following steps: (1) selecting: low-grade magnesite is taken as a raw material, and magnesite with the magnesium oxide content of 40-45% is selected; (2) cleaning: washing magnesite; (3) refining: refining magnesite; (4) roasting: delivering the concentrate powder to a rotary kiln or a fluidized bed furnace for roasting, and cooling to room temperature to obtain light-burned magnesium oxide; (5) dry pressing: sending the light-burned magnesium oxide into a ball press machine for dry pressing to prepare a ball body; (6) electric melting: and (5) conveying the spheres prepared in the step (5) to an electric arc furnace for electric melting, and carrying out heat preservation, cooling and crystallization. The large-crystal magnesite prepared by the method has good performance advantages, and the test parameters such as particle volume density, magnesium oxide content, silicon dioxide content, calcium oxide content, ferric oxide content, aluminum oxide content, yield and the like show significant differences, so that the large-crystal magnesite is high-quality large-crystal magnesite.
Description
Technical Field
The invention belongs to the technical field of mineral resource processing, and particularly relates to a preparation method of large-crystal magnesia with low silicon dioxide content.
Background
The large-crystal magnesite has good erosion resistance due to coarse crystal grains, is one of the main export magnesium refractory materials in China, is mainly applied to the industrial fields of metallurgy, aerospace and the like, is a main raw material of high-grade magnesia carbon bricks, magnesia chrome bricks and other magnesium refractory material products, and is also an excellent high-temperature insulating filling material. The market demand of large-crystal fused magnesium is large, and particularly, the large-crystal fused magnesium is exported to developed countries of Russia, America, Japan, Germany and Korea every year, so that a large amount of foreign exchanges are exchanged for China.
However, in recent years, with the increasing demand and demand of international markets for macrocrystalline fused magnesium, as the demand for magnesia content of macrocrystalline fused magnesium is higher, the demand for silica is lower, and meanwhile, the domestic high-quality magnesite reserves are reduced, so that fewer magnesite resources are required to meet the conditions. And the large crystal magnesia on the market has the problem of higher silicon dioxide, and the corrosion resistance of the large crystal magnesia is seriously influenced. According to statistics, the product silicon dioxide produced by domestic large crystal magnesite manufacturers is generally higher, for example, the content of 97.5 percent large crystal magnesite silicon dioxide is more than 0.6 percent, thereby greatly influencing the high-temperature corrosion resistance of magnesite. In addition, the yield of the product is very low, wherein the yield is more than 97.5 percent in the production process. The light burnt magnesia is the main raw material for producing large-crystal electric melting magnesia, the quality of the light burnt magnesia directly affects the product quality, and good raw materials are selected for producing good products. Therefore, the low-grade magnesite resource is reasonably utilized, and a novel process route is developed; the research and development of novel medicaments and the development of low-silicon-dioxide large-crystal magnesia have important significance.
The project utilizes the low-grade magnesite flotation purification technology mastered by a company to produce light-burned magnesium from concentrate powder prepared by flotation purification of low-grade magnesite, develops low-silicon dioxide large-crystal magnesite by developing a new process, optimizing process links, screening and developing novel medicaments and the like and combining field tests, and remarkably improves the yield of the large-crystal magnesite by more than 97.5 percent.
Disclosure of Invention
1. Problems to be solved
Aiming at the problems in the prior art, the invention provides the preparation method of the large-crystal magnesite with low silicon dioxide content, compared with the prior art, the large-crystal magnesite prepared by the invention has good performance advantages, and the experimental parameters such as particle volume density, magnesium oxide content, silicon dioxide content, calcium oxide content, iron oxide content, aluminum oxide content, yield and the like all show significant differences and is high-quality large-crystal magnesite. The invention aims to improve the yield of large crystals by over 97.5 percent and obviously reduce the content of silicon dioxide. The present invention is at an international advanced level.
2. Technical scheme
In order to solve the problems, the technical scheme provided by the invention is as follows:
a preparation method of large crystal magnesite with low silicon dioxide content comprises the following steps:
(1) selecting: low-grade magnesite is taken as a raw material, and magnesite with the magnesium oxide content of 40-45% is selected;
(2) cleaning: cleaning the magnesite which is selected in the step (1), and removing mud and micro-fine particle minerals on the surface of the magnesite for later use;
(3) refining: refining the magnesite cleaned in the step (2), wherein the refining process is divided into six steps, the first step is to crush the magnesite, the second step is to wash the crushed magnesite, the third step is to grind the washed magnesite, the fourth step is to add water into the ground magnesite to prepare raw ore pulp, the fifth step is to desliming the raw ore pulp, and the sixth step is to float the deslimed raw ore pulp to obtain refined ore powder for later use;
(4) roasting: delivering the concentrate powder prepared in the step (3) to a rotary kiln or a fluidized bed furnace for roasting, and cooling to room temperature to obtain light-burned magnesium oxide for later use;
(5) dry pressing: sending the light-burned magnesium oxide prepared in the step (4) to a ball press machine for dry pressing to prepare a ball for later use;
(6) electric melting: and (5) conveying the spheres prepared in the step (5) to an electric arc furnace for electric melting, and carrying out heat preservation, cooling and crystallization to obtain the spherical spheres.
In the preparation method of the large-crystal magnesite with low silicon dioxide content, the mass percentage range of the magnesite in the low-grade magnesite in the step (1) is 30-45%, wherein the mass percentage range of the dolomite is 10-30%, the mass percentage range of the quartz is 5-15%, and the balance is other mineral impurities;
in the step (1), magnesite with the magnesia content of 42-44% is selected.
In the preparation method of the large-crystal magnesite with low silicon dioxide content, the size fraction of the crushed magnesite in the step (3) is 5 mm;
the grinding equipment in the step (3) is a ball mill, and the rotating speed of the ball mill is 80 r/min;
the ground particle size in the step (3) is 0.1 mm;
the desliming equipment in the step (3) is a desliming cyclone;
the water content of the concentrate powder in the step (3) is less than 10 percent, and the MgO content is 40 to 45 percent.
In the preparation method of the large crystallized magnesia with low silicon dioxide content, the flotation device in the step (3) is a flotation tank which is divided into a dosing reaction zone, a standing aeration separation zone, a concentrate collecting tank, a tailing tank and a tailing collecting tank by a wall plate, the bottom surface of the dosing reaction zone is an inclined plane and inclines downwards near the standing aeration separation zone, an electric stirrer is arranged at the top of the dosing reaction zone, an ore pulp inlet is arranged at the lower part of the outer side wall, a mixed ore pulp inlet is arranged on the wall plate between the standing aeration separation zone and the dosing reaction zone, the mixed ore pulp inlet is connected with a lifting pump through a pipeline, a bubble generator is arranged at the bottom of the standing aeration separation zone, a tailing collecting device is arranged near one side of the tailing tank, the top of the standing aeration separation zone is communicated with the concentrate collecting tank, a slag scraper is arranged at the.
In the above method for preparing large crystalline magnesite with low silica content, the specific roasting method in step (4) is as follows: heating to 200 deg.C, maintaining for 4h, heating to 650 deg.C, and maintaining for 1 h;
the parameters of the light-burned magnesium oxide in the step (4) are as follows: the weight percentage content of MgO is more than or equal to 95 percent, and the particle size is less than 0.088 mm.
In the preparation method of the large-crystal magnesite with low silicon dioxide content, the pressure of dry pressing in the step (5) is 600 KN;
the diameter of the sphere in the step (5) is 30 mm.
In the above method for preparing large crystal magnesite with low silica content, step (5) further comprises a premixing step, specifically as follows: and (4) sending the light-burned magnesium oxide prepared in the step (4) and a stabilizer to a pre-mixer for pre-mixing, and then sending to a ball press for dry pressing.
In the above method for preparing large crystal magnesite with low silica content, the stabilizer is a mixture of zirconia and yttria, and the weight ratio of zirconia to yttria is 1: 2;
the weight ratio of the light-burned magnesia to the stabilizer is 101: 2.
in the preparation method of the large crystal magnesite with low silicon dioxide content, the electric melting temperature in the step (6) is 3000 ℃;
the electric melting time in the step (6) is 6.5 h.
In the above method for preparing large crystal magnesite with low silica content, step (6) further includes a step of adding a reducing agent, which is specifically as follows: mixing the spheres prepared in the step (5) with a reducing agent, and then sending the mixture to an electric arc furnace for electric melting;
wherein the reducing agent is high-purity graphite powder.
3. Advantageous effects
Compared with the prior art, the invention has the beneficial effects that:
compared with the prior art, the large-crystal magnesite prepared by the invention has good performance advantages, and the test parameters such as particle volume density, magnesium oxide content, silicon dioxide content, calcium oxide content, iron oxide content, aluminum oxide content, yield and the like all show significant differences, so that the large-crystal magnesite is high-quality large-crystal magnesite. Specifically, the invention fully utilizes the basic conditions of magnesite tailing flotation purification and novel suspension furnace, and the like applied by the company in the prior art, researches and develops the volume density of 3.5g/cm3The large crystal magnesite with low silicon dioxide improves the yield of large crystals by more than 97.5 percent and obviously reduces the content of silicon dioxide.
Drawings
FIG. 1 is an SEM scan of large crystal magnesite prepared in example 1 of the invention;
FIG. 2 is an XRD scan of the large crystal magnesite prepared in example 1 of the present invention.
Detailed Description
The invention is further described with reference to specific embodiments and the accompanying drawings.
Example 1
The preparation method of the large crystal magnesite with low silica content comprises the following steps:
(1) selecting: low-grade magnesite is taken as a raw material, and magnesite with the magnesium oxide content of 40% is selected;
(2) cleaning: cleaning the magnesite which is selected in the step (1), and removing mud and micro-fine particle minerals on the surface of the magnesite for later use;
(3) refining: refining the magnesite cleaned in the step (2), wherein the refining process is divided into six steps, the first step is to crush the magnesite, the second step is to wash the crushed magnesite, the third step is to grind the washed magnesite, the fourth step is to add water into the ground magnesite to prepare raw ore pulp, the fifth step is to desliming the raw ore pulp, and the sixth step is to float the deslimed raw ore pulp to obtain refined ore powder for later use;
(4) roasting: delivering the concentrate powder prepared in the step (3) to a rotary kiln or a fluidized bed furnace for roasting, and cooling to room temperature to obtain light-burned magnesium oxide for later use;
(5) dry pressing: sending the light-burned magnesium oxide prepared in the step (4) to a ball press machine for dry pressing to prepare a ball for later use;
(6) electric melting: and (5) conveying the spheres prepared in the step (5) to an electric arc furnace for electric melting, and carrying out heat preservation, cooling and crystallization to obtain the spherical spheres.
In the preparation method of the large-crystal magnesite with low silicon dioxide content, the mass percentage range of magnesite in the low-grade magnesite in the step (1) is 30-45%, wherein the mass percentage range of dolomite is 20%, the mass percentage range of quartz is 10%, and the balance is other mineral impurities;
in the step (1), magnesite with the magnesia content of 43% is selected.
In the preparation method of the large-crystal magnesite with low silicon dioxide content, the size fraction of the crushed magnesite in the step (3) is 5 mm;
the grinding equipment in the step (3) is a ball mill, and the rotating speed of the ball mill is 80 r/min;
the ground particle size in the step (3) is 0.1 mm;
the desliming equipment in the step (3) is a desliming cyclone;
the water content of the concentrate powder in the step (3) is less than 10 percent, and the MgO content is 43 percent.
In the preparation method of the large crystallized magnesia with low silicon dioxide content, the flotation device in the step (3) is a flotation tank which is divided into a dosing reaction zone, a standing aeration separation zone, a concentrate collecting tank, a tailing tank and a tailing collecting tank by a wall plate, the bottom surface of the dosing reaction zone is an inclined plane and inclines downwards near the standing aeration separation zone, an electric stirrer is arranged at the top of the dosing reaction zone, an ore pulp inlet is arranged at the lower part of the outer side wall, a mixed ore pulp inlet is arranged on the wall plate between the standing aeration separation zone and the dosing reaction zone, the mixed ore pulp inlet is connected with a lifting pump through a pipeline, a bubble generator is arranged at the bottom of the standing aeration separation zone, a tailing collecting device is arranged near one side of the tailing tank, the top of the standing aeration separation zone is communicated with the concentrate collecting tank, a slag scraper is arranged at the. This section is prior art to the present company, application No.: CN201521098716.6, publication No.: CN205436031U discloses a flotation device for low-grade magnesite, which comprises a flotation tank, wherein the flotation tank is divided into a dosing reaction area 1, a standing and aerating separation area 2, a concentrate collecting tank 3, a tailing tank 4 and a tailing collecting tank 5 by a wall plate, the bottom surface of the dosing reaction area 1 is an inclined surface, and one side of the dosing reaction area close to the standing and aerating separation area 2 is inclined downwards; the top of the dosing reaction zone 1 is provided with an electric stirrer 6, and the lower part of the outer side wall is provided with an ore pulp inlet 8; a mixed ore pulp inlet 12 is arranged on a wall plate between the standing aeration separation area 2 and the dosing reaction area 1 and is connected with a lift pump 15 through a pipeline, a bubble generator 14 is arranged at the bottom of the standing aeration separation area 2, and a tailing collecting device 17 is arranged at one side close to the tailing pond 4; the top of the standing aeration separation area 2 is communicated with a concentrate collecting tank 5, and the upper part of the communicated part is provided with a slag scraper 16; the top of the tailing pond 4 is communicated with a tailing collecting groove 5. The bubble generator 14 is connected with the water pump 10 through a first connecting pipeline 19, the water pump 10 is connected with the dosing reaction area 1 through a second connecting pipeline 20, an opening and closing valve 11 is arranged on the first connecting pipeline 19, and a filter 9 is arranged on the second connecting pipeline 20. The electric stirrer 6 is controlled by a variable frequency motor 7. A liquid level regulator 18 is arranged at the separation part of the tailing pond 4 and the tailing collecting groove 5. The tailing collecting device 17 is composed of a plurality of collecting pipes arranged side by side, the other ends of the collecting pipes extend into the tailing pond 4, and a plurality of through holes are uniformly formed in each collecting pipe along the radial direction and the axial direction. The bubble generators 14 are arranged side by side, liquid inlet pipes at the bottoms of the bubble generators 14 are fixed on the connecting main pipe 13, and the connecting main pipe 13 is communicated with the first connecting pipeline 19. The utility model discloses during the use, the ore pulp is got into by ore pulp entry 8 and is added medicine reaction zone 1, starts electric mixer 6, adds flotation reagent such as dispersant, collecting agent and pH value regulator respectively under the stirring state, makes flotation reagent and ore pulp intensive mixing. The mixed ore pulp after adding the chemicals and mixing is sent into the standing aeration separation area 2 through the mixed ore pulp inlet 8 by the lifting pump 15, in the standing aeration separation area 2, the ore pulp fully reacts with the flotation reagents, and a plurality of bubble generators 14 at the bottom of the standing aeration separation area 2 generate a large amount of micro bubbles, so that the probability that the concentrate particles float to the liquid surface to form concentrate foam can be increased, and the improvement of the grade and the recovery rate of the concentrate is facilitated. The concentrate foam floating to the liquid surface is discharged to the concentrate collecting tank 3 by the slag scraper 16, and the tailings are collected to the tailing pond 4 by the tailing collecting device 17 and separated to the tailing separating tank 5, which are conventional processes and will not be described in detail herein.
In the above method for preparing large crystalline magnesite with low silica content, the specific roasting method in step (4) is as follows: heating to 200 deg.C, maintaining for 4h, heating to 650 deg.C, and maintaining for 1 h;
the parameters of the light-burned magnesium oxide in the step (4) are as follows: the weight percentage content of MgO is more than or equal to 95 percent, and the particle size is less than 0.088 mm.
In the preparation method of the large-crystal magnesite with low silicon dioxide content, the pressure of dry pressing in the step (5) is 600 KN;
the diameter of the sphere in the step (5) is 30 mm.
In the above method for preparing large crystal magnesite with low silica content, step (5) further comprises a premixing step, specifically as follows: and (4) sending the light-burned magnesium oxide prepared in the step (4) and a stabilizer to a pre-mixer for pre-mixing, and then sending to a ball press for dry pressing.
In the above method for preparing large crystal magnesite with low silica content, the stabilizer is a mixture of zirconia and yttria, and the weight ratio of zirconia to yttria is 1: 2;
the weight ratio of the light-burned magnesia to the stabilizer is 101: 2.
in the preparation method of the large crystal magnesite with low silicon dioxide content, the electric melting temperature in the step (6) is 3000 ℃;
the electric melting time in the step (6) is 6.5 h.
In the above method for preparing large crystal magnesite with low silica content, step (6) further includes a step of adding a reducing agent, which is specifically as follows: mixing the spheres prepared in the step (5) with a reducing agent, and then sending the mixture to an electric arc furnace for electric melting;
wherein the reducing agent is high-purity graphite powder.
Comparative example 1
Chinese invention patent, application number: 201810435525.6, publication No.: CN108585553A discloses a method for preparing low-silicon high-calcium macrocrystalline fused magnesia, which comprises the following steps, as described in example 1,
preparation of low-silicon high-calcium macrocrystalline fused magnesia
(1) Preparation of high-activity MgO: selecting 1000kg of magnesite with the bulk degree of 100-200mm and the MgO content of more than 45%, placing the magnesite in a light burning kiln for continuous burning for 4 hours at 900 ℃, and uniformly adding Na with the mass concentration of 5% in the burning process2CO380kg of solution, and crushing and grinding the obtained product to 200-300 meshes after calcining and sintering to obtain high-activity MgO powder;
(2) smelting in an electric arc furnace: taking 900kg of high-activity MgO powder, adding 9kg of high-purity graphite powder as a reducing agent, uniformly stirring, pressing balls, placing in a full-automatic electric arc furnace, continuously electrifying and smelting for 8 hours at 2800 ℃, preserving heat, cooling and crystallizing for 6 days after smelting is finished, and then carrying out graded crushing to obtain the low-silicon high-calcium macrocrystalline fused magnesia.
Comparative example 2
Chinese invention patent, application number: 201710430446.1, publication No.: CN107244818A, discloses a one-step method for producing large-crystal fused magnesia, as described in example 1,
the one-step process of producing large-crystal electrically fused magnesia includes the following steps:
(1) magnesite refining: selection of MgCO3Magnesite with medium MgO content of 45-47.81%;
(2) grinding: preparing magnesite into powder with the granularity of 3 meshes to 3500 meshes;
(3) pressing the ball: adding a sintering agent into the powder obtained in the step (2), adding water, uniformly stirring, and pressing into material balls in a ball press machine, wherein the ball diameter is 3-200 mm;
(4) and (3) sintering: finally, the pellets are put into a submerged arc furnace for roasting, and the large-crystal fused magnesia can be produced.
The sintering agent adopted by the large-crystal fused magnesia produced by the embodiment comprises magnesium oxide, graphite and borax, and is prepared from the following raw materials in percentage by weight:
magnesite ore granularity is 3 meshes to 3500 meshes and 80 percent;
the granularity of the magnesium oxide is 3 meshes to 3500 meshes by 10 percent;
the graphite granularity is 3 meshes, 3500 meshes and 8 percent;
the granularity of the boron sand is 3 meshes, 3500 meshes and 2 percent.
Comparative example 3
Chinese invention patent, application number: 201910682413.5, publication No.: CN110395917A, which discloses a high-purity fused magnesite produced by using magnesium oxide as a secondary product and a method thereof, wherein, as mentioned in the detailed description, the "high-purity fused magnesite produced by using magnesium oxide as a secondary product is prepared from the following raw materials in parts by weight: 20-50 parts of magnesite raw ore, 20-40 parts of flotation powder magnesium balls and 20-40 parts of large crystal auxiliary material.
The flotation powder magnesium ball is formed by instantly extruding magnesite flotation powder under the pressure of 2000-3000 tons, the particle size of the flotation powder magnesium ball is 40-60mm, and the specific gravity of the flotation powder magnesium ball is 2-2.3g/cm3。
The large crystal auxiliary material is an auxiliary material for producing large crystal fused magnesium, and the particle size of the large crystal auxiliary material is 10-200 mm.
The physicochemical index of the large crystal auxiliary material is less than or equal to 0.15 wt% after ignition，SiO2≤3.0wt％，GaO≥3.0wt％，Fe2O3≤0.8wt％，Al2O3Not more than 0.4 wt%, MgO not less than 92.0 wt%, and bulk density not more than 3.0g/cm3。
A method for producing high-purity fused magnesia by using magnesium oxide byproducts comprises the following steps of:
in the sintering process, large crystallization auxiliary material 1 is independently distributed, and magnesite raw ore and flotation powder magnesium balls are mixed and distributed;
the large crystal auxiliary material 1 is distributed in a triangular circumscribed circle formed by three sintering electrodes 3, the area can not be discharged, and magnesite raw ore and flotation powder magnesium balls are transversely distributed outside the large crystal auxiliary material 1;
and distributing materials in layers in the sintering process, wherein each layer of the longitudinal thickness is 500mm in 300-one, and distributing materials in layers according to the sintering and smelting speed until smelting is finished.
The electric furnace shell 4 is shaped like a pot bottom, is hollow in the middle and is high at the periphery, so that large-crystal auxiliary materials are firstly distributed, then magnesite raw ore and floating powder magnesium balls are mixed and distributed, and meanwhile, the distribution layer height is 300-500mm, so that the distribution area stability of the materials can be ensured.
Example 2
The large crystal magnesite prepared in example 2 and the magnesite prepared in comparative examples 1 to 3 were selected and tested with reference to QB/T002-.
TABLE 1 comparison of the test parameters
Compared with comparative examples 1-3, the large-crystal magnesite prepared in example 1 of the invention has good performance advantages, and the test parameters such as particle volume density, magnesium oxide content, silicon dioxide content, calcium oxide content, iron oxide content, aluminum oxide content, yield and the like all show significant differences, and is high-quality large-crystal magnesite. In particular, the invention takes full advantage of the company's antecedentsThe magnesite tailing flotation and purification and the novel suspension furnace are researched and developed under the basic conditions that the volume density reaches 3.5g/cm3The large crystal magnesite with low silicon dioxide improves the yield of large crystals by more than 97.5 percent and obviously reduces the content of silicon dioxide.
Example 3
In combination with the test results of example 2, the large crystal magnesite prepared in example 1 was selected for SEM and XRD tests. The specific method refers to the following documents (Wangchun. influence of the smelting process on the structure and the performance of fused magnesia and magnesia-alumina spinel [ D ]), and the analysis is carried out by combining SEM and XRD.
As shown in figures 1 and 2, the main crystal phase of the large-crystal magnesite prepared by the invention is a trigonal rhombohedral system without impurity peaks, which shows that the large-crystal magnesite has extremely high purity and almost no impurity mineral phases, is matched with the high purity obtained by chemical analysis, and simultaneously has stronger diffraction peaks, which shows that the crystal form in the magnesite is relatively complete and the crystallinity is relatively high.
The present invention and its embodiments have been described above schematically, without limitation, and what is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if the person skilled in the art receives the teaching, without departing from the spirit of the invention, the person skilled in the art shall not inventively design the similar structural modes and embodiments to the technical solution, but shall fall within the scope of the invention.
Claims (10)
1. A preparation method of large crystal magnesite with low silicon dioxide content is characterized by comprising the following steps:
(1) selecting: low-grade magnesite is taken as a raw material, and magnesite with the magnesium oxide content of 40-45% is selected;
(2) cleaning: cleaning the magnesite which is selected in the step (1), and removing mud and micro-fine particle minerals on the surface of the magnesite for later use;
(3) refining: refining the magnesite cleaned in the step (2), wherein the refining process is divided into six steps, the first step is to crush the magnesite, the second step is to wash the crushed magnesite, the third step is to grind the washed magnesite, the fourth step is to add water into the ground magnesite to prepare raw ore pulp, the fifth step is to desliming the raw ore pulp, and the sixth step is to float the deslimed raw ore pulp to obtain refined ore powder for later use;
(4) roasting: delivering the concentrate powder prepared in the step (3) to a rotary kiln or a fluidized bed furnace for roasting, and cooling to room temperature to obtain light-burned magnesium oxide for later use;
(5) dry pressing: sending the light-burned magnesium oxide prepared in the step (4) to a ball press machine for dry pressing to prepare a ball for later use;
(6) electric melting: and (5) conveying the spheres prepared in the step (5) to an electric arc furnace for electric melting, and carrying out heat preservation, cooling and crystallization to obtain the spherical spheres.
2. The method for producing large crystalline magnesite grain with low silica content as claimed in claim 1,
the mass percentage range of magnesite in the low-grade magnesite in the step (1) is 30-45%, wherein the mass percentage range of dolomite is 10-30%, the mass percentage range of quartz is 5-15%, and the balance is other mineral impurities;
in the step (1), magnesite with the magnesia content of 42-44% is selected.
3. The method for producing large crystalline magnesite grain with low silica content as claimed in claim 1,
the particle size of the crushed magnesite in the step (3) is 5 mm;
the grinding equipment in the step (3) is a ball mill, and the rotating speed of the ball mill is 80 r/min;
the ground particle size in the step (3) is 0.1 mm;
the desliming equipment in the step (3) is a desliming cyclone;
the water content of the concentrate powder in the step (3) is less than 10 percent, and the MgO content is 40 to 45 percent.
4. The method for producing large crystalline magnesite grain with low silica content as claimed in claim 1,
the flotation equipment in the step (3) is a flotation tank, the flotation tank is divided into a dosing reaction zone, a standing aeration separation zone, a concentrate collecting tank, a tailing tank and a tailing collecting tank by a wall plate, the bottom surface of the dosing reaction zone is an inclined plane, one side of the dosing reaction zone close to the standing aeration separation zone inclines downwards, an electric stirrer is arranged at the top of the dosing reaction zone, an ore pulp inlet is arranged at the lower part of the outer side wall, a mixed ore pulp inlet is arranged on the wall plate between the standing aeration separation zone and the dosing reaction zone, the wall plate is connected with a lifting pump through a pipeline, a bubble generator is arranged at the bottom of the standing aeration separation zone, a tailing collecting device is arranged at one side close to the tailing tank, the top of the standing aeration separation zone is communicated with the.
5. The method for producing large crystalline magnesite grain with low silica content as claimed in claim 1,
the specific roasting method in the step (4) is as follows: heating to 200 deg.C, maintaining for 4h, heating to 650 deg.C, and maintaining for 1 h;
the parameters of the light-burned magnesium oxide in the step (4) are as follows: the weight percentage content of MgO is more than or equal to 95 percent, and the particle size is less than 0.088 mm.
6. The method for producing large crystalline magnesite grain with low silica content as claimed in claim 1,
the pressure of dry pressing in the step (5) is 600 KN;
the diameter of the sphere in the step (5) is 30 mm.
7. The method for producing large crystalline magnesite grain with low silica content as claimed in claim 1,
the step (5) further comprises a premixing step, which is as follows: and (4) sending the light-burned magnesium oxide prepared in the step (4) and a stabilizer to a pre-mixer for pre-mixing, and then sending to a ball press for dry pressing.
8. The method for producing large crystalline magnesite grain with low silica content as claimed in claim 7,
the stabilizing agent is a mixture of zirconium oxide and yttrium oxide, and the weight ratio of the zirconium oxide to the yttrium oxide is 1: 2;
the weight ratio of the light-burned magnesia to the stabilizer is 101: 2.
9. the method for producing large crystalline magnesite grain with low silica content as claimed in claim 1,
the temperature of electric melting in the step (6) is 3000 ℃;
the electric melting time in the step (6) is 6.5 h.
10. The method for producing large crystalline magnesite grain with low silica content as claimed in claim 1,
the step (6) further comprises a step of adding a reducing agent, which comprises the following specific steps: mixing the spheres prepared in the step (5) with a reducing agent, and then sending the mixture to an electric arc furnace for electric melting;
wherein the reducing agent is high-purity graphite powder.
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| CN113548874A (en) * | 2021-09-03 | 2021-10-26 | 辽宁荣邦科技有限公司 | Method and device for producing fused magnesia by magnesite through microwave/electric arc heating |
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Application publication date: 20201218 |