阅读说明：本技术 一种含高钙硅铝酸盐类矿物全组分综合利用的方法 (Method for comprehensively utilizing full components of mineral containing high-calcium aluminosilicate ) 是由 邹晶晶 宋永红 郭春彬 赵晓亮 李思雯 叶鸣雨 王灿 于 2021-09-07 设计创作，主要内容包括：本发明涉及一种含高钙硅铝酸盐类矿物全组分综合利用的方法,包括以下步骤：将高钙硅铝酸盐类矿物、NH-(4)F和NH-(4)HSO-(4)混合均匀后焙烧,产生的气体通入水中；继续焙烧,产生的SO-(3)气体通入水中回收；得到的固体加入NaOH溶液中搅拌反应后过滤；含硅溶液加入氨水,反应后过滤,将氟化铵溶液蒸发结晶,将氟化铵固体回用至步骤一；将步骤二得到的硫酸加入到步骤三得到的Ca(OH)-(2)溶液中,加热搅拌、过滤并蒸发结晶；将步骤三得到的片状氧化铝湿料和步骤四得到的SiO-(2)湿料烘干。本发明整个反应过程无需对高钙硅铝酸盐类矿物预处理,工艺简单,反应过程没有“三废”产生。获得的材料纯度高,材料可循环使用。(The invention relates to a method for comprehensively utilizing all components of high-calcium aluminosilicate-containing minerals, which comprises the following steps: mixing high calcium aluminosilicate mineral and NH 4 F and NH 4 HSO 4 Mixing uniformly, roasting, and introducing the generated gas into water; continuing the calcination to produce SO 3 Introducing gas into water for recovery; adding the obtained solid into NaOH solution, stirring for reaction, and filtering; adding ammonia water into the silicon-containing solution, filtering after reaction, evaporating and crystallizing the ammonium fluoride solution, and recycling ammonium fluoride solid to the step one; adding the sulfuric acid obtained in the second step into the Ca (OH) obtained in the third step 2 Heating and stirring the solution, filtering the solution, and evaporating the solution for crystallization; the wet flake alumina material obtained in the third step and the SiO obtained in the fourth step 2 And (5) drying the wet material. The whole reaction process of the invention does not need to be carried out on high-calcium silicon aluminumThe pretreatment of the acid salt minerals has simple process and no three wastes are generated in the reaction process. The obtained material has high purity and can be recycled.)

1. A method for comprehensively utilizing all components of high-calcium aluminosilicate-containing minerals is characterized by comprising the following steps: the method comprises the following steps:

step one, mixing high-calcium aluminosilicate mineral and NH₄F and NH₄HSO₄Uniformly mixing and roasting to obtain a mixture of flaky alumina and calcium sulfate, introducing gas generated in the roasting process into water and recovering to obtain a silicon-containing solution;

step two, continuously roasting the mixture of the flaky alumina and the calcium sulfate to obtain the flaky alumina and CaO, and continuously roasting SO generated in the process₃Introducing gas into water to recover sulfuric acid;

step three, adding the continuously calcined flaky alumina and CaO into NaOH solution, stirring for reaction, and filtering to obtain wet flaky alumina and Ca (OH)₂A solution;

step four, adding ammonia water into the silicon-containing solution obtained in the step one to adjust the pH value, then adding a surfactant, heating, stirring, reacting and filtering to obtain an ammonium fluoride solution and SiO₂Wet material, evaporating and crystallizing the ammonium fluoride solution to obtain ammonium fluoride solid, and recycling the ammonium fluoride solid to NH in the step I₄F, raw material preparation;

step five, adding the sulfuric acid obtained in the step two into the Ca (OH) obtained in the step three₂Heating and stirring the solution to obtain CaSO₄Precipitating, filtering, evaporating and crystallizing to obtain gypsum;

step six, the wet flake alumina material obtained in the step three and the wet flake alumina material obtained in the step fourSiO₂And drying the wet material to obtain the flaky alumina powder and the white carbon black.

2. The method for comprehensive utilization of the full components of the minerals containing high-calcium aluminosilicates according to claim 1, characterized in that: in the step one, NH₄F and SiO in high calcium aluminosilicate minerals₂The mol ratio of (3-8) to 1, NH₄HSO₄And the mol ratio of CaO in the high-calcium aluminosilicate mineral is (1-3):1, the roasting temperature is gradually increased within the range of 100-1200 ℃, and the roasting time is 2.5-8.5 h.

3. The method for comprehensive utilization of the full components of the minerals containing high-calcium aluminosilicates according to claim 1, characterized in that: in the second step, the temperature for continuous roasting is 1400-1500 ℃, and the time for continuous roasting is 1-3 h.

4. The method for comprehensive utilization of the full components of the minerals containing high-calcium aluminosilicates according to claim 1, characterized in that: in the third step, the mass concentration of the NaOH solution is 10-50%, the mol ratio of CaO to NaOH is 0.5-2, and the stirring reaction time is 0.5-6 h.

5. The method for comprehensive utilization of the full components of the minerals containing high-calcium aluminosilicates according to claim 1, characterized in that: in the fourth step, the mass concentration of the ammonia water is 10-20%, the volume ratio of the ammonia water to the ammonium fluoride solution is 0.05-0.2, the pH value is adjusted to 9-10, the surfactant is polyethylene glycol, the reaction temperature is 30-50 ℃, and the reaction time is 1-12 h.

6. The method for comprehensive utilization of the full components of the minerals containing high-calcium aluminosilicates according to claim 1, characterized in that: in the fifth step, the heating and stirring reaction temperature is 50-95 ℃, and the heating and stirring reaction time is 0.5-8 h.

7. The method for comprehensive utilization of the full components of the minerals containing high-calcium aluminosilicates according to claim 1, characterized in that: in the sixth step, the drying temperature is 80-110 ℃, and the drying time is 2-6 h.

8. The method for comprehensive utilization of the full components of the minerals containing high-calcium aluminosilicates according to claim 1 or 2, characterized in that: in the first step, firstly, the high calcium aluminosilicate mineral and NH are mixed₄F, uniformly mixing, putting the mixture into a mould to be pressed into a flaky mixture, putting the pressed flaky mixture into a crucible, and then flatly paving NH on the upper surface of the flaky mixture₄HSO₄Powder to form high calcium aluminosilicate mineral, NH₄F and NH₄HSO₄And then, stacking the mixed sheets in the crucible for 3-100 layers in sequence, placing the mixed sheets in a kiln for roasting to obtain a mixture of flaky alumina and calcium sulfate, and introducing gas generated in the roasting process into water for recycling to obtain a silicon-containing solution.

9. The method for comprehensive utilization of the full components of the minerals containing high-calcium aluminosilicates according to claim 8, characterized in that: the pressing pressure of the flaky mixture is 5-20MPa, the thickness of the mixed flaky layer is 0.5-5mm, the roasting process is carried out in 3 sections, the temperature is gradually increased within a 200 ℃ region of 100-.

10. The method for comprehensive utilization of the full components of the minerals containing high-calcium aluminosilicates according to claim 9, characterized in that: the side wall of the crucible is vertically provided with a plurality of side holes, the side holes are all arranged on the side surface of the flaky mixture, the periphery and the upper part of the crucible are covered with a crucible cover, the upper end of the crucible cover is provided with an extraction part, the side holes can be completely covered by the crucible cover, quartz sand with the thickness of 10-20mm is paved at the bottom in the crucible, and the particle size of the quartz sand is 0.5-1 mm; when the roasting temperature is within the range of 100-600 ℃, the crucible cover is covered on the crucible; when the roasting temperature reaches the interval of 600-1200 ℃, the crucible cover is separated from the crucible.

Technical Field

The invention belongs to the field of utilization of aluminosilicate mineral materials, and relates to a method for comprehensively utilizing all components of high-calcium aluminosilicate minerals.

Background

The aluminosilicate is an inorganic substance with the molecular formula of xAl2O 3. ySiO 2. The silicate minerals are various and widely distributed, account for about one fourth of the total number of the minerals, constitute 75% of the total weight of the earth crust, and the aluminosilicate accounts for an important proportion in the silicate, and the common silicate mainly comprises mullite, kaolinite, montmorillonite, feldspar and the like. The high-calcium aluminosilicate is aluminosilicate, and calcium replaces aluminum in minerals in the process of forming or utilizing the aluminosilicate to form calcium-containing aluminosilicate solid solution, such as anorthite. Or in the processing process, calcium oxide, calcium hydroxide, calcium carbonate and the like enter aluminosilicate to form a mixture, for example, XRD of desulfurized fly ash discharged from a certain coal-fired power plant is shown in figure 1, and as can be seen from figure 1, the fly ash contains calcium-containing aluminosilicate such as calcium oxide, calcium sulfate, mullite, quartz, calcium aluminosilicate and the like, wherein the content of calcium is up to 19.48%. The high-calcium aluminosilicate has received wide attention from academia and industry due to its advantages of large reserves, high total content of valuable elements, etc.

The high-calcium aluminosilicate has high calcium content, complex components and difficult processing and utilization. In recent years, researchers have done a lot of work on the comprehensive utilization of high-calcium aluminosilicate resources, and the comprehensive utilization is classified into two schemes, namely application in the field of building materials and pretreatment by hydrochloric acid. Although the high-calcium aluminosilicate can realize the bulk utilization of the high-calcium aluminosilicate, the high-calcium aluminosilicate has low additional value, and free calcium oxide is easy to generate calcium carbonate, so that the volume expansion is caused, and the stability of the building material is influenced. The hydrochloric acid is used for pretreating the high-calcium aluminosilicate, so that most of calcium elements can be removed, but the process cost is high, and the calcium-containing acid liquid is difficult to treat and is easy to cause secondary pollution.

Disclosure of Invention

Object of the Invention

In order to solve the problems of low additional value of high-calcium aluminosilicate utilization, high difficulty in treating calcium-containing acidic waste liquid and complex process flow of aluminosilicate minerals in the prior art, the invention provides a method for comprehensively utilizing all components of high-calcium aluminosilicate minerals.

Technical scheme

A method for comprehensively utilizing all components of high-calcium aluminosilicate-containing minerals comprises the following steps:

step one, mixing high-calcium aluminosilicate mineral and NH₄F and NH₄HSO₄Uniformly mixing and roasting to obtain a mixture of flaky alumina and calcium sulfate, introducing gas generated in the roasting process into water and recovering to obtain a silicon-containing solution;

step two, continuously roasting the mixture of the flaky alumina and the calcium sulfate to obtain the flaky alumina and CaO, and continuously roasting SO generated in the process₃Introducing gas into water to recover sulfuric acid;

step three, adding the continuously calcined flaky alumina and CaO into NaOH solution, stirring for reaction, and filtering to obtain wet flaky alumina and Ca (OH)₂A solution;

step four, adding ammonia water into the silicon-containing solution obtained in the step one to adjust the pH value, then adding a surfactant, heating, stirring, reacting and filtering to obtain an ammonium fluoride solution and SiO₂Wet material, evaporating and crystallizing the ammonium fluoride solution to obtain ammonium fluoride solid, and recycling the ammonium fluoride solid to NH in the step I₄F, raw material preparation;

step five, adding the sulfuric acid obtained in the step two into the Ca (OH) obtained in the step three₂Heating and stirring the solution to obtain CaSO₄Precipitating, filtering, evaporating and crystallizing to obtain gypsum;

step six, the wet flake alumina material obtained in the step three and the SiO obtained in the step four₂And drying the wet material to obtain the flaky alumina powder and the white carbon black.

Further, in the step one, NH₄F and SiO in high calcium aluminosilicate minerals₂The mol ratio of (3-8) to 1, NH₄HSO₄And the mol ratio of CaO in the high-calcium aluminosilicate mineral is (1-3):1, the roasting temperature is gradually increased within the range of 100-1200 ℃, and the roasting time is 2.5-8.5 h.

Further, in the second step, the temperature for continuous roasting is 1400 ℃ to 1500 ℃, and the time for continuous roasting is 1-3 h.

Further, in the third step, the mass concentration of the NaOH solution is 10-50%, the molar ratio of CaO to NaOH is 0.5-2, and the stirring reaction time is 0.5-6 h.

Further, in the fourth step, the mass concentration of the ammonia water is 10-20%, the volume ratio of the ammonia water to the ammonium fluoride solution is 0.05-0.2, the pH value is adjusted to 9-10, the surfactant is polyethylene glycol, the reaction temperature is 30-50 ℃, and the reaction time is 1-12 hours.

Further, in the fifth step, the heating and stirring reaction temperature is 50-95 ℃, and the heating and stirring reaction time is 0.5-8 h.

Further, in the sixth step, the drying temperature is 80-110 ℃, and the drying time is 2-6 h.

Further, in the first step, the high calcium aluminosilicate mineral and NH are firstly mixed₄F, uniformly mixing, putting the mixture into a mould to be pressed into a flaky mixture, putting the pressed flaky mixture into a crucible, and then flatly paving NH on the upper surface of the flaky mixture₄HSO₄Powder to form high calcium aluminosilicate mineral, NH₄F and NH₄HSO₄And then, repeatedly stacking the mixed sheets in the crucible for 3-100 layers in sequence, placing the mixed sheets into a kiln for roasting (the kiln is connected with a negative pressure device), obtaining a mixture of flaky alumina and calcium sulfate after roasting, and then introducing gas generated in the roasting process into water for recycling to obtain the silicon-containing solution.

Further, the pressing pressure of the flaky mixture is 5-20MPa, the thickness of the mixed flake layer is 0.5-5mm, the roasting process is carried out in 3 sections, the temperature is gradually increased within a 200 ℃ region of 100-.

Furthermore, a plurality of side holes are vertically arranged on the side wall of the crucible, the side holes are all arranged on the side surface of the flaky mixture, the periphery and the upper part of the crucible are covered with a crucible cover, the upper end of the crucible cover is provided with an extraction part, the side holes can be completely covered by the crucible cover, quartz sand with the thickness of 10-20mm is paved at the bottom in the crucible, and the particle size of the quartz sand is 0.5-1 mm; when the roasting temperature is within the range of 100-600 ℃, the crucible cover is covered on the crucible; when the roasting temperature reaches the interval of 600-1200 ℃, the crucible cover is separated from the crucible.

Advantages and effects

1. The invention takes the mineral containing high calcium aluminosilicate as the raw material, and three high value-added products of gypsum, white carbon black and flaky alumina can be obtained simultaneously by adding ammonium fluoride and ammonium bisulfate for roasting. The whole reaction process does not need to pretreat the high-calcium aluminosilicate minerals, the process is simple, and three wastes are not generated in the reaction process. Provides a new solution for the comprehensive utilization of minerals containing high-calcium aluminosilicate, and is suitable for industrial popularization.

2. The gypsum, white carbon black and flaky alumina obtained by the method have high purity, single phase and no impurity. The ammonium fluoride prepared by recycling the gas generated in the roasting process can be recycled, thereby greatly reducing the production cost and saving resources.

Drawings

The invention is further described with reference to the following figures and detailed description. The scope of the invention is not limited to the following expressions.

FIG. 1 is an XRD pattern of desulfurized fly ash from a coal-fired power plant;

FIG. 2 is a process flow diagram of the method of the present invention;

FIG. 3 is an X-ray diffraction (XRD) pattern of the tabular alumina prepared in example 1 of the present invention;

FIG. 4 is a Scanning Electron Microscope (SEM) spectrum of the flaky alumina prepared in example 1 of the present invention;

FIG. 5 is a Scanning Electron Microscope (SEM) spectrum of the white carbon black prepared in example 1 of the present invention;

FIG. 6 is an X-ray diffraction (XRD) pattern of white carbon black prepared in example 1 of the present invention;

FIG. 7 is a Scanning Electron Microscope (SEM) spectrum of the flaky alumina prepared in example 2 of the present invention;

FIG. 8 is a Scanning Electron Microscope (SEM) spectrum of the flaky alumina prepared in example 3 of the present invention;

FIG. 9 is a schematic view of a crucible structure;

FIG. 10 is a schematic view of a crucible cover structure;

FIG. 11 is a schematic view of the structure when materials are all put into the crucible and the crucible cover is covered.

Description of reference numerals: 1. crucible cover, 2. crucible, 3. extraction part, 4. side hole, 5. quartz sand, 6. flaky mixture, 7.NH₄HSO₄Powder and 8. mixing the lamellar.

Detailed Description

Example 1

A method for comprehensively utilizing all components of high-calcium aluminosilicate-containing minerals comprises the following steps:

firstly, high calcium aluminosilicate mineral and NH₄F, uniformly mixing, putting the mixture into a mould to be pressed into a flaky mixture 6, putting the pressed flaky mixture 6 into a crucible 2, and then flatly paving NH on the upper surface of the flaky mixture 6₄HSO₄Powder 7, forming high calcium aluminosilicate mineral, NH₄F and NH₄HSO₄Mixed lamella 8, NH of₄F and SiO in high calcium aluminosilicate minerals₂At a molar ratio of 3:1, NH₄HSO₄The mol ratio of the mixed slice layer to CaO in the high-calcium aluminosilicate mineral is 1:1, the thickness of the mixed slice layer is 5mm, then the mixed slice layer 8 is sequentially stacked in the crucible 2 for 50 layers in sequence, the mixture is placed in a kiln for roasting (the kiln is connected with a negative pressure device), the roasting process is carried out in 3 sections, the temperature is respectively 100 plus-heat-up temperature within 200 ℃ interval and 200 plus-heat-up temperature within 600 ℃ interval and 600 plus-heat-up temperature within 1200 ℃, the corresponding roasting time is respectively 0.5h, 1h and 1h, as shown in figures 9, 10 and 11, a plurality of side holes 4 are vertically arranged on the side wall of the crucible 2, the side holes 4 are all arranged on the side surface of the slice mixture 6, the peripheral ring of the crucible 2 and the upper cover are arranged on the side wall of the crucible 2The crucible cover 1 is arranged, the upper end of the crucible cover 1 is provided with an extraction part 3, the crucible cover 1 can completely cover the side hole 4, the bottom in the crucible 2 is paved with quartz sand 5 with the thickness of 10mm, and the particle size of the quartz sand 5 is 0.5 mm; when the roasting temperature is within the range of 100-600 ℃, the crucible cover 1 is covered on the crucible 2; when the roasting temperature reaches the range of 600-1200 ℃, the crucible cover 1 is separated from the crucible 2, a mixture of flaky alumina and calcium sulfate is obtained after roasting, and then gas generated in the roasting process is introduced into water to be recovered to obtain a silicon-containing solution;

step two, continuously roasting the mixture of the flaky alumina and the calcium sulfate at the temperature of 1400 ℃ for 3 hours to obtain flaky alumina and CaO, and continuously roasting SO generated in the process₃Introducing gas into water to recover sulfuric acid;

thirdly, adding the continuously calcined flaky alumina and CaO into a NaOH solution, stirring for reaction, and filtering, wherein the mass concentration of the NaOH solution is 10%, the molar ratio of CaO to NaOH is 0.5, and the stirring reaction time is 6 hours to obtain a wet flaky alumina material and Ca (OH)₂A solution;

step four, adding ammonia water into the silicon-containing solution obtained in the step one to adjust the pH value, wherein the mass concentration of the ammonia water is 20%, the volume ratio of the ammonia water to the ammonium fluoride solution is 0.05, the pH value is adjusted to 9, then adding a surfactant, heating, stirring, reacting and filtering, wherein the surfactant is preferably polyethylene glycol, the reaction temperature is 50 ℃, and the reaction time is 1h, so that an ammonium fluoride solution and SiO are obtained₂Wet material, evaporating and crystallizing the ammonium fluoride solution to obtain ammonium fluoride solid, and recycling the ammonium fluoride solid to NH in the step I₄F, raw material preparation;

step five, adding the sulfuric acid obtained in the step two into the Ca (OH) obtained in the step three₂Heating and stirring the solution to obtain CaSO₄Precipitating, filtering, evaporating and crystallizing to obtain gypsum; the heating and stirring reaction temperature is 50 ℃, and the heating and stirring reaction time is 8 h.

Step six, the wet flake alumina material obtained in the step three and the SiO obtained in the step four₂And drying the wet material at the drying temperature of 110 ℃ for 2h to obtain the flaky alumina powder and the white carbon black.

The crystal form of the flaky alumina prepared by the embodiment is alpha-Al 2O3, the diameter-thickness ratio is about 4, and the specific surface area of the white carbon black is 348m²(ii) in terms of/g. FIG. 3 provides an X-ray diffraction (XRD) pattern of the tabular alumina of this example, and it can be seen from FIG. 3 that the tabular alumina phase prepared in this example is a pure phase of α -Al2O 3; FIG. 4 provides a Scanning Electron Microscope (SEM) spectrum of the flaky alumina of the present embodiment, and it can be seen from FIG. 4 that the flaky alumina of the present embodiment has a hexagonal shape, a regular and complete morphology, and a uniform aspect ratio; fig. 5 provides a Scanning Electron Microscope (SEM) spectrum of the white carbon black of the present embodiment, and it can be seen from fig. 4 that the white carbon black of the present embodiment is in a nanometer scale; fig. 6 provides an X-ray diffraction (XRD) pattern of the silica of this example, and it can be seen from fig. 6 that the silica prepared in this example has no detectable crystalline phase, and only has a clearly raised "bulge peak" between 20 ° and 30 °, indicating that it is an amorphous substance of SiO 2. XRD pictures of the flaky alumina and the white carbon black prepared in other examples are similar to those in figures 3 and 6, and phases of the obtained product are alpha-Al 2O3 pure phase and SiO2 amorphous phase.

Example 2

A method for comprehensively utilizing all components of high-calcium aluminosilicate-containing minerals comprises the following steps:

firstly, high calcium aluminosilicate mineral and NH₄F, uniformly mixing, putting the mixture into a mould to be pressed into a flaky mixture 6, putting the pressed flaky mixture 6 into a crucible 2, and then flatly paving NH on the upper surface of the flaky mixture 6₄HSO₄Powder 7, forming high calcium aluminosilicate mineral, NH₄F and NH₄HSO₄Mixed lamella 8, NH of₄F and SiO in high calcium aluminosilicate minerals₂At a molar ratio of 8:1, NH₄HSO₄The mol ratio of the mixed layer to CaO in the high-calcium aluminosilicate mineral is 3:1, the thickness of the mixed layer is 0.5mm, then the mixed layer 8 is sequentially stacked in 100 layers in the crucible 2 repeatedly according to the sequence, the mixture is placed in a kiln for roasting (the kiln is connected with a negative pressure device), the roasting process is carried out by 3 sections, the temperature is gradually increased to 200 ℃ and 200 ℃ within the interval of 100-plus-200℃ respectivelyGradually raising the temperature to 600 ℃ within a 600 ℃ interval, gradually raising the temperature to 1200 ℃ within a 600-1200 ℃ interval, wherein the corresponding roasting time is 1.5h, 3h and 4h respectively, as shown in fig. 9, 10 and 11, a plurality of side holes 4 are vertically arranged on the side wall of the crucible 2, the side holes 4 are all arranged on the side surface of the sheet mixture 6, the crucible cover 1 is covered on the periphery and the upper part of the crucible 2, the extraction part 3 is arranged at the upper end of the crucible cover 1, the crucible cover 1 can completely cover the side holes 4, quartz sand 5 with the thickness of 20mm is paved at the bottom in the crucible 2, and the particle size of the quartz sand 5 is 1 mm; when the roasting temperature is within the range of 100-600 ℃, the crucible cover 1 is covered on the crucible 2; when the roasting temperature reaches the range of 600-1200 ℃, the crucible cover 1 is separated from the crucible 2, a mixture of flaky alumina and calcium sulfate is obtained after roasting, and then gas generated in the roasting process is introduced into water to be recovered to obtain a silicon-containing solution;

step two, continuously roasting the mixture of the flaky alumina and the calcium sulfate at 1500 ℃, wherein the continuous roasting time is 1h, obtaining the flaky alumina and CaO, and continuously roasting SO generated in the process₃Introducing gas into water to recover sulfuric acid;

thirdly, adding the continuously calcined flaky alumina and CaO into NaOH solution, stirring for reaction, and filtering, wherein the mass concentration of the NaOH solution is 50%, the molar ratio of CaO to NaOH is 2, and the stirring reaction time is 0.5h to obtain wet flaky alumina and Ca (OH)₂A solution;

step four, adding ammonia water into the silicon-containing solution obtained in the step one to adjust the pH value, wherein the mass concentration of the ammonia water is 10%, the volume ratio of the ammonia water to the ammonium fluoride solution is 0.2, adjusting the pH value to 10, then adding a surfactant, heating, stirring, reacting and filtering, wherein the surfactant is preferably polyethylene glycol, the reaction temperature is 30 ℃, and the reaction time is 12 hours to obtain an ammonium fluoride solution and SiO₂Wet material, evaporating and crystallizing the ammonium fluoride solution to obtain ammonium fluoride solid, and recycling the ammonium fluoride solid to NH in the step I₄F, raw material preparation;

step five, adding the sulfuric acid obtained in the step two into the Ca (OH) obtained in the step three₂Heating and stirring the solution to obtain CaSO₄Precipitating, filtering, evaporating and crystallizing to obtain gypsum; heating stirrerThe stirring reaction temperature is 95 ℃, and the heating stirring reaction time is 0.5 h.

Step six, the wet flake alumina material obtained in the step three and the SiO obtained in the step four₂And drying the wet material at the drying temperature of 80 ℃ for 6h to obtain the flaky alumina powder and the white carbon black.

The crystal form of the flaky alumina prepared by the embodiment is alpha-Al 2O3, the radius-thickness ratio is about 10, and the specific surface area of the white carbon black is 330m²(ii) in terms of/g. FIG. 7 is a Scanning Electron Microscope (SEM) spectrum of the flaky alumina powder prepared in the example of the present invention.

Example 3

A method for comprehensively utilizing all components of high-calcium aluminosilicate-containing minerals comprises the following steps:

firstly, high calcium aluminosilicate mineral and NH₄F, uniformly mixing, putting the mixture into a mould to be pressed into a flaky mixture 6, putting the pressed flaky mixture 6 into a crucible 2, and then flatly paving NH on the upper surface of the flaky mixture 6₄HSO₄Powder 7, forming high calcium aluminosilicate mineral, NH₄F and NH₄HSO₄Mixed lamella 8, NH of₄F and SiO in high calcium aluminosilicate minerals₂At a molar ratio of 6:1, NH₄HSO₄And CaO in the high-calcium aluminosilicate mineral in a molar ratio of 2:1, the thickness of the mixed slice layer is 3mm, then, the mixed slice layer 8 is sequentially stacked in the crucible 2 for 3 layers in sequence, the mixture is placed in a kiln for roasting (the kiln is connected with a negative pressure device), the roasting process is carried out in 3 sections, the temperature is respectively 100-plus-one-temperature 200 ℃ region, 200-plus-one-temperature 600 ℃ region, 600-plus-one-temperature 1200 ℃ region, 200-plus-one-temperature region, and 1200-plus-one-temperature region, the corresponding roasting time is respectively 1h, 2h and 2.5h, as shown in figures 9, 10 and 11, a plurality of side holes 4 are vertically arranged on the side wall of the crucible 2, the side holes 4 are all opened on the side surface of the slice mixture 6, the crucible cover 1 is covered on the peripheral ring and the upper part of the crucible cover 1, an extraction part 3 is arranged on the upper end of the crucible cover 1, the crucible cover 1 can completely cover the side holes 4, and quartz sand 5 with the thickness of 15mm is laid on the bottom in the crucible 2, the particle size of the quartz sand 5 is 0.7 mm; when the baking temperature is within the range of 100-600 DEG CWhen the crucible cover 1 is covered on the crucible 2; when the roasting temperature reaches the range of 600-1200 ℃, the crucible cover 1 is separated from the crucible 2, a mixture of flaky alumina and calcium sulfate is obtained after roasting, and then gas generated in the roasting process is introduced into water to be recovered to obtain a silicon-containing solution;

step two, continuously roasting the mixture of the flaky alumina and the calcium sulfate at 1450 ℃ for 2h to obtain flaky alumina and CaO, and continuously roasting SO generated in the process₃Introducing gas into water to recover sulfuric acid;

adding the continuously calcined flaky alumina and CaO into a NaOH solution, stirring for reaction, and filtering, wherein the mass concentration of the NaOH solution is 35%, the molar ratio of CaO to NaOH is 1.2, and the stirring reaction time is 4h to obtain a flaky alumina wet material and Ca (OH)₂A solution;

step four, adding ammonia water into the silicon-containing solution obtained in the step one to adjust the pH value, wherein the mass concentration of the ammonia water is 10-20%, the volume ratio of the ammonia water to the ammonium fluoride solution is 0.1, the pH value is adjusted to 9.5, then adding a surfactant, heating, stirring, reacting and filtering, wherein the surfactant is preferably polyethylene glycol, the reaction temperature is 40 ℃, and the reaction time is 7 hours to obtain an ammonium fluoride solution and SiO₂Wet material, evaporating and crystallizing the ammonium fluoride solution to obtain ammonium fluoride solid, and recycling the ammonium fluoride solid to NH in the step I₄F, raw material preparation;

step five, adding the sulfuric acid obtained in the step two into the Ca (OH) obtained in the step three₂Heating and stirring the solution to obtain CaSO₄Precipitating, filtering, evaporating and crystallizing to obtain gypsum; the heating and stirring reaction temperature is 75 ℃, and the heating and stirring reaction time is 4 hours.

Step six, the wet flake alumina material obtained in the step three and the SiO obtained in the step four₂And drying the wet material at the drying temperature of 95 ℃ for 4h to obtain the flaky alumina powder and the white carbon black.

The crystal form of the flaky alumina prepared by the embodiment is alpha-Al 2O3, the radius-thickness ratio is about 8, and the specific surface area of the white carbon black is 325m²(ii) in terms of/g. FIG. 8 shows a tabular alumina prepared according to an example of the present inventionScanning Electron Microscope (SEM) spectra of the powder.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the invention, and are not intended to limit the embodiments of the present invention, and it will be obvious to those skilled in the art that various changes and modifications can be made on the basis of the above description, and all embodiments cannot be exhaustive, and obvious changes and modifications included in the technical solutions of the present invention are within the scope of the present invention.