阅读说明：本技术 一种保护天然矿石介孔结构的煅烧方法 (Calcination method for protecting mesoporous structure of natural ore ) 是由 刘坤吉 徐前进 于 2020-04-30 设计创作，主要内容包括：本发明提供了一种保护天然矿石介孔结构的煅烧方法,属于天然矿石煅烧技术领域。本发明的煅烧方法包括以下步骤：(1)将天然矿石、水和炭黑进行混合,得到炭-石混合浆料；所述天然矿石为具有介孔结构的氧化硅天然矿石；(2)将所述炭-石混合浆料与强酸溶液混合后进行反应,得到混合料液；(3)将所述混合料液进行过滤,得到滤饼；(4)将所述滤饼依次进行第一煅烧和第二煅烧；所述第一煅烧的温度为650～850℃,所述第一煅烧在保护氛围下进行；所述第二煅烧的温度为200～350℃,所述第二煅烧在氧气氛围下进行。采用本发明的煅烧方法在提高氧化硅产品纯度和白度的同时,可以防止氧化硅的介孔孔道坍塌。(The invention provides a calcining method for protecting a mesoporous structure of natural ore, belonging to the technical field of calcining of natural ore. The calcination method of the invention comprises the following steps: (1) mixing natural ore, water and carbon black to obtain carbon-stone mixed slurry; the natural ore is silicon oxide natural ore with a mesoporous structure; (2) mixing the carbon-stone mixed slurry with a strong acid solution and then reacting to obtain a mixed feed liquid; (3) filtering the mixed feed liquid to obtain a filter cake; (4) sequentially carrying out first calcination and second calcination on the filter cake; the temperature of the first calcination is 650-850 ℃, and the first calcination is carried out in a protective atmosphere; the temperature of the second calcination is 200-350 ℃, and the second calcination is carried out in an oxygen atmosphere. The calcination method can prevent the collapse of mesoporous pore canals of the silicon oxide while improving the purity and whiteness of the silicon oxide product.)

1. A calcination method for protecting a mesoporous structure of natural ore comprises the following steps:

(1) mixing natural ore, water and carbon black to obtain carbon-stone mixed slurry; the natural ore is silicon oxide natural ore with a mesoporous structure;

(2) mixing the carbon-stone mixed slurry with a strong acid solution and then reacting to obtain a mixed feed liquid;

(3) filtering the mixed feed liquid to obtain a filter cake;

(4) sequentially carrying out first calcination and second calcination on the filter cake; the temperature of the first calcination is 650-850 ℃, and the first calcination is carried out in a protective atmosphere; the temperature of the second calcination is 200-350 ℃, and the second calcination is carried out in an oxygen atmosphere.

2. The calcination process of claim 1, wherein the silica natural ore having a mesoporous structure in step (1) comprises diatomaceous shale or opal shale.

3. The calcination method according to claim 1, wherein the mass of the natural ore in the step (1) is 10 to 25% of the total mass of the natural ore and water.

4. The calcination method according to claim 3, wherein the mass of the carbon black in the step (1) is 0.5 to 2% of the mass of the natural ore.

5. The calcination process of claim 1, wherein the mixing in step (1) comprises: soaking natural ore in water, crushing and stirring, adding carbon black, and performing ball milling on the obtained mixture to obtain the carbon-stone mixed slurry.

6. The calcination method as claimed in claim 1, wherein the strong acid solution in the step (2) comprises hydrochloric acid or sulfuric acid, and the mass concentration of the strong acid solution is 10-40%; the liquid-solid ratio of the strong acid solution to the natural ore is (2-5) mL: 10 g.

7. The calcination method according to claim 1 or 6, wherein the reaction in the step (2) is carried out at a temperature of 80 to 100 ℃ for 1 to 4 hours.

8. The calcination method according to claim 1, wherein the time of the first calcination in the step (4) is 1 to 3 hours.

9. The calcination process according to claim 1 or 8, wherein the time of the second calcination in the step (4) is 0.5 to 3 hours.

10. Calcination process according to claim 1 or 8, characterized in that the gas providing the protective atmosphere for the first calcination in step (4) comprises nitrogen or an inert gas.

Technical Field

The invention relates to the technical field of natural ore calcination, in particular to a calcination method for protecting a mesoporous structure of natural ore.

Background

The silicon oxide material has high thermal stability and can bear high temperature, the silicon oxide prepared by a precipitation method has a random mesoporous structure, the specific surface area of the silicon oxide can be increased, the silicon oxide material can better interact with rubber molecular chains in a rubber formula, the rubber strength is improved, and simultaneously, chemical active points reacted with silane are increased, so that the rubber is further reinforced. The mesoporous silica prepared by fine synthesis has good particles, uniform distribution, extremely high specific surface area and wall thickness, and simultaneously has pore channel structures which are regularly arranged and adjustable in a nanometer range, and has wide application prospects in the fields of fine chemical engineering, petroleum, natural gas and the like.

The natural silica ore with mesoporous structure is an ideal substitute for synthetic silica due to its abundant reserves, low price and similar properties. Because the purity and color of natural ore can not reach the degree of synthesizing silicon oxide, calcination treatment is usually needed before use, but calcination in a rotary furnace obviously causes collapse of silicon oxide pore channels, generally represents silicon oxide with the same particle size, and after calcination, the specific surface area is obviously reduced, thus obviously influencing the use performance.

Disclosure of Invention

The invention aims to provide a calcination method for protecting a mesoporous structure of natural ore, which can prevent the collapse of mesoporous channels of silicon oxide while improving the purity and whiteness of the silicon oxide product.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a calcining method for protecting a mesoporous structure of natural ore, which comprises the following steps:

(1) mixing natural ore, water and carbon black to obtain carbon-stone mixed slurry; the natural ore is silicon oxide natural ore with a mesoporous structure;

(2) mixing the carbon-stone mixed slurry with a strong acid solution and then reacting to obtain a mixed feed liquid;

(3) filtering the mixed feed liquid to obtain a filter cake;

(4) sequentially carrying out first calcination and second calcination on the filter cake; the temperature of the first calcination is 650-850 ℃, and the first calcination is carried out in a protective atmosphere; the temperature of the second calcination is 200-350 ℃, and the second calcination is carried out in an oxygen atmosphere.

Preferably, the silica natural ore having a mesoporous structure in the step (1) includes diatomite shale or opal shale.

Preferably, the mass of the natural ore in the step (1) is 10-25% of the total mass of the natural ore and water.

Preferably, the mass of the carbon black in the step (1) is 0.5-2% of the mass of the natural ore.

Preferably, the mixing in step (1) comprises: soaking natural ore in water, crushing and stirring, adding carbon black, and performing ball milling on the obtained mixture to obtain the carbon-stone mixed slurry.

Preferably, the strong acid solution in the step (2) comprises hydrochloric acid or sulfuric acid, and the mass concentration of the strong acid solution is 10-40%; the liquid-solid ratio of the strong acid solution to the natural ore is (2-5) mL: 10 g.

Preferably, the reaction temperature in the step (2) is 80-100 ℃, and the reaction time is 1-4 h.

Preferably, the time of the first calcination in the step (4) is 1-3 h.

Preferably, the time of the second calcination in the step (4) is 0.5-3 h.

Preferably, the gas for providing the protective atmosphere for the first calcination in the step (4) includes nitrogen or an inert gas.

The invention provides a calcining method for protecting a mesoporous structure of natural ore, which comprises the following steps: (1) mixing natural ore, water and carbon black to obtain carbon-stone mixed slurry; the natural ore is silicon oxide natural ore with a mesoporous structure; (2) mixing the carbon-stone mixed slurry with a strong acid solution and then reacting to obtain a mixed feed liquid; (3) filtering the mixed feed liquid to obtain a filter cake; (4) sequentially carrying out first calcination and second calcination on the filter cake; the temperature of the first calcination is 650-850 ℃, and the first calcination is carried out in a protective atmosphere; the temperature of the second calcination is 200-350 ℃, and the second calcination is carried out in an oxygen atmosphere.

The main component of the silicon oxide natural ore with the mesoporous structure is silicon oxide, and a large number of hydroxyl groups exist on the surface of the silicon oxide; then mixing the carbon-stone mixed slurry with a strong acid solution, and removing metal oxides in natural ores by using strong acid so as to achieve the purpose of improving the purity and whiteness of silicon oxide products; after filtering, sequentially carrying out first calcination and second calcination on the filter cake, wherein the first calcination is carried out at a high temperature (650-850 ℃) and in a protective atmosphere, so that the carbon black can be prevented from being decomposed by oxygen in high-temperature air, groups formed by the carbon black and the silicon oxide can be damaged, the silicon oxide can be activated in the temperature range, the silicon oxide and the surface of the carbon black are promoted to further carry out a microscopic reaction, and the carbon black strengthens the skeleton structure of natural ore, so that the calcination in the temperature range can maintain the pore structure, and other organic matters can be removed, and the purity and whiteness of a silicon oxide product are further improved; and finally, carrying out secondary calcination at a lower temperature (200-350 ℃) in an oxygen atmosphere, achieving the purpose of maintaining the proportion of the combined water in the product silicon oxide on the premise of preventing the carbon black from being decomposed (if the combined water is too little, the structure is unstable, pores collapse), and reducing energy consumption to prevent the high-temperature activation time from being too long.

The results of the examples show that the natural ore without calcination treatment has a purity of 73.32%, a whiteness of 56.03 and a specific surface area of 52.37m³The purity of the product silicon oxide calcined by the method is 87.23-90.76%, the whiteness is 86.12-88.90, and the specific surface area is 49.55-51.98 m³The calcination method can improve the purity and whiteness of the silicon oxide product and simultaneously can prevent the collapse of mesoporous channels of the silicon oxide.