阅读说明：本技术 一种降低高岭土细粉粒度的方法 (Method for reducing particle size of kaolin fine powder ) 是由 刘洪涛 胡清勋 刘宏海 孙雪芹 刘涛 赵晓争 王久江 赵红娟 张莉 熊晓云 于 2019-12-04 设计创作，主要内容包括：本发明涉及一种采用六甲基磷酰三胺的水溶液插入高岭土层间进而降低高岭土细粉粒度的方法,通过以下步骤实现：以六甲基磷酰三胺为原料,采用去离子水对其进行稀释,配制六甲基磷酰三胺的水溶液,其质量分数为0.1-10％。高岭土的插层反应：将高岭土溶解在六甲基磷酰三胺的水溶液中,二者的质量比为1∶(2-10),在20℃-70℃条件下搅拌2-4h。经过滤,洗涤和干燥得到插层后的高岭土。本发明所公开的制备方法,采用六甲基磷酰三胺的低浓度水溶液作为高岭土的插层剂,其插层率高,剥离效果好,大幅降低了高岭土插层剂的成本。(The invention relates to a method for reducing the granularity of fine kaolin powder by inserting an aqueous solution of hexamethylphosphoric triamide between kaolin layers, which is realized by the following steps: hexamethylphosphoric triamide is used as a raw material and diluted by deionized water to prepare an aqueous solution of hexamethylphosphoric triamide, and the mass fraction of the aqueous solution is 0.1-10%. Intercalation reaction of kaolin: dissolving kaolin into an aqueous solution of hexamethylphosphoric triamide, wherein the mass ratio of the kaolin to the hexamethylphosphoric triamide is 1 to (2-10), and stirring for 2-4h at the temperature of 20-70 ℃. Filtering, washing and drying to obtain the intercalated kaolin. The preparation method disclosed by the invention adopts the low-concentration aqueous solution of hexamethylphosphoric triamide as the intercalating agent of the kaolin, has high intercalation rate and good stripping effect, and greatly reduces the cost of the kaolin intercalating agent.)

1. A method for reducing the particle size of kaolin fine powder is characterized by comprising the following steps:

(1) preparing a solution of hexamethyl phosphoric triamide;

(2) intercalation reaction of kaolin: dissolving kaolin in an aqueous solution of hexamethylphosphoric triamide, stirring, filtering, washing and drying to obtain the intercalated kaolin.

2. The method of claim 1, wherein the solution of hexamethylphosphoric triamide is formulated by: hexamethylphosphoric triamide is used as a raw material and diluted by a solvent to prepare a solution of hexamethylphosphoric triamide.

3. The method of claim 2, wherein the solvent is deionized water.

4. The method according to claim 1, wherein the solution of hexamethylphosphoric triamide has a concentration of 0.1-10 wt.%.

5. The method according to claim 1, wherein in the step (2), the mass ratio of the kaolin to the hexamethylphosphoric triamide is 1: 2-10.

6. The production method of the production according to claim 1, wherein in the step (2), the stirring conditions are: the temperature is 20-70 ℃ and the time is 2-4 h.

7. The method of claim 1, wherein the intercalated kaolin has a crystallite thickness of 40-10 nm.

8. The method of claim 1, wherein the kaolin has a crystallite thickness of 50 to 60 nm.

9. The production method according to claim 1, wherein the intercalation reaction has an insertion rate of 60 to 95%.

Technical Field

The invention belongs to the technical field of catalysts, and relates to a method for reducing the particle size of kaolin fine powder, wherein the kaolin fine powder is used for preparing an in-situ synthesis catalyst.

Background

The kaolin contains a silicon source and an aluminum source, and active silicon oxide and aluminum oxide in the kaolin are dissolved through high-temperature calcination or under the acid/alkaline condition, so that the kaolin can be used as a raw material for synthesizing the molecular sieve. The in-situ crystallization synthesis of the molecular sieve by using the kaolin has the following characteristics: (1) the molecular sieve and the kaolin matrix are bonded through chemical bonds, and the synthesized product has both molecular sieve active components and a carrier; (2) the heat capacity of the carrier is large, the structure is stable, and the structure is not easy to collapse under the condition of high temperature, so that the service life of the catalyst can be greatly prolonged; (3) the activated kaolin has rich pore channel structures; (4) the kaolin is cheap, and the production cost can be greatly reduced by using the kaolin as a raw material to synthesize the molecular sieve. Based on the above advantages, kaolin has attracted much attention as a raw material. Although many research units at home and abroad aim to improve the crystallinity of the in-situ synthesized molecular sieve and obtain certain results, the crystallinity of the synthesized product is generally not very high. Engelhard as a pioneer, made a lot of effort in the field of in situ crystallization of molecular sieves synthesis, which externally disclosed that the crystallinity of molecular sieves can reach 70%, but in the published information, there is no crystallinity higher than 45%. The newly developed in-situ synthesis catalyst products of landification corporation in Lanzhou province have LB-1 and LB-2, and the crystallinity is 18% and 28%.

The reason is that kaolin is firstly molded to obtain kaolin microspheres, most pore channels of the kaolin microspheres are wrapped in a bulk phase, and the molecular sieve cannot enter the pore channels in the kaolin microspheres in the synthesis process, so that the crystallinity of the kaolin microspheres is reduced. The NaY molecular sieve with high crystallinity is synthesized by taking kaolin fine powder as a raw material and adopting an in-situ crystallization technology, and a brand new research idea is provided for the development of the field. For the research on the kaolin fine powder, a large amount of research is carried out by scholars at home and abroad, and the research mainly focuses on reducing the particle size of the kaolin fine powder.

The special layered structure of the kaolin is easy to strip along the direction parallel to the layer surface, thereby reducing the particle size of the kaolin, and the stripping of the kaolin not only can realize the application of the kaolin on the nanometer scale, but also can improve other performances of the existing products. However, the kaolin layers are strongly covalent within the layers and hydrogen bonding between the layers. Because of strong hydrogen bonding and no replaceable ions, a few small organic molecules can be directly inserted into the kaolin layers, and the small organic molecules mainly comprise: dimethyl sulfoxide, formamide, N-methylformamide, potassium acetate, PNO and the like. In addition, it can also be inserted in an indirect manner, for example using: benzamide, 1, 4-butanediol, p-nitroaniline, alkylamine, and the like.

CN201410663447.7 reports a powder grinding aid for kaolin ultrafine powder, which is prepared from the following substances in parts by weight: 1-5 parts of polyalcohol amine, 1-10 parts of polyethylene glycol, 5-15 parts of polyacrylamide, 1-15 parts of sodium pyrophosphate and 20-50 parts of wollastonite powder. The grinding aid is prepared by compounding a mining raw material and common chemical raw materials, and is simple and convenient to operate; the grinding aid provided by the invention can effectively reduce the surface energy of kaolin ultrafine powder, avoid particle agglomeration and improve the fineness of the kaolin ultrafine powder while improving the grinding efficiency and reducing the energy consumption.

CN201711315334.8 reports a method for preparing active kaolin powder, which comprises, grinding and homogenizing kaolin raw material in a dry vertical mill, entering into a three-stage preheating cylinder, entering into a calcinator to complete flash calcination, separating high temperature powder and hot air by a separating cylinder, feeding the micro powder into a cylinder cooler via a pipeline, cooling the high temperature material block by primary air in the cylinder cooler and collecting the material block at the kiln tail, the collected material can be ground into fine powder less than or equal to 0.044mm or micro powder less than or equal to 0.010 mm. The calcined product has the advantages of high activity, low production cost and the like, and is used for replacing or partially replacing silica fume and alumina micro powder for refractory concrete or admixture of building concrete and cement, thereby achieving the purposes of fully utilizing resources, reducing emission, increasing income and saving expenses.

CN200910093113.X reports a method for improving the pore structure of in-situ crystallization products of kaolin microspheres; the kaolin mixed slurry is prepared into kaolin spray microspheres with the particle size of 20-110 mu m through spray drying, the mixed slurry comprises kaolin, deionized water, a dispersing agent and a pore channel generation organic template agent, the dispersing agent is sodium silicate or sodium pyrophosphate, the pore channel generation organic template agent is polyvinylpyrrolidone or polyvinyl alcohol, the spray microspheres are roasted for 1-3h at the temperature of 900-1100 ℃ to obtain kaolin roasted microspheres, the kaolin roasted microspheres with the mullite content of 2-12%, the sodium silicate, a guiding agent, a sodium hydroxide solution and the deionized water are mixed, and the mixture is crystallized at the temperature of 90-95 ℃ for 16-36h, filtered and dried to obtain a crystallized product with a medium-large pore structure containing a NaY molecular sieve.

Cn201510784515.x reports a method for preparing nano NaY molecular sieve by in-situ crystallization. The method comprises the following steps: taking kaolin as a raw material, adding deionized water and a binder, and performing spray drying on the prepared mixed slurry to obtain kaolin microspheres; roasting the kaolin spraying microspheres at the temperature of 920-; treating the high-soil microspheres with an inorganic acid solution at 20-65 ℃, mixing the acid-treated high-soil microspheres with a silicon source, an alkali solution and a guiding agent, adding a nonionic surfactant and chlorinated alkaline earth for crystallization, and filtering, washing and drying a filter cake to obtain an in-situ crystallized product. The crystal grain size of the NaY molecular sieve contained in the prepared in-situ crystallization product is nano-scale, and the nano molecular sieve has the characteristics of easy separation and good stability.

CN201010122094.1 reports a method for modifying kaolin, which comprises using kaolin as a raw material, first performing high-temperature calcination treatment on kaolin, then uniformly stirring the high-temperature calcined kaolin with an aluminum source and an acidic solution to obtain a mixed slurry, and reacting under certain conditions, and then directly using the mixed slurry as a raw material for preparing a catalytic cracking catalyst without filtering. The modified kaolin has developed medium-large pore volume and certain activity, and the slurry containing the modified kaolin also has certain binding property, so that the catalyst prepared by the slurry containing the modified kaolin has stronger heavy metal resistance.

CN201010122110.7 reports a method for modifying kaolin, which comprises the following steps: the preparation method is characterized in that the acid solution is a mixed acid system consisting of inorganic acid and organic acid. The modified kaolin has developed medium-large pore volume, good hydrothermal stability and certain L acid characteristic, and the catalyst prepared by the slurry containing the modified kaolin has stronger heavy oil conversion capacity.

CN201510041952.2 reports a preparation method of an active matrix with large pore size and rich in protonic acid active sites, a catalytic cracking catalyst containing the active matrix and a preparation method thereof, wherein the preparation method of the active matrix comprises the following steps: preparation of a large-aperture active matrix precursor: mixing sucrose, aluminum nitrate nonahydrate and distilled water, stirring, and adding acrylamide, N, N methylene bisacrylamide and ammonium persulfate. Preparing a large-aperture protonic acid-rich active site active matrix: taking active matrix precursor powder and a protonic acid generating component, mixing, adding distilled water, stirring under a water bath condition until the water is evaporated to dryness, then roasting, and grinding into powder. The catalyst can effectively promote heavy oil macromolecule presplitting reaction by improving the number of protonic acid active sites on the surface of the substrate and the diameter of corresponding pore channels, thereby achieving the purpose of effectively improving the heavy oil conversion rate and the target product yield.

Disclosure of Invention

In view of the above-mentioned drawbacks, the present invention provides a method for reducing the particle size of fine kaolin powder, which employs hexamethylphosphoric triamide to insert into the layers of kaolin, thereby reducing the particle size of kaolin.

The invention provides a method for reducing the granularity of kaolin fine powder, which comprises the following steps:

(1) preparing a solution of hexamethyl phosphoric triamide;

(2) intercalation reaction of kaolin: dissolving kaolin in an aqueous solution of hexamethylphosphoric triamide, stirring, filtering, washing and drying to obtain the intercalated kaolin.

The method for reducing the particle size of the kaolin fine powder is characterized in that preferably, the preparation of the solution of hexamethyl phosphoric triamide comprises the following steps: hexamethylphosphoric triamide is used as a raw material and diluted by a solvent to prepare a solution of hexamethylphosphoric triamide.

In the method for reducing the particle size of the kaolin fine powder, the solvent is preferably deionized water.

The method for reducing the particle size of the fine kaolin powder, provided by the invention, has the preferable concentration of the solution of hexamethylphosphoric triamide being 0.1-10 wt%.

In the method for reducing the particle size of the kaolin fine powder, the mass ratio of the kaolin to the hexamethyl phosphoric triamide in the step (2) is preferably 1: 2-10.

In the method for reducing the particle size of the kaolin fine powder, preferably, in the step (2), the stirring conditions are as follows: the temperature is 20-70 ℃ and the time is 2-4 h.

The method for reducing the particle size of the kaolin fine powder is characterized in that the crystal grain thickness of the intercalated kaolin is preferably 40-10 nm.

The method for reducing the particle size of the kaolin fine powder, provided by the invention, has the advantages that the crystal grain thickness of the kaolin is preferably 50-60 nm.

The method for reducing the particle size of the kaolin fine powder is characterized in that the intercalation reaction has an insertion rate of 60-95%.

The invention has the beneficial effects that:

the method for reducing the granularity of the fine kaolin powder disclosed by the invention adopts the low-concentration solution of hexamethylphosphoric triamide as the intercalating agent of the kaolin, has high intercalation rate and good stripping effect, and greatly reduces the cost of the kaolin intercalating agent.

Drawings

FIG. 1 is an SEM photograph of a kaolin clay feedstock.

FIG. 2 is a flow chart of a method of reducing the particle size of kaolin fines according to the present invention.

Fig. 3 is a flowchart of embodiment 1 of the present invention.

Fig. 4 is a flowchart of embodiment 2 of the present invention.

Fig. 5 is a flowchart of embodiment 3 of the present invention.

Fig. 6 is a flowchart of embodiment 4 of the present invention.

Fig. 7 is a flowchart of embodiment 5 of the present invention.

Detailed Description

The following examples illustrate the invention in detail: the present example is carried out on the premise of the technical scheme of the present invention, and detailed embodiments and processes are given, but the scope of the present invention is not limited to the following examples, and the experimental methods without specific conditions noted in the following examples are generally performed according to conventional conditions.

The test methods in the following examples are all conventional methods unless otherwise specified; the reagents are commercially available, unless otherwise specified.

The raw material sources are as follows: kaolin was from petroleum lanzhou petrochemical company, china. Hexamethylphosphoric triamide was obtained from Chongqing Jiashan Biotech Ltd.

The analysis method comprises the following steps:

calculation of insertion rate IR: through kaolin d₁₀₀Diffraction peak intensity change.

The kaolin grain thickness L ═ λ k/(β cos θ), where k ═ 0.89 is a constant, λ ═ 0.15406nm is the X-ray wavelength, β is the half-peak width, and is taken in radians.

Examples 1 to 1

Preparation of hexamethylphosphoric triamide solution: hexamethylphosphoric triamide is used as a raw material and diluted by deionized water to prepare an aqueous solution of hexamethylphosphoric triamide, and the mass fraction of the aqueous solution is 0.1-10%.

Hexamethylphosphoric triamide solution 1:

hexamethylphosphoric triamide is used as a raw material and diluted by deionized water to prepare an aqueous solution of hexamethylphosphoric triamide, wherein the mass fraction of the aqueous solution is 0.1%.

Hexamethylphosphoric triamide solution 2:

hexamethylphosphoric triamide is used as a raw material and diluted by deionized water to prepare an aqueous solution of hexamethylphosphoric triamide, wherein the mass fraction of the aqueous solution is 0.5%.

Hexamethylphosphoric triamide solution 3:

hexamethylphosphoric triamide is used as a raw material and diluted by deionized water to prepare an aqueous solution of hexamethylphosphoric triamide, wherein the mass fraction of the aqueous solution is 1%.

Hexamethylphosphoric triamide solution 4:

hexamethylphosphoric triamide is used as a raw material and diluted by deionized water to prepare an aqueous solution of hexamethylphosphoric triamide, wherein the mass fraction of the aqueous solution is 2%.

Hexamethylphosphoric triamide solution 5:

hexamethylphosphoric triamide is used as a raw material and diluted by deionized water to prepare an aqueous solution of hexamethylphosphoric triamide, wherein the mass fraction of the aqueous solution is 5%.

Hexamethylphosphoric triamide solution 6:

hexamethylphosphoric triamide is used as a raw material and diluted by deionized water to prepare a hexamethylphosphoric triamide aqueous solution, wherein the mass fraction of the hexamethylphosphoric triamide aqueous solution is 10%.

Example 1:

(1) hexamethylphosphoric triamide solution 1.

(2) Dissolving kaolin in hexamethylphosphoric triamide aqueous solution at a mass ratio of 1: 2, and stirring at 20 deg.C for 2 hr. Filtering, washing and drying to obtain the intercalated kaolin J-1.

Example 2:

(1) hexamethylphosphoric triamide solution 2.

(2) Dissolving kaolin in hexamethylphosphoric triamide aqueous solution at a mass ratio of 1: 5, and stirring at 30 deg.C for 4 hr. And filtering, washing and drying to obtain the intercalated kaolin J-2.

Example 3:

(1) hexamethylphosphoric triamide solution 3.

(2) Dissolving kaolin in hexamethylphosphoric triamide aqueous solution at a mass ratio of 1: 10, and stirring at 40 deg.C for 3 hr. And filtering, washing and drying to obtain the intercalated kaolin J-3.

Example 4:

(1) hexamethylphosphoric triamide solution 4.

(2) Dissolving kaolin in hexamethylphosphoric triamide aqueous solution at a mass ratio of 1: 10, and stirring at 50 deg.C for 4 hr. And filtering, washing and drying to obtain the intercalated kaolin J-4.

Example 5:

(1) hexamethylphosphoric triamide solution 5.

(2) Dissolving kaolin in hexamethylphosphoric triamide aqueous solution at a mass ratio of 1: 10, and stirring at 60 deg.C for 4 hr. Filtering, washing and drying to obtain the intercalated kaolin J-5.

Example 6:

(1) hexamethylphosphoric triamide solution 6.

(2) Dissolving kaolin in hexamethylphosphoric triamide aqueous solution at a mass ratio of 1: 10, and stirring at 70 deg.C for 4 hr. And filtering, washing and drying to obtain the intercalated kaolin J-6.

Comparative example 1:

the same conditions as in example 4 were used, except that: the intercalating agent is hexamethylphosphoric triamide alone and not in aqueous solution.

Dissolving kaolin in hexamethylphosphoric triamide at a mass ratio of 1: 10, and stirring at 50 deg.C for 4 hr. Filtering, washing and drying to obtain the intercalated kaolin D-1.

Table 1 shows the insertion rate and the grain thickness of the products obtained in examples 1 to 6.

TABLE 1 insertion rate and grain thickness of the product kaolin

	The rate of insertion%	Thickness of crystal grain, nm
			Kaolin raw material	0	54
D-1	62	45
			J-1	60	40
J-2	74	33
			J-3	82	32
J-4	93	14
			J-5	85	18
J-6	83	22

As can be seen from Table 1, the insertion rate of the product obtained by intercalating the kaolin with hexamethylphosphoric triamide solution is high and can reach 93%, the thickness of the crystal grain is greatly reduced and can reach 14nm at least. The hexamethylphosphoric triamide solution has better intercalation effect on the kaolin. In contrast, when the hexamethylphosphoric triamide is adopted to intercalate the kaolin, the insertion rate and the crystal grain thickness are only 62 percent and 45nm, which shows that the hexamethylphosphoric triamide solution prepared by the invention achieves the best intercalation effect under moderate concentration and moderate temperature, and the cost of the kaolin intercalation is greatly reduced.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore intended that all such changes and modifications as fall within the true spirit and scope of the invention be considered as within the following claims.