阅读说明：本技术 一种硅酸镁及其衍生物及制备方法 (magnesium silicate and its derivatives and preparation method ) 是由 林亚庆 林景琼 郑素花 于 2019-10-16 设计创作，主要内容包括：本发明提供一种硅酸镁及其衍生物的制备方法,其包括如下步骤：S1、溶液配制：S2、反应前驱体制备；S3、水热晶化；S4、后处理；所述硅酸镁及其衍生物的分子式为：(Si<Sub>8</Sub>Mg<Sub>x</Sub>A<Sub>y</Sub>O<Sub>20</Sub>(OH)<Sub>m</Sub>B<Sub>n</Sub>)·tH<Sub>2</Sub>O,本发明利用镁的氧化物在水中会反生部分电离生成镁离子,再与硅反应生成水合硅酸镁,降低了反应pH值,使反应得到顺利进行。(The invention provides a preparation method of magnesium silicates and derivatives thereof, which comprises the following steps of S1, solution preparation, S2, reaction precursor preparation, S3, hydrothermal crystallization, S4 and post-treatment, wherein the molecular formulas of the magnesium silicates and the derivatives thereof are (Si) 8 Mg x A y O 20 (OH) m B n )·tH 2 O, the invention utilizes the fact that the oxide of magnesium can generate partial ionization in water to generate magnesium ions, and then reacts with silicon to generate hydrated magnesium silicate, thereby reducing the pH value of the reaction and leading the reaction to be carried out smoothly.)

The preparation method of magnesium silicates and their derivatives is characterized by comprising the following steps:

s1, solution preparation:

adding water into the compound containing A and stirring to obtain solution A, adding water into the compound containing B and stirring to obtain solution B, adding water into the compound containing silicon and stirring to obtain silicon solution, adding water into the compound containing magnesium and stirring to obtain magnesium solution;

s2 reaction precursor preparation

Adding the magnesium liquid, the A liquid, the B liquid and the silicon liquid after constant temperature treatment into a reaction kettle, adding a pH regulator for reaction, taking a reaction liquid after the reaction is finished, testing the content of silicon and magnesium elements in a reaction centrifugate to be less than 3 percent of the content of the silicon and magnesium elements in the step S1 and the distribution of test colloid particles, and preparing a reaction precursor, wherein D50 is less than 0.5 mm;

s3 hydrothermal crystallization

Adding the precursor prepared in the step S2 into a high-temperature high-pressure reaction kettle for reaction to prepare magnesium silicate colloid;

s4, post-processing

And (4) post-processing the magnesium silicate colloid prepared in the step (S3) to obtain finished products of magnesium silicate and derivatives thereof.

2. The method for producing magnesium silicate and derivatives thereof according to claim 1, wherein the magnesium-containing compound, the silicon-containing compound, the A-containing compound, the B-containing compound and the pH adjuster are each an acetic acid-or hydrofluoric acid-soluble compound.

3. The method for preparing magnesium silicate and its derivatives according to claim 1, wherein said magnesium-containing compound is or more selected from magnesium oxide, magnesium carbonate, magnesium hydroxide, and basic magnesium carbonate.

4. The method for preparing magnesium silicate and its derivatives according to claim 1, wherein said compound A is or more selected from lithium carbonate, lithium fluoride, lithium hydroxide, lithium silicate, aluminum carbonate, aluminum hydroxide, sodium metaaluminate, zinc oxide, zinc hydroxide, zinc carbonate, basic zinc carbonate, nickel hydroxide, nickel carbonate, nickel ammine, iron hydroxide, iron carbonate, manganese hydroxide, manganese carbonate, copper hydroxide, copper carbonate, basic copper carbonate, copper ammine, calcium oxide, calcium hydroxide, and calcium carbonate.

5. The method for producing magnesium silicate and derivatives thereof according to claim 1, wherein said compound containing B is or more selected from phosphoric acid, sodium phosphate, disodium hydrogen phosphate, pyrophosphoric acid, sodium pyrophosphate, polyphosphoric acid, sodium polyphosphate, diammonium hydrogen phosphate, ammonium phosphate, phosphorus-containing modified organic substances, boric acid, sodium borate, boron-containing modified organic substances, sodium fluoride, hydrofluoric acid, fluorosilicic acid, magnesium fluorosilicate, sodium fluorosilicate, fluorine-containing modified organic substances.

6. The method for preparing magnesium silicate and its derivatives according to claim 1, wherein said silicon-containing compound is or more selected from silica, silica sol, sodium silicate and potassium silicate.

7. The method for preparing magnesium silicate and its derivatives according to claim 1, wherein said pH regulator is or more selected from ammonia, urea, carbon dioxide, sodium hydroxide, sodium carbonate, potassium hydroxide, and potassium carbonate.

8. The process for producing magnesium silicate and derivatives thereof according to claim 1, wherein in step S2, a reaction precursor is obtained by reacting at 0 to 120 ℃ for 0.1 to 72 hours while controlling the reaction pH to 7 to 13; in step S2, the ratio of the magnesium solution: the silicon liquid: the solution A comprises: the solution B is (4-7): 8: (0-1): (0-4); in step S3, the reaction temperature is 120-350 ℃, and the reaction time is 0.1-72 h.

9. The process for preparing magnesium silicate and derivatives thereof according to claim 1, wherein the post-treatment is drying and dehydrating, crushing and screening, batch mixing, and packaging.

10, magnesium silicates and their derivatives prepared by the process for the preparation of said magnesium silicates and their derivatives of any of claims 1-9 through .

Technical Field

The invention relates to magnesium silicates and derivatives thereof and a preparation method.

Background

In the traditional method for producing magnesium silicate and derivatives thereof, magnesium salt is selected as magnesium sulfate or magnesium chloride as a reaction raw material, and the problem of discharge of reaction by-products of sulfate or chloride is inevitably caused after the production process. Although there are some reports in the literature that magnesium oxide or magnesium hydroxide can be used as a raw material for the reaction, for example, in the case of "Hydrothermal Crystallization of magnesium-Containing silica" published by Carrado K A in Inorganic Chemistry in 1991, magnesium chloride is reacted with aqueous ammonia to produce fresh magnesium hydroxide, according to the following equation: magnesium hydroxide: the lithium magnesium silicate product can be synthesized by metering the reaction of silicon dioxide which is 0.2:1.0:1.52, but the actual operation is not much different from the traditional synthesis.

Disclosure of Invention

In order to solve the defects of the prior art, the invention provides magnesium silicates and derivatives thereof and a preparation method thereof.

The purpose of the invention is realized by the following technical scheme:

A process for preparing magnesium silicate and its derivatives, which comprises the following steps:

s1, solution preparation:

adding water into the compound containing A and stirring to obtain solution A, adding water into the compound containing B and stirring to obtain solution B, adding water into the compound containing silicon and stirring to obtain silicon solution, adding water into the compound containing magnesium and stirring to obtain magnesium solution;

s2 reaction precursor preparation

Adding the magnesium liquid, the A liquid, the B liquid and the silicon liquid after constant temperature treatment into a reaction kettle, adding a pH regulator for reaction, taking a reaction liquid after the reaction is finished, testing the content of silicon and magnesium elements in a reaction centrifugate to be less than 3 percent of the content of the silicon and magnesium elements in the step S1 and the distribution of test colloid particles, and preparing a reaction precursor, wherein D50 is less than 0.5 mm;

s3 hydrothermal crystallization

Adding the precursor prepared in the step S2 into a high-temperature high-pressure reaction kettle for reaction to prepare magnesium silicate colloid;

s4, post-processing

And (4) post-processing the magnesium silicate colloid prepared in the step (S3) to obtain finished products of magnesium silicate and derivatives thereof.

The molecular formula of the magnesium silicate and the derivatives thereof is as follows: (Si)₈Mg_xA_yO₂₀(OH)_mB_n)·tH2O

Wherein, A is metal elements, or more than of Li, Na, K, Al, Zn, Ni, Cu, Mn, Ca, Fe and NH4+, B is or more than of anionic compounds containing F, P, B and C, 0< K <1, 4< x + y <7, 0< y <1, m + n is less than or equal to 4, and t is the amount of bound water.

Based on the technical scheme, the method has no waste gas and liquid discharge, the preparation process is green and environment-friendly,

, the magnesium-containing compound, the silicon-containing compound, the A-containing compound, the B-containing compound and the pH regulator are all acetic acid or hydrofluoric acid soluble compounds.

, the magnesium-containing compound is or more of magnesium oxide, magnesium carbonate, magnesium hydroxide and basic magnesium carbonate.

Based on the technical scheme, the magnesium-containing compound reacts in water to partially ionize to produce magnesium ions, and then reacts with silicon to generate neutral hydrated magnesium silicate, so that the pH value of the reaction is reduced, and the reaction is smoothly carried out.

, the compound A is selected from lithium carbonate, lithium fluoride, lithium hydroxide, lithium silicate, aluminum carbonate, aluminum hydroxide, sodium metaaluminate, zinc oxide, zinc hydroxide, zinc carbonate, basic zinc carbonate, nickel hydroxide, nickel carbonate, nickel ammine, iron hydroxide, iron carbonate, manganese hydroxide, manganese carbonate, copper hydroxide, copper carbonate, basic copper carbonate, copper ammine, calcium oxide, calcium hydroxide, and calcium carbonate or more.

, the compound B is selected from phosphoric acid, sodium phosphate, disodium hydrogen phosphate, pyrophosphoric acid, sodium pyrophosphate, polyphosphoric acid, sodium polyphosphate, diammonium hydrogen phosphate, ammonium phosphate, modified organic matter containing phosphorus, boric acid, sodium borate, modified organic matter containing boron, sodium fluoride, hydrofluoric acid, fluosilicic acid, magnesium fluosilicate, sodium fluosilicate and modified organic matter containing fluorine or mixture thereof.

, the silicon-containing compound is or more selected from silica, silica sol, sodium silicate and potassium silicate.

, the pH regulator is or mixture of ammonia, urea, carbon dioxide, sodium hydroxide, sodium carbonate, potassium hydroxide and potassium carbonate.

And , controlling the pH value of the reaction to be 7-13 in step S2, and reacting for 0.1-72h at 0-120 ℃ to obtain a reaction precursor, wherein the reaction temperature is 120-350 ℃ and the reaction time is 0.1-72h in step S3.

, in step S2, the molar ratio of the magnesium solution, the silicon solution, the A solution and the B solution is (4-7), (8), (0-1) and (0-4).

And , drying, dewatering, crushing, sieving, mixing and packing.

Based on the technical scheme, before drying and dewatering, if soluble elements exist, in order to improve the product quality, a washing and pressure filtration process can be added, redundant ions are removed, and the filtrate enters a material mixing link for repeated use, so that the zero emission requirement is also met.

The invention also provides magnesium silicates and derivatives thereof prepared by the preparation method.

The invention has the beneficial effects that:

1. the reaction process can achieve green reaction, and the problem of pollutant emission due to impurities is solved, so that the environmental protection requirement is met;

2. the reaction solid content is high, and the product can be directly dried to prepare a finished product, so that the production energy consumption is greatly reduced;

3. simple process, less equipment investment and contribution to industrial scale-up production.

Drawings

FIG. 1 is a production flow chart of the process

FIG. 2 production process diagram of the product of example 1

FIG. 3 the product of example 1 was formulated into a 5 mt% aqueous solution to form a clear gel which disappeared upon addition of the viscosity reducing agent

Detailed Description

The principles and features of this invention are described below in conjunction with the drawings of specific embodiments, the examples given are intended to illustrate the invention and not to limit the scope of the invention.