JP2007254188A - Method for producing acid-expandable mica - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an expandable mica by which production cost can be reduced. <P>SOLUTION: The method for producing an expandable mica comprises: a mixing step of mixing a powdery mica and a metal alkali substance in a mass ration of 1:1 to 1:20; a heating step of heating the powdery mica and the alkali substance after the mixing to 150-230°C and keeping the temperature for 30 min to diffuse metal ions of the alkali substance into the mica; a cooling/washing step of lowering the temperature of the powdery mica by diluting the powdery mica and the alkali substance after the heating with cold water; a first solid/liquid separation step of separating an alkali solution and the powdery mica solid after the dilution; a neutralization step of neutralizing an alkali substance in the mica by using an acidic solution after dilution with cold water, wherein when the pH of the mica is <7, the mica causes an expansion phenomenon; and a second solid/liquid separation step of obtaining the desired expandable mica by diluting the acidic solution with water and separating the acidic solution and the mica solid after the dilution. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention particularly relates to a method for producing expandable mica that can reduce the production cost.

  In general, layered aluminosilicates (montmorillonite clay, mica) are often used to produce nanocomposites. Mica is a layered aluminosilicate mineral, generally a non-expandable mica ore, which is not very practical and used mainly as a filler.

  For studies that convert non-expandable mica to expandable mica, for example, in a study by Mr. Isaozaki in Japan, high surface area can be obtained by polishing lithium nitrate, sodium nitrate, potassium nitrate or rubidium nitrate and sericite together. It is known to obtain a sericite powder having According to the announcement, the content of potassium ions in sericite is related to the change in surface area, and after polishing the sericite, the crystal structure is destroyed, so that potassium ions can exchange ions. The research results also indicate that rubidium nitrate is the most suitable abrasive.

As for a method for producing expandable mica, for example, in Taiwan Patent Publication No. 460427 “Method for producing expandable sericite and its use”, expandable sericite is obtained by ion exchange of lithium nitrate and sericite powder. It has been disclosed that it can be obtained.
Taiwan Patent Notice 460427

  However, lithium nitrate described in the Taiwan patent, or sodium nitrate, potassium nitrate or rubidium nitrate studied by Mr. Isazaki is a neutral treatment agent, and ion exchange of lithium nitrate described in the Taiwan patent. The temperature is 260 ° C. to 420 ° C., and the heating time described in Example 1 needs to be up to 40 hours, and Example 2 also needs to be 16 hours, 40 hours, and 96 hours, respectively. There was a high cost problem. In addition, the lithium nitrate researched by Mr. Isosaki also has a problem that the cost of manufacturing the expandable mica increases because the price is very high.

  Therefore, the present invention has been filed and an object thereof is to provide a method for producing expandable mica that can reduce the production cost.

The invention of claim 1 of the present application includes a mixing step of mixing powdery mica and a metal alkali substance in a mass proportion of 1: 1 to 1:20,
A heating step of diffusing the metal ions of the alkali substance into the mica by heating the powdered mica and the alkali substance after mixing to 150 ° C. to 230 ° C. and maintaining the temperature for 30 minutes as it is,
A cooling / washing step for reducing the temperature of the powdered mica by diluting the heated powdered mica and the alkaline substance with cold water;
A first solid / liquid separation step for separating the diluted alkaline solution and the powdered mica solid;
Neutralizing the alkaline substance in the mica by diluting the acidic solution with cold water after being diluted with cold water, and when the PH value of the mica is less than 7;
A second solid / liquid separation step of diluting the acidic solution with water and again separating the diluted acidic solution from the mica solids to obtain the desired expandable mica; Method.

  In the invention of claim 2 of the present application, the metal alkaline substance used in the mixing step is lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide or barium hydroxide and a mixture thereof. A method for producing mica expandable with an acid according to claim 1.

  The invention according to claim 3 of the present application is characterized in that the acidic solution used in the neutralization step is sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, acetic acid, or oxalic acid. A method for producing mica is provided.

  In the invention of claim 4 of the present application, in the neutralization step, the acidic solution is diluted with cold water and then used for mica to neutralize the alkaline substance in mica, thereby reducing the PH value of mica to less than 4. A method for producing mica expandable with an acid according to any one of claims 1 to 3, characterized in that:

  The invention according to claim 5 of the present application is characterized in that the first solid / liquid separation step and the second solid / liquid separation step perform solid / liquid separation by a dehydrator, and are expanded by an acid according to claim 4 A method for producing mica is provided.

  According to a sixth aspect of the present invention, the metal alkaline substance used in the mixing step is a mixture of sodium hydroxide and lithium hydroxide, and the mixture contains 80 wt% or more of sodium hydroxide and lithium hydroxide. The method for producing mica expandable with an acid according to any one of claims 1 to 3, wherein the other substance is another alkaline substance.

  The invention according to claim 7 of the present application is characterized in that the mica is muscovite, colored mica, sericite, phlogopite, or pyrophyllite. A manufacturing method is provided.

  The present invention solves the above-described problems, and can provide an expandable mica that can reduce the production cost without using expensive lithium nitrate and without heating at a high temperature.

  Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a flowchart of a method for producing mica expandable with an acid according to the present invention. The manufacturing method of the mica which can be expanded by the acid which concerns on this invention has the following processes.
Mixing step (1): Powdery mica and alkaline substance of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide or barium hydroxide are in a quantity ratio of 1: 1 to 1: 20 wherein the preferred alkaline material is a mixture of sodium hydroxide and lithium hydroxide, the mixture containing 80 wt% or more of sodium hydroxide and lithium hydroxide, the other materials being other alkaline materials. It is a substance. Suitable mica is, for example, muscovite, colored mica, sericite, phlogopite or pyrophyllite.

  Heating step (2): The powdered mica and the alkali substance after mixing are heated to 150 ° C. to 230 ° C. and kept at the temperature for 30 minutes, thereby diffusing the metal ions of the alkali substance into the mica.

  Cooling / washing step (3): The temperature of the powder mica is lowered by diluting the heated powder mica and the alkaline substance with cold water.

  First solid / liquid separation step (4): The diluted alkaline solution and the powdered mica solid are separated by a dehydrator, the separated mica solid is diluted / washed with water, and the solid / liquid is separated again. Repeat several times until the content of sodium hydroxide and lithium hydroxide in the mica solid is 1 wt% or less.

  Neutralization step (5): After diluting an acidic solution such as sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, acetic acid or oxalic acid with cold water, the alkaline substance in mica is neutralized by using it in mica, and the mica PH When the value is less than 7, preferably less than 4, the mica causes an expansion phenomenon. A preferred acidic solution is nitric acid.

  Second solid / liquid separation step (6): The acidic solution is diluted with water, and the diluted acidic solution and the mica solid are separated again by a dehydrator to obtain a desired expandable mica.

  After mixing 1 kg of powdered mica, 5 kg of sodium hydroxide and 1 kg of lithium hydroxide, the mixture is heated to 220 degrees to melt sodium hydroxide and lithium hydroxide, and kept at that temperature for 30 minutes. After that, by adding 2 liters of cold water at room temperature to molten sodium hydroxide and lithium hydroxide, the concentration of sodium hydroxide and lithium hydroxide is diluted, and the temperature of the mica is lowered. The solution of sodium hydroxide and sodium hydroxide and lithium hydroxide was separated into solid / liquid with a dehydrator, and after diluting 100 grams of nitric acid with cold water, the diluted solution of nitric acid was used as the separated mica. Neutralizing and diluting the concentration of alkaline substances in mica, PH value of mica after dilution is 7, again diluting the concentration of acidic solution with cold water at room temperature, at this time, mica expands Occurs, and finally by separating an acidic solution and mica after dilution by the dehydrator, the resulting 0.85 kg mica products.

  According to the present invention, it is possible to obtain expandable mica that can reduce the manufacturing cost without using expensive lithium nitrate and without heating at high temperature.

It is a flowchart of the manufacturing method of the mica expandable with the acid which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mixing process 2 Heating process 3 Cooling / washing process 4 1st solid / liquid separation process 5 Neutralization process 6 2nd solid / liquid separation process

Claims (7)

A mixing step of mixing powdery mica and a metal alkali substance in a mass proportion of 1: 1 to 1:20;
A heating step of diffusing the metal ions of the alkali substance into the mica by heating the powdered mica and the alkali substance after mixing to 150 ° C. to 230 ° C. and maintaining the temperature for 30 minutes as it is,
A cooling / washing step for reducing the temperature of the powdered mica by diluting the heated powdered mica and the alkaline substance with cold water;
A first solid / liquid separation step for separating the diluted alkaline solution and the powdered mica solid;
Neutralizing the alkaline substance in the mica by diluting the acidic solution with cold water after being diluted with cold water, and when the PH value of the mica is less than 7;
A second solid / liquid separation step of diluting the acidic solution with water and again separating the diluted acidic solution from the mica solids to obtain the desired expandable mica; Method. The metal alkali substance used in the mixing step is lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide or barium hydroxide and a mixture thereof. Of Mica Expandable with Acid The method for producing mica expandable with an acid according to claim 1, wherein the acidic solution used in the neutralization step is sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, acetic acid, or oxalic acid. The neutralization step is that the pH value of the mica is set to less than 4 by neutralizing an alkaline substance in the mica by using the acidic solution diluted with cold water and then using it in the mica. The manufacturing method of the mica expandable with the acid in any one of 1-3. 5. The method for producing mica expandable with acid according to claim 4, wherein the first solid / liquid separation step and the second solid / liquid separation step perform solid / liquid separation by a dehydrator. The metal alkaline substance used in the mixing step is a mixture of sodium hydroxide and lithium hydroxide, the mixture contains 80 wt% or more of sodium hydroxide and lithium hydroxide, and the other substance is another alkaline substance. The method for producing mica expandable with an acid according to any one of claims 1 to 3, wherein the mica is expandable with an acid. 2. The method for producing mica expandable with acid according to claim 1, wherein the mica is muscovite, colored mica, sericite, phlogopite, or pyrophyllite.

Images