CN100436318C - Method for preparing swelled fluorine mica by kaoline - Google Patents

Abstract

The invention relates to a method for preparing bentonite fluoromica from kaolin, which comprises uniformly mixing 25-75wt% kaolin, 10-35wt% fluorine compound and 15-40wt% magnesium compound, and calcining the mixture at 850-900°C for 4 After ~12 hours, swelling fluoromica was obtained. The fluorine compound is Na ₂ SiF ₆ or NaF; the magnesium compound is MgO, Mg(OH) ₂ , brucite, MgCO ₃ (including basic magnesium carbonate) or magnesite. The method of the invention can prepare swollen fluoromica with cheap raw materials and at relatively low temperature. The preparation method has low cost, no environmental pollution, and has broad application prospects.

Description

A method for preparing bentonite fluoromica from kaolin

technical field

The invention relates to a preparation method of fluoromica, in particular to a method for preparing bentonite fluoromica from natural mineral kaolin.

Background technique

Fluormica is a general term for a class of layered hydrous aluminosilicates containing potassium, aluminum, magnesium, iron, lithium and other elements. A complex silicon-oxygen layer composed of octahedrons. Its chemical formula is: R ⁺ R ₃ ²⁺ [AlSi ₃ O ₁₀ ]F ₂ or R ⁺ R ₂ ³⁺ [AlSi ₃ O10] F ₂ where R ⁺ is K ⁺ , Na ⁺ ; R ²⁺ is Mg ²⁺ , Fe ²⁺ , Mn ²⁺ ; R ³⁺ is Al ³⁺ , Fe ³⁺ , Mn ³⁺ .

Fluormica for industrial use is divided into swelling and non-swelling fluoromica according to the degree of change in interlayer spacing after absorbing water. Among them, the swelling fluoromica refers to the fluoromica that swells due to the increase of the interlayer distance after absorbing water. This fluoromica is mainly used as a Inorganic fillers, lubricants, inorganic binders and exchangers are widely used in various fields.

The existing fluoromica is mostly prepared by melting method and solid state reaction method. The reaction temperature of these methods is too high, which is very uneconomical in industrial production, and generally only non-swellable fluoromica can be obtained. For example, Chinese patent CN1552622 discloses a method for preparing fluoromica by fusion method, which is prepared by melting quartz sand, magnesia, alumina powder, potassium fluorosilicate and potassium carbonate at a high temperature above 1300°C. Non-swellable fluoromica KMg ₃ (AlSi ₃ O ₁₀ ) F ₂ .

JP-P-5-306115 discloses a preparation method of fluoromica, which mixes clay materials, transition metal compounds, fluorides, magnesium oxide, etc., grinds them, and treats them at 1000°C for 5 hours to obtain KMg _2.5 Zn _0.5 [ AlSi ₃ O ₁₀ ]F ₂ . Although this method reduces the reaction temperature, the obtained fluoromica is also non-swellable.

Contents of the invention

The purpose of the present invention is to overcome the excessively high reaction temperature of the prior art, which is very uneconomical in industrial production, and generally can only obtain the defect of non-swelling fluoromica, thereby providing a kind of low temperature, using cheap kaolin As a raw material, a method for preparing expanded fluoromica.

The purpose of the present invention is achieved through the following technical solutions:

The method for preparing bentonite fluoromica from kaolin provided by the invention is to mix 25-75 wt% (weight) kaolin, 10-35 wt% (weight) fluorine compound and 15-40 wt% (weight) magnesium compound, and mix the mixture Calcined at 850-900°C for 4-12 hours to obtain expanded fluoromica Na _2x+a Mg _3-x [(Al _a Si _4-a )O ₁₀ ]F ₂ , where 0≤x≤0.5, 0< a≤2, and 0.3≤2x+a≤2.

The fluorine compound is Na ₂ SiF ₆ or NaF;

The magnesium compound is MgO, Mg(OH) ₂ , brucite, MgCO ₃ (including basic magnesium carbonate) or magnesite.

以上，可作为离子交换剂、填料等应用于工业水处理、造纸、涂料等行业中。The fluoromica obtained by the method of the present invention is swelling fluoromica, and its interlayer spacing can reach

The above can be used as ion exchangers, fillers, etc. in industrial water treatment, papermaking, coatings and other industries.

One of the raw materials used in the present invention——kaolin is an important non-metallic mineral resource, which is widely used in industries such as ceramics, electronics, papermaking, rubber, plastics, enamel, petrochemicals, coatings and printing inks. my country is very rich in kaolin mineral resources. Therefore, the development of kaolin as raw material to prepare bentonite fluoromica will not only enrich the preparation method of bentonite fluoromica, but also expand the new way of comprehensive utilization of my country's rich kaolin resources.

The method of the invention can prepare swollen fluoromica with cheap raw materials and at relatively low temperature. The preparation method has low cost, no environmental pollution, and has broad application prospects.

Detailed ways

Example 1:

Mix kaolin 55wt% (weight), sodium fluorosilicate Na ₂ SiF ₆ 20wt% (weight), and magnesium oxide 25wt% (weight), put it into a platinum crucible, and bake it in an electric furnace at 850°C for 6 hours. The expanded fluoromica was obtained. Using X-ray powder diffraction method, the interlayer spacing of the product in the C-axis direction is measured as

Example 2:

Mix kaolin 56wt% (weight), sodium fluoride NaF18wt% (weight), and magnesium oxide 26wt% (weight), put them into a platinum crucible, and bake them in an electric furnace at 850°C for 12 hours to obtain the expanded fluorine Mica. Using X-ray powder diffraction method, the interlayer spacing of the product in the C-axis direction is measured as

Example 3:

Mix kaolin 36wt% (weight), sodium fluorosilicate Na ₂ SiF ₆ 27wt% (weight), basic magnesium carbonate 37wt% (weight), put it into a platinum crucible, and bake it in an electric furnace at 900°C for 4 hours, the expanded fluoromica was obtained. Using X-ray powder diffraction method, the interlayer spacing of the product in the C-axis direction is measured as

Claims (1)

1. A method for preparing bentonite fluoromica from kaolin, comprising uniformly mixing 25 to 75 wt% kaolin, 10 to 35 wt% fluorine compounds and 15 to 40 wt% magnesium compounds, and calcining the mixture at 850 to 900°C for 4 to 12 hours, obtain swelling fluoromica; The fluorine compound is Na ₂ SiF ₆ or NaF; The magnesium compound is MgO, Mg(OH) ₂ , brucite, MgCO ₃ or magnesite.