CN102030338B - Method for hydrothermally synthesizing kalsilite by using potassium feldspar powder - Google Patents

Abstract

The invention discloses a process for synthesizing hexagonal kalephine by using potassium feldspar powder as a raw material through a hydrothermal method. The process is to crush, grind and beneficiate the raw potassium feldspar ore to obtain potassium feldspar powder with a certain particle size, then mix it with potassium hydroxide or a mixed solution of sodium hydroxide and potassium hydroxide, and place it in a nickel-lined In a stainless steel reaction kettle, the hydrothermal reaction is carried out at 220-280°C for 2-8 hours, and after filtration, washing and drying, the hexagonal kacryptite powder is obtained. Compared with the existing kanepheline synthesis technology, the process has the advantages of low raw material cost, mild synthesis conditions, simple process operation, good crystallization of the product and uniform crystal chemical composition and the like.

Description

Method for hydrothermally synthesizing hexagonal kalephine by utilizing potassium feldspar powder

technical field

The invention relates to a method for preparing hexagonal kalephine by hydrothermal method using potassium feldspar powder as raw material.

Background technique

Hexagonal nepheline is a framework silicate with high content of potassium oxide, its potassium ions are located in the crystal lattice, its structure is stable at high temperature, and potassium ions are not easy to lose. It is an excellent catalyst additive and is widely used in hydrocarbon Hydrogen production by steam reforming, ethylbenzene dehydrogenation to styrene and synthetic ammonia industry. Recent studies have shown that lithium-modified hexagonal kacryptite is a good heterogeneous catalyst for the conversion of soybean oil and methanol to biodiesel. At present, the most important methods of synthesizing kalephine are sol-gel method and co-precipitation method. The sol-gel method uses tetraethyl orthosilicate and metal alkoxide as raw materials, and the co-precipitation method uses potassium silicate, potassium hydroxide and inorganic aluminum salts as raw materials. Both methods are the precursors of kalpheline , and then it needs to be roasted under the condition of 800-1200℃ to obtain kacryptite.

Contents of the invention

The present invention provides a method for hydrothermally synthesizing K-feldspar with K-feldspar powder as raw material, wherein K-feldspar is a natural silicate mineral with abundant reserves and can be used as silicon source, aluminum source and part of potassium source at the same time to prepare kalnite; the hydrothermal synthesis process adopted in the present invention has simple operation, mild reaction conditions, and no high-temperature roasting, so it is an economically feasible method for preparing hexagonal kallinite with development potential.

This process is achieved through the following steps:

(1) After the potassium feldspar ore is crushed and beneficiated and pretreated, it is ground to obtain the potassium feldspar powder;

(2) Potassium hydroxide and sodium hydroxide are formulated into a mixed lye, and the potassium feldspar powder and the mixed lye are placed in a nickel-lined stainless steel reaction kettle, and the hydrothermal reaction is carried out at 220-280°C for 2-8 hours. After filtering, washing and drying, hexagonal kacryptite powder was obtained.

The particle size of the potassium feldspar powder is -200 mesh>95%.

The concentration of the mixed lye is 5-12M, and the molar ratio of NaOH to KOH in the mixed lye is 7/3-0/10.

The mass ratio of the mixed lye to the potassium feldspar powder is 2-8.

Stirring is carried out during the hydrothermal reaction process, and the stirring rate is 100-200 rpm.

The potassium feldspar powder used in the invention has low raw material price, wide sources, simple process operation, and has economic feasibility and technical feasibility.

Description of drawings

Fig. 1 is the X-ray powder crystal diffraction figure of raw material potassium feldspar powder;

Fig. 2 is the X-ray powder crystal diffraction figure of embodiment 1 hydrothermally synthesized hexagonal kacryptite powder KAS-01;

Fig. 3 is a scanning electron micrograph of the hexagonal kacryptite powder KAS-01 hydrothermally synthesized in Example 1.

Detailed ways

Example 1

(1) The raw potassium feldspar ore is crushed, and after mineral processing pretreatment, it is ground to a particle size of -200 mesh and greater than 95%. The chemical composition analysis results are shown in Table 1. The main phase of the potassium feldspar ore is microplagioclase , the X-ray powder crystal diffraction pattern of the raw material potassium feldspar powder is shown in Figure 1.

The chemical composition analysis result (w _B %) of table 1 potassium feldspar powder

(2) Take 150 g of ground potassium feldspar powder, mix it with 650 g of KOH solution with a concentration of 9 M, place it in a nickel-lined stainless steel reactor with a volume of 1 L, heat it to 280 ° C and react at a constant temperature for 2 h, the reaction process The stirring rate in the process is 200 rev/min. After the reaction is completed, filter, wash and dry to obtain the hexagonal kacryptite powder KAS-01. The X-ray powder crystal diffraction pattern of hexagonal kassine powder KAS-01 is shown in Figure 2. Figure 2 shows that the diffraction lines of the synthesized product are in good agreement with the standard hexagonal kcryptite. The scanning electron microscope photo of the hydrothermally synthesized hexagonal ka-nepheline powder KAS-01 in this example 1 is shown in Figure 3, and Figure 3 shows that the synthesized hexagonal ka-nepheline grains are in a relatively intact hexagonal plate shape, and the particle size distribution is relatively good. Uniform, particle size about 1-3μm. The main chemical composition analysis results of hexagonal kacryptite powder KAS-01 are shown in Table 2. The X-ray diffraction data of the synthesized product was indexed and calculated, and its lattice constant was close to the standard value of hexagonal kapherite in the standard JCPDS card (card number 11-0579) (Table 3).

Table 2 Chemical composition analysis results of hexagonal kalephine powder KAS-01 (w _B %)

Table 3 Comparison of the lattice constants of the hexagonal kalephine powder KAS-01 and the standard value of the JCPDS card

Example 2

(1) The potassium feldspar raw ore is crushed, and after mineral processing pretreatment, it is ground to a particle size of -200 mesh and greater than 95%. The chemical composition analysis results are shown in Table 1.

(2) Take 100g of the ground potassium feldspar powder, mix it with 575g of 5M mixed lye (wherein the molar ratio of NaOH/KOH is 7/3), and place it in a nickel-lined stainless steel with a volume of 1L for reaction In the kettle, heat to 220°C and react at a constant temperature for 6 hours. During the reaction, the stirring rate is 100 rpm. After the reaction, filter, wash and dry to obtain the hexagonal kacryptite powder KAS-02. The analysis results of the main chemical components of the hexagonal kacryptite powder KAS-02 are shown in Table 4. The X-ray diffraction data of the synthesized product was indexed and calculated, and its lattice constant was close to the standard value of hexagonal kapherite in the standard JCPDS card (card number 11-0579) (Table 5).

Table 4 Chemical composition analysis results of hexagonal kalephine powder KAS-02 (w _B %)

Table 5 Comparison of lattice constants of hexagonal kalephine powder KAS-02 with JCPDS card standard values

Example 3

(1) The potassium feldspar raw ore is crushed, and after mineral processing pretreatment, it is ground to a particle size of -200 mesh and greater than 95%. The chemical composition analysis results are shown in Table 1.

(2) Take 200g of the ground potassium feldspar powder, mix it with 700g of 10M mixed lye (wherein the molar ratio of NaOH/KOH is 1/1), and place it in a nickel-lined stainless steel with a volume of 1L for reaction In the kettle, heat to 260°C and keep it warm for 3 hours. During the reaction, the stirring rate is 200 rpm. After the reaction, filter, wash and dry to obtain the hexagonal kalephine product KAS-03. The analysis results of the main chemical components of the hexagonal kacryptite powder KAS-03 are shown in Table 6. The X-ray diffraction data of the synthesized product was indexed and calculated, and its lattice constant was close to the standard value of hexagonal kalpheline in the standard JCPDS card (card number 11-0579) (Table 7).

The chemical composition analysis result of table 6 hexagonal kalephine powder KAS-03 (w _B %)

Table 7 Comparison of lattice constants of hexagonal kalephine powder KAS-03 with JCPDS card standard values

Claims (4)

1. a kind of method taking potassium feldspar powder as raw material hydrothermal synthesis of hexagonal kalephine, is characterized in that, comprises the following steps: (1) After the potassium feldspar ore is crushed and beneficiated and pretreated, it is ground to obtain the potassium feldspar powder; (2) Potassium hydroxide and sodium hydroxide are made into mixed lye or KOH solution, and potassium feldspar powder and mixed lye or KOH solution are placed in a nickel-lined stainless steel reactor, and the mixed lye or The concentration of the KOH solution is 8-12M, the molar ratio of NaOH to KOH in the mixed lye or KOH solution is 7/3-0/10, and the hydrothermal reaction is carried out at 220-280°C for 2-8 hours, after filtration, washing and Dried to obtain hexagonal kacrime powder. 2. a kind of as claimed in claim 1 is the method for raw material hydrothermal synthesis hexagonal feldspar with potassium feldspar powder, it is characterized in that, in described step (1), grinding potassium feldspar, potassium feldspar The particle size of the stone powder is required to be -200 mesh > 95%. 3. a kind of as claimed in claim 1 or 2 is the method for hydrothermally synthesizing hexagonal kalephine with potassium feldspar powder as raw material, it is characterized in that, described mixed lye or KOH solution and potassium feldspar powder The mass ratio is 2-8. 4. a kind of as claimed in claim 1 is the method for hydrothermally synthesizing hexagonal ka-nepheline with potassium feldspar powder as raw material, it is characterized in that, in described hydrothermal reaction process, stir, stirring speed is 100～ 200 rpm.

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