Method for preparing NaX molecular sieve from yellow phosphorus slag

Abstract

The invention relates to a method for preparing a NaX molecular sieve from yellow phosphorus slag. The method comprises the following steps: pretreatment, acid leaching, alkali fusion, aging, washing after crystallization, drying and grinding to obtain a powdery NaX molecular sieve; the X-type molecular sieve is prepared by taking the yellow phosphorus slag as a main raw material, the yellow phosphorus slag and the value thereof are utilized to the greatest extent, no yellow phosphorus slag residue is left in the preparation process, chemical raw materials can be saved, and the prepared NaX-type molecular sieve also has the characteristics of large raw material quantity and low cost.

Description

Technical Field

[0001] The invention relates to the field of molecular sieve preparation technology and secondary utilization of solid waste, and in particular to a method for preparing NaX molecular sieve from yellow phosphorus slag. Background Art

[0002] Yellow phosphorus slag (YPS) is a solid waste generated during the production of yellow phosphorus. The production of yellow phosphorus uses coke as a reducing agent and silicon dioxide as a flux. Phosphate ore is heated to 1400°C in an electric furnace. CaO produced by the decomposition of phosphate ore reacts with silicon dioxide to form yellow phosphorus slag (YPS). Yellow phosphorus slag can be divided into two categories: water-cooled slag and naturally cooled slag. Factories generally use water to quickly cool the molten yellow phosphorus slag from high temperature to room temperature to obtain water-quenched yellow phosphorus slag, whose main components are CaO and SiO2, Al2O3, P2O5, and a small amount of Fe2O3, MgO, etc. About 10-12 tons of yellow phosphorus slag are produced for every ton of yellow phosphorus produced.

[0003] How to effectively, reasonably and safely dispose of yellow phosphorus slag has become a top priority, and research has been carried out to convert yellow phosphorus slag into valuable products such as cement, concrete, supplementary cementitious materials (SCM), ceramics and glass-ceramics, etc. Therefore, converting yellow phosphorus slag into high value-added products is also a good research direction.

[0004] X-type zeolite can be used for gas purification, removal of organic matter and hydrothermal, deep drying of gas, and can be used as an organic catalyst, adsorbent and detergent additive after modification. It is one of the most widely used zeolites.

[0005] Elements such as silicon and aluminum in yellow phosphorus slag are ideal components for preparing NaX molecular sieves, but there is no prior art that discloses the use of yellow phosphorus slag to prepare NaX molecular sieves. Summary of the invention

[0006] The invention provides a method for preparing NaX molecular sieve from yellow phosphorus slag. The yellow phosphorus slag is used as a raw material, and the NaX molecular sieve is prepared through acid leaching, alkali melting, aging and hydrothermal crystallization.

[0007] The specific technical solutions of the present invention are as follows:

[0008] A method for preparing NaX molecular sieve from yellow phosphorus slag comprises the following steps:

[0009] (1) drying the yellow phosphorus slag, treating it in a sample preparation pulverizer, and then sieving it to obtain yellow phosphorus slag powder;

[0010] (2) Acid leaching: yellow phosphorus slag powder and nitric acid are placed in a three-necked flask and mixed, and heated and stirred in a constant temperature magnetic stirrer. The obtained mixture is washed, filtered, and dried in an oven to obtain acid leaching residue;

[0011] (3) Alkali fusion: The acid leached residue is mixed with sodium hydroxide and ground, then placed in a crucible and placed in a muffle furnace for roasting. After cooling, the mixture is ground to obtain alkaline fused slag;

[0012] (4) Aging: Mix the alkali molten slag, aluminum source and water evenly, and stir at room temperature for aging;

[0013] (5) Crystallization: After aging, the mixture is transferred to a reactor and then placed in an oven for crystallization. After crystallization, the mixture is filtered, washed, dried, and ground to obtain a NaX molecular sieve.

[0014] In step (1), the yellow phosphorus slag is dried in an electric oven at a constant temperature of 80-100° C. for 24 hours, and then processed by a sample preparation crusher and sieved through a 200-mesh sieve to obtain yellow phosphorus slag powder.

[0015] In step (2), the mass concentration of nitric acid is 10-30%, and the mass ratio of yellow phosphorus slag powder to nitric acid is 1:10; the heating and stirring temperature is 80-100°C, and the stirring time is 2-5h; the mixture is washed until the pH value is neutral, and the drying temperature in the oven is 80-100°C, and the drying time is 12-24h.

[0016] In step (3), the mass ratio of the acid leaching residue to the sodium hydroxide is 1:1.2-1:1.5; the roasting temperature is 500-600°C, and the roasting time is 3-5h.

[0017] In step (4), the aluminum source is sodium aluminate or the like.

[0018] In step (4), the solid-liquid ratio of the alkali slag to water is g:mL 1:5-1:6, and the molar ratio of silicon in the alkali slag to aluminum in the aluminum source is Si / Al=1.6.

[0019] In step (4), stirring aging is carried out on a constant temperature magnetic stirrer for 3-5 hours.

[0020] In step (5), the temperature of the oven during crystallization is 100-120° C., and the crystallization time is 24-48 hours; the drying temperature is 80-100° C., and the drying time is 12-24 hours.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] The invention adopts yellow phosphorus slag as raw material instead of chemical reagents, and can prepare NaX molecular sieve with regular morphology and structure through a simple acid leaching-alkali melting-hydrothermal method; the raw material cost of molecular sieve preparation is greatly reduced, and an effective yellow phosphorus slag utilization method is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A flow chart of NaX prepared by the present invention;

[0024] Figure 2 XRD pattern of NaX prepared by the present invention;

[0025] Figure 3 This is the SEM image of NaX prepared in the present invention. DETAILED DESCRIPTION

[0026] In order to further illustrate the present invention, a method for preparing NaX molecular sieve from yellow phosphorus slag provided by the present invention is described in detail below in conjunction with examples, but they should not be construed as limiting the scope of protection of the present invention.

[0027] Example 1

[0028] A method for preparing NaX molecular sieve from yellow phosphorus slag, such as Figure 1 As shown, the specific steps are as follows:

[0029] (1) taking yellow phosphorus slag and drying it in an electric oven at 80° C. for 24 h, and sieving it through a 200-mesh sieve in a sample preparation grinder to obtain yellow phosphorus slag powder;

[0030] (2) 20 g of yellow phosphorus slag powder and 200 g of 10% nitric acid were placed in a three-necked flask and mixed, placed in a constant temperature magnetic stirrer, stirred at 100° C. for 3 h, the obtained mixture was washed until the pH value was neutral, filtered, and dried in an oven at 80° C. for 24 h to obtain acid leaching residue;

[0031] (3) taking the acid leaching residue and NaOH powder in a mass ratio of 1:1.2, uniformly mixing and grinding, then pouring into a crucible, placing in a muffle furnace, roasting at 600° C. for 3 h, and grinding into powder after cooling to room temperature to obtain alkaline molten slag;

[0032] (4) Take 10 g of calcined material alkaline slag, 60 mL of water, and take aluminum source sodium aluminate according to the molar ratio of silicon in the alkaline slag to aluminum in the aluminum source Si / Al=1.6, mix the three together in a beaker, and then place the beaker on a constant temperature magnetic stirrer. After stirring at room temperature for 3 hours, transfer it to a hydrothermal reactor and crystallize it in an oven at 100°C for 48 hours. After the reaction is completed, cool it to room temperature. After filtering and washing with water to neutrality, the sample is dried at 80°C for 24 hours and ground to obtain a NaX type molecular sieve.

[0033] like Figure 2 The figure shows the XRD pattern of the prepared NaX, from which it can be seen that the prepared material completely coincides with the characteristic diffraction peaks of the X-type molecular sieve; Figure 3 The SEM image of the prepared NaX is shown in FIG. 1 , from which it can be seen that the present invention synthesizes a NaX type molecular sieve having a typical octahedral structure.

[0034] Example 2

[0035] A method for preparing NaX molecular sieve from yellow phosphorus slag, the specific steps are as follows:

[0036] (1) taking yellow phosphorus slag and drying it in an electric oven at 90° C. for 24 h, and sieving it through a 200-mesh sieve in a sample preparation grinder to obtain yellow phosphorus slag powder;

[0037] (2) 20 g of yellow phosphorus slag powder and 200 g of 10% nitric acid were placed in a three-necked flask and mixed, placed in a constant temperature magnetic stirrer, stirred at 80° C. for 5 h, the obtained mixture was washed until the pH value was neutral, filtered, and dried in an oven at 80° C. for 24 h to obtain acid leaching residue;

[0038] (3) taking the acid leaching residue and NaOH powder in a mass ratio of 1:1.5, uniformly mixing and grinding, then pouring into a crucible, placing in a muffle furnace, roasting at 500° C. for 5 h, cooling to room temperature, grinding into powder, and obtaining alkaline slag;

[0039] (4) Take 10 g of calcined material alkaline slag, 50 mL of water, and take aluminum source sodium aluminate according to the molar ratio of silicon in the alkaline slag to aluminum in the aluminum source Si / Al=1.6, mix the three together in a beaker, and then place the beaker on a constant temperature magnetic stirrer. After stirring at room temperature for 3 hours, transfer it to a hydrothermal reactor and crystallize it in an oven at 100°C for 48 hours. After the reaction is completed, cool it to room temperature. After filtering and washing with water to neutrality, the sample is dried at 100°C for 12 hours and ground to obtain a NaX type molecular sieve.

[0040] Example 3

[0041] A method for preparing NaX molecular sieve from yellow phosphorus slag, the specific steps are as follows:

[0042] (1) taking yellow phosphorus slag and drying it in an electric oven at 80° C. for 24 h, and sieving it through a 200-mesh sieve in a sample preparation grinder to obtain yellow phosphorus slag powder;

[0043] (2) 20 g of yellow phosphorus slag powder and 200 g of 20% nitric acid were placed in a three-necked flask and mixed, placed in a constant temperature magnetic stirrer, stirred at 100° C. for 2 h, the obtained mixture was washed until the pH value was neutral, filtered, and dried in an oven at 80° C. for 24 h to obtain acid leaching residue;

[0044] (3) taking the acid leaching residue and NaOH powder in a mass ratio of 1:1.2, uniformly mixing and grinding, then pouring into a crucible, placing in a muffle furnace, roasting at 550° C. for 4 h, and grinding into powder after cooling to room temperature to obtain alkaline slag;

[0045] (4) Take 10 g of calcined material alkaline slag, 60 mL of water, and take aluminum source sodium aluminate according to the molar ratio of silicon in the alkaline slag to aluminum in the aluminum source Si / Al=1.6, mix the three together in a beaker, and then place the beaker on a constant temperature magnetic stirrer. After stirring at room temperature for 4 hours, transfer it to a hydrothermal reactor and crystallize it in an oven at 100°C for 48 hours. After the reaction is completed, cool it to room temperature. After filtering and washing with water to neutrality, the sample is dried at 90°C for 18 hours and ground to obtain a NaX type molecular sieve.

[0046] Example 4

[0047] A method for preparing NaX molecular sieve from yellow phosphorus slag, the specific steps are as follows:

[0048] (1) taking yellow phosphorus slag and drying it in an electric oven at 100° C. for 24 h, and sifting it through a 200-mesh sieve in a sample preparation grinder to obtain yellow phosphorus slag powder;

[0049] (2) 20 g of yellow phosphorus slag powder and 200 g of 20% nitric acid were placed in a three-necked flask and mixed, placed in a constant temperature magnetic stirrer, stirred at 90° C. for 4 h, the obtained mixture was washed until the pH value was neutral, filtered, and dried in an oven at 90° C. for 18 h to obtain acid leaching residue;

[0050] (3) taking the acid leaching residue and NaOH powder in a mass ratio of 1:1.5, uniformly mixing and grinding, then pouring into a crucible, placing in a muffle furnace, roasting at 600° C. for 3 h, and grinding into powder after cooling to room temperature to obtain alkaline slag;

[0051] (4) Take 10 g of calcined material alkaline slag, 50 mL of water, and take the aluminum source sodium aluminate according to the molar ratio of silicon in the alkaline slag to aluminum in the aluminum source Si / Al=1.6, mix the three together in a beaker, and then place the beaker on a constant temperature magnetic stirrer. After stirring at room temperature for 4 hours, transfer it to a hydrothermal reactor and crystallize it in an oven at 120°C for 24 hours. After the reaction is completed, cool it to room temperature. After filtering and washing with water to neutrality, the sample is dried at 80°C for 24 hours and ground to obtain a NaX type molecular sieve.

[0052] Example 5

[0053] A method for preparing NaX molecular sieve from yellow phosphorus slag, the specific steps are as follows:

[0054] (1) taking yellow phosphorus slag and drying it in an electric oven at 90° C. for 24 h, and sieving it through a 200-mesh sieve in a sample preparation grinder to obtain yellow phosphorus slag powder;

[0055] (2) 20 g of yellow phosphorus slag powder and 200 g of 30% nitric acid were placed in a three-necked flask and mixed, placed in a constant temperature magnetic stirrer, stirred at 100° C. for 3 h, the obtained mixture was washed until the pH value was neutral, filtered, and dried in an oven at 100° C. for 12 h to obtain acid leaching residue;

[0056] (3) taking the acid leaching residue and NaOH powder in a mass ratio of 1:1.3, uniformly mixing and grinding, then pouring into a crucible, placing in a muffle furnace, roasting at 500° C. for 5 h, cooling to room temperature, grinding into powder, and obtaining alkaline slag;

[0057] (4) Take 10 g of calcined material alkaline slag, 60 mL of water, and take the aluminum source sodium aluminate according to the molar ratio of silicon in the alkaline slag to aluminum in the aluminum source Si / Al=1.6, mix the three together in a beaker, and then place the beaker on a constant temperature magnetic stirrer. After stirring at room temperature for 5 hours, transfer it to a hydrothermal reactor and crystallize it in an oven at 110°C for 36 hours. After the reaction is completed, cool it to room temperature. After filtering and washing with water to neutrality, the sample is dried at 80°C for 24 hours and ground to obtain a NaX type molecular sieve.

[0058] Example 6

[0059] A method for preparing NaX molecular sieve from yellow phosphorus slag, the specific steps are as follows:

[0060] (1) taking yellow phosphorus slag and drying it in an electric oven at 90° C. for 24 h, and sieving it through a 200-mesh sieve in a sample preparation grinder to obtain yellow phosphorus slag powder;

[0061] (2) 20 g of yellow phosphorus slag powder and 200 g of 30% nitric acid were placed in a three-necked flask and mixed, placed in a constant temperature magnetic stirrer, stirred at 100° C. for 3 h, the obtained mixture was washed until the pH value was neutral, filtered, and dried in an oven at 100° C. for 12 h to obtain acid leaching residue;

[0062] (3) taking the acid leaching residue and NaOH powder in a mass ratio of 1:1.5, uniformly mixing and grinding, then pouring into a crucible, placing in a muffle furnace, roasting at 500° C. for 5 h, cooling to room temperature, grinding into powder, and obtaining alkaline slag;

[0063] (4) Take 10 g of calcined material alkaline slag, 55 mL of water, and take the aluminum source sodium aluminate according to the molar ratio of silicon in the alkaline slag to aluminum in the aluminum source Si / Al=1.6, mix the three together in a beaker, and then place the beaker on a constant temperature magnetic stirrer. After stirring at room temperature for 5 hours, transfer it to a hydrothermal reactor and crystallize it in an oven at 110°C for 36 hours. After the reaction is completed, cool it to room temperature. After filtering and washing with water to neutrality, the sample is dried at 80°C for 24 hours and ground to obtain a NaX type molecular sieve.

[0064] The specific implementation modes of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A method for preparing NaX molecular sieve from yellow phosphorus slag, characterized in that: The following steps are involved: (1) drying and crushing yellow phosphorus slag and then sieving to obtain yellow phosphorus slag powder; (2) mixing yellow phosphorus slag powder with nitric acid, heating and stirring, washing, filtering, and drying the obtained mixture to obtain acid leaching residue; (3) mixing the acid leaching residue with sodium hydroxide, grinding the mixture, roasting the mixture, and grinding the mixture after cooling to obtain alkali slag; (4) mixing the alkali molten slag, the aluminum source and water uniformly, and stirring at room temperature for aging; (5) After aging, the product is crystallized, filtered, washed, dried, and ground to obtain NaX molecular sieve.

2. A method for preparing NaX molecular sieve from yellow phosphorus slag according to claim 1, characterized in that: In step (1), the drying step is to dry the yellow phosphorus slag at a constant temperature of 80-100° C. for 24 hours; and the sieving step is to pass the slag through a 200-mesh sieve.

3. A method for preparing NaX molecular sieve from yellow phosphorus slag according to claim 1, characterized in that: In step (2), the mass concentration of nitric acid is 10-30%, and the mass ratio of yellow phosphorus slag powder to nitric acid is 1:

10.

4. A method for preparing NaX molecular sieve from yellow phosphorus slag according to claim 1, characterized in that: In step (2), the heating and stirring temperature is 80-100° C. and the stirring time is 2-5 hours; the mixture is washed until the pH value is neutral, the drying temperature is 80-100° C. and the drying time is 12-24 hours.

5. A method for preparing NaX molecular sieve from yellow phosphorus slag according to claim 1, characterized in that: In step (3), the mass ratio of the acid leaching residue to the sodium hydroxide is 1:1.2-1:1.5; the roasting temperature is 500-600°C, and the roasting time is 3-5h.

6. A method for preparing NaX molecular sieve from yellow phosphorus slag according to claim 1, characterized in that: In step (4), the aluminum source is sodium aluminate.

7. A method for preparing NaX molecular sieve from yellow phosphorus slag according to claim 1, characterized in that: In step (4), the solid-liquid ratio of the alkali slag to water is 1:5-1:6, and the molar ratio of silicon in the alkali slag to aluminum in the aluminum source is Si / Al=1.

6.

8. A method for preparing NaX molecular sieve from yellow phosphorus slag according to claim 1, characterized in that: The aging time in step (4) is 3-5 hours under normal temperature stirring.

9. A method for preparing NaX molecular sieve from yellow phosphorus slag according to claim 1, characterized in that: In step (5), the crystallization temperature is 100-120° C., and the crystallization time is 24-48 h; the drying temperature is 80-100° C., and the drying time is 12-24 h.

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