4a-type molecular sieve synthesis method

Patent metadata

Field	Value
Publication number	US-2016185609-A1
Application number	US-201314895481-A
Country	US
Kind code	A1
Filing date	Dec 2, 2013
Priority date	Jun 3, 2013
Publication date	Jun 30, 2016
Grant date	—

Abstract

The present invention relates to a synthesis method of zeolite 4A, wherein natural clay mineral, provided as the total silicon source and aluminum source required for molecular sieve synthesis, is activated before they are crystallized under hydrothermal conditions to synthesize zeolite 4A. In the method of the present invention, a simple process is employed and inexpensive raw materials are used, resulting in zeolite 4A having a whiteness of 90% or more and a calcium ion exchange capacity of no less than 310 mg CaCO 3 /g zeolite. According to the present invention, the range of raw materials for the preparation of molecular sieve materials is broadened, and therefore not only the cost for molecular sieve production is greatly reduced by using the sub-molten salt activation method, but also the greenness in the production process of molecular sieve materials is significantly improved.

First claim

1 . A synthesis method of zeolite 4A, comprising:
providing the total silicon source and aluminum source required for molecular sieve synthesis by using natural clay mineral, and activating the natural clay mineral followed by crystallization under hydrothermal conditions to synthesize zeolite 4A.

2 . The synthesis method of zeolite 4A according to claim 1 , wherein the natural clay mineral is selected from the group consisting of natural kaolin, natural montmorillonite, natural attapulgite, natural rectorite and mixtures of one or more of the foregoing minerals.

3 . The synthesis method of zeolite 4A according to claim 1 , wherein the natural clay mineral is activated by means of sub-molten salt activation.

4 . The synthesis method of zeolite 4A according to claim 3 , wherein the sub-molten salt is a NaOH-H2O sub-molten salt system.

5 . The synthesis method of zeolite 4A according to claim 1 , wherein the zeolite 4A has high whiteness and high calcium ion exchange capacity.

6 . The synthesis method of zeolite 4A according to claim 1 , wherein the activation is carried out as follows:
the natural clay mineral is evenly mixed with a NaOH solution in a mass ratio of 1:2 to 1:20, and then oven dried at 100° C. to 300° C. to give a product as activated clay mineral; wherein, the NaOH solution is prepared by mixing solid NaOH with water in a mass ratio of 1:1 to 1:10.

7 . The synthesis method of zeolite 4A according to claim 3 , wherein the activation is carried out as follows:
the natural clay mineral is evenly mixed with a NaOH solution in a mass ratio of 1:2 to 1:20, and then oven dried at 100° C. to 300° C. to give a product as activated clay mineral; wherein, the NaOH solution is prepared by mixing solid NaOH with water in a mass ratio of 1:1 to 1:10.

8 . The synthesis method of zeolite 4A according to claim 1 , wherein, in the preparation of zeolite 4A with activated clay mineral, the activated natural clay is used as the total silicon source and aluminum source, a synthesis system is adjusted into a molar ratio of 1 to 6 Na2O:1.8 to 2.2 SiO2:Al2O3:20 to 200 H2O, and then subjected to crystallization under hydrothermal conditions to synthesize zeolite 4A.

9 . The synthesis method of zeolite 4A according to claim 3 , wherein, in the preparation of zeolite 4A with activated clay mineral, the activated natural clay is used as the total silicon source and aluminum source, a synthesis system is adjusted into a molar ratio of 1 to 6 Na2O:1.8 to 2.2 SiO2:Al2O3:20 to 200 H2O, and then subjected to crystallization under hydrothermal conditions to synthesize zeolite 4A.

10 . The synthesis method of zeolite 4A according to claim 1 , comprising the following steps:
(1) activating the natural clay mineral, wherein the natural clay mineral is evenly mixed with a NaOH solution in a mass ratio of 1:2 to 1:20, and then oven dried at 100° C. to 300° C. to give the raw material for zeolite 4A synthesis, wherein the NaOH solution is prepared by mixing solid NaOH with water in a mass ratio of 1:1 to 1:10; (2) adding deionized water and NaOH into the synthesis raw material obtained in step (1), and adjusting the molar ratio of the material is to 1 to 6 Na2O:1.8 to 2.2 SiO2:Al2O3:20 to 200 H2O, followed by aging under stifling and crystallization to obtain a crystallized product; and (3) cooling and filtering the crystallized product obtained in step (2) to remove the mother liquid, wherein the filter cake is washed with deionized water to have a neutral pH and then dried to obtain zeolite 4A.

11 . The synthesis method of zeolite 4A according to claim 3 , comprising the following steps:
(1) activating the natural clay mineral, wherein the natural clay mineral is evenly mixed with a NaOH solution in a mass ratio of 1:2 to 1:20, and then oven dried at 100° C. to 300° C. to give the raw material for zeolite 4A synthesis, wherein the NaOH solution is prepared by mixing solid NaOH with water in a mass ratio of 1:1 to 1:10; (2) adding deionized water and NaOH into the synthesis raw material obtained in step (1), and adjusting the molar ratio of the material is to 1 to 6 Na2O:1.8 to 2.2 SiO2:Al2O3:20 to 200 H2O, followed by aging under stirring and crystallization to obtain a crystallized product; and (3) cooling and filtering the crystallized product obtained in step (2) to remove the mother liquid, wherein the filter cake is washed with deionized water to have a neutral pH and then dried to obtain zeolite 4A.

12 . The method according to claim 10 , wherein, in step (2), the aging is performed at a temperature of 20° C. to 70° C. with a duration of 0 h to 24 h.

13 . The method according to claim 11 , wherein, in step (2), the aging is performed at a temperature of 20° C. to 70° C. with a duration of 0 h to 24 h.

14 . The method according to claim 10 , wherein, in step (2), the crystallization is performed at a temperature of 80° C. to 120° C. with a duration of 1 h to 12 h.

15 . The method according to claim 11 , wherein, in step (2), the crystallization is performed at a temperature of 80° C. to 120° C. with a duration of 1 h to 12 h.

Assignees

• Univ China Petroleum

Inventors

• Bao Xiaojun
• Yue Yuanyuan
• Li Tiesen
• Liu Haiyan
• Shi Gang
• Yang Jinbiao

Classifications

• C01B39/18 Primary

  from a reaction mixture containing at least one aluminium silicate or aluminosilicate of a clay type, e.g. kaolin or metakaolin or its exotherm modification or allophane {(C01B39/145 takes precedence)} · CPC title