JPS60191018A - Molecular sieve type zeorite - Google Patents

Abstract

PURPOSE:To produce molecular sieve type zeolite inexpensively by a hydrothermal synthesis method by using rice hull ash (modified substance) as a silica source. CONSTITUTION:Calcined ash of rice hull obtained in rice plant culture or the modified substance obtained by crushing the rice hull and heat-treating it at high temp. (about >=900 deg.C) is used as a silica source. Namely, an alkaline metal source, an alumina source, said silica source and water are mixed in proportion of Na2O/SiO2=0.3-1.7, SiO2/Al2O3=1.5-30, H2O/Na2O=15-250 as molar value expressed in terms of oxide. Then, the obtained gelling substance is charged in a closed vessel and after it is allowed to stand at room temp. for about 0- 130hr, it is subjected to hydrothermal reaction at about 50-110 deg.C for 1-150hr to produce molecular sieve type zeolite (sodium zeolite).

Description

[Detailed description of the invention] The present invention relates to a method for producing a molecular sieve type synthetic zeolite.

The general formula of synthetic zeolite is Me 2 /nO・Al12
03・X5i (Iz・Vll 20 (Me is an alkali metal or alkaline earth metal, n is the number of charges) They are prefixed with the name of each Zeorai 1.

The Me ion in the -L formula can be exchanged with other cations by various ion exchange methods. Synthetic zeolite crystals are crystals with internal spaces, which are usually filled with water molecules. This water can be easily removed.

These synthetic zeolites have the property of using their pores to exhibit high molecular sieving and adsorption effects.
Taking advantage of its properties, it is used industrially as a highly desiccant agent, adsorption/separation agent, catalyst, etc.

The aforementioned synthetic zeolite is generally produced using reagents such as a silica source such as sodium silicate, an alumina source such as sodium aluminate, and an alkali source such as sodium hydroxide. However, since these raw materials are expensive, natural minerals (
Acid clay, kaolin, feldspar, nacre, bentonite, etc.) have been studied, and several methods have already been proposed.

The present invention is a method for producing zeolite using J7i (f, +, ?br, Inai vT, 0.ゎ66 type ash) to replace the silica component in the zeolite composition.

Most of the rice husk ash used in the present invention is amorphous and consists of a high silica component, but also contains free carbon.

In the case of the present invention, this free carbon does not participate in the production of zeolite, is harmless to the synthesis reaction, and remains in the product as it is. In addition, this rice husk ash is used by subjecting it to treatments such as pulverization and high-temperature heating as necessary.6 The modified rice husk ash referred to in the present invention is the ash obtained by burning rice husk. In addition, it means a product that has been further subjected to treatments such as pulverization and high-temperature heating as described above. High temperature heating (temperature 900℃
The rice husk ash modified product obtained by the above) is converted into a mineral whose main component is alpha-cristobalite.

The method for producing the synthetic zeolite of the present invention can be carried out according to a conventionally known hydrothermal synthesis method, except that the above-described rice husk ash or a modified product thereof is used as a silica source.

To preferably carry out the method of the present invention, a gel sample adjusted to a predetermined starting material composition is charged into an airtight container, left to stand at room temperature for a predetermined period of time, aged, and then heated to a predetermined temperature. Heat and react under closed conditions. The synthesized product is filtered and washed, and water washing is repeated until the PU of the filtrate becomes 10 or less, and the resulting cake is sufficiently dried at 40 to 50°C to form a product. The zeolite production conditions at this time are in the following range.

1) Molar composition of starting material Na20/Si02 =0.3-1.4SiOz/A
fl203=1.5~30H20/Na20=1
5 to 250 2) Standing time at room temperature 0 to 130 hours 3) Synthesis temperature and time 50°C to 110°C, 1 to 150 hours Below Examples demonstrate the production of molecular sieve type zeolite (sodium zeolite) by the method of the present invention. Explain in detail.

Example 1 To 5 g of ashes obtained by incinerating rice husks, add 1 l of sodium aluminate.
og, 6.4 g of sodium hydroxide, and 93.6 g of water are stirred together. What are the analytical values of this rice husk ash?

This is the value of the value further incinerated at 1000℃, and S
i02 96.2%, AQ 203 0.1%, Fe2
O30.1%, Ca00.8%, Mg00.3%, Mn
0.3%, etc.

The composition of this reactant mixture, expressed as a molar ratio of oxides, is approximately as follows.

Na zO/Si02 = 1.2, Si02/An 2
03 =2.0. H20/Na20=40.0 After stirring the mixture in the flask well for 30 minutes,
The mixture was placed in a constant temperature bath of C for 70 hours for synthesis.

The solids were separated from the mixture by filtration and washed with distilled water to p+110. This was dried in a hot air dryer at 50° C. for 24 hours. This dried sample was subjected to X-ray diffraction analysis and calcium exchange capacity test.

The X-ray diffraction diagram is shown in FIG. 1, and it was confirmed that this product was mainly composed of A-type zeolite, but also faujasite-type (X, Y-type) zeolite, hydroxysodalite, etc.

Although quartz is confirmed in FIG. 1, this is quartz in the raw material, and is a mineral that does not participate in the production of zeolite and remains in the product.

The results of the calcium exchange ability test for this product are shown in FIG. 2, and the amount of CaO exchanged at a contact time of 15 minutes was about 32 ppI11. The CaO value in this case was determined by adding 0.2 g of the product (Na zeolite) to a 200 rn Q calcium chloride aqueous solution (126 ppm as CaO) and stirring to perform ion exchange to Ca zeolite.
At this time, the decrease in calcium ions over time was measured using an ion meter, and this was expressed as Can fl'.

Example 2 The amount of starting materials and synthesis conditions were adjusted as follows to prepare Na
-A type zeolite was produced. That is, rice husk ash was adjusted to 10 g, sodium aluminate 20 g, sodium hydroxide 13 g, and water 93.6 g. In this case, the molar ratio of the composition is Na20/Si02 = 1.2, Si
02/AQ 203=2.0, It 20/Na 2
0=20.0.

This reaction mixture was pretreated in the same manner as in the previous example, and then
It was placed in a constant temperature bath at 5°C for 30 hours, and one pouch was made. The produced solid was treated in the same manner as in the previous example, and the resulting dry sample was subjected to X-ray analysis and a calcium exchange capacity test. The X-ray diffraction pattern is shown in Figure 3, and it was confirmed that this product was a ^-type zeolite. Moreover, the calcium exchange ability of this was similar to the results shown in FIG.

Example 3 The composition was the same as in Example I, and the synthesis conditions were the same as in Example 2, at a synthesis temperature of 75° C. and a synthesis time of 30 hours.

The results of X-ray analysis of the solid produced under these conditions are shown in FIG. 4, indicating that it is A-type zeolite.

This example had better crystallinity and production rate among the A-type zeolites described in Examples (1 to 4). The calcium exchange ability of the product was comparable to that shown in Figure 2.

Example 4 Next, in order to remove free carbon from rice husk ash, it was calcined at 1050°C for 30 minutes. This calcined ash was used to produce zeolite as before.

The composition of the raw materials and the synthesis conditions are the same as in Example 3. The results of X-ray analysis of the resulting mixture are shown in FIG. In addition to ^-type zeolite, e-type zeolite and hydroxysodalite 1- were confirmed in this solid. Moreover, the calcium exchange ability of this product was comparable to that shown in FIG.

[Brief explanation of the drawing]

Figures 1, 3, 4 and 5 are X-ray diffraction diagrams of solids produced by synthesis, where the horizontal axis represents the diffraction angle 2θ and the vertical axis represents the diffraction intensity of each mineral. There is. Also, each peak L is marked with A, 1.゛, Q, P, )IY, and these represent minerals as described in the figure. Note that quartz in the figure is a mineral contained in the raw materials, as described in Example 1 of the text, and is a mineral that does not participate in the synthesis. Therefore, it remains intact in the product. FIG. 2 shows an example of the results of measuring calcium exchange capacity. The horizontal axis shows the contact time rill (minutes) for calcium exchange, and the vertical axis shows the exchange amount (ppm). It is shown that the amount of calcium exchange increases with the passage of contact time. In FIGS. 1, 3, 4 and 5. F: faujasite type zeolite, A: A type zeolite, psp type zeolite, 1]y: hydroxysodalite, Q: quartz. To continuation amendment February 19, 1985 1,! Display of IT matters Patent application No. 0461 of 1982
85 No. 2, Title of the invention Min-r sieve type zeolite'3
, Relationship with the 11 amendments Patent applicant (j Tokyo 1FLR, 'F 1R1 Ward 1-3-1 Kasumigaseki Name (114) Director of the Agency of Industrial Science and Technology Tatsu Todoroki 4
, Adjustment agent ■06101 8. Contents of amendment (1) Specification page 4, 51″S I'Naz O/S i Ox ”0.3 to 1.4 J
t-Nag O/S i Ot =0. 3-1.
Correct it to 7J. (2) Specification page 5, line 4 1-N az O/S + Oz = 1-2, S
;o□/Δ120. . =2.0.11□0/N, lz O=40.0.1 as r
Naz O/5i()z = 1.63.5iOz/Al
z Ol"1.46, Hz O/Naz 0-40.2
Correct as 6.1. (3) Page 5 of the specification, lines 42 to 13 “The molar ratio of the composition is Na, O/S iOx =1.2, S i O
f /A I 203-'-2, (1, Hz O/N
a 20 ``20.0.'' is changed to ``If)&[Ly戊のMO)l/Ratio is N a 2 o/
S + Ox = 1-1 (i, S i 02 /A
1203 = 1.46, Hz O/N; 3z 0-
It is 27.83. ” he corrected.

Claims (1)

[Claims] (1) A method for producing a molecular sieve type zeolite, characterized in that rice husk ash or a modified product thereof is used as a silica source.