JPS58167421A - Preparation of zeolitic composition - Google Patents

Abstract

PURPOSE:To obtain a zeolitic composition advantageously in terms of resources and energy from a blast furnace slag, by melting an alkali metallic carbonate in the blast furnace slag in a molten state, solidifying the resultant melt, and subjecting the resultant solidified material to the hydrothermal treatment. CONSTITUTION:An alkali metallic carbonate at 0.1-0.3 molar ratio based on Ca contained in a blast furnace slag and a component supplementary substance are added to he blast furnace slag in a molten state and molten to give a modified melt, which is then cooled at >=50 deg.C per 1sec temperature reducing rate to afford a solidified material. The resultant solidified material is then subjected to the hydrothermal treatment with water or an aqueous solution of an alkali. If the amount of the alkali metallic carbonate is <=0.1 molar ratio, a calcium silicate is mostly formed in the hydrothermal treatment after cooling the modified melt containing the molten additive, and the formation of the zeolite structure is inhibited. On the other hand, at >=0.3 molar ratio, the modified melt is cooled to form a dense composition structure, and the induction into the zeolite structure by the subsequent hydrothermal treatment is actually impossible.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a zeolitic composition, and aims to provide a method for efficiently producing a zeolitic composition from blast furnace slag, which is advantageous in terms of resources and energy. It is.

Blast furnace slag is a by-product generated during the production of pig iron, and has traditionally been used as a raw material for cement, aggregate for concrete, soil improvement material, etc. However, due to the large amount generated, its use is being developed. And for more effective and high-value-added usage]! There are many points that need to be considered, and research is being carried out in various fields to expand its application fields.

The present invention was devised through detailed research and repeated practical examinations in view of the above-mentioned circumstances, and it effectively removes the K-containing components of blast furnace slag (hereinafter simply referred to as slag) as described above (: :69m 3・~46 fk -'40m
= 11-18% sio 14-40-calcium silicate composition.

On the other hand, the zeolitic composition has cao=0a~4g61.14/go as the average main component of the natural product 1 synthetic product.
s ffi 10~311G,! Os! 32~
68%, N%0 (*Tahani, 0) = 2~26%i
It is an aluminosilicate composition containing kP. As can be understood from the composition of both components as described above, slag is compared with a zeolitic composition.

Contains excessive Ca and is alkali gold II! It can be seen as a composition lacking -, and it is also a different composition in terms of crystal structure. Therefore, as a compositional modification method, for example, a method in which natural minerals are melted with an alkali and then subjected to hydrothermal treatment (+% Kosho 38-6807,% ■Sho 51, &2911
8) Even when applied to slag, CaO#
Since compounds of the sOs-&0= system are preferentially produced, they cannot be induced into a zeolite structure.Therefore, in the present invention, the amount of Ca contained in the cough slag is 01 to 03 mol relative to the slag kept in a molten state. A proportion of alkali metal carbonate is first added and melted together with supplementary substances to form a modified melt, and the modified melt is then cooled at a temperature drop rate of 1°C or more to form a solidified product.

Then, by hydrothermally treating the kneaded assimilate with water or an aqueous alkali solution, it is possible to obtain a zeolitic composition from the slag.

The above-mentioned feeding conditions in the method of the present invention were selected after careful consideration of the composition, physicochemical properties, thermodynamic properties, etc. of the slab. Targeting the slag as a partial layer, by utilizing its sensible heat and fluidity, the added alkali metal carbonate and component supplementary substances are rapidly melted, and each component is uniformly dispersed in the slag in molecular or ionic form. The first condition is that carbonates or bicarbonates such as sodium and potassium are used as the alkali metal carbonates added to the molten slag, and the slag contains a quantitative proportion of these to the slab. The second condition is to set the molar ratio of Ca to 01 to 01, and if the molar ratio of Ca is less than 01, calcium silicate is removed in the hydrothermal treatment after cooling the modified melt in which the additive is melted. The production of system compounds will be the main one, and the production of zeolite structures will be the main focus. If the molar ratio with one of the two is a1 or more, when the modified melt is cooled, it becomes a transparent or translucent glassy solid regardless of the cooling rate fK, forming a several-order structure, and the zeolite structure due to subsequent hydrothermal treatment. It becomes virtually impossible to guide In addition, when general inorganic acid salts other than alkali metal salts such as sodium chloride, potassium sulfate, and sodium phosphate are added and melted in a reasonable amount to induce a zeolite structure. However, the above-mentioned uniform problems occur, and the effects brought about by adding a certain range of alkali metal carbonates in the method of the present invention cannot be expected.

The component supplementary substance added to the molten slag along with the alkali metal carbonate is an additive substance to supplement the missing constituent components necessary to induce the zeolite structure and to obtain the desired zeolitic composition. Specifically, powdered or granular sodium hydroxide, potassium hydroxide,
metal aluminum, aluminum hydroxide, metal silicon,
Silicon oxide, clay fist.

Feldspar, silica, etc. are listed, and in addition to these, Alζ
Red mud, fly asche, glass scraps, and other waste materials from children's industries can be used alone or in combination as appropriate. However, the addition amount of these component supplementary substances includes the components contained in the raw material slag and the components derived from the alkali metal carbonate, and the sum of each component in the entire system when the component supplementary substances are added is N as a molar ratio. a @ 0/5tOs (K@o/
5Lol)-Q Oh ~Q 3. &Os /A1m
It is desirable to set IIm so that Os=1 to 1h.

Regarding the above-mentioned application for addition of alkali metal carbonates and genus brownstone substances, there is no %KIIIJ approximately, and these can be added to the molten slag individually or in a mixed state, and by means such as stirring. It is preferable to promote its melting and homogenization of the dispersion of the components, provided that the melting section layer is carried out in such a way that the sensible heat and fluidity of the slag are not significantly moxibusted.

The modified flI fist obtained by melting m1lK as described above is completely different from molten slag both in terms of acid content and physical properties, and the type of product that can be induced into a zeolite structure by hydrothermal treatment is determined by the cooling conditions. I can't stand it. If wholesale cooling is slow, a brown arrangement of ions will occur during the cooling process,
This results in the formation of a chemically stable heterogeneous compound, and if the solidified material is hydrothermally treated after cooling, it becomes difficult to induce it into a zeolite structure.

According to the results of studies on this point, it is necessary to cool the modified melt at a rate of 1 1L falling at a rate of 50 C/we or more. It is a condition. / The solidified product cooled at the above cooling rate is amorphous and can be easily converted into a zeophytic composition by subjecting it to a normal hydrothermal treatment. In this hydrothermal treatment, in order to accelerate the reaction, it is desirable to refine the cooled and solidified material in an extremely fine step, and the hydrothermal treatment medium should be 2 to 16%
Water** such as sodium hydroxide, potassium hydroxide, sodium silicate, and sodium aluminate may be appropriately selected depending on the desired zeolite structure type 11, and an alkali metal as a supplementary substance for the above-mentioned components. When a hydroxide is used, depending on the amount added, a zeolite composition can be obtained by performing hydrothermal treatment with water alone.

Specific examples according to the present invention will be described below.

Example 1 A pulverized slag of 100 mesh or less (CaO: 411%) was placed in a cylindrical test melting furnace with an internal volume of 3 tons and a stirrer lined with magnesia-based refractories.

MsOs: 1 to 7% -&O Snow: JHL&I
G) 1- was charged and heated to 1460 C to melt the slag and reproduce the same condition as molten slag from a blast furnace.

While this state was maintained, the weighed alkali metal carbonate and component supplementary material were sequentially added, and the mixture was kept under stirring for 30 minutes to melt the additives.

Next, the content of the molten material in the melting furnace is 200-
The crucible was placed in a crucible made by Aluita, and this crucible was transferred to a separate box-shaped cooling tester with an exhaust device (contents α6J), and cold air or mist* droplets were blown toward the crucible under closed conditions. The crucible was cooled (cold air was used for gradual cooling, and sac-like water droplets were used for rapid cooling).To set the cooling conditions at this time, a thermocouple was placed in the crucible in advance and connected to the automatic temperature controller. [The indicated temperature and the temperature and amount of wind or b-shaped water droplets blown onto the crucible were matched to adjust the temperature drop of the molten material.After cooling, the solidified material f in the crucible was taken out, -
Grind it into 100 meshes, put it in a 2t autoclave, add %a% sodium hydroxide solution $@L2A,
6#f Sekisui heat treatment was performed at 200°C.

After the hydrothermal treatment, the contents of the autoclave were taken out, washed with water, and after drying, the composition and physical properties were measured.

That is, based on the above operations, the results obtained for the product compositions when the amount of alkali metal carbonate added and when the cooling rate of the intrinsic melt was varied are summarized in the following first group. As shown in Figure 1, all of the products according to the present invention have excellent ion adsorption performance.

It was confirmed that this was a preferable zeolitic composition.

Saishi 11z Processed according to the procedure of Example 1 described above.

The results obtained for the products produced when inorganic acid salts other than alkali metal carbonates are used and when the types of supplementary substances are changed are summarized in the following second group.
In the table, experiment numbers . and . indicate that b-potassium hydroxide water was used as the hydrothermal treatment medium. Experiment numbers according to the present invention and . . . all have excellent ion adsorption performance.

According to the present invention as explained above, a zeolitic composition can be efficiently produced from blast furnace slag,
This invention is industrially very effective because it makes effective use of resources and energy and achieves desirable high added value.

Patent applicant: Nippon Kokan Co., Ltd. Inventor: Toshi Kasuya
Shigeo Oshige 103-

Claims (1)

[Claims] The alkali metal carbonate in the molten blast furnace slag in a molar ratio of 01 to 03 Ca contained in the axillary blast furnace slag is added together with component supplementary substances and melted to form a modified melt, followed by #denaturation. 1. A method for producing a zeolitic composition, which comprises cooling a molten material at a temperature drop rate of 60° C. or more per second to form a solidified material, and then hydrothermally treating the solidified material with water or an aqueous alkali solution.