JPH08301638A - Solidification and materialization of kaolin powder with geopolymer - Google Patents

Abstract

PURPOSE: To simplify the production method by solidifying a sodium silicate aqueous solution and kaolin powder as raw materials at the ordinary temperature or in a steam-ageing state without calcining the kaolin powder. CONSTITUTION: For example, a sodium silicate aqueous solution in an amount of 42.9 pts.wt. kaolin powder in an amount of 51.4 pts.wt., potassium silicofluoride or blast-furnace water-granulated slag as a reaction accelerator in an amount of 5.7 pts.wt. based on the whole weight of the mixture are mixed, aged and solidified in air at room temperature for 28 days, and subsequently immersed in water for three days to obtain a specimen (A) from which unstable components are removed. Further, the specimen A is dried at room temperature for seven days to obtain a specimen (B). The specimen A has a flexural strength of 2.1-4.1MPa and a compression strength of 3.4-7.2MPa, and the specimen B has a flexural strength of 2.6-22.4MPa and a compression strength of 5.2-34.3MPa.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention uses an aqueous sodium silicate solution and kaolin powder as essential raw materials, uses potassium silicofluoride (K ₂ SiF ₆ ) or granulated blast furnace slag as a reaction accelerator, and solidifies by non-firing. Related to the materials manufactured by

[0002]

2. Description of the Related Art In order to solidify a kaolin powder without burning it into a material, the kaolin powder is once calcined and then solidified by using a cementitious solidifying agent such as gypsum and lime. When using a so-called geopolymer solution such as potassium silicate or sodium silicate, calcination is necessary, and sodium silicofluoride or amorphous silicic acid is added as a reaction accelerator. In the literature, Minutes of the 9th International Conference on Cement Chemistry, Volume 4, 671-677, 1992, anhydrous gypsum and slaked lime were used. In Volume 5, p. 505-511, sodium silicate and caustic soda solution are used, and kaolin is calcined and steam-cured. Ceramic Transaction, Volume 40, 247-256, 1994 uses potassium silicate, amorphous silicic acid anhydride, and sodium silicofluoride.

[0003]

Conventionally, in order to solidify kaolin powder using a geopolymer liquid without firing,
For the purpose of promoting the reaction, the kaolin-based powder had to be temporarily calcined at a temperature of around 800 ° C. In order to further accelerate the reaction, steam curing is generally performed, and sodium silicofluoride and silicic acid anhydride are added as reaction accelerators.

[0004]

According to the present invention, an aqueous solution of sodium silicate is used as a solidifying agent, and potassium silicofluoride or granulated blast furnace slag is used as a reaction accelerator, so that kaolin powder is not calcined. Solidify at room temperature to manufacture materials.

[0005]

[Function] The kaolin powder is used to manufacture materials that can be used as building materials.

[0006]

[Examples] Table 1 shows the chemical composition of the aqueous sodium silicate solution used.

[0007]

[Table 1]

Table 2 shows the chemical composition of the kaolin powder used.

[0009]

[Table 2]

According to the powder X-ray diffraction analysis, the constituent minerals of the present kaolin powder include kaolin and quite a lot of quartz.

The potassium silicofluoride used as the accelerator is pure chemical K ₂ SiF ₆ .

Table 3 shows the chemical composition of granulated blast furnace slag used as an accelerator.

[0013]

[Table 3]

The kaolin powder was used as it was, but for comparison, a calcined product which was heat-treated at 800 ° C. for 1 hour was also prepared.

Table 4 shows the physical properties of the raw materials.

[0016]

[Table 4]

Table 5 shows the mixing ratio of the raw materials.

[0018]

[Table 5]

Strength tests were carried out on the specimens A, B, C and D which were aged at room temperature for 28 days in air to solidify them, and then immersed in water for 3 days to remove unstable components (test W). Further, the same test was performed on the test piece thus treated in water, which was further dried at room temperature for 7 days (Test D).

Table 6 shows the results of the strength test.

[Table 6]

In order to investigate the reaction process, the fragments of the material after the strength test were analyzed by powder X-ray diffraction, and no crystalline reaction product was observed. Therefore, the reaction product is produced as an amorphous substance, and the high bending / compression strength ratio of this material suggests that an inorganic polymer, also known as a geopolymer, or a mineral polymer is produced.

[0022]

INDUSTRIAL APPLICABILITY According to the present invention, the kaolin powder is solidified into a material without being subjected to a calcination process, and since the manufacturing method is simple, it can be used in a large amount in building materials and the like.

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Claims (2)

[Claims] 1. A material obtained by solidifying an aqueous solution of sodium silicate and a kaolin powder as raw materials and curing at room temperature or steam. 2. A material obtained by adding potassium silicofluoride and / or granulated blast furnace slag as a reaction accelerator in addition to the two raw materials according to claim 1 and solidifying by room temperature curing or steam curing.