JPS6088400A - Method of solidifying silicon carbide - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a method for assimilating silicon carbide.

Radioactive 1 waste incinerators are equipped with a secondary combustion chamber to completely burn the unburned materials from the primary combustion chamber.
This secondary combustion chamber is filled with silicon ash, which is stable even at the temperature of porous C, in order to filter unburned substances in the exhaust gas and burn the unburned substances on its surface. If this silicon carbide is used for a long period of time, ash etc. will seep into the gaps and the efficiency will decrease, so it will last for half a year. Conventionally, the silicon ash recovered during this exchange was packed into drums as radioactive 1j'6 waste and subjected to fV'W. However, as the number of empty drums has increased recently, the poor filling rate of silicon ash into the drums has become noticeable, and when the drums are torn, the silicon ash and the ash packed together with the drums have become conspicuous. There was a problem that the particles would scatter.

The purpose of the present invention is to solve such problems by mixing silicon carbide, sodium sulfate, and clay whose main components are acidic acid ζ This objective is achieved by providing a method for assimilating silicon carbide, in which the generated glassy substance is poured into a container and gradually cooled to form a vitreous solidified body. , silicon ash can be made into a glass assimilate that is strong, heat resistant, I/-1 water soluble, and can improve the filling rate into the container a, as well as prevent damage to the container even if it is broken. Also, there is no need to scatter silicon ash or ash at all.

The method of the present invention will be explained in detail below with reference to one embodiment.

In the figure, (1) is silicon carbide recovered from the secondary combustion chamber of a radioactive waste incinerator, and (2) is concentrated waste liquid generated from a nuclear power plant that is dried using a dryer (not shown). The obtained sodium sulfate, (3) is clay whose main component is silicon oxide, and (14), (5), and (6) are the respective storage hoppers. (7) is for each storage hopper (4+ (51(
A pulverizing mixer for pulverizing and mixing ash silicon (υ, sulfur) finished soda (2) and clay (3) supplied from 61 at a predetermined mixing ratio; This is a melting furnace that melts the mixed mixture (9) at high temperature. Akira is poured with the glassy substance αυ produced in the melting furnace (8),
This is an assimilation vessel for solidifying this, and it is inserted into the lehr (6) to gradually cool the glassy substance u11.

With this configuration, first, each storage hopper L4) (5)
Ashed silicon (υ, sodium sulfate (2) and clay (3) are extracted from L6) and supplied to the crushing mixer (7).The clay (3) used at this time is used to improve the columnar shape of the glass produced. About 20-30% At20.,CaO
It is desirable that it contains glass-forming atomized substances such as
In addition, to mix each substance, add 4 f#, acid soda (2) to 1, and add 1.2 to 1.2 to
1B is preferable, in which case silicon ash (1)
vitrification will not be successful unless it is less than half the weight of the clay (3).17 Next, these crushed mixtures are sifted in a crush mixer (7). At this time, since silicon carbide (1) is a pebble-sized lump, sufficient time is required for pulverization and mixing. If the grinding and mixing is insufficient, it will be difficult to form a homogeneous glass, so pouring will be necessary. Next, the pulverized mixture (5 J) is supplied to the melting furnace (8). As a heating method for the melting furnace (8), methods such as high frequency heating, microwave heating, Joule heating, etc. can be applied. Melting (mixture (9) in furnace (8)
causes the following reaction.

Na2SO,+n(Sio2+MOx)-HnS i
C+lO2-ma201IMOx ・(n-+4n)S
i02+SO2↑+lηC02↑Here, SiO-4
-MOx is clay, MOxv'1A1203, galley such as CaO, formed oxide, Na 20 ・nMOx ・C
n-1-+n) S102 produces glass Uυ. Ashed silicon (υ) forms 5I02 on the surface in air and does not decompose unless the temperature exceeds 2000'C, but according to the method of the present invention, 5I0 formed on the surface by heating.
2 reacts with Na25o4, so 1,200 "C8
Melt at 300°C. Furthermore, carbon contained in silicon carbide (1) acts as a super-priming agent for sodium sulfate (2), promoting the vitrification reaction. SO2,C generated by the reaction
Waste gas such as O2 is treated in an exhaust gas treatment facility (not shown). Next, the produced glassy substance O]) is poured into a solidification vessel (4) and gradually cooled in an annealing furnace (2) to form a glass assimilate. Next, I will give an experimental example.

<Experimental Example> A sample prepared by mixing 22% of silicon carbide (1), 2137% of sodium sulfate, and 41% of clay (3) by weight was melted in an electric melting furnace (8). Clay (3) containing 29% of stable oxide such as alumina was used. The kidney melting temperature was 1.200°C, and the mixture was melted for 2 hours. The produced glassy substance uI) was poured into a solidification container ttUK, and was slowly cooled in a slow cooling furnace @ for 5:11 hours. The composition of the glass thus obtained is! 1) 10259%, Na, 023%, stable oxide such as alumina 18%. Next, when applied to the prepared glass, the amount of alkali eluted was 22 mg. As a result, it was found that the glass produced had performance equivalent to or better than that of ordinary glass.

As described above, according to the method of the present invention, silicon ash can be made into a hard, heat-resistant, water-resistant glass assimilated material, and as a result,
It is possible to improve the filling rate of the container, and even if the container is torn, there is no need to scatter silicon ash, ash, etc. at all. In addition, the uninvented method was applied to ashed silicon recovered from the secondary combustion chamber of radioactive waste incineration and sizing waste liquid generated from a power plant. Sodium sulfate obtained by drying e! When applied to the treatment of silicon carbide, radioactive waste attached to silicon carbide can be assimilated using a silica sealed inside glass, and soda sulfate can also be treated, making it extremely effective. Furthermore, the produced glass assimilate has excellent water solubility resistance, is solid, and is resistant to heat, so it is stable for long-term storage and can be applied as a treatment for radioactive waste.

[Brief explanation of drawings]

Fig. 1 Seedlings are cured on the left side of Kiutsuji Akira 7. (1)...Silicon carbide, (2)...Soda sulfate, i
3)...Modern earth, (8)...K melting furnace, ([Il...
Solidification valley language, Uυ... glassy substance agent Morimoto
Yoshihiro

Claims (1)

[Claims] 1. Mix silicon ash, sodium sulfate, and clay mainly composed of silicon oxide, melt this mixture at high temperature in a melting furnace, pour the resulting glassy substance into a container, and gradually cool it. A method for assimilating silicon carbide by converting it into a glass l1ff product.