JPS5964563A - Manufacture of lightweight formed body - 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 an advantageous method for producing lightweight molded bodies using sludge generated in water treatment plants.

Conventionally, lightweight molded bodies used as insulation materials, lightweight building materials, etc. are made of calcium silicate (+-bamolyl-) produced from lime and silica sand as raw materials. Since this lightweight molded body is consumed in large quantities, it is particularly desirable to use Ansen 1, but since the raw material is a sea urchin natural product, it is difficult to reduce the manufacturing cost any further. My sister is in trouble.

Incidentally, a large amount of sludge is generated at water treatment plants, and with the progress of urbanization, it is currently becoming difficult to secure a landfill site to dispose of the sludge.

Therefore, the present invention was made for the purpose of effectively utilizing sludge generated in water purification plants and providing an inexpensive lightweight molded body. After adding calcareous material, water glass and silicic acid material to field sludge and causing a hydrothermal reaction in the presence of water,
It is characterized by being molded.

Hereinafter, the configuration of the present invention will be explained in detail.

The water treatment plant sludge used in the present invention is sludge generated when treating sewage at a water treatment plant, and is in the form of a dehydrated cake,
They are in various forms such as concentration tank slurry and dried products of each of these. This sludge generally has an alumina content of 20 to 3
It contains 5 to 10% by weight of iron oxide.

Furthermore, the calcareous substance used in the present invention is quicklime (Ca
b) or slaked lime (Ca(oH)2), and the water glass is a sodium silicate aqueous solution, commercially available water glass; No. 3 is preferred. The silicic material is, for example, silica sand.

Note that, as mentioned above, silicic acid cal/rum (tomomolite) can be produced by reacting lime and silica sand, but in this case, if the above water treatment plant sludge is used in addition to lime and silica sand, its alumina content will be reduced. It also causes side reactions in the reaction between iron oxide or lime and silica sand, which inhibits the formation of good calcium silicate crystals. In order to improve this point, water glass is used in the present invention, and as a result of the inventors' diligent efforts, the addition of water glass significantly reduces the interfering effects of alumina and iron oxide, and the calcium silicate This is due to the discovery that it promotes the formation of crystals. This is clear from the diagram showing the effect of water glass addition on the bulk specific gravity of the molded article.

In the present invention, a calcareous substance, water glass, and a silicic acid substance are added to water treatment plant sludge and subjected to a hydrothermal reaction in the presence of water, but the addition meter in this case is not particularly limited. , 70 parts by weight of water treatment plant sludge (dry matter basis), 30 to 501 parts of calcareous material, 10 to 90 parts of hydraulic glass (preferably No. 3 water glass), 5 to 5 parts of silicic material.
The amount may be 20 parts by weight. Also, water is 1% of the weight of solid matter.
A difference of 0 times or more is good. The amount of water glass added varies depending on the amount of lime, but water glass No. 3 is 40~
65 parts by weight is optimal. Regarding the amount of water, when using the thickener sludge directly, as a pretreatment, heat it at 130°C or higher for 30 minutes in the presence of water less than 4 times the weight of the solids to foam, and then Just add water to make it more than 10 times the volume. When using sludge that has been pulverized after drying, foaming is not necessary, so the amount of water is 1% of the weight of the solids.
It is good if it is 0 times or more. The hydrothermal reaction may be carried out in an autoclave with stirring. The hydrothermal temperature is 170°C or higher, preferably around 180°C, and the hydrothermal time is 4 hours or more, preferably about 8 hours. The reaction product after the hydrothermal treatment can be left as is, or it can be shaped into a desired shape after adding fibers or fibers such as asbestos or glass fiber for reinforcement. After molding, it is preferable to dry at a temperature of 100°C or higher.

Examples are illustrated below.

Example 1 Thickening tank sludge 80 heavy bullets (dry matter), (semi-), 50 parts by weight of quicklime, 10 parts by weight of silica sand, 27 parts by weight of water glass No. 3, 2 parts by weight of water
800 parts by weight were subjected to a hydrothermal reaction in an autoclave at 180°C for 8 hours. The reactant was pressure molded at a pressure of 15 Kg/c1 to give a ftff 4N molded body with a bulk specific gravity of 0.35.

Example 2 Thickening tank sludge was dried at 450°C and pulverized for about 15 hours using a porcelain sit mill. 70 parts by weight of sludge (40 parts by weight of quicklime, 10 parts by weight of silica sand, No. 3 water glass in dry matter^ (semi)) 40 parts by weight and 2400 parts by weight of water were mixed and hydrothermally treated at 180°C for 18 hours in an autoclave.
5 and '7/[ to obtain a lightweight molded product with a force/force specific gravity of 0.25.

Example 3 Thickening tank sludge was dried at 450°C and pulverized for 10 hours using a Sitsu mill made by 1. 65 parts by weight of Shirasu No. 1 and 2,500 parts by weight of water were subjected to hydrothermal treatment at 180°C in a 4:1 autoclave. After the reaction, 10 parts of asbestos by weight were mixed into the material, and the mixture was subjected to Calorie pressure molding at 15 K9/cnf to obtain a lightweight molded product with a bulk specific gravity of 030.

[Brief explanation of drawings]

The figure is an explanatory diagram that graphically shows the influence of water glass addition 11 on the bulk specific gravity of a molded article. Agent Patent Attorney Isamu Ogawa − Patent Attorney Ken Noguchi Patent Attorney Kazuhiko Saishita

Claims (1)

[Claims] A method for producing a lightweight molded body, which comprises adding a calcareous substance, water glass, and a silicic acid substance to water treatment plant sludge, causing a hydrothermal reaction in the presence of water, and then molding the mixture.