SU1763409A1 - Raw mixture for preparation of porous aggregate - Google Patents

Description

(21) 4821187/33 (22) 02.04.90 (46) 09/23/92. Bul № 35 (75) F. Yu. Ibadullaev, V. Yu. Askerov and A. R. Ga Gyla

(56) USSR Copyright Certificate Ms 1271841, cl. S 04 V 14/12, 1985. USSR Copyright Certificate No. 1065378, cl. From 04 To 14/12, 1982.

(54) RAW MATERIALS TO MAKE A POROUS FILLER (57) SUMMARY OF THE INVENTION: 15-20% by weight of the additive from an aerobic-stabilized mixture of fermented sludge from primary settlers and activated sludge from a biological wastewater treatment plant are introduced into the clay. Characteristics of expanded clay: density of 270 - 330 kg / m. strength 4.9 - 7.1 MPa. 1 tab.

The invention relates to the building materials industry and can be used to obtain porous aggregates, in particular, expanded clay.

The known raw material mixture for the production of aggregates from clay raw materials and additives, the composition of which uses sewage sludge from electroplating industry.

Closest to the proposed is a raw material mixture for the manufacture of a porous aggregate, including clay and the addition of activated sludge after the wastewater treatment industry.

A disadvantage of the known aggregate is the increased density and low strength.

The purpose of the invention is to increase the strength of the aggregate, reducing its density.

The additive used in the clay composition — an aerobic-stabilized mixture of fermented sludge from primary sedimentation tanks and active sludge from a biological wastewater treatment plant — is the end product of the combined treatment of two types of sediment formed during the treatment of urban wastewater. Of the total amount of precipitation formed, the share of precipitation of the primary settlers of the initial moisture content of 98.5% is 30–40%, and the proportion of activated sludge of the initial moisture content of 99.6% is 60-70%. At most large biological wastewater treatment plants, sludge is treated according to the technological scheme, which includes the following main steps: anaerobic digestion of raw sludge from primary sedimentation tanks, compaction of excess activated sludge from aeration tanks, aerobic stabilization of the mixture of fermented sediment of primary sedimentation tanks and compacted excess active sludge, dehydration stabilized sediment mixtures (on sludge beds or on mechanical dewatering devices). As a result of dehydration, an organo-mural mass is obtained with a moisture content of 77-82% with a dry matter concentration of 1.8–2.3 kg / m3 to be removed from treatment plants and disposed of or squeezed. The mineral part of the urban sewage sludge mixture is characterized by the following component composition, wt%:

with

WITH

XI about with

О Oh Yu

Si02 13-14,8; 12.3-14.1;

Rea Oz 12.1 - 13.8;

MgO 0.05-0.12; Ca04.3-5.8;

K20 0.76-0.81;

NaaO 0.56-1.3; 50z 3.8-4.1;

CrssO 8.3 - 9.2;

ZnO 6.3 - 7.8; CuO 6.8 - 7.4; NiO 5.4 - 6.2;

MnO 0.1-9.35; CdO 4.7-5.5,

ppt 12.7-19.2

The organic part of the precipitation mixture has the following component composition, wt.%: C 55.7, H 9.6, O 28.6, S 1.9, N 4.2.

Sewage sludge contains organic substances that burn out during firing, contributing to the porisation of the mass and thereby ensuring an even distribution of small closed pores, which lower the bulk density while maintaining the high strength of claydite granules. The sediments also contain heavy metal oxides, the presence of which has a positive effect on the strength properties of the resulting claydite. Uniformly distributed colloidal compounds of heavy metals envelop and glue the particles of the raw material mixture, and during firing on the surface of the clay granules as a result of the interaction of ions of metal compounds with clay particles, a metal-like solid film is formed.

Example. Prepare a raw material mixture of clay raw material and additives.

The normal molding moisture of the raw material mixture (19–22%) with the indicated ratio of components is reached at a moisture content of clay raw material of 7–9% (natural composition of the raw mix and technical indicators of porous aggregates

Venn clay moisture in the quarry during the summer-autumn period) and moisture content of the additive 77 - 82% (humidity of the precipitation mixture after dehydration). Under production conditions, the raw material mixture is prepared in a clay mixer, where the additive is introduced, and then in a perforated processing roll. Raw granules are formed in a perforated forming roll. The drying of the raw granules is carried out in a tumble dryer for 20 minutes. at the inlet gas temperature of 400–450 ° C and at the outlet of 120–200 ° C. The prepared granules are roasted in rotary kilns for 30 minutes. at the temperature of the material in the zone of expansion 1150 - 1170 ° С. Claydite is cooled in a free-flow-bed cooler with a material passage time of 35 minutes.

The properties of the resulting aggregate (expanded clay) are presented in the table.

Claims (1)

Expanded clay has a density in the piece of 270 - 330 kg / m3 and strength of 4.9 - 7.1 MPa. The raw material mixture for the manufacture of a porous aggregate, including clay and an additive, characterized in that, in order to increase the strength of the aggregate and reduce its density, it contains as an additive an aerobic-stabilized mixture of fermented sediment of primary sedimentation tanks and active sludge of the biological treatment plant wastewater in the following ratio, wt.%: clay80 - 85 specified supplement15-20 Table continuation