SU1730072A1 - Method of producing anhydrite binder - Google Patents

Abstract

The invention can find application in the building materials industry. The method of obtaining anhydrite in zhu-. It involves mixing the gypsum-containing and fluorine-containing components, followed by calcining the raw material mixture and grinding, with fluorosilicic acid, which is neutralized with lime suspension to pH 8-10, followed by concentration of the neutralization product with T: F 1: 4-1: 5 in the following ratio of components of the raw mix, wt.%: gypsum-containing component 90-98; fluorine-containing component (in terms of dry substance) 2-10. In this case, calcium sulfate phosphotonegidrate can be used as a gypsum-containing component. The coefficient of water resistance anhydrite in the shear 0.9.2 table.

Description

The invention relates to the production of building materials, namely to the production of anhydrite hardening based on phosphogypsum.

 The purpose of the invention is to eliminate the high formation and increase the water resistance of anhydrite resin.

To carry out this method of obtaining an anhydrite grit, raw sludge based on phosphogypsum and a fluorine-containing component is prepared. The chemical compositions of the initial raw materials are given in table. one.

The fluorinated component is prepared as follows. .

Fluorosilicic acid with a concentration of 1-12% is neutralized with an excess of lime suspension containing 40-60% CaCO3 (calculated on the dry matter).

Fluorosilicic acid is a waste product of mineral fertilizers and is formed as a result of absorption of waste fluorine-containing gases. The chemical composition of the neutralization product is given in table. one.

The neutralized fluorine-containing component having a humidity of 94-96%. sent to the tank for deposition. After 12 hours, during which time

the precipitation, the clarified water is pumped out, and the suspension of the fluorine-containing component, having a moisture content of 80-85%, is directed to the preparation of the raw sludge. Raw sludge is prepared by mixing phosphogypsum and fluorine-containing component, the amount of which varies from 2 to 10 wt.% (Calculated on the dry matter). The prepared raw sludge is fed to the calcining in a rotary kiln at 800-1000 ° C. The resulting clinker is ground to a specific surface area of 300 m2 / kg. The mineralogical composition of clinker is as follows, wt%: CaS04 80-95; Sar2 2-8; CaOSiOa 1-5; .2 CaOSi021-5; Saz (ROF 0.5-1; CaO 0.5-1.

With the introduction of the fluorine-containing component in the slurry slurry less than 2 wt.% (In terms of dry substance), after firing, poorly treated clinker with low hydraulic activity is obtained.

With an increase in the content of the fluorine-containing component in the raw sludge over 10 May. % (in terms of dry substance) during calcination, an excess amount of melt appears, which leads to calcification in the rotary kiln. As a result of cooling of the clinker, the melt which has hardened as a glass phase impairs the quality of the slurry, the setting time is prolonged and its brand strength is reduced.

In this case, as a result of roasting, no water-soluble products are formed, which increases the water resistance of the substance and leads to the absence of efflorescence on the surface of the products.

One of the largest energy expenditures in the preparation of an anhydrite host is the cost of phosphogypsum dehydration and evaporation of crystallization water. These energy costs make up about 20% of the total.

In order to save fuel, it is proposed to use phospho-hemihydrate instead of phosphogypsum dihydrate in the production of anhydrite as a main raw material component.

The energy consumption for the dehydration of phosphogypsum dihydrate to amhydrite is 145 kcal / kg, and the energy consumption for the dehydration of phosphohemihydrate to anhydrite is 35 kcal / kg.

Saving energy from replacing phosphogyptic sagdihydrate with phospho-hemihydrate will be:

3i 145-35 110kkal / kg

 1.10-10 kcal / t.

 From the anhydrite to the slurry, sample beams of 4x4x16 cm are formed, from a solution of a rigid consistency into the slant: sand - 1: 3. Samples are stored in air and air-wet conditions. Coef. The water resistance rate is determined on the 28th day of air-wet hardening and is taken as the ratio of the compressive strength of the water-saturated samples to the compressive strength of the samples solidified under the air-wet conditions.

The effervescence is determined visually on samples stored under air conditions.

The results of all tests are given in table. 2

The anhydrite suspension obtained by the proposed method is characterized by short setting times - start not earlier than 15 minutes, end no later than 180 minutes, low water demand - 20-23%, high brand strength - compressive strength for 28 days of air-moisture hardening of the samples. -spins made from a 1: 3 solution with sand, was 48.0-51.0 MPa, with a bend of 9.0-11.0 MPa.

On samples made by the proposed method, no efflorescence is formed; their water resistance coefficient is 0.8–0.9.

These properties extend the field of application to a visitor, allowing it to be used in plastering solutions, in bases under linoleum, for the manufacture of artificial marble both in ordinary rooms and in rooms with high humidity.

Claims (2)

1. The method of obtaining anhydrite in the gutter by preparing the raw mixture by mixing the gypsum-containing and fluorine-containing components, followed by roasting and grinding, characterized in that Neftoristo native acid, which is previously neutralized with lime suspension to a pH of 8-10, followed by concentration of the obtained product to T: W from 1: 4 to 1: 5 in the following ratio of components of the raw mix, wt.%: Gypsum-containing component 90-98. Fluorine-containing component (in terms of dry substance) 2-10 2. A method for producing an anhydrite stranger according to claim 1, characterized in that. 51730072b that, in order to reduce energy costs, as calcium phosphate hemihydrate, the calcium of the gypsum-containing component is .Table 1 - Table 2 The ratio of solid: liquid fluorine-containing component is 1; 4-1: 5 Continued table. 2