SU903333A1 - Composition for extrusive moulding of gypsum articles - Google Patents

Description

(54) COMPOSITION FOR EXTRUSION FORMING OF PLASTER PRODUCTS

The invention relates to building materials, namely, compositions used for the extrusion molding of gypsum-based articles.

It is known to have 1, which includes gypsum hemihydrate, a narinizer — quartz sand, plasticizer — a derivative of cellulose, reinforcing fibers, and adhesives of animal origin as retarding agents of gypsum in the following ratio of components, wt.%:

Gypsum 35-65

Quartz sand 35-50 Derivatives of cellulose 0, 2-0,8 Reinforcing fibers 2-8 Klevmtsie animal matter

of origin up to 15 The disadvantage of the above composition, the raw mix is the need to use high-grade gypsum in the market and a large number of special additives - adhesives of animal origin, plasticizing the mixture and slowing it down to ensure the required technological characteristics.

The closest to the proposed is a mixture comprising 50-95% of gypsum - hemihydrate of a specially selected fractional composition 5. (specific surface 2500-5000 cm / g, dispersion factor not less than 4.6), 0-4% quicklime, 0 -45% young limestone and 0.05-0.5% cellulose ether. To adjust the setting time, it is recommended to add 0.15-0.25% crushed animal glue and 0-5% ground gypsum stone, as well as tartaric acid 2 to the composition.

The disadvantages of the above composition are the need to use high-grade plaster in a treadmill and special selection of its fractional composition, as well as the use of special additives to adjust the setting time. These additives are scarce, and are sensitive to processing during formation (mechanical, chafing of the mass dramatically reduces the retarding efficiency of such compounds).

The purpose of the invention is to increase the strength and toughness and reduce the cost of the composition.

The goal is achieved by the fact that the composition for extrusion molding of gypsum products, including gypsum in a binder, sand, -dispersed fiber, methyl de pulp, slaked lime and an additive, as a binder, contains a -.- phospho-L-hydrate as an additive, potassium nitrate, or potassium chloride, or potassium sulfate in the following ratio of componenton, wt%: oi-phosphono-hemihydrate

Calcium sulfate 60.0-90.0 Sand4.0-15.0

Dispersed fibers 1.0-30.0 Methylcellulose 0.2-1.0 Slaked lime 0.5-6.0 Potassium hydroxide or potassium nitrate,

or potassium chloride ,.

or potassium sulfate 0.5-4.0 The ratio of calcium hydroxide and one of potassium salts or its hydroxide 1: 1 - 1: 3 with a total content of the complex additive in the mixture in the range from 1 to 10% provides a non-additive effect of its components on activating hardening and stabilization of the phosphogypsum seizure time - semi-known to the ground sand. Asbestos Clay bone Lime is quenched. Potassium sulfate Me ty of tsel tsell l Julo z and the Plaster stone ground Acid vinna

hydrate within the required limits and allows to obtain products with a sufficiently high strength.

The molding paste is prepared by mixing a thoroughly mixed mixture of all the above components with water or a mixture of phosphogypsum, filler and fibers with an aqueous solution of additives.

The amount of water is chosen so as to obtain a paste-like paste of the desired consistency, with a relative humidity of 20-30%,

An example. Phosphogypsum hemihydrate is mixed with sand, fibrous material and methylcellulose. Water is added to the resulting mixture with potassium salts previously dissolved in it and suspended calcium hydroxide. The plastic mass thus obtained is extruded on a screw press. Extruded samples harden in the open air (under normal conditions) for 24 hours, then they are dried to constant weight with bo for 4-6 hours.

Specific examples of the composition are given in table. one.

Table 1 24.8924.64 0.20.2 0.80.8 0.250.5 0.83 0.83 0.03 0.03 3 3 Samples of Ijr2vl3 size are formed from the above compositions using a piston viscometer cm.

Timing of the seizure

mixes

Start

end

The output of samples from the mixture,%

Foimueti indicator

Flexural strength, MPa

Shock viscosity

2 kJ / m

Compounds 1, 2, and 3 do not detect from; Compositions 4 and 5 have a good surface finish in Te ieHHe 35, without defects. 2 dry Samples made from table. 3 shows the composition

compounds 1, 2 and 3, have on the surface-comprising various components,

These grid cracks and bitten, image-additive, and properties of samples from them. Thus, the composition for the extrusions of the plaster molding molding is 65

12 10 10 3 3

5 4,2

48 69 92

36 46

0.27 0.55 0.57 1.2 1.8

1.1 2.4 2.7 12.3 13.6

0.63 0.77 0.66 0.9 0.95

Table 3 Formation parameters and properties of the samples are given in Table. 2. Table2 provides - an increase of 1.5-3 times as compared to

an increase in impact strength of 30–35%, a reduction in cost by a factor of 2–3.

Claims (2)

1. The patent of Switzerland No. 454722, cl. 80 on 6/04, 04/06/1963. 2. The patent of France 1597214, cl. From 04 To 11/09, 1970.