SU1761719A1 - Composition for production of pressed building materials - Google Patents

Abstract

Use: in construction. SUBSTANCE: composition for the manufacture of building materials, comprising in wt.%: Magnesium oxide 10-25; wood waste 38 -45; calcium carbonate 15-29; low basic silicates and / or calcium aluminates 2.0-1.0; an aqueous solution of magnesium chloride with a density of 1.18-1.2 g / cm 5 is the total. The composition is prepared by mixing the indicated components. Water absorption,% -3.0, swelling;% - 0.13. 1 tab.

Description

The invention relates to compositions based on magnesia binder and wood waste, intended for the manufacture of pressed billets for construction purposes.

A composition based on caustic magnesite and woody finely divided materials is known. This composition is characterized by slow curing, as well as a large bulk density, and therefore cannot be used as a construction material.

A composition for the manufacture of a compressed structural bar from caustic magnesite, magnesium chloride and wood waste is also known.

The known composition with a good level of physicomechanical properties has a high level of water absorption and swelling, which hinders its use in certain conditions.

The aim of the invention is to reduce water absorption and reduce swelling.

This goal is achieved in that the composition for the manufacture of extruded building materials, including magnesium oxide, wood waste and an aqueous solution of magnesium chloride with a density of 1.18-1.20 g / cm, additionally contains calcium carbonate and low-base silicates and / or calcium aluminates at the following the ratio of components, wt.%;

Magnesium oxide 10-25

Wood waste38 - 45

Calcium carbonate 15-29

Low basic silicates and / or calcium aluminates

Water solution

magnesium chloride,

density

1.18-1.20 g / cm3

As an aqueous solution of chloride

magnesium is used bischofite solution

density of 1.18 - 1.20 g / cm3. Technical magnesium bischofite chloride GOST 775973.

The effect of reducing water absorption and, as a result, reducing the swelling of the composite material, is associated with

2-10

Rest

J

Vj

About v4

YU

the formation of poorly soluble solidification structures due to the hydration interaction of silicates and calcium aluminates, as well as calcium carbonate in the medium of aqueous solutions of magnesium salts.

The interaction in such systems leads to the formation of compounds such as calcium hydroxochlorides, hydrocarbon-aluminates and calcium carbosilicates. The formation of these compounds reduces the total solubility of the substance, increases the density of the structure, which probably reduces the water absorption and swelling of the material.

The invention is illustrated by the following examples of specific embodiments (Table 1).

1. The composition is prepared by mixing magnesium oxide, calcium carbonate, silicates and low-base calcium aluminates, bischofite and wood waste in the ratio indicated in Table 1 (number of Example 1).

2-5. Compositions are prepared analogously to example 1 with a different ratio of components (numbers of examples 2-5).

6. The composition is prepared by mixing caustic magnesite (GOST 7759-73), natural limestone, products of low-temperature roasting of the charge, composed of limestone and rocks containing clay minerals and designed to produce low-base silicates and calcium aluminates, sawdust and bischofite in the ratio indicated in Example 6 (Table 1).

7.8. The composition is prepared analogously to example 6 with a different ratio of components (number of examples 7.8).

9. The composition is prepared by mixing the product of special calcination of natural calcium-magnesium rocks, providing in the finished product the presence of magnesium oxide, calcium carbonate and low-base silicates and calcium aluminates, forest waste and bischofite in the ratio specified in Example 9 (Table 1) .

10. The composition is prepared by mixing caustic magnesite of hydraulic lime containing low basic calcium silicates and calcium aluminates, limestone, wood waste and bischofite in the ratio indicated in Example 10 (Table 1).

11. The composition is prepared analogously to example No. 10 with a different ratio of components (number of example 11).

12.13. The composition is prepared analogously to example 1 with a different ratio of components (numbers of examples 12 and 13).

From the above examples, it is clear that the exorbitant compositions of 4.5 and 12 have the worst performance compared with the prototype. Beyond the composition number 13 gives high rates, but with a decrease in the amount of wood waste significantly increases the weight of the product, which is unacceptable for building blanks. Therefore, it is advisable to limit the lower limit to wood waste 38 wt.% When the bulk weight of the workpiece 1 2 g / cm3.

Claims (1)

Claims of the Invention Composition for the manufacture of extruded building materials, including magnesium oxide, wood waste, and an aqueous solution of magnesium chloride with a density of 1.18-1.20 g / cm. It is characterized in that, in order to reduce water absorption and reduce swelling, it also contains carbonate. calcium and low basic silicates and / or calcium aluminates in the following ratio of components, wt,%: magnesium oxide - 10 - 25: wood waste-38-45; calcium carbonate -15-29; low basic silicates and / or calcium aluminates -2.0-10.0; water solution of magnesium chloride density .3 1.18-1.20 g / cm4 - the rest. Examples of compositions confirming the invention (prototype) Magnum oxide Carbonate eltsi Niekosusuvnye calcium silicates CnS Bishofit solution Wood waste Magnesium oxide Calcium carbonate Low-basic calcium aluminates CmA Bishofit solution Wood waste Magnesium oxide Calcium carbonate Low basic calcium silicates Bishofit solution Wood waste in magnesium oxide Calcium carbonate Low basic calcium silicates SP3 Biiyufit solution Wood waste Magnesium oxide Calcium carbonate Low-base calcium aluminates C „A Bishofit solution Wood waste Caustic magnesite Known to Calcium CnS Calcium Silicates Biiyufit solution Wood waste Caustic magnesite Known to Low-base calcium silicates and aluminates Rastaor bischofite Wood waste Caustic magnesite Known to Low-basic calcium aluminates Bishofit solution Wood waste Burnt Dolomite Bishofit Solution Wood Sawdust Caustic magnesite Hydrated lime Known to Bishofit solution Sawdust Caustic magnesite Hydrated lime Known to Bishofit solution Sawdust  Magnesium oxide Calcium carbonate Calcium low calcium silicates CnS Bishofit solution Wood waste 13. Magnesium oxide Calcium Carbonate Low basic aluminates calcium Biiyufit solution Wood waste ten 25 14 29 13 17 32.5 26 ten 17 25 ten 12 15 THAT 20 29 nineteen 1st 29 nineteen 2k sixteen ten 1.5 2.5 2.0 ten 2.0 18 k 38 kZ 6-U0.15-1.010-19 5.60,611 3,00,1318 50.1716 161,138 Beyond composition 46 151.05 12 Beyond composition 13 5.80,7 18 5,40,2 14 18 k0.15 sixteen 18 50.16 17 18 5.70.5 14 18 5.9 0.9 9.41.02 Beyond composition k 37 3.2 0.25 nineteen Extreme composition, with a decrease in the amount of wood waste increases bulk weight