section Home Production, Amateur Radio amateur Model aircraft, rocket- Useful, entertaining	Stealth master Electronics Physics Technologies invention	space Mystery Earth Mysteries Secrets of the Ocean Stealth section Map
Use of material is permitted for reference (for websites - hyperlinks)

INVENTION
Russian Federation Patent RU2290380

Composition based on a magnesia astringent

Name of the inventor: Kramar Lyudmila (RU); Nuzhdin Sergey (RU); Trofimov Boris Y.
The name of the patentee: Kramar Lyudmila (RU); Nuzhdin Sergey (RU); Trofimov Boris Y.
Address for correspondence: 454016, Chelyabinsk, st. Tchaikovsky, 185, kv.503, LY Kramar
Starting date of the patent: 2005.07.27

The invention relates to the construction materials industry and can be used to produce cast mixtures for the manufacture of decorative plates and panels, parapet boards, stair steps and the device monolithic structures and floors, but also in the production of dry mixtures, designed for interior and exterior of buildings and structures. The technical result - increasing resistance to cracking products on a magnesia astringent while providing both water resistance and strength required. Composition based on magnesia binder contains, in wt.%: 10-30 caustic magnesite, 0.7-1.4 active mineral additive, fine magnesium hydrosilicate 0,35-0,95 aqueous solution of magnesium chloride density 1,2-1 25 g / cm ³ - 30-35, NaCl 0,3-0,6, MeCl, where ^Me - K + or ^Li +, or 4 0.3-0.6, filler - rest.

DESCRIPTION OF THE INVENTION

The invention relates to the building materials industry and can be used to produce cast mixtures manufacturing finishing plates and panels, parapet slabs, stairs and apparatus monolithic structures and floors, but also the production of dry mixtures intended for interior and exterior finishing of buildings .

It is known that obtaining a high-strength and frost-resistant materials and products based on magnesia binder and magnesium chloride (less magnesium sulfate or iron sulfate) together with organic and mineral aggregates impossible without modifying additives, with preference given to active and other mineral additives, such as silica fume, slag smelting industry and micronized minerals (SI Kilesso Decorative concrete in architecture - M .: Stroyizdat 1941, p.66;.. B. Schulze, B. Tisher and other solutions and concrete on netsementnyh binders -. M .: Stroyizdat, 1990, s.223-228).

Special magnesia binder, is strictly regulated structure and quality, in our country are not currently made for building purposes. Producing caustic magnesite brand PMC-75 is a byproduct of the production of periclase refractories at the combine "Magnesite" g.Satka. Experience with this binding indicates that based articles often have a tendency to crack. This, first of all, due to the presence of variable amounts of a binder burnout magnesium oxide - periclase. As a result of the hydration of the binder in the hardened magnesian stone remain unreacted grains of periclase, which later in the formed stone attached water to form magnesium hydroxide, which leads to a significant increase in these grains, the appearance of internal stresses and cracking after three months, six months and sometimes in a year.

For the formation of magnesia stone structure, not prone to cracking, it is necessary to accelerate the hydration of periclase in the early stages of hardening of the binder, which is possible with the application of heat treatment or administration of activators additives.

Known raw moldable mixture on the basis of a magnesia astringent (RU 2114087, C 04 B 35/05, 9/00, 06.27.1998), which has the following composition: wt% caustic magnesite 25.2 ... 27.0;. ground granulated blast furnace slag basic ... 30.1 31.75; unmilled iron waste blast furnace (blast furnace dust or sludge gas purification) 4.20 ... 9.34; bischofite solution density of 1.3 g / cm ³ 32.77 ... 37.6; mullite-siliceous wool 0.94 ... 1.1.

Undoubtedly, the advantage of this mixture are its high strength characteristics in compression and bending, adhesion to steel and other materials, and dimensional stability and hardening.

However, the invention does not discuss data on water resistance and tendency to cracking of the material obtained after hardening.

Known raw mixture (RU 2130437 C1, 20.05.1999) containing, by mass% caustic magnesite 15 ... 21.5;. ground granulated blast furnace slag basic 24.0 ... 28.5; milled flue dust or sludge gas cleaning blast furnaces 9 ... 30; bischofite solution density of 1.3 g / cm ³ 9.30 ... 11.16; aluminosilicate additive 1 ... 5, and water.

This mixture is sufficiently water resistant, has a high performance mobility, viability and compressive strength.

However, the mixture has a longer initial setting time - from 21 to 28 hours at 20 ° C. This increases the commissioning dates of products require additional care mixture. Furthermore, there is no information about the tendency to cracking of the mixture obtained from the material.

Known raw moldable mixture on the basis of a magnesia astringent (RU 2062763, C 04 B 28/30, 9/00, 15.07.1993), which has the following composition in parts by weight of caustic magnesite .: 1 ... 1.5; wood sawdust ... 2.8 3.3; magnesium chloride brine carnallite production density 1,2-1,25 g / cm ³ 1,4 ... 1,9; kaolin 0.04 ... 0.08; polyorganosiloxane 0.01 ... 0.03; ultramarine blue 0.03 ... 0.07.

Undoubtedly, the advantage of this mixture are its high strength properties under compression, water resistance, adhesion to steel and other materials, and dimensional stability and hardening.

However, in this invention, and are not discussed data obtained propensity to cracking after hardening material, dimensional stability and does not guarantee the absence of cracks in the material during operation.

Known compositions based on magnesia binder (RU 2238251 C2, C 04 B 28/30, 29.07.2002) containing, wt.%: Caustic magnesite 15 ... 30, ground granulated blast furnace slag basic 1.0 ... 3, 5, a magnesium hydrosilicate 1.3 ... 3.5, a solution of magnesium chloride density 1,18-1,26 g / cm ³ and 10 ... 25 filler.

This composition has high water resistance, has high rates of frost resistance and compressive strength.

However, the products based on this composition may be prone to cracking in the presence of a substantial amount of binder periclase.

The closest the technical essence to the claimed invention is a composition according to the patent RU 2246464 C2, C 04 B 28/30, 20.06.2003, containing, by mass% caustic magnesite 20 ... 30;. a highly amorphous silica 1.5 ... 4.5; magnesium hydrosilicate 1.0 ... 3.5; magnesium chloride solution density of 1.2 ... 1.25 g / cm ³ and of 15 ... 25 filler.

This composition has high water resistance, has high rates of frost resistance and compressive strength.

However, the products based on this composition may be prone to cracking due to hydration of the unreacted higher periclase included in caustic magnesite.

The tendency to cracking of materials based on magnesia binder along with water resistance and frost resistance is the main characteristic that determines the longevity and area of ​​application materials.

The invention solves the problem of eliminating the propensity to cracking products on a magnesia astringent while ensuring water resistance and strength required by the directed formation of complex structures by introducing modifying additives.

This is achieved in that the composition is a magnesia-based binder comprises a caustic magnesite active mineral supplement, magnesium hydrosilicate, a mixing - an aqueous solution of magnesium chloride (bishofit) density of 1.20 ... 1.25 g / cm ^3, and a filler, with a mixing It includes modifying the complex of alkali metal chlorides total content 8 ... 12% by weight of magnesium chloride, in the following ratio, wt.%:

. The content of caustic magnesite 10 ... 30 wt% of active mineral additives (in which quality can be used silica fume or blast furnace slag powder basic) 0.7 ... 1.4% by weight of magnesium silicate -. 0.35 of builder 0.95 ... and aggregate within these limits is necessary and sufficient to produce a water-resistant, cold-resistant structure with the required strength.

The content of the modified solution of magnesium chloride density of 1.20 ... 1.25 g / cm ³ in an amount of 30 ... 35 wt.% Is necessary and sufficient to create a workable mixture and obtaining further waterproof and durable system. Fewer in its composition will lead to an undesirable decrease in mobility mixture, and more - and unnecessarily increase the cost of mobility, resulting in reduced strength and increased porosity due to air entrainment and separation processes. Besides it leads to considerable shrinkage and vysoloobrazovaniyu material.

The content in a mixing of the two chlorides complex supplements in the specified amounts (0.3 ... 0.6) is necessary and sufficient to generate a magnesia stone structure, not prone to cracking in service. Fewer their composition is insufficient to produce the desired effect, and more - will reduce the strength, increased shrinkage phenomena vysoloobrazovaniyu hygroscopicity.

Chloride additives operate with one hand the role of periclase hydration activator contained in caustic magnesite, and on the other - form magnesia stone structure, different low crystallinity that allows to relax internal stresses in the material arising from ongoing hydration.

For these purposes, a mixing of the magnesia binder, we propose to introduce a complex of two chloride supplementation with active cations ^{Na +, K +, Li +} , NH ₄^+.

Additives complex is a combination of NaCl + KCl, NaCl + LiCl, NaCl + NH ₄ Cl. The action of each of the additives in the periclase and the emerging structure of magnesia stone ambiguous. The addition of NaCl activates periclase in the initial period of hardening (up to 1 day), and the rest - a little later (day 1 ... 3) during the active formation of the structure. All this contributes to regulate curing, reducing the strain and reduce defects in the structure.

The composition for the manufacture of building purpose prepared as follows.

Caustic magnesite, ground to a specific surface 3000-4000 cm ² / g, silica fume (granulated blast furnace slag), and finely divided magnesium silicate with a specific surface area of not less than 3000 cm ² / g, dry blended, then add placeholders: small - quartz sand or screenings of crushing dolomite and large - dolomite or granite rubble, and again stirred. Then, the resultant dry mass is stirred vigorously for 1 ... 3 minutes with a mixing modified density of 1.20 ... 1.25 g / cm ^3, which was previously introduced additives necessary amount of chloride. The resulting composition was poured into molds and held for the required time, but not less than 5.4 hours.

Results of the study investigated the characteristics balochek-samples with dimensions 4 × 4 × 16 cm, made of compositions with varying amounts of additives on a mixing medium density equal to 1.23 g / cm ³ are shown in Table 1.

The table shows that the use of complex additives submitted produces products that are not prone to cracking, water-resistant with sufficient strength, while the consumption of binder and crystalline magnesium chloride is reduced by the amount of additives.

As is known to use a mixing carnallite (KCl-MgCl ₂ · H ₂ O), contains in its structure in addition to magnesium chloride, potassium chloride and sodium in an amount of 19.3% and 24.4% (GOST 16109) by weight of magnesium chloride, respectively. Introduced in the modified request differs from a mixing carnallite limited total content of sodium chloride and potassium supplements (within 8 ... 12% by weight of magnesium chloride). Raising or lowering the dosage of chlorides do not bring the desired effect. Moreover, the claimed invention is possible to use NaCl in conjunction not only with KCl, but in conjunction with LiCl or NH ₄ Cl. Therefore, to avoid cracking of products during operation while maintaining the strength and water resistance must be used bishofit (magnesium chloride) modified with these additives.

Effect of additives on the flow properties chloride magnesia stone obtained is shown in Table 2. The binder composition is adopted, wherein the increased water resistance and strength in said patent. A mixing flow is assumed constant.

From the data presented in the table shows that use of one of the additives, as well as two complex additions in an amount less than or greater than proposed in the application is not effective for not prone to cracking structure with improved water resistance and durability. The increased amount of chloride additives although produces a structure is not prone to cracking, but it significantly reduces its durability and water resistance, increasing the hygroscopicity and vysoloobrazovanie.

These modifications binder not only provide additional sealing structure of magnesia stone waterproof crystalline phases of the preferred composition, causing the increase in strength, water resistance and frost resistance of the resulting materials and products, but also to create a structure that is not prone to cracking.

Increasing the strength of the material allows, by using an organic insulating filler effective to receive concrete and using special fillers with high hardness characteristics - abrasives.

CLAIM

Composition based on magnesia binder comprising caustic magnesite active mineral additive, fine magnesium hydrosilicate, a mixing - an aqueous solution of magnesium chloride density of 1.20 ... 1.25 g / cm ^3, and a filler, characterized in that a mixing additives modified alkali chlorides metal total content 8 ... 12% by weight of magnesium chloride, in the following ratio, wt.%:

print version
Publication date 06.04.2007gg

NEW ARTICLES AND PUBLICATIONS
	The technology of manufacture of universal joints for besvarochnogo, threadless, besflyantsevogo connection pipe segments in high-pressure pipelines (a video)
	Oil and petroleum products purification technology
	On the possibility of moving mechanical system due to internal forces
	Glow liquid in a thin dielectric kanaloh
	The relationship between quantum and classical mechanics
	Millimeter waves in medicine. A New Look. IIM therapy
	Magnetic engine
	The heat source on the basis of units nososnyh