CZ2006561A3 - Process for producing dry mortar mixtures - Google Patents

Abstract

The method of producing dry building mixtures, especially mortar, by means of calcium oxide, is carried out in such a way that the calcium oxide is quenched together with the filler filler, in particular sand, aggregate and crushed in an undried state, i.e. the excess water in the filler, so that the water content of the filler is sufficient to form a full-blown lime hydrate, wherein the calcium oxide is mixed with the wet filler so that the temperature of the dry lime hydrate production temperature does not exceed 96-99 degC by adding water where the filler also ensures perfect mixing and grinding of the lime hydrate formed. On the other hand, the purity requirements of the sand component and the clay content due to the oxide content increase the hydraulic properties of the mortar. The reaction in the filler is such that the content of lime hydrate formed corresponds directly to the ratio of the mortar. Additives to improve the properties of the mortar, ie, cements, cellulose derivatives, vinyl acetate and others, are added to the resulting mixture of filler and binder, i.e. sand, grit, aggregate to a level of 95 to 99% of the dry matter content. The heat generated in the calcium oxide extinguishing process is a possibility to be used for other purposes.

Description

Process for producing dry mortar mixtures

Technical field

The invention relates to a process for the production of dry building mixtures, in particular mortars, by means of calcium oxide.

BACKGROUND OF THE INVENTION

Presently, dry mortar mixtures are used for construction production.

Mortars prepared from dry mortar mixtures meet the requirements of the respective standards for each type of mortar, and their advantage is standard quality, space saving on the construction site and practically minimal demands on the construction site equipment. Dry mortar mixtures are produced in the whole assortment, ie masonry mortars, plaster mortars, screed mortars, special mortar mixtures. Dry mortar mixtures for plastering are produced as core, top, stucco, special, these mixtures are usually produced in two versions, namely as mortar for manual application and as mortar for machine application. Dry mortar mixtures contain dried aggregates, grits and sands of defined granulometric composition, the proportion of individual fractions depends on the type of mortar. The other component is a mineral binder or a mixture of binders. Most often it is a mixture of lime hydrate and Portland cement, the amount and type of binder again depends on the type of mortar. In addition to these basic components, the mortar mixtures also contain additives which modify the processability, increase water retention, increase adhesion to the substrate, have a hydrophobic effect. Typically, water-soluble cellulose derivatives are used to adjust the processability. Very quickly soluble types are used for machine plastering because the mortar mixing time is short in this case. Cellulose derivatives also increase the water retention as well as the redispersible polymer powders, which in particular increase the adhesion of the fresh mortar and the adhesion of the hardened mortar to the substrate. There are a number of hydrophobizing additives, the most commonly used are stearates such as calcium stearate, zinc stearate. An essential component, in varying proportions according to the type of mortar, is lime, which is used in the form of hydrate / calcium hydroxide, which, when mixed with water and suitable sand in a suitable ratio, creates a mortar which can be used for masonry plastering. The preparation of the hydrate is carried out in two ways: wet and dry. In the wet process, the lime is mixed with excess water and the reaction of the calcium oxide with water takes place at temperatures close to 70 ° C. The temperature increase can only occur locally. This wet slaking process produces a lime slurry which is a suspension of solid calcium hydroxide in a saturated solution thereof. After separation of the water from the suspension, a buttery mass is formed, which consists of very fine calcium hydroxide particles. Due to the submicron and micron size of the calcium hydroxide particles, the hydrated calcium hydrate has excellent rheological properties, which it then imparts to the mortar when mixed with sand.

Today, the industrial method of preparing calcium hydrate is the so-called dry hash. In this method of hydration, lime (calcium oxide) is extinguished with less excess water at temperatures close to the boiling point of water. Hydration takes place in hydration baths, where a measured amount of warm water is added to the calcium oxide in a continuous process. The resulting semi-dry mixture is stirred, the temperature rises to 96-99 ° C, and boiling of the mixture produces almost dry calcium hydrate. It has a temperature of 98-99 ° C when the outlet from the hydration bath is intensively vaporizing excess water in the form of steam. The final product has about 1% moisture. When considering this industrially produced hydrate in terms of its theological properties, it can be stated that the hydrate prepared by the wet route has these properties much better. However, for construction purposes, it will very well comply with the requirements imposed on this product. Method for the production of dry mortar mixtures

-2the process is to mix the individual components of the mortar, ie dry lime hydrate, fillers - dried aggregates, grits and sands of defined granulometric composition, Portland cement, or Portland slag cement, clinker, limestone, blast furnace slag, fly ash and additives improving final properties mortar mixes. The main disadvantage of the dry mortar mixtures prepared in this way is the energy intensity of drying the fillers and thus the high cost of the final product. For this purpose industrial dryers burning natural gas or solid fuels are used. Another important factor is the purity of the filler, especially dredged sands, which contain both rounded and sharp-edged grains and have a wider particle size distribution, but usually contain a certain proportion of washable clay elements. The cleanliness of the sand is very important as dirt can adversely affect the properties of the hardened mortar. Therefore, for example, the clay content in the sand for masonry mortar must be less than 15% and in the sand for plaster mortar less than 3%. Organic impurities (humus) and, in particular, soluble salts and substances from which soluble salts can form have an adverse effect.

SUMMARY OF THE INVENTION

The above-mentioned drawbacks largely eliminate the process for the production of dry mortar mixtures using the calcium oxide of the invention. It is a method of production where the calcium oxide is extinguished together with the filler of the mortar, ie mainly sand, aggregates and crushed in an undried state, ie an excess of water in the filler, so that the water content of the filler is sufficient to form a full lime hydrate. The calcium oxide is mixed with the wet filler so that the temperature corresponds to the temperature in the production of dry lime hydrate 96-99 ° C. The filler also ensures perfect mixing and grinding of the lumps of the resulting lime hydrate. During the process, the filler will dry completely and the filler and binder will bind. In this way, the process of drying the filler of the mortar mixtures is eliminated. There is no significant energy cost for drying. Furthermore, the purity requirements of the sand in terms of the humus content are slightly reduced, while the clay content, due to the oxides content, increases the hydraulic properties of the mortar. Calcium oxide extinguishing process can be controlled in terms of water content by selection of filler in open storage. The calcium oxide slaking process in the filler is carried out so that the lime hydrate content directly corresponds to the ratio for the mortar. If the resulting mixture of filler and binder, ie sand, grit, aggregate decreases to 95-99% of dry matter content, additives can be added to improve the properties of mortar, ie cement, cellulose derivatives, vinilacetates, etc. utilization of the heat generated in the calcium oxide extinguishing process. Last but not least, due to the perception of calcium oxide as a lime hydrate concentrate, transportation costs and storage requirements are also reduced. For the preparation of dry mortar mixtures in this way, existing mixing equipment supplemented with temperature and humidity sensors, water dosing equipment and treated dust filters can be used. In general, the production method according to the invention can be used in the production of not only mortars but also other dry building mixtures, for example certain types of concrete, where the lime hydrate present does not reduce the utility properties of the dry building mixture.

DETAILED DESCRIPTION OF THE INVENTION

Example no

1 volume of calcium oxide and 5 volumes of wet sand are fed into a cyclone slow-speed mixer complete with temperature, humidity sensors, water mist dispenser. Originated • t ··· · t · t · · ··· · · · · ·

The mixture is stirred briefly. As the temperature rises above 50 ° C, the mixture is again stirred and the temperature is monitored, which gradually increases to the boiling point of water with vigorous water vapor. If the temperature is too low. ie does not reach min. 85 ° C, the mixer speed is reduced. When the temperature begins to exceed 99 ° C, water mist is metered into the mixture. After the process has stabilized, when the temperature no longer increases with stirring, the mixture is stirred until dry lime hydrate is formed in the entire volume of the mixture. When the temperature of the mixture fell to 70 ° C and the dry matter content was 95%, the mixture was allowed to cool to silo. The result is pure lime stucco.

Example 2

The cyclone slow-speed mixer is equipped with temperature, humidity sensors, water mist dispenser and is filled with 1 volume of calcium oxide and 7 volumes of wet sand. The resulting mixture is stirred briefly. As the temperature rises above 50 ° C, the mixture begins to stir again and the temperature is monitored, which gradually increases in the boiling point of water with vigorous water vapor. If the temperature is too low, ie below min. 85 ° C, the mixer speed is reduced. When the temperature begins to exceed 99 ° C, water mist is metered into the mixture. After the process has stabilized, when the temperature no longer increases with stirring, the mixture is stirred until dry lime hydrate is formed in the entire volume of the mixture. When the temperature of the mixture dropped to 70 ° C and the dry matter content was 95%, the mixture was allowed to cool down. The result is a lime core plaster.

Example 3

1 volume of calcium oxide and 10 volumes of wet sand are filled into a cyclone slow-speed mixer with temperature, humidity sensors, water mist dispenser. The resulting mixture is stirred briefly. As the temperature rises above 50 ° C, the mixture begins to stir again and the temperature is monitored, which gradually increases in the boiling point of water with vigorous water vapor. If the temperature is too low, ie below min. 85 ° C, the mixer speed is reduced. When the temperature begins to exceed 99 ° C, water mist is metered into the mixture. After the process has stabilized, when the temperature in the agitators no longer increases, the mixture is agitated to form a dry lime hydrate throughout the volume of the mixture. When the temperature of the mixture dropped to 70 ° C and the dry matter content was 95%, 0.5 part by volume of Portland cement was added to the mixture and the mixture was allowed to cool. The result is a lime-cement universal core and masonry mortar.

Example 4

1 volume of calcium oxide and 10 volumes of wet sand are filled into a cyclone slow-speed mixer with temperature, humidity sensors, water mist dispenser. The resulting mixture is stirred briefly. As the temperature rises above 50 ° C, the mixture is again stirred and the temperature is monitored, which gradually increases to the boiling point of water with vigorous water vapor. If the temperature is too low, ie below min. 85 ° C, the mixer speed is reduced. When the temperature begins to exceed 99 ° C, water mist is metered into the mixture. After the process has stabilized when the temperature in the agitator no longer increases, the mixture is agitated to form a dry lime hydrate throughout the volume of the mixture. When the temperature of the mixture fell to 70 ° C and the dry matter content was 95%, 1 part by volume of Portland cement was added to the mixture and the mixture was allowed to cool. The result is a cement-lime universal core and masonry mortar for aerated concrete.

Example 5

The cyclone slow-speed mixer is equipped with temperature, humidity sensors, water mist dispenser and is filled with 1 volume of calcium oxide and 7 volumes of wet sand. The resulting mixture is stirred briefly. As the temperature rises above 50 ° C, the mixture begins to stir again and the temperature is monitored, which gradually increases in the boiling point of water with vigorous water vapor. If the temperature is too low, ie below min. 85 ° C, the mixer speed is reduced. When the temperature begins to exceed 99 ° C, water mist is metered into the mixture. After the process has stabilized, when the temperature in the agitators no longer increases, the mixture is agitated to form a dry lime hydrate throughout the volume of the mixture. When the temperature of the mixture has dropped to 70 ° C and the dry matter content is 95%, 0.2% is added to the mixture.

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-4 vol. Of Portland cement, 0.2 vol. Of blast furnace finely ground slag, and the mixture allowed to cool. The result is a universal core and masonry mortar with extended pot life.

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Claims (5)

PTENT Claims Process for the production of dry building mixtures, in particular mortar, by means of calcium oxide, characterized in that the calcium oxide is extinguished together with a filler of mortar, in particular sand, aggregates and crushed in an undried state, ie excess water in the filler, so that the water content of the filler was sufficient to form a full lime hydrate, the calcium oxide being mixed with the wet filler so that the temperature corresponded to the dry lime hydrate production temperature and did not exceed 96-99 ° C by adding water where the filler also ensures perfect mixing and grinding lumps of lime hydrate formed. Method according to claim 1, characterized in that the purity requirements of the sand in terms of the humus content and the clay content, by virtue of the oxides content, in turn increase the hydraulic properties of the mortar. Method according to claims 1 and 2, characterized in that the reaction in the filler is carried out in such a way that the content of the resulting lime hydrate directly corresponds to the ratio for the malt wine. Production method according to claims 1 to 3, characterized in that additives to improve the properties of the mortar, ie cements, derivatives, can be added to the resulting mixture of filler and binder, i.e. sand, gravel, aggregate to a level of 95-99% of the dry matter content. celluloses, vinilacetates and others. Method according to any one of the preceding claims, characterized in that the heat generated in the calcium oxide slaking process can be used for other purposes.