Technical characteristics and properties of lime, its area of ​​​​use and types. Technical characteristics and properties of lime, its area of ​​​​use and types Quicklime building lime characteristics

Lime is a versatile substance that, due to its extensive and varied properties, can be used in almost any field of activity. It can be of various types, depending on the selection criteria, and is divided into several varieties. The options for preparing solutions with its content do not differ much from each other and do not cause difficulties, so this raw material can be used independently without the involvement of specialists.

Quicklime is calcium oxide obtained by roasting calcium carbonate, it has a finely porous structure. Sometimes quicklime is called boiled lime.

It has many advantages over the slaked variety:

• high strength;
• absorbs less moisture;
• work with this material can be carried out in winter;
• no waste;
• very wide scope.

Quicklime is dangerous to human health, so it is advisable to carry out work in open space, using protective equipment.

A good advantage of quicklime can be considered a low cost in comparison with other mixtures. Lime material is resistant to temperature extremes, it does not crack, it has antimicrobial properties.

Lime is a substance that is often found in nature (mainly in rocks), and the production of the product takes place with full compliance established standards, because mixtures on such a basis should high level perform protective functions.

Ready lime should consist only of carbonate rocks (limestone) with a small clay content. Various additives and impurities are allowed in the composition of the material based on GOSTs, depending on the application.

Limestone looks very similar to chalk or coke, but they have various properties and are not interchangeable. To distinguish limestone from chalk, you can drop water on them. The chalk will not give any reaction, but the limestone will begin to foam and give off heat. If you use chalk to whitewash walls, it will leave marks on clothes and surfaces in contact with the wall. Lime does not leave any traces, so it is most often used for whitewashing walls.

Quicklime is divided into three grades (1, 2 and 3), and slaked lime is subdivided into 1st and 2nd grade. The exception is powdered quicklime, it is divided into two grades and has additives. Other types are made without impurities.

By external physical indicators, for example, by color, it is possible to determine the grade of the material. After heat treatment of limestone, quicklime is obtained, and if it has a white color, this means that the material does not contain additives and belongs to a high grade. In other cases, the material has a grayish color, most often it is dolomitic and hydraulic lime.

The production of lime material consists of the extraction of the rocks themselves, their crushing to the required size and subsequent firing in special kilns. Currently, shaft and rotary tube furnaces are most commonly used because they provide a uniform temperature effect on the material and a continuous firing process.

The strength of raw materials is affected by the temperature during firing and the production process itself. There are three strength options finished product: hard burnt, medium burnt and soft burnt lime.

Soft lime is very popular in construction, due to the following properties:

• the extinguishing process is fast, about 3 minutes;
• this material has small size and low density.

Lime belongs to a low hazard class, but safety precautions must be observed during transportation and storage. Since quicklime reacts violently with water, it is necessary to make sure that moisture cannot get on the material.

The composition of lime most often includes various mineral additives that improve the properties of the material: granulated blast-furnace slag, quartz sands and other substances.

There are two types of lime, which are distinguished by the amount of calcium silicate and aluminoferrite content in them: air and hydraulic. They perform various functions, for example, air speeds up the concrete hardening process, and hydraulic speeds up reactions in water.

It is important that all fragments of the substance are of the same size. This moment indicates that the raw material was completely calcined in the furnace. If pieces that are too large or too small are encountered, they may not be fully cooked and the quality will be reduced. finished material.

According to the type of processing, several types of material are distinguished:

• quick-cooked lump (boiler);
• quicklime ground (powdered);
• slaked hydrate - Ca (OH) 2;
• lime dough;
• lime milk.

Lump lime is a mixture of lumps that differ in size. It consists of calcium oxide and magnesium, as well as materials such as calcium carbonate, aluminates, silicates. Magnesium or calcium ferrites, which are formed during the firing of raw materials, can be added.

The good strength of concrete is ensured by the fact that lump lime requires very little water (due to the fine grinding of the material) and generates practically no waste.

Ground lime has the same composition as lump lime, but the difference lies in the fact that lumps of raw materials are ground much stronger and more thoroughly.

The main advantages of ground lime:

• strength;
• water resistance;
• fast hardening.

To increase or decrease the hardening rate, calcium chloride or sulfuric acid is often used (also suitable gypsum material).

Hydrated lime (also called fluff) is a slaked type of material with a highly dispersive composition. Quenching occurs by adding water to the lime raw material. To prepare such a solution, 70 to 100% water is added to the powder.

In order for the lime to completely go through the slaking process, it must be placed in a special pit for 2-3 weeks. So it will gain optimal strength and ductility. Most minimum term extinguishing is 36 hours. In order to prevent the raw material from burning out, it is advisable to add water gradually until the moment when steam ceases to be released.

Lime dough is formed when sufficient water is added to form a plastic material. You can also find a solution such as milk of lime (mainly used for whitewashing tree trunks). Milk of lime is obtained by adding excess water to lime paste.

Depending on the scope of application, the following types of compositions are distinguished:

• Building lime - it is added for the preparation of concrete and cement mixtures in order to increase the strength of the composition;
• Hydraulic - also used for the production of concrete, but low grades. Ideal for structures that are located in areas with high humidity;
• Lumpy - mainly used to prepare a solution for whitewashing;
• Garden - used in agriculture as a soil fertilizer, treating plants from pests, protecting against decay and improving growth, it is highly undesirable to use it simultaneously with other types of additives and fertilizers;
• Sodium - used in the chemical industry and in medicine;
• Chlorine - used as a disinfectant and for water purification.

• quick-extinguishing (up to 8 minutes);
• medium extinguishing (up to 25 minutes);
• slow-extinguishing (from 25 minutes).

Depending on the percentage of presence in the composition of magnesium oxide, there are such types of air lime:

• calcium;
• magnesian;
• dolomite.

Lime is used in many areas.

• In agriculture, lime is used to control pests, reduce soil acidity, prevent the appearance of fungus, supplement animal nutrition, improve land cultivation, replenish calcium and phosphorus. It is best to treat heavy soil with quicklime. Lime is widely used as a material for whitewashing trees and processing plants.
• Construction. It is used to accelerate the hardening of cement and impart plasticity to the composition, is involved in the production of thermal insulation materials and dry building mixtures, serves as a connecting link in building structures.
• Ferrous metallurgy - enriches ferruginous and polymetallic ores.
• Chemical industry - used in the paint and varnish, perfumery and pharmaceutical industries. It is used as a reagent and as a neutralizer of acid tars.
• Pulp and paper industry.
• Textile industry.

The chlorine variety of lime is used for disinfection and washing of public places, as it has disinfecting properties. Quicklime is used even in Food Industry for mixing substances, and milk of lime is used to make sugar. Soda lime is used in medicine (artificial ventilation of the lungs or for anesthesia) and for respiratory systems (scuba gear, respirators and other devices).

Lime mortar coating wooden surfaces protects them from the processes of decay and the occurrence of fires.

When preparing a lime mortar, it is important to ensure the safe interaction of raw materials with water for humans. It is advisable to carry out work in a well-ventilated area, and preferably in an open space. Since the substances used are chemicals, it is necessary to adhere to safety rules when working with such materials.

The powder substance can be used both in dry form and in liquid form. To prepare a liquid solution, the powder is poured into a container and filled with water. The solution must be mixed and diluted to the desired consistency.

For whitewashing trees, the raw material is diluted with water and applied to the tree trunk with a wide brush. But due to the liquid consistency of the solution, it will be necessary to process the barrel several times. In order to reduce the time of work, you can add clay, milk, PVA glue to the solution. These ingredients will make the mixture thick and viscous, it will evenly fall on the surface. Before processing the tree, all dead layers of bark must be removed, while not damaging the trunk.

To protect plants from fungus, you can use soda ash instead of lime, because soda dissolves faster and completely in water.

Do not work the soil too much large quantity lime, as it will become alkaline, which will also not contribute good growth and development of plants. It is impossible to use manure and lime at the same time, because such a combination will prevent the formation of useful substances.

Before using bleach, check the reaction of the surface. To do this, you can process small plot, and if it remains intact after about 10 minutes, then you can use bleach for the entire surface. First, water is added to the raw material in a small amount and mixed until sour cream, and then more water is gradually added, also stirring, until a liquid solution is formed. In dry form, bleach is used only on wet surfaces.

In construction, it is recommended to use quicklime for the manufacture of plasters, slag concrete, and coloring elements. In other cases, slaked lime is used, which, due to its moisture resistance, prevents the formation of mold.

Pushonka has a wide range of applications: from household needs to construction. To prepare fluff, it is necessary to pour raw materials into a metal container without rust (or into a plastic one) and gradually add water, stirring the solution. Once the mixture is ready, it is necessary to leave it to brew for several hours or days. The longer it will stand, the higher its quality and strength will be.

• If necessary, store the finished lime mortar for a long time, you can periodically add water to it. Initially, water is added until the material stops absorbing it. This rule does not apply to the preparation of milk of lime.
• The optimal depth of lime digging into the soil is 20 cm, but if the dose of fertilizer is small, then the depth should be less. From above, lime is covered with a layer of sand. For storage in winter time it is recommended to pour another layer of soil 70 cm high on top of the sand layer.
• Before applying to any surface (wooden, concrete, cement, metal), it is necessary to completely remove dirt, grease, defects, rust from them.
• It may happen that lime has got into an unnecessary area and should be washed off. To do this, first of all, it is necessary to moisten this area abundantly, wait for the lime to dissolve well, and then remove the material with a hard metal sponge. If necessary, repeat these steps. On sale there are ready-made solutions for such needs, for example, Guard Industrie or "Probel". You can also use homemade solutions based on hydrochloric acid.

• It is not recommended to carry out a primer before whitewashing, since lime will not be fixed on such a base. It is also desirable to whitewash with brushes, and not with a spray gun. The brush will better distribute the lime mortar, and the finish will be better.
• The longer the holding time ready mix, the better it will perform its functions.
• For cooking mortars it is best to add more sand.
• This material is not suitable for the manufacture of cement for a fireplace or stove, as carbon dioxide is released when heated.
• To get insulation, you can add sawdust and gypsum to the fluff. In other cases, the lime mortar should be free of sawdust, lumps and other inclusions in order to uniformly and completely cover the surface.
• Chloric lime must be stored in a dark room, because under the influence sun rays part of the active chlorine is lost.

For information on how to determine the quality of lime, see the following video.

www.stroy-podskazka.ru

Lump lime. Properties and subtleties of use. How to use lump lime

The history of the use of lime has more than one millennium. This product has taken a strong place in many areas of human activity. The material has many valuable properties, its manufacturing technology is quite simple, and the necessary raw materials are very affordable. Lump lime is one of the components of mortars with astringent properties.

Material features

The concept of "lime" is the name of the products of burning carbonate rocks, such as limestone, chalk and others. As a result of calcining these rocks with the help of fire, calcium carbonate turns into calcium oxide. After this procedure, the materials lose 44% of their weight and acquire porosity. The substance formed in this way, when interacting with water, takes the form of a fine powder, and by using an excess amount of water, a product is produced that has the state of a plastic dough. Such dough also plays the role of an astringent component. Under conditions of evaporation of moisture, the dough becomes thick, and then takes on a stone-like shape.

Depending on the chemical composition, lime is divided into varieties:

1. The substance produced by roasting rocks with the main chemical component - calcium oxide, is quicklime. According to their physical properties given material represents fragments with a finely porous structure, the size of which varies from 5 cm to 10 cm.
2. Slaked lime is produced by hydration. The consequence of this process is an increase in the volume of the substance and its subsequent disintegration into the smallest fragments.

The order of production work

Manufacturing process lime production involves several stages:

• limestone mining;
• its subsequent crushing;
• burning.

To obtain high-quality lime, the fragments of the raw materials used must have as much as possible the same size. Otherwise, firing will be uneven. As a result, small parts are burned out, and the material becomes inactive. Fragments of large size are fired insufficiently, as a result of which part of the raw material does not pass into calcium oxide.

Lump quicklime is produced by grinding raw materials in ball mills, where in the process required dimensions particles are separated by a separator.

Advantages of a lump lime product

Technological lump lime has the following advantages:

1. Unlike slaked lime, the lump variety is a virtually waste-free product. This is ensured by the finest grinding of the mixture.
2. Also, this material requires less water consumption. This feature has a positive effect on strength indicators concrete composition when it hardens. Hardening, quicklime releases heat in a significant amount. This contributes to better adhesion of the compositions at low temperatures.
3. Greater strength is achieved by rapid heat dissipation. Due to these properties, lump lime has been widely used in construction industry.

hardening process

The composition of the lime product test is represented by a saturated solution of water and small fragments of lime that could not dissolve. When water from a given substance evaporates, it acquires the state of a supersaturated solution. The hardening substance undergoes shrinkage, which in some cases forms cracks in the material. Such a result, for example, can be seen when lime adheres to a hard plaster layer. In order to avoid such consequences, the use of lime is carried out with binders that ensure the plasticity of the material.

If the lime mass is placed in conditions that prevent drying, it will retain its plastic properties for an unlimited amount of time. This is due to the fact that such a lime product does not have the possibility of setting. If the lime mass is moistened after it has hardened, it will again acquire its former plastic qualities, since lime is not resistant to moisture.

However, under certain conditions, lump building lime can acquire relative moisture resistance. During a rather long hardening process, which can last several decades, a certain chemical process occurs. On the outdoors lime composition and carbon dioxide react, which ultimately causes the formation of calcium carbonate. This element characterized by good strength and insolubility as a result of exposure to water.

Areas of use

Lime has found application in many areas of industry and economy:

1. In the chemical industry, the substance is used in such industries as: paint and varnish, perfumery, petrochemical, cable, electrical, pharmaceutical, rubber industries.
2. In metallurgy, this product is used to enrich ferrous and polymetallic ores. Lime is also used in industries such as processing and mining.
3. In the food industry, the lime product is used to saponify fats. And in the textile industry, with the help of lime, the dyeing procedure is carried out.
4. Lime is also widely used in construction. It is an indispensable component in mortars and in thermal insulation materials.
5. In the agricultural sector, the material neutralizes the acidity in the soil, which negatively affects crops. In addition, thanks to lime, the soil is enriched with calcium, and the tillage indicators are improved. The need to enrich the soil with nitrogen fertilizers is also significantly reduced.
6. In addition to agriculture, lime is also used in the livestock sector. With its help, farms and household premises are disinfected. And the addition of lime to the diet of animals helps to eliminate the lack of calcium.

It should also be noted the significant role of the lime product in stabilizing the ecological situation. Lime removes sulfur oxide from flue gases. In addition, the material improves quality characteristics water. The presence of the lime component in the water contributes to the precipitation of organic elements, which makes the water softer.

Storage and transportation

1. During storage or in the case of transport of lump lime, measures must be taken to prevent moisture from entering the material. Lime substance in powder form can extinguish even the moisture in the air.
2. The shelf life of the product depends on the container used. If the lime is in paper bags, its performance will be maintained for 25 days. If sealed conditions are provided, it will acquire an unlimited storage period.

In the premises where the storage process is carried out, the floors must be made of wooden material and raised above ground level by at least 30 cm. It is necessary to completely exclude the possibility of water getting on the lime. Otherwise, a fire will occur, as the water heats up the lime material. In case of fire, water must not be used to extinguish the lime composition.

Safety measures when interacting with lime

Lime is a strong alkaline component. Therefore, before you start working with this product, you need to take care of the following precautions:

• lime material should not be allowed to enter the eyes, the mucous membrane of the respiratory tract, as well as on exposed skin;
• extremely dangerous is quicklime. It is mandatory for any manipulations with this component to wear special protective clothing, rubberized shoes, gloves, a special headgear, a respirator and goggles.

Conclusion

Lump lime is a product with universal qualities. The popularity of the use of lime material is facilitated by the low cost of raw materials, tk. lump lime is affordable for a wide range of consumers, as well as the technological simplicity of the process. However, the substance is not a safe material; safety measures should be taken into account when working with it. Also, in order for lime to retain its properties for a longer period, it is necessary to ensure right conditions for its storage.

Features of the use of lump lime are presented in the video:

Lump lime. Properties and subtleties of use

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VolgaIzvest - building lump lime, quicklime, calcium

Lump quicklime is widely used in various fields human activity. The largest consumers include: ferrous metallurgy, Agriculture as well as the field of ecology.

In metallurgy, lime is a cleaning component. It is involved in the processes of slag formation and desulfation. Cast iron is smelted from iron ore using lime in blast furnaces. The task of lime in this process is to remove excess impurities from cast iron and raw steel. Lime is also necessary for the further refinement of steel, it binds such harmful impurities as phosphorus and sulfur.

In industrial gas purification processes, lime helps to reduce emissions harmful substances in atmosphere. Lime is used to neutralize wastewater in treatment facilities. Residual products of oil refining processes or sludge washed out of wells are treated with lime. It neutralizes harmful acids, binds heavy metals and accelerates the decomposition of harmful substances.

Lime is used in construction silicate brick, silicate and foam silicate products, cinder blocks, aerated concrete (gas silicate), dry building mixtures. Lime - essential element construction industry, the use of which does not harm the environment.

volgaizvest.ru

Quicklime: types and applications

Chemical substance- calcium oxide, better known to us as lime, is very widespread in the construction industry. Its use is justified for obtaining various coatings and mortars, especially in the manufacture of so-called lime cement. Building lime production characteristics and scope - all this is our article.

• 1 Manufacturing
• 2 Classification
• 3 Application in construction and everyday life

Manufacturing

Despite the long history and use of lime in the most various industries life activity of a person, in its pure form, quicklime is quite difficult to meet. The manufacture of this material involves a certain chemical process.

How to use lime plaster mortar

Lime can be obtained in two ways:

1. Thermal decomposition of limestone rock. A traditional and very costly method that requires special equipment. Main disadvantage- release of a large amount of carbon dioxide.
2. Heat treatment of oxygen-containing calcium salts - alternative method, in recent times more and more common. Roasting does not consume a large amount of oxygen, so it is more environmentally friendly.

How to use crushed limestone GOST 8267 93 can be found in this article.

For the heat treatment of raw materials, special equipment is used, most of which is already obsolete. Modern technologies allow the use of less expensive and harmful ways receipt of quicklime.

On the video - the use of quicklime:

What is lime mortar masonry can be found in this article.

Furnaces are used different design:

• The most popular is the gas-fired shaft-type furnace. A compromise solution will make it possible to obtain a product of normal quality at a very moderate cost.
• Less often you can find furnaces with a transfer principle of operation, which use coal for heating. This is a more economical and productive method, the main disadvantage of which will be significant pollution. environment.
• A special type of furnace - a rotating design will allow you to get a product highest quality, but this method is quite expensive and therefore is rarely used.
• The device of the furnace with a remote furnace ensures good purity of the finished substance, the content of impurities in it will be minimal. The furnace operates on solid fuel and is much inferior in power to its counterparts.
• The type of annular and floor furnaces is practically not used due to low productivity. Old models are still functioning, but new units are gradually pushing them out of production.

Cement-lime mortar proportions and other data can be read from the article.

Specifications quicklime are regulated by the state quality standard GOST No. 9179–77. The substance belongs to the second class of chemical hazard. Pure lime has three grades of classification, the substance with additives has two grades, and the hydrated solution has two grades.

On the video - building quicklime lump lime:

How lime is used building gost 9179 77 can be found in this article.

Classification

The substance used in construction is of two main types: air, which helps the concrete mortar to harden in normal conditions and hydraulic, the undoubted advantage of this type will be the acceleration of reactions in the aquatic environment. The second type is most often in demand during the construction load-bearing supports bridges and other hydraulic structures.

You can learn how to use building lime mortar from this article.

The physical properties of lime are also well studied. It is usually crystalline white color and characteristic "viscous" structure.

Usually you can find the following types of lime on sale:

When lime is quenched with water, irreversible processes occur, and the process itself requires maximum caution. The use of personal protective equipment is recommended, and splashes of lime on exposed skin or mucous membranes should not be allowed. Extinguishing the composition can take quite a long time, sometimes up to a day. The addition of water must be controlled. Usually the volume of liquid should be determined by the tasks.

There are three types of lime mortar:

• Hydrated lime, the so-called fluff. Used in construction, the consistency of the solution assumes approximately equal proportions.
• Lime dough is the second type of slaked lime. It is also used in construction or domestic purposes. The proportions are about 4:1, so the mixture is quite thick.
• Lime milk is the most liquid suspension, the content of dry lime is rather insignificant compared to the mass of water.

Depending on the ultimate goal and the use of slaked lime, a suitable solution is made. Cooking usually takes from 8 minutes for quick-cooked to several hours for slow-cooked. It is not recommended to use lime before the final slaking, as in this case there is no guarantee of obtaining a high-quality coating.

About how many bags of cement in one cube of concrete, and by analogy, lime can be found in the article

Chemical processes in such a solution are suspended, but reappear when water enters. This promotes the growth of fungus and mold, which is why slaked lime is commonly used in construction.

You can find out how long the cement floor screed under the tile dries from this article.

Application in construction and everyday life

The use of quicklime is extremely wide. Dry matter is added to cement mortars for rapid hardening and imparting the necessary plasticity. Lime is used for whitewashing walls and ceilings. This method is still very relevant due to good decorative effect and the highest available price. A big advantage is the ease of application and the environmental friendliness of the solution.

for video application in construction:

Find out what the composition is cement mortar for plaster can be from this article.

Several options for using lime for domestic needs:

As already described earlier, a special type of this substance - bleach is widely used for disinfection and disinfection of surfaces. This is especially true in crowded places, so bleach is traditionally used to wash latrines and sanitary equipment. For disinfection, bleach is used in hospitals, children's institutions and other similar premises. Due to the high toxicity of the substance, it is increasingly being replaced by analogues that do not have such a pronounced negative impact.

The chemical composition of lime may vary slightly. According to the percentage of calcium silicates and aluminoferrites contained in lime, two main types are distinguished:

• air lime. This type of lime allows mortars to harden under normal humidity conditions;
• hydraulic lime. Such lime ensures the hardening of solutions used both in air and in water.

For air lime, the typical amount of calcium silicates and aluminoferrites is usually 4-12%, in rare cases up to 20%. Lime with a percentage of 25-40% clinker minerals is called weakly hydraulic, as it exhibits weak hydraulic properties. Highly hydraulic lime contains from 40% to 90% calcium silicates and aluminoferrites.
Lime is also classified according to the type of basic oxide contained in air lime. There are three types of lime:

• calcium lime;
• magnesian lime;
• dolomitic lime.

Calcium lime contains 70-96% CaO and up to 2% MgO.
The composition of low magnesian lime consists of 70-90% CaO and 2-5% MgO. In magnesian lime, MgO is contained in the range - 5-20%, in dolomite - 20-40%.
Further, depending on the methods of further processing of the burnt product, several types of air lime are distinguished:

• quicklime- boiling water, consisting mainly of Ca (OH);
• quicklime- powdered product of grinding lump lime;
• hydrated lime (slaked)- fluff - a fine powder obtained by quenching lump lime with a certain amount of water and consisting mainly of Ca (OH);
• lime dough- pasty product of slaking lump lime, consisting mainly of Ca(OH) and mechanically mixed water;
• milk of lime- a white suspension in which calcium hydroxide is partly dissolved and partly suspended.

According to the extinguishing time, all varieties of air quicklime are divided into three groups:

• fast-extinguishing- extinguishing time no more than 8 minutes;
• medium extinguishing- extinguishing time no more than 25 minutes;
• slow-extinguishing- extinguishing time not less than 25 min.

Powdered lime obtained by grinding or slaking (hydrating) lump lime is divided into: lime without additives and with additives.

Properties and specifications
Lime intended for the construction industry is produced in accordance with the requirements of the state standard according to a certain technological regulation.
The following components are required for the production of building lime: carbonate rocks, mineral additives (granulated blast-furnace or electrothermophosphorus slags, active mineral additives, quartz sand). All additives must comply with the relevant regulations in force.
The subdivision of lime into grades is carried out as follows: air quicklime without additives is divided into three grades (1, 2, 3); quicklime powdered with additives - for two grades (1, 2); hydrated (slaked) without additives and with additives for two grades (1, 2).

Requirements for air lime.

Notes:
1. The content of MgO for dolomite lime is indicated in brackets.
2. CO2 in lime with additives is determined by the gas volume method.
3. For calcium lime of the 3rd grade used for technological purposes, the content of unextinguished grains is allowed, in agreement with consumers, not more than 20%.
The moisture content of hydrated lime should not be more than 5%. The grade of lime is determined by the value of the indicator corresponding to the lowest grade, if it corresponds to different grades in terms of individual indicators.

Requirements to chemical composition hydraulic lime.

Ultimate strength of specimens, MPa (kgf/cm2), after 28 days. hardening must be at least:
a) when bending:
0.4 (4.0) - for weakly hydraulic lime;
1.0 (10) - for highly hydraulic lime;
b) when compressed:
1.7 (17) - for weakly hydraulic lime;
5.0 (50) - for highly hydraulic lime.

It is permissible to determine the type of hydraulic lime according to the compressive strength, if, according to individual indicators, it belongs to different types.
The content of hydrated water in quicklime should not exceed 2%.

The degree of dispersion of powdered air and hydraulic lime must be such that when sifting a lime sample through a sieve with meshes No. Maximum size pieces of crushed lime should be no more than 20mm.

Air and hydraulic lime must pass the test for uniformity of volume change.

The scope of lime is extremely wide - lime is involved in many technological processes for several millennia. Technologies are developing, involving lime and its derivatives in an ever wider production horizon. Lime consumers are ferrous metallurgy, construction industry, pulp and paper industry, chemical industry, sugar industry and agriculture. Lime is also used in significant volumes for environmental protection (neutralization of wastewater and flue gases).

The Samara plant "Strommashina" manufactures equipment and assembles with its equipment complexes for firing and. We can offer both rotary kilns and shaft kilns. In order to determine in which type of kilns it is more correct and more profitable to roast limestone to obtain lime in your particular case (whether it be construction or metallurgical), we advise you to read the article "", or (even more correctly) contact our contact managers data from the section of the site "". We will definitely help you.

STATE STANDARD OF THE UNION OF THE SSR

LIME FOR CONSTRUCTION

TECHNICAL CONDITIONS

GOST 9179-77

USSR STATE CONSTRUCTION COMMITTEE

Moscow

STATE STANDARD OF THE UNION OF THE SSR

Introduction date 01.01.79

Non-compliance with the standard is punishable by law

This standard applies to building lime, which is a product of roasting carbonate rocks or a mixture of this product with mineral additives. Building lime is used for the preparation of mortars and concretes, binders and the production of building products.

1. CLASSIFICATION

1.1. Building lime, depending on the hardening conditions, is divided into air, which ensures the hardening of mortars and concretes and maintains their strength in air-dry conditions, and hydraulic, which ensures the hardening of mortars and concretes and maintains their strength both in air and in water.

1.2. Air quicklime, depending on the content of calcium and magnesium oxides in it, is divided into calcium, magnesia and dolomite.

1.3. Air lime is divided into quicklime and hydrated (slaked), obtained by slaking calcium, magnesia and dolomitic lime.

1.4. Hydraulic lime is divided into low-hydraulic and high-hydraulic.

1.5. According to the fractional composition, lime is divided into lump, including crushed, and powdered.

1.6. Powdered lime obtained by grinding or slaking (hydrating) lump lime is divided into lime without additives and with additives.

1.7. According to the slaking time, building quicklime is divided into quick-extinguishing - no more than 8 minutes, medium-extinguishing - no more than 25 minutes, slow-extinguishing - more than 25 minutes.

2. TECHNICAL REQUIREMENTS

2.1. Building lime should be produced in accordance with the requirements of this standard according to the technological regulations approved in the prescribed manner.

(Revised edition, Rev. No. 1).

2.2. Materials used in the production of building lime: carbonate rocks, mineral additives (granulated blast-furnace or electrothermophosphorus slag, active mineral additives, quartz sand) must meet the requirements of the relevant regulatory documents in force.

2.2.1. Mineral additives are introduced into powdered building lime in amounts allowed by the requirements for the content of active CaO + M in it. g About according to p.

2.3. Air quicklime without additives is divided into three grades: 1, 2 and 3; quicklime powdered with additives - into two grades: 1 and 2; hydrated (slaked) without additives and with additives in two grades: 1 and 2.

quicklime

hydrated

calcium

magnesia and dolomite

grade

Active

CaO + M gO, not less than:

without additives

with additives

Active МgO, no more

20(40)

20(40)

20(40)

CO 2 , not more than:

without additives

with additives

Unquenched grains, no more

Notes:

1. The content of MgO for dolomite lime is indicated in brackets.

2. CO 2 in lime with additives is determined by the gas volume method.

3. For calcium lime of the 3rd grade, used for technological purposes, it is allowed, in agreement with consumers, the content of unextinguished grains is not more than 20% .

(Revised edition, Rev. No. 1).

2.4.1. Humidity of hydrated lime should not be more than 5%.

2.4.2. The grade of lime is determined by the value of the indicator corresponding to the lowest grade, if for individual indicators it corresponds to different grades.

2.5.(Deleted, Rev. No. 1).

2.6. Hydraulic lime chemical composition must meet the requirements specified in table. .

table 2

2.7. The tensile strength of the samples, MPa (kgf / cm 2), after 28 days of hardening should be at least:

a) when bending:

0.4 (4.0) - for weakly hydraulic lime;

1.0 (10) - for highly hydraulic lime;

b) when compressed:

1.7 (17) - for weakly hydraulic lime;

5.0 (50) - for highly hydraulic lime.

2.7.1. The type of hydraulic lime is determined by the compressive strength, if, according to individual indicators, it belongs to different types.

2.8. The content of hydrated water in quicklime should not exceed 2%.

5.2. To determine the average gross weight of sacks, 20 randomly selected sacks of lime are weighed simultaneously and the result is divided by 20. The average net weight of a sack is determined by subtracting the average net weight of a sack from the gross weight. The deviation of the average net weight of bags of lime from that indicated on the package should not exceed ± 1 kg.

5.3. The manufacturer, along with the shipping details, is obliged to send each consumer a passport, which should indicate:

the name of the manufacturer and (or) its trademark;

date of shipment of lime;

passport and party number;

batch weight;

full name of lime, its guaranteed type and grade, indicators of product compliance with the requirements of this standard;

time and temperature of quenching;

type and amount of additive;

designation of the standard according to which lime is supplied.

In addition, a label must be enclosed in each transport unit, which indicates: the name of the manufacturer and (or) its trademark, the full name of the lime, its guaranteed type and grade, the designation of the standard according to which the lime is supplied.

5.4. When shipping lime in paper bags, they must be marked with: the name of the enterprise and (or) its trademark, the full name of the lime, its guaranteed type and grade, the designation of the standard according to which the lime is supplied.

5.3,5.4 (Revised edition, Rev. No. 1).

5.4.1. It is allowed to replace all designations on bags with digital codes agreed with the consumer.

5.4.2. When shipping lime of one name and grade by wagon deliveries in non-transshipment railway communication it is allowed to apply marking only on bags stacked at the doors of the car on each side in the amount of at least four.

5.4.1, 5.4.2. (Revised edition, Rev. No. 1).

5.5. The manufacturer is obliged to deliver lime in a serviceable and cleaned vehicle.

5.6. During transportation and storage, lime must be protected from moisture and contamination by foreign impurities.

5.6.1. Lime is transported by all types of covered transport in accordance with the rules for the carriage of goods in force for this type of transport. With the consent of the consumer, the supply of lump lime in all-metal gondola cars and open cars is allowed, provided that its quality is maintained and the necessary measures are taken to prevent spraying and exposure to precipitation.

(Revised edition, Rev. No. 1).

5.6.2. Lime should be stored and transported separately by type and grade.

6. MANUFACTURER WARRANTY

6.1. The manufacturer guarantees compliance of lime with the requirements of this standard subject to the conditions of its transportation and storage.

6.2. Guaranteed shelf life of lime - 30 days from the date of its shipment to the consumer.

(Revised edition, Rev. No. 1).

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of Industry building materials USSR

PERFORMERS

V. A. Sokolovsky; L. I. Setyusha; N. V. Petukhova; N. E. Mikirtumova; A. B. Morozov

2. APPROVED AND PUT INTO EFFECT by the Decree of the State Committee of the Council of Ministers of the USSR on Construction Affairs of July 26, 1977 No. 107

3. REPLACE GOST 9179-70 in terms of specifications

4. REFERENCE REGULATIONS AND TECHNICAL DOCUMENTS

5. RE-ISSUED (July 1989) with Amendments No. 1 approved March 1989

Lump quicklime is a semi-product. If it is used in slaked form, then it is pre-processed into hydrated lime (fluff) or into lime dough.

Chemical formula: CaO

In industry, calcium oxide is obtained by thermal decomposition of limestone (calcium carbonate) or by thermal decomposition of calcium hydroxide and calcium salts of certain oxygen-containing acids.

lime classification.
Building lime, depending on the hardening conditions, is divided into air, which ensures the hardening of mortars and concretes and maintains their strength in air-dry conditions, and hydraulic, which ensures the hardening of mortars and concretes and maintains their strength both in air and in water.
Air quicklime, depending on the content of calcium and magnesium oxides in it, is divided into calcium, magnesia and dolomite.
Air lime is divided into quicklime and hydrated (slaked), obtained by slaking calcium, magnesia and dolomitic lime.
Hydraulic lime is divided into low-hydraulic and high-hydraulic.
According to the fractional composition, lime is divided into lump, including crushed, and powdered.
Powdered lime obtained by grinding or slaking (hydrating) lump lime is divided into lime without additives and with additives.
According to the slaking time, building quicklime is divided into quick-extinguishing - no more than 8 minutes, medium-extinguishing - no more than 25 minutes, slow-extinguishing - more than 25 minutes.

The use of quicklime.
The main volumes are used in construction as lime cement, when mixed with water, calcium oxide turns into hydroxide, which further, absorbing carbon dioxide from the air, hardens strongly, turning into calcium carbonate. However, at present, they try not to use lime cement in the construction of residential buildings, since the resulting structures have the ability to absorb and accumulate dampness.
It is categorically unacceptable to use lime cement when laying stoves due to thermal decomposition and the release of asphyxiating carbon dioxide into the air.
It also finds some use as an affordable and inexpensive refractory material - fused calcium oxide, which has some resistance to water, which allows it to be used as a refractory where the use of more expensive materials is impractical.
Small amounts of calcium oxide are also used in laboratory practice to dry substances that do not react with it.
In the food industry, it is registered as a food additive E-529.

Packing, transportation and storage.
Lump lime is shipped in bulk, powdered lime is shipped in bulk or in paper bags. It is allowed to use four-layer paper bags.
Lime is transported by covered transport of all types in accordance with the rules for the carriage of goods in force for this type of transport. With the consent of the consumer, the supply of lump lime in all-metal gondola cars and open cars is allowed, provided that its quality is maintained and the necessary measures are taken to prevent spraying and exposure to precipitation.
During transportation and storage, lime must be protected from moisture and contamination by foreign impurities.
Lime should be stored and transported separately by type and grade.
Guaranteed shelf life of the product - 30 days from the date of its shipment to the consumer.

FASTEKH LLC supplies chemical products from a warehouse in Belgorod on time and at affordable prices, on favorable terms for you.

Lime is a binder obtained by high-temperature annealing (1000 -1200 ° C) in shaft or rotary kilns of sedimentary rocks, consisting mainly of calcium carbonate CaCO 3 (limestone, chalk, dolomite).

Depending on the content of clay impurities in the carbonate rock, it is possible to obtain either air lime (clay content is not more than 8%), or hydraulic lime (clay content in the rock is not more than 8 - 20%). Distinctive feature air lime is that it hardens only in air and does not have water resistance, and hydraulic lime has a faster hardening and acquires water resistance - after it has been hardened in air for at least two weeks, it can be placed in aquatic environment. Air lime is the most widespread and during its production, under the influence of temperature, the following occurs: chemical reaction CaCO 3 →CaO + CO 2

At the same time, calcium carbonate loses carbon dioxide(CO 2) up to 44% of its mass, becomes light and porous. The product obtained in this case is lump quicklime (finely porous pieces 5-10 cm in size). Subsequently, lump quicklime is subjected to either slaking with water or additional grinding to obtain quicklime powder.

Depending on the amount of water used for slaking lump lime, the following products can be obtained:

• Hydrated lime ( fluff)
• lime dough
• milk of lime

Hydrated lime ( fluff)

The finest white powder obtained by slaking lime, usually in the factory (continuous hydrators) with a small amount of water (slightly higher than theoretically required - 50-70% of water by weight of lime). When quenched in fluff, lime increases in volume by 2 - 2.5 times.

Bulk density - 400-450 kg / m 3

Humidity - no more than 5%

lime dough

It is obtained by quenching lime with water, when the amount of water is 3-4 times the mass of lump lime. The extinguishing process is carried out in special extinguishing boxes (creators). Lump lime is loaded into the box no more than 1/3 of its height (layer thickness is about 10 cm), since lime increases in volume by 2.5-3.5 times during slaking. Quickly quenched lime is poured immediately with a large amount of water to prevent overheating and boiling of water, slow-extinguishing - in small portions, making sure that the lime does not cool. From 1 kg of lump lime, depending on its quality, 2-2.5 liters of lime paste are obtained. The water content in lime paste is not standardized. Usually in a well-aged dough, the ratio of water and lime is about 1:1. The time required for the final completion of the extinguishing process is at least two weeks.

milk of lime

When quenching, the amount of water exceeds the theoretically required 8-10 times.

The advantage of powdered quicklime over lumpy lime is that when mixed with water, it behaves like gypsum binders: first it forms a plastic dough, and after 20-40 minutes it seizes. This is due to the fact that the mixing water, which forms the dough, is partially spent on lime slaking. In this case, the lime dough thickens and loses plasticity. Due to the lower amount of free water, powdered lime based materials are less porous and more durable. In addition, lime is heated during slaking, which makes it easier to work with it in cold weather. Depending on the quality of lime, the water required for mixing is 100-150% by weight of lime (determined empirically).

The most important indicators of the quality of quicklime powder are:

• Activity - the percentage of oxides that can be extinguished.
• The number of unextinguished grains (underburnt or burnt).

Underburned (undecomposed CACO 3) obtained at too low a firing temperature reduces the quality of the lime, since does not have astringent properties.

Burnout is formed when too high temperature firing. Burnt grains are slowly quenched and can cause cracking and breakage of already hardened material.

• Extinguishing time. Depending on the quenching time, lime is divided into types:
• quick-extinguishing - up to 8 min
• medium extinguishing - up to 25 min
• slow-extinguishing - at least 25 minutes

According to the characteristics of the composition, lime is divided into 3 grades

OOO "GeoStyle" +7 495 663 93 93 offers slaked hydrated lime

from four factories - manufacturers

Comparative table of characteristics of slaked hydrated lime

OOO "GeoStyle" offers for its customers

high-quality ground quickcalcified lime of the 2nd grade without additives

produced by JSC "Lime Production Plant" (Vladimir region)

Quality indicators of ground quicklime

GOST 9179-77

JSC "Lime plant"