Lime construction quicklime 1 grade. Quicklime: features and scope

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%). A distinctive feature of air lime is that it hardens only in air and does not have water resistance, while 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 an aquatic environment. Air lime is the most widespread and during its production, under the influence of temperature, the following chemical reaction takes place CaCO 3 → CaO + CO 2

At the same time, calcium carbonate loses up to 44% of its mass with carbon dioxide (CO 2), 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.

SLAKED LIME

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 immediately poured 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. Typically, in a well-aged dough, the ratio of water to 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.

QUICKLY POWDERED LIME

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.

Overburning occurs when the firing temperature is too high. 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

Name of indicator	Variety
Name of indicator	1	2	3
not less, %

LIME APPLICATION

	Construction Lime is used for the preparation of mortars, in the production of lime-pozzolanic binders, in the production of thermal insulation materials, for the manufacture of artificial stone materials - silicate bricks, gas silicate blocks, as well as in the production of paint compositions, in the production of dry building mixtures: plaster, adhesive, grouting , masonry compositions, putties.
	Water treatment and water treatment Lime softens water, precipitates organic substances in water, and also neutralizes acidic natural and waste water.
	Agriculture When lime is added to the soil, acidity harmful to agricultural plants is eliminated. The soil is enriched with calcium, the workability of the land is improved, the decay of humus is accelerated, and the need for large doses of nitrogen fertilizers is noticeably reduced. In animal husbandry and poultry farming, hydrated lime is used for feeding in order to eliminate calcium deficiency in the diet of animals, as well as to improve the overall sanitary conditions of livestock.
	Lime Safety Air lime of all kinds is a fairly strong alkali. Therefore, when working with it, it is necessary to take measures to prevent contact of lime with open areas of the skin and especially the respiratory tract and eyes. Quicklime is especially dangerous. The concentration of lime dust in the air should not exceed 2 mg/m 3 .

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

from four factories - manufacturers

Comparative table of characteristics of slaked hydrated lime

Options	KrasnoselskSM	Uglovsky plant	Kovrov plant	Donizvest
GOST	9179-77	9179-77	9179-77	9179-77
Lime grade
	84,39	68,04	67,32	71,0
	5,80	2,98
Humidity, %	0,87	0,36		0,28
Grinding fineness:
The rest of the particles on the sieve with mesh No. 02,%	0,19	1,48
The rest of the particles on the sieve with mesh No. 008,%	1,28	9,20		0,31

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

OJSC "Lime plant"

Name of indicator	Analysis result
Variety	second
	80,10
including МgO, %	2,34
Extinguishing speed, min.

Hydrated water, %
Extinguishing temperature, o C
Dispersion:
Residues on sieve No. 02, %
Residues on sieve No. 008, %

Lime is widely used in the production of building materials and as a raw material for the treatment of certain surfaces. Lime is produced by firing in special equipped kilns at a temperature of 1000 to 1200 degrees of carbonate rocks. Heat-treated lime takes the form of pieces of irregular shape, which are subjected to various processing in the process of further use.

Chemical formula and composition of lime

No chemical catalysts are used for the production of lime, the main condition for its production is only the appropriate thermal regime. Thanks to this, a completely natural material is made during the manufacturing process, the content of small clay impurities in lime is allowed.

Limestone has the formula CaCO3 because it is predominantly composed of calcium. In the process of temperature exposure, carbon dioxide is released and the raw material produced has the formula CaO.

The process of contact of lump lime with water looks like this - CaO + H2O? Ca (OH) 2, there is a specific term for this reaction, referred to as lime slaking.

Slaked lime can be in several states:

Fluff or fine powder is obtained by mixing pieces of lime with water, and the percentage of moisture should be from 60 to 70%.
Lime dough is a combination of the starting material with water, it takes about 3.5 times more. As a result of such quenching, a dense mass is formed, which is used in various fields.
If you dilute pieces of lime with water in a ratio of 1:10, you can get milk of lime. Such slaked lime is used for whitewashing the interior of buildings, facades, outbuildings.
If slaked lime is not used for a long time, then the reverse process occurs, that is, the solution absorbs carbon dioxide and hardens. On sale, you can most often find lime - fluff or lump.

Photo of ground construction lime

Technical properties

There are special requirements for the manufacture of slaked and quicklime, regulated by the state standard (GOST 9179-77):

In the production of lime, only carbonate rocks and a certain amount of mineral additives are used. The amount of additives should not exceed the amount specified in the standards for a particular grade of lime.
Quicklime is divided into three grades and should not contain additives, powdered lime with additives is produced in two grades, slaked lime may or may not have additives and is divided into two grades.
In calcium lime, the main component is calcium, the percentage of MgO should not be more than 5.
Dolomitized lime contains MgO up to 20%
Dolomitic up to 40% MgO.
The hydraulic may include silica, iron oxides, a small amount of clay.

The properties of lime are determined by the rocks used for firing and by the manufacturing process itself. As a result of the heat treatment of limestone, solid pieces of quicklime come out of the kilns, its color depends on the additives present, the whiter the shade, the higher the grade of the material. Dolomitic and hydraulic lime have a grayish tint.

- This is a substance known to almost everyone, which is in demand in various fields. It is indispensable in the production of concrete, mortar, binders, artificial stone, all kinds of parts, etc.

When in contact with water, carbon dioxide is released and lime passes into a liquid state, the concentration of which depends on the amount of water. Depending on the firing process and temperature, lime of different strength can be obtained - hard-burned, intermediate and soft-burned.

As a building material, soft-fired is more common, it has the following characteristics:

The smallest grain size.
Less density.
The shortest blanking time. Hard-fired liquefies in 10 minutes, soft-fired in 3 minutes.

In the process of extinguishing lime, heat is released, therefore, if safety precautions are not followed, a severe burn can also occur.

The density of quicklime depends on the temperature used in the kilns. Lime, fired at 800 degrees, has a density of 1.6, an increase in temperature to 1300 degrees allows you to get pieces of raw materials with a density of 2.9 g / cm3.

According to the hazard class, lime belongs to low-hazard substances. But there are certain requirements for its storage and transportation. Quicklime must be protected from moisture, as moisture ingress and heat escaping can cause a fire.

The certificate of conformity of lime must contain information about its grade, percentage of impurities, condition. The certificate is issued to certain organizations that comply with GOST for the manufacture of this building material.

Lime is well tolerated by people with allergic respiratory diseases. But at the same time, one should not forget that when extinguishing the material, it is possible to get burns, and the vapors released at this time are dangerous for the mucous membranes of the respiratory tract and eyes. Subject to safety measures when working with lime, it is completely safe and not harmful to health.

It is obtained by mixing unslaked lime with water, the name of the latter is calcium oxide. The chemical quenching process is accompanied by an increase in temperature

Stamps and some types of lime

Lime is subdivided both by grades and by primary raw materials used.

The type and brand of lime determines the main scope of its application:

building lime made from calcium and magnesium rocks. Apply building lime for introduction as a plasticizer in concrete mixes, solutions. Building lime is produced in lumps, in the form of small fluff or lime paste.
hydraulic lime- a product of roasting limestone containing from 6 to 20% clay impurities. This type of lime is used for the production of low-grade concrete, since, along with high strength, it has low ductility. Hydraulic lime is often used in the construction of buildings, the operation of which involves being in a humid environment.
lump lime it is a semi-finished product used for the manufacture of powdered raw materials or solutions. Lumps of lime are stored in closed warehouses, protected from moisture. Lump lime goes on sale for the preparation of solutions for whitewashing.
garden lime necessary for the enrichment of acidic soils. In acidic soils, the calcium content is minimal, which leads to poor plant growth and development. The introduction of slaked and quicklime into the soil is carried out in spring or autumn, and preferably during rains, so the limestone dissolves better. Lime is not applied simultaneously with the use of other fertilizers, and during operation it is imperative to protect your eyes and hands.
Soda (soda) lime- porous white mass, which is a mixture of caustic soda and slaked lime. Soda lime is used as an absorber of carbon dioxide and moisture from the air. It is used in chemical laboratories, for the production of gas masks, diving equipment. In medicine, it is used as a sorbent for anesthesia machines and pressure chambers.
Bleaching powder obtained by a complex combination of free chlorine and calcium hydroxide. Chlorine lime has strong disinfecting properties, and was previously used in its pure form in healthcare facilities. Today, bleach is used to disinfect toilets, cesspools, and to produce solutions for disinfection. Chlorine also has bleaching properties.

Photo of soda and bleach

Soda lime packaging Soda lime Bleach packaging Bleach

Mining and production technology

Lime production basically consists of two steps:

Extraction of limestone and other used rocks. For the production of lump lime, waste products from industries that use limestone for other purposes can also be used.
Roasting of prepared rocks.

Limestone is mined in open pits using explosives. Selective mining of rocks makes it possible to prepare raw materials that are homogeneous in their density and chemical composition, which affects the quality of the lime produced in the future.

Preparation of raw materials is carried out by its crushing. Since the temperature in the furnaces is set in advance, the use of fractions that differ greatly in size leads to the fact that small pieces can burn out, and large ones cannot be completely heat treated.

Limestone calcination is the main technological stage in the manufacture of air lime. Depending on the content of impurities, different temperature conditions are also used. All technological conditions must be observed, since the burning of limestone leads to the formation of a material with low quality characteristics. Burnt lime is poorly soluble in water, has a high density and adversely affects concrete solutions.

The starting material is calcined in different kilns. Shaft furnaces are widely used, they are characterized by a continuous cycle of operation, efficiency, ease of control. Rotary kilns produce soft burnt lime of the highest quality.

Installations have been developed and are used that allow firing the material in a fluidized bed or in a suspended state. It is good to use such installations for roasting the smallest fractions of rocks, but they are characterized by low efficiency.

Educational film about lime, how it is made, from what and where it is used:

lime substitute

The lime used for the preparation of concrete mortars can be replaced by its analogues. Builders use Azolit, Cemplas, Zetesol. All these are plasticizers and all of them are endowed with something better, and in something worse qualities compared to lime. Therefore, the decision to choose an analogue should be made specifically in each case.

Dolomite flour is dolomite ground into a fine powder. The scope of its use is limited to soil fertilization. Liming improves the biological and physical properties of the soil, enhances plant nutrition, and eliminates pests.

How to distinguish chalk from lime

Sometimes it is necessary to distinguish chalk from lime, this can be done in several ways:

Lump lime dissolves in water with a characteristic hiss and splash. With chalk, this reaction does not occur.
Chalk is calcium carbonate and lime is calcium hydroxide. If you drop acid on the chalk, then a hiss will occur, lime does not react with acid. As an acid, you can take hydrochloric or acetic.
Chalk from fingers under running water is washed off quickly and without residue, lime is lathered and it is quite difficult to remove it.
Chalk-whitened surfaces are smeared quite intensively, this does not happen with lime.

Lime is one of the most inexpensive materials for redecorating premises. Lime solution is used both for and for outbuildings.

Lime with sawdust as a heater

Sawdust from different tree species is often used as insulation for walls, attics and floors. But they have a significant drawback - the possibility of decay and development of insects. This problem can be eliminated by adding lime to the sawdust.

Prepared sawdust must be mixed with fluffy lime, it must be taken about 10% of the bulk of the chips. Both materials mix well in a container and are used to fill voids. From sawdust and lime, non-flowing material can also be prepared.

To prepare it, you need 10% lime, 5% gypsum and the rest of the sawdust. Dry mixtures are mixed and diluted with water until a viscous mass is formed, which is immediately used. The liquid mass must be prepared in small portions, since the gypsum sets very quickly.

Water purification

For water purification, bleach is used, which has high disinfection properties. Water chlorination helps to avoid outbreaks of intestinal infections and other epidemics.

The constant use of such water leads to allergic reactions, promotes the formation of carcinogens in the body. In water, chlorine can combine with other substances, which affects the appearance of intoxication.

In order to reduce the effect of chlorine on the body, it is necessary to drink water passed through coal or other high-quality filters. At the same time, bleach is considered one of the most effective means, it prevents the occurrence of cholera, dysentery. Chlorine must be used to disinfect wastewater.

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.

Peculiarities

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

Advantages over slaked 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 broad scope.

Quicklime is dangerous to human health, therefore 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.

Specifications

Lime is a substance that is often found in nature (mainly in rocks), and the product is manufactured in full compliance with established standards, because mixtures based on this basis must perform protective functions at a high level.

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 is very similar in appearance to chalk or coke, but they have different 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 for the 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;
such material has a 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 sand and other substances.

Kinds

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 too large or too small pieces are encountered, they may not be completely heat treated, and this will reduce the quality of the 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

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

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 rate of hardening, calcium chloride or sulfuric acid is often used (gypsum material is also suitable).

Hydrated lime

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. The minimum redemption period 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.

Formulation types

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;
Komovaya- mainly used to prepare a solution for whitewashing;
Sadovaya- used in agriculture as a soil fertilizer, treatment of plants from insect pests, protection from decay and improvement of growth, it is highly undesirable to use it simultaneously with other types of additives and fertilizers;
soda– used in the chemical industry and in medicine;
Chloric- used as a disinfectant and for water purification.

Lime classification by slaking time

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

Types of air lime

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

calcium;
magnesian;
dolomite.

Scope of application

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, and serves as a 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.

Chlorine lime is used for disinfection and washing of public places. because it has disinfectant properties. Quicklime is used even in the 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).

Coating wooden surfaces with lime mortar protects them from rotting processes and fires.

How to use?

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.

You should not treat the soil with too much lime, as it will become alkaline, which will also not contribute to 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 treat a small area, 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.

The fluff has a wide scope: 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, 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 aging time of the finished mixture, the better it will perform its functions.
For the preparation of mortars, it is best to add sand as well.
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.

is a white crystalline solid. Refers to basic oxides, reacts with acid oxides and acids, forming salts. It dissolves in water with the release of energy, forming calcium hydroxide.
Density 3.37 g/cm³. Melting point 2570°C, boiling point 2850°C.

Lump quicklime is a semi-product. If it is used in slaked form, then it is preliminarily 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 some 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.

Physical and chemical indicators of quicklime GOST 9179-77

Name of indicator	Norm for lime,%, by weight
	calcium			magnesia and dolomite
	1 grade	2 grade	3 grade	1 grade	2 grade	3 grade
Active CaO + MgO, not less than: without additives with additives	90 65	80 55	70 3/4	85 60	75 50	65 3/4
Active MgO, no more	5	5	5	20 (40)	20 (40)	20 (40)
CO 2 , not more than: without additives with additives	3 4	5 6	7 3/4	5 6	8 9	11 3/4
Unquenched grains, no more	7	11	14	10	15	20

Note:
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, the content of unextinguished grains is allowed, in agreement with consumers, not more than 20%.

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.

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 (granular blast-furnace or electrothermophosphorus slag, 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.

	Norm for lime,%, by weight
	quicklime		hydrated
Name of indicator	calcium	magnesia and dolomite


Active CaO + MgO, not less than:
without additives
with additives
Active MgO, no more
CO2, no more than:
without additives
with additives
Unquenched grains, no more

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 for the chemical composition of 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. The maximum size of 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 has been 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 waste water and flue gases).

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.