Slaked lime - what is it, production, history, main characteristics

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It is obtained by reacting calcium oxide (quicklime) with water, a process called “slaking lime.” When slaking lime, a significant amount of heat is released, amounting to 65 kJ per 1 mole, or 1160 kJ per 1 kg of calcium oxide. In this case, the temperature of the slaking lime can reach values ​​at which not only water can boil, but also wood can ignite.

Classification of lime. Construction lime, depending on the hardening conditions, is divided into air lime, which ensures the hardening of mortars and concretes and their preservation of strength in air-dry conditions, and hydraulic lime, which ensures the hardening of mortars and concretes and their preservation of strength both in air and in water. Airy quicklime, depending on the content of calcium and magnesium oxides in it, is divided into calcium, magnesium and dolomite. Air lime is divided into quicklime and hydrate (slaked), obtained by slaking calcium, magnesium and dolomite lime. Hydraulic lime is divided into weakly hydraulic and strongly hydraulic. Based on its fractional composition, lime is divided into lump lime, including crushed lime, and powdered lime. Powdered lime, obtained by grinding or slaking (hydration) of lump lime, is divided into lime without additives and with additives. Based on the slaking time, construction quicklime is divided into fast slaking - no more than 8 minutes, medium slaking - no more than 25 minutes, slow slaking - more than 25 minutes.

Physico-chemical indicators of slaked lime GOST 9179-77:

Note: 1. CO2 in lime with additives is determined by the gas-volume method. 2. The moisture content of hydrated lime should not be more than 5%.

Packaging, transportation and storage. Lump lime is shipped in bulk, powdered lime is shipped in bulk or in paper bags. Four-layer paper bags can be used. Lime is transported by covered transport of all types in accordance with the rules of cargo transportation in force for this type of transport. It is permitted, with the consent of the consumer, to supply lump lime in all-metal gondola cars and open vehicles, provided that its quality is maintained and the necessary measures are taken against 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. The guaranteed shelf life of the product is 30 days from the date of its shipment to the consumer.

Do you use expired food for cooking at home?

Yes, the main thing is to process it if it is meat or expired kefir for pancakes.

27.72%

No, it is very dangerous and not useful.

36.37%

If the products have fungus or mold, then we throw them away; if they are a couple of days past their expiration date, we use them for food, even without heat or other treatment.

35.91%

Voted: 1952

LLC Plasma Company® supplies chemical products from a warehouse in Kharkov on time and at affordable prices, on terms favorable to you.

Packaging, transportation and storage. Lump lime is shipped in bulk, powdered lime is shipped in bulk or in paper bags. Four-layer paper bags can be used. Lime is transported by covered transport of all types in accordance with the rules of cargo transportation in force for this type of transport. It is permitted, with the consent of the consumer, to supply lump lime in all-metal gondola cars and open vehicles, provided that its quality is maintained and the necessary measures are taken against 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. The guaranteed shelf life of the product is 30 days from the date of its shipment to the consumer.

Application of lime

1. Hydraulic construction lime (slaked):

Preface

1 DEVELOPED by the Limited Liability Company "Research Engineering (LLC "NIITs "Sintez")

2 INTRODUCED by the Technical Committee for Standardization TC 60 “Chemistry”

4 INTRODUCED FOR THE FIRST TIME

5 REPUBLICATION. April 2021

The rules for applying this standard are established in Article 26 of the Federal Law of June 29, 2015 N 162-FZ “On Standardization in the Russian Federation”. Information about changes to this standard is published in the annual (as of January 1 of the current year) information index “National Standards”, and the official text of changes and amendments is published in the monthly information index “National Standards”. In case of revision (replacement) or cancellation of this standard, the corresponding notice will be published in the next issue of the monthly information index “National Standards”. Relevant information, notices and texts are also posted in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet (www.gost.ru)

Pros and cons of slaked lime

The main advantage of slaked lime is its low cost with extensive use in many areas. Other advantages:

• great strength;
• does not allow moisture to pass through;
• does not ignite;
• lye is caustic lime, which prevents mold and fungi from developing on the walls;
• slow hardening;
• keeps the room warm.

Disadvantages of slaked lime:

• We do not recommend using the material in places of high moisture;
• manual extinguishing may take two or three weeks;
• slow drying on the walls can increase the repair time.

Storage - quicklime

Storage of quicklime is provided in a closed, dry, unheated room designed for a 15-day supply. Increasing the shelf life of lime leads to its carbonization, which complicates the preparation of lime and reduces its active capacity. It is rational to store lime in special bunkers, loaded with a forklift and equipped with feeders for supplying it to the tanks. [1]

Storage of quicklime is provided in a closed, dry, unheated room designed for a 15-day supply. Increasing the shelf life leads to carbonation of the lime, which makes preparation difficult and reduces the active capacity. It is rational to store lime in special bunkers, loaded with a forklift and equipped with feeders for supplying it to the tanks. [2]

The shelf life of quicklime in paper bags from the moment of manufacture should not exceed 15 days, and the shelf life of quicklime in airtight containers is not limited. [3]

It is believed that when storing quicklime, contact with moisture can lead to such heating that the wood can ignite. [4]

The roofs of sheds intended for storing quicklime must be impermeable to precipitation. [5]

The shelf life of quicklime in paper bags from the moment of manufacture should not exceed 15 days, and the shelf life of quicklime in airtight containers is not limited. [6]

Cement and quicklime (kipelka) are stored in silos or closed warehouses with a dense wooden floor. When storing quicklime, it is necessary to especially carefully protect it from moisture. [7]

Quicklime must be stored in closed, separate warehouses. When storing quicklime, measures should be taken to prevent the ingress of moisture and water. [8]

Cement and quicklime (kipelka) are stored in silos or closed warehouses with a dense wooden floor. When storing quicklime, it is necessary to especially carefully protect it from moisture. [9]

Quicklime must be stored in closed, separate warehouses. When storing quicklime, measures should be taken to prevent the ingress of moisture and water. [10]

The lime facility of the chemical shop (Fig. 2.12) is intended for storing quicklime, preparing lime milk and dosing it into clarifiers. The maintenance of this facility is carried out by an overhead crane operator and a VPU operator. The lime production area is dusty, so it must be equipped with supply and exhaust ventilation. Lime samples are taken from each incoming wagon to determine its quality. The volume of the cell for storing dry lime must be selected taking into account its minimum reserve for uninterrupted operation of the water treatment unit for 15 days. [12]

Hydrated lime is shipped in cement trucks, containers or unimpregnated kraft cellulose bags. The shelf life of powdered types of pneumatic quicklime in paper bags should not exceed 15 days from the date of manufacture. The shelf life of quicklime in an airtight container is not limited. [13]

Diatomite chips, andesite and diabase powders are stored in bins in closed warehouses. Mortars, fire-resistant powders, fire-resistant fillers for heat-resistant concrete are stored in bunkers (silos), in bins, in closed warehouses or under a canopy separately under conditions that do not allow their mixing with each other, contamination with foreign impurities and moistening by precipitation. Cement and quicklime (kipelka) are stored in silos or closed warehouses with a dense wooden floor. When storing quicklime, it is necessary to especially carefully protect it from moisture. [14]

Characteristics of slaked lime

According to GOST, slaked lime material has the following characteristics:

• The specific gravity of the fluff should be from 450 to 550 m³.
• The main properties of hydraulic lime are strength and compression.
• 90% of the calcium and magnesium content in the composition, in relation to 10% water, is slaked lime according to GOST. Less quality products have a small amount of these substances, with a higher percentage of water.
• A high-quality composition is considered to be one in which changes in volume do not affect uniformity.
• Slaked lime includes: mineral additives, quartz sand, carbonate rocks, blast furnace slag.
• The acidity of slaked lime is 12.4 pKa.
• Product density 2.211 g/cm³.
• It is interesting that slaked lime changes its technical characteristics if there was an admixture of clay in its original composition.

Safety Notes

According to the degree of influence on the body, bleach has a toxic effect. Purchasing bleach means seriously taking care of its precise transportation and conservation.

The main thing to remember here is that the products of the chemical industry are considered a powerful oxidizing agent (not flammable on their own) and, when coming into contact with other organic solutions, can provoke their ignition.

Containers containing bleach can ignite when heated, an explosion can cause the element to bond with petroleum products, as well as impact and friction. After disinfection with chlorine substances, it is recommended to ventilate the room.

You should know that the instructions for using slaked lime are considered an important step before starting disinfection procedures. Here is its formula. When working with this substance, it is necessary to use personal protective equipment: gloves, respirators, special safety glasses and rubberized aprons.

Toxicity

It is necessary to purchase chemical products after the consumer has read all the necessary recommendations for use with the drug. One should not lose sight of the likely consequences of improper use or direct contact with dermatological surfaces and inhalation of a caustic substance.

Once on the skin and mucous membranes, unpleasant pain, swelling and superficial ulcers of various sizes occur.

If the substance enters the respiratory tract, it causes shortness of breath, difficulty breathing and a sore throat.

There is also lacrimation, pain in the abdomen, nausea and yellowing of the dermis. First, you must immediately wash off the entire solution from the body, including the eyes and nasopharynx, with plenty of water. Then the victim should be taken outside and given milk until medical personnel arrive.

Storage and shelf life of chlorine solution

The substance must be left out of the reach of children and animals. Information with the name of the drug and expiration date is always printed on the packaging. Storage bags are made of polyethylene and are closed.

The main conditions for saving are:

• warehouses without heating;
• protection from light;
• regular ventilation;
• the floors are asphalted, brick or concrete.

Shelf life: 12 months.

Poisoning

Intoxication can result in complete loss of consciousness or even lead to the death of the victim.

When interacting with this element, the main thing is to be extremely careful and carefully read the instructions for using bleach.

Intoxication with bleach is possible in 2 ways: through intensive inhalation of the vapors of the drug, and the penetration of toxic elements into the body through the skin or gastrointestinal tract.

Bleach poisoning is likely in the following cases:

• the predominance of the maximum possible amount of toxic substances in water;
• when used in closed, unventilated rooms;
• ignoring recommendations for making solutions. Here are the proportions of cement-lime mortar for plaster;
• visiting swimming pools with an increased level of the drug;
• occurrence of problems in production;
• lack of protective equipment.

When children are in the building, 100% care must be taken to protect them from the effects of toxic chlorine-based products.

Intoxication

4 levels of intoxication are emphasized due to the severity of the person’s condition. The first level is characterized by tickling in the throat area due to damage to the mucous layer of the respiratory tract. There is severe lacrimation, coughing, and a feeling of chlorine aroma, even when in the fresh air.

Treatment of such a condition during intoxication will not be required, since after a certain period everything goes away on its own. The second level of severity contains the following properties - a person begins to choke, discomfort occurs in the chest area, and sudden tingling in the eyes.

In this condition, you should immediately seek medical help. Otherwise, there is a risk of developing swelling of the respiratory organs.

The third level is a severe form of intoxication, which is formed under the influence of a person’s long-term presence in a room with a toxic drug.

Heavy breathing may eventually stop if you faint. Muscle spasms and cramps also appear. The veins in the neck become very distended. The victim should be immediately taken to intensive care, connecting the patient to an artificial respiration apparatus.

The fourth level is a rapidly flowing stage. If timely assistance is provided to the victim, it will not give the slightest positive change, but will only lead to death in a matter of minutes.

Slaked lime - application

The most common uses for slaked lime are construction and gardening, but there are many other ways to use the material:

• water softening by producing hydrogen oxide;
• tanning of many types of natural leather materials;
• for chemical calcium compounds;
• for the production of organic acids;
• for detecting carbon dioxide indoors;
• dentists use disinfectants that contain slaked lime;
• for whitewashing walls and ceilings;
• as a food additive E526;
• for treating wooden houses as protection against fire and rot;
• for whitewashing trees with lime;
• for cleaning waste pipes;
• for laying the inside of a Russian stove.

What is slaked lime?

When calcium oxide and water interact, a white powder material or a lumpy mixture is obtained - slaked lime, formula (Ca(OH)2). The chemical process is accompanied by an increase in temperature, which carries a certain danger to humans. In strength, it is equal to the amount of energy that is released when water boils. Lime differs in slaking time, so the process can last from eight minutes to more than half an hour.

• calcium;
• magnesia;
• dolomite.

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Bleach stock solution: preparation

When mixing the components of the disinfectant, it is important to follow safety rules: wear protective gloves, goggles, a gown, a cap, a respirator, an apron made of rubberized fabric, and rubber boots. The recipe is as follows:

• Pour 1 kg of dry material into an enamel container with a small amount of water, grind with a wooden spatula until it becomes a homogeneous paste;
• Bring the amount of liquid to 10 l, stir until a homogeneous mixture is obtained and leave for 24 hours in an enamel container with a lid, stirring periodically for the first 4 hours;
• Carefully pour the resulting substance into a labeled glass or enamel resealable container and fill the oilcloth label. The permissible storage period is 7-10 days.

Working solutions of bleach of various concentrations are prepared from this disinfectant. They have bactericidal, fungicidal, virucidal, sporicidal properties. They have an even shorter shelf life - from 1 to 3-4 days, after which they lose their effect, so it is recommended to mix the ingredients immediately before use.

Working trains

Disinfectant solutions containing the active ingredient 0.25%, 0.5%, 1%, 2%, 3%, 5% are used to disinfect certain items. To prepare them, a ten percent bleach solution is diluted with water in accordance with the desired saturation: for example, to get 0.5 liters of a 0.5% product, you need to dilute the first with 9.5 liters of liquid.

Such substances are prepared to achieve the following purposes:

• disinfection of hands and equipment (0.25%);
• preventive disinfection of equipment in somatic departments, rinsing dishes, washing floors (0.5%);
• disinfection of objects for intestinal infectious diseases, doors, walls, floors (1%);
• processing of cleaning tools, car bodies, tables (2%);
• disinfection treatment for HIV infection, viral hepatitis (3%);
• disinfection of tools, surfaces in sanitary facilities, toilets (5%).

To enhance the disinfecting effect, it is possible to use a special activator - for example, ammonium hydroxide. The amount of activator depends on the weight and the content of active chlorine in the disinfectant composition of a given concentration.