Slaked lime: characteristics and scope

Slaked lime is a chemical substance that is used by humans in many fields of activity. The scope of repair work is no exception. But for the work to be truly productive, it is important to apply the composition correctly. In order to avoid mistakes, it is necessary to familiarize yourself in advance with the features of the slaked substance, various classifications of compositions and recommendations for their competent use.

Slaked lime is a substance that is formed when water and calcium oxide are mixed. In another way, such lime is called fluff. When hydrated lime is obtained, such an amount of energy is released, which would be enough to boil water or ignite a tree. An important role in the formation of the slaked composition is played by the temperature of the water with which the quicklime reacts. Sometimes this substance is obtained by burning coal.

Slaked lime is a white powder. Sometimes it looks like white crystals that can withstand exposure to rather high temperatures, up to 560 degrees. However, if the temperature exceeds this value, then the reverse process of decomposition into quicklime and water occurs. The composition is insoluble in alcohol. Its chemical formula is Ca (OH) 2.

The material has a number of valuable advantages:

• able to protect the surface from moisture;
• has a disinfectant effect;
• improves the quality of various concrete and cement mortars.

A small drawback is the inability to use such a substance for finishing work. It is usually used as an intermediate layer.

Hydrated lime is different. It is the belonging of the composition to a certain variety that determines the features of the scope of its application. There are several types of classifications for this substance.

The first sign is the time it takes to quench the calcium oxide. There are several types.

• The fast-extinguishing composition is extinguished in no more than 10 minutes (regardless of the initial volume). Sometimes the process takes place even in a shorter period of time.
• Lime slaked at an average speed usually changes its composition in a quarter of an hour.
• When the duration of the chemical process exceeds 30 minutes, lime is classified as slowly extinguishing.

The second sign of the classification of slaked limestone mixture is the size of its fractions.

There are compositions of various grindings.

• Lump lime has the largest fractions, usually it is produced in tons.
• Composition with medium fractions - crushed lime. Such a product is usually stored in mounds and warehouses.
• The powdery material is sold in smaller quantities. One package usually weighs several kilograms.

The composition of the material may include various axid inclusions.

According to this feature, substances are divided into:

• calcium (usually used for laying);
• dolomite (they deoxidize the soil well);
• magnesian compositions (used for plastering surfaces).

An important characteristic is the hardening feature of the limestone composition.

This process can occur in two ways, which subsequently determine the scope of the composition.

• Hydraulic hardening forms substances that are used for additional strength.They are added to solutions used for work in direct contact with water. This product is used in the construction of port fortifications or bridges. It is characterized by a viscous composition and a dough-like consistency. There are also highly hydraulic and weakly hydraulic varieties of such a substance.

• Air hardening provides a composition that is less viscous in consistency. This material is often used in the construction industry. It is often used to make plaster, various coloring mixtures and solutions for masonry. The main function of such a product is to enhance the hardening of various solutions in conditions with low humidity levels. In combination with calcium carbonate, such lime is used to make some building mixtures (Portland cement and others).

Freshly slaked lime occupies a special place in limestone hydrates. It is the same calcium hydroxide. The difference is that no more than 6 hours should elapse from the moment of its extinguishing. This composition is usually suitable for making milk of lime.

Lime, being a viscous inorganic substance, in combination with asbestos fibers can also take on special forms and form derivatives. These products include asbestos board and asbestos paper

Hydrated lime, like any building material of chemical origin, has a number of technical parameters officially enshrined in GOST 9179-77.

There are several main characteristics of this material.

• The composition of this building mixture may include the following components: mineral additives such as electrothermophosphoric, granular or blast-furnace slags, quartz sands, active mineral additives, carbonate rocks. All substances must comply with the requirements of special regulatory documents.
• The type of hydraulic lime is characterized by properties such as compressive strength.

• Both air and hydraulic formulations are considered usable if they remain uniform when the volume changes.
• The quality of varieties of lime compositions is determined by the ratio of calcium and magnesium oxides to water. The premium product contains 90% of these substances in relation to the percentage of water. The decrease in quality is directly proportional to the amount of magnesium and calcium.
• The fluff should have a specific gravity in the range of 450 to 550 m3.
• Calcium hydroxide must meet specific physical properties such as strength. It is checked 28 days after the preparation of the substance during its bending and compression.
• The acidity of the composition should be 12.4 pKa.
• The density of the substance is 2, 211 g / cm3.

Slaked lime is used in various branches of human activity.

This substance has become indispensable in many types of work, as well as in everyday life.

• In a garden or vegetable garden, hydrated lime is needed in order to lime the soil. This procedure significantly increases the fertility of the soil. Thanks to liming, the acidity level of the earth is reduced, and favorable conditions are created for the cultivation of various crops. Also, lime compositions save many plants from pests and parasitic larvae.

• Since the substance is capable of imparting strength to various materials, it is often covered with wooden structures (benches, fences, gazebos, and even pegs in the beds). Also, such a coating protects various structures from the effects of fire.
• In certain seasons, whitewashing of garden trees is carried out with the help of slaked lime. They are covered with a special solution based on slaked lime, which saves plants from the influence of temperature extremes.
• To prevent mold from forming on garden tools or in rooms such as a cellar, calcium hydroxide is also used.

In addition to gardening, fluff is actively used in many construction work and some other areas.

• Calcium hydroxide is used in masonry. It creates high adhesion to both brick surface and cinder block materials.
• In order to save money during construction work, a lime mortar known from antiquity is sometimes made by mixing slaked lime with sand.
• On the basis of calcium hydroxide, a composition such as bleach is produced. It is an excellent disinfectant.

• The substance is used for the manufacture of a special type of concrete - silicate. It hardens more quickly.
• With the help of this substance, not only the street structures and trees are whitewashed, but also the walls and ceilings in the room.
• Slaked lime is a part of calcium-based compounds, thanks to which water purification is carried out.

• Fluff is used in leather tanning.
• Calcium hydroxide is used in dental procedures such as root canal cleaning.
• Slaked lime is even added to food. The substance is used as part of the E526 additive.

Fluff is actively used in various industries:

• metallurgical;
• chemical;
• sugar;
• construction;
• pulp and paper.

Usually fluff is made in the factory. Such a product turns out to be of better quality. Quenching is carried out using a hydrator in a special container. The second third of the container is filled with water, and the last unfilled part is left for lime, because the volume of the substance increases during the reaction.

You can also extinguish lime directly at the construction site. However, products made at the plant have a longer shelf life than products made under stationary conditions. As time passes, the properties of such a mixture also improve.

There are 3 ways to create hydrated lime.

• In the first version, lime clods are used. They are laid out in layers 0.25 m thick. These layers are poured over with water. Wet sand is also added. After a couple of days, the quenching process will be completed, and the mixture will be ready for use.
• In the second option, you need to dig a hole and install a wooden box in it, at the bottom of which there should be a damper made of a fine mesh. The lumpy material is placed in a box, then it must be filled with water. Liquid is added as the lumps break down into smaller fractions. As soon as the extinguishing process occurs, it will be necessary to drain the excess water through the damper, while the mixture must be covered with a 10-centimeter layer of sand. This technique protects the composition from drying out.

• The third option involves slaking lime by mixing it with water. You can prepare a calcium hydroxide solution using the third method yourself, by analogy with the production process.

It is important to follow a certain sequence of actions.

• Take care of safety measures. To do this, be sure to wear tight clothing, gloves and protect your eyes. Remember that if the composition comes into contact with the mucous membrane of the eye, vision can be severely affected.
• Use a plastic container to dilute the compound. If you chose a container made of metal, then check it for rust. There shouldn't be such formations.

• An ordinary wooden stick or even a stalk from a garden appliance is suitable as a tool for mixing the composition.
• Before preparing the mixture, measure out the required amount of dry lime and calculate its proportions with water. Remember that the consumption of the substance per 1 sq. m. will depend on its consistency and on the number of layers that you plan to apply to the surface.
• Pour lime into the container first, and then add water in portions. In this case, be sure to stir the composition throughout the entire time. The water should be cold.If you add water at high or even room temperature, then the quality of the final composition will significantly deteriorate.

• The readiness of the solution can be determined by the trace on the stick. If it has a pronounced white tint, then the composition has reached readiness.
• In order for the solution to infuse, after stirring it should be left for a while. If possible, wait a few days, but if this is not possible, insist the slaked lime for several hours.

A separate process is the dilution of the fluff to the consistency of milk of lime. After obtaining calcium hydroxide by mixing an equal amount of lime and water, the substance is left for some time to dry out. Then the resulting composition must be diluted with 9 liters of water. The finished milk of lime is a 10% mixture of lime.

If you decide to whitewash the walls with slaked lime at home, consider the method of obtaining the composition. If you made the mixture not with the help of a special hydrator-separator, but manually, then you must thoroughly mix the solution immediately before whitewashing. The composition is applied to the ceiling and walls with a large brush. The procedure starts from the left corner of the window. It is important to try to apply the solution without gaps, but in any case it is more advisable to apply several layers of the substance.

If a lime composition is used to whitewash trees, a certain sequence of actions must be followed.

• Fill a bucket with a volume of approximately 10 liters with water.
• A couple of kilograms of fluff should be diluted with 1.5 kilograms of clay and 300 grams of copper sulfate added to the solution.
• Then all components should be thoroughly mixed in water until a finished composition with the consistency of sour cream is obtained.
• The resulting solution is applied to the tree trunk. When doing this, do not scoop too much of the substance to avoid smudges. The finished layer should not exceed a thickness of 4 millimeters.

Inexperienced builders do not always use the slaked lime composition correctly. To learn how to use calcium hydroxide, to protect your health and get an effective result, it is necessary to listen to certain recommendations.

• If you decide to treat a summer cottage greenhouse with slaked lime, apply the substance both inside and outside the building to provide reliable protection against pests.
• Do not add ready-made mortar, such as concrete, to the freshly slaked mixture. A certain time must pass for all powder particles to acquire a uniform consistency. If you add the finished solution ahead of time, then the quality and consistency of the final mixture will significantly deteriorate.

• When using slaked lime to get rid of the soil from acidity, you need to correctly calculate the amount of the composition. It is determined by the acidity level. Only by measuring this level with the help of special pH devices, you can understand how much calcium hydroxide you need.
• Only freshly quenched limestone is suitable for treating garden tools.
• If the hydration solution gets on the skin, it is necessary to remove the composition with a cotton pad soaked in vegetable oil. After that, make a gauze compress, which must be moistened with 5% vinegar essence.

• If you are going to make a lime-based solution, then pre-sifted sand can be gradually added to the pasty composition. After mixing, strain the finished solution through a special sieve, thereby improving its uniformity.
• To speed up the setting period of the composition, add gypsum to it. Thanks to this material, the lime mortar will set in less than 5 minutes.

• You can store slaked lime for various periods of time. The specific period determines the solution in which it is included.The storage of the plaster mixture with the addition of sodium hydroxide is about a month, while the mortar for masonry can be stored for no more than two weeks. If you plan to store lime in winter, you must protect it from freezing. You can even bury containers with the composition in the ground, but the depth of the pit should be at least 70 centimeters. If you have materials available for thermal insulation, then they will also come in handy for storing slaked lime.
• If you dilute the lime yourself, it is important that the process takes place outdoors. Remember that lime fumes are quite toxic and can be hazardous to your health.

• When you first use a slaked lime solution that you made yourself, chances are, you will end up with small lumps of lime. You should not get rid of them right away, you can find them re-use by soaking them with water.
• Pay attention to the consistency of the mortar immediately prior to application. Sometimes such a composition needs to be diluted.

Hydrated lime is a truly useful and useful material.

See the following video for the slaked lime production process.