What is calcareous

Calcareous is a class of minerals such as calcium carbonate.

All natural rocks with calcium carbonate as the main component, such as limestone, chalk, dolomitic limestone, etc., can be used to produce lime.

The natural rock whose main component is calcium carbonate is calcined at an appropriate temperature to remove the decomposed carbon dioxide, and the product with calcium oxide (CAO) as the main component is lime, also known as quicklime.

In actual production, in order to speed up the decomposition, the calcination temperature is often increased to 1000 1100. Due to the large size of the limestone raw material or the uneven temperature distribution in the kiln during calcination, lime often contains under-fired lime and over-fired lime. The calcium carbonate in the o-flint lime is not completely decomposed, and it lacks cohesion when used.

The structure of the flint lime is dense, the surface is often covered with a layer of molten matter, and the curing is very slow. Because the production raw materials often contain magnesium carbonate (MGO3), quicklime also contains the minor component magnesium oxide (MGO5), according to the amount of magnesium oxide content, quicklime is divided into calcareous lime (MGO5) and magnesia lime (MGO>5).

Quicklime is white or gray in the form of blocks, and for ease of use, block quicklime often needs to be processed into quicklime powder, slaked lime powder or lime paste. Quicklime powder is a fine powder obtained by grinding bulk quicklime, and its main component is CAO; Slaked lime powder is a powder obtained by curing lumpy quicklime with an appropriate amount of water, also known as hydrated lime, and its main component is Ca(OH)2;Lime plaster is a paste obtained by curing block quicklime with more water (about 3-4 times the volume of quicklime), also known as lime paste. Its main component is also Ca(OH)2.

Is it a calcareous soil, a soil with a high calcium carbonate content, which is generally neutral or weakly alkaline.

1. Lime powder is a white powdery substance with calcium carbonate as the main component. The range of applications is very wide, the most common is for the construction industry, that is, for industrial calcium carbonate; The other is food-grade calcium carbonate, which is widely used as a common calcium supplement. There are two types of calcium carbonate, which are commonly used as calcium supplementation nutrient fortifiers

One is heavy calcium carbonate, which is limestone crushed to a certain fineness and used as a food additive; The other is light calcium carbonate, which is made by calcination of limestone.

2. Production process: The original lime production process is to lay limestone and fuel (wood) in layers, and calcine it for a week. Lulingkuan modern uses mechanized and semi-mechanized vertical kilns, rotary kilns, boiling furnaces and other equipment for production.

The calcination time is also correspondingly shortened, and it only takes 2 hours to produce lime with rotary kiln for 4 hours, which can improve the production efficiency by more than 5 times compared with vertical kiln production. In recent years, there have been cross-flow type, double-slope type, oil-fired circular vertical kiln and short-turn kiln with preheater and other energy-saving processes and equipment, and the fuel has also been expanded and dismantled to coal, coke, heavy oil or liquefied gas.

3. The main uses of lime:

1. Lime milk and mortar: slaked lime powder or lime paste mixed with a large amount of stucco. Lime mortar or cement-lime mixed mortar can be prepared with lime paste or slaked lime powder for masonry or plastering projects.

2. Lime stabilized soil: the mixture obtained after mixing, compacting and curing the slaked lime powder or quicklime powder mixed with various crushed or originally loose soils is called lime stabilized soil. It includes limestone soil, lime-stabilized gravel soil, lime gravel soil, etc.

Lime stabilized soil has a certain strength and water resistance. It is widely used as the foundation of buildings, the cushion of the ground and the pavement base of roads.

3: Silicate products: lime slaked lime powder or quicklime powder) and siliceous material sand, fly ash, volcanic ash, slag, etc.) as the main raw materials, after batching, mixing, molding and curing can be made of bricks, blocks and other products.

Because the cementitious substance inside is mainly hydrated calcium silicate, it is called silicate products, and commonly used are lime sand bricks, fly ash bricks, etc.