What is Leica?

The word Lika is derived from the term “light expanded clay aggregate”. These grains are obtained from the expansion of clay in rotary kilns at a temperature of about 1200 degrees Celsius. Lika grains style (Lika industrial pumice) have an almost round shape and a rough and uneven surface. The outer microscopic surface of the seeds has small and brown pores and the inner part of the seeds has black cell tissue. A set of remarkable features such as light weight, low thermal conductivity, good noise reduction, fire resistance, durability and chemical stability, etc. cause the expansion of the applications of these artificial aggregates in the construction industry, construction projects, agriculture, and the environment. , has been built and.

Lika light grains (Lika industrial pumice) are produced in the following 3 stages:

1) Primary processing: After entering the clay from the feeding box, it moves on a belt with a weight gauge embedded in its path. This weight meter measures the amount of material passed in time units of hours and day and night. Usually, an electric magnet device is also designed in this part, whose main task is to stop the movement of the tape when the iron piece enters with the mineral material, because the presence of these pieces is very dangerous for the machines.

Is. The raw materials enter a type of stone mill from the belt, and the bottom plate of this mill has mesh holes with a diameter of 14 to 18 millimeters. The holes of this network can be adjusted to any size. In this mill, water is added to the soil to become a mud pan and pass through the holes. Mud enters from the lower plate of the mill to another mill which is more of a mixer. The mixer mill consists of 2 axes whose blades move forward with a spiral movement. In this mill, if the mud does not have enough moisture, water is added again. In this stage, the flower is mixed with special additives if needed, and in the initial processing stageThe most time for flower processing takes place in this mill, which is a slow process. This slowness of movement makes the flower absorb water completely and is kneaded to get a uniform state. After that, the material enters another mixer, where the raw materials are kneaded and become completely uniform, and then it is poured in a string on the feed bar.

2) Drying stage: In this stage, the flower is gradually dried by moving in the drying oven and turns into pellets.

3) Cooking stage: In this stage, the dried seeds (gondoles) are exposed to heat, and in this part, the rising temperature is almost sudden. The temperature in the drying oven reaches from natural temperature (200°C) to 400°C in approximately 2 hours and increases from 400°C to 1200°C in the second stage. A sudden increase in heat brings the substance to the melting point, and at the same time, all combustible materials try to escape from the environment. But due to the nature of clay, in which the particles are strongly bonded together, the pressure of the resulting gases creates pressure and creates a porous environment, and thus it is produced in a light-grained manner. After the cooking stage, the product enters the cooler.

The history of Leica in the world

Natural light grains have attracted the attention of mankind for many years. The Romans used a light type in the construction of the Pantheon temple and the Colosseum stadium, and in the sixth century it was also used in the first construction of the Hagia Sophia in Istanbul. In the second century AD, Roman engineers used pumice stone in the construction of the Roman Pantheon. After 1000 years, the style was used in a building in the Vatican.

The use of lightweight concrete entered a new stage after the production of artificial and processed lightweight concrete in the early 20th century. Around 1917, Heidi in Kansas, United States, invented the method of industrial production of expanded clay using a rotating cylindrical furnace, and this product was called Heidit. Due to the possibility of processing in production, this product has unique features and was widely welcomed. During this period, more than 150 bridges and buildings in the United States and Canada were used with this type of concrete. The largest lightweight concrete building is a 52-story office building with a height of 215 meters in Houston, Texas. In Iran, after being aware of the advantages of light production in the country of production unitLeica was launched by the private sector in 1357. Today, artificial light bulbs, especially Leica, are produced in different countries with different brand names, and the names of some of the countries with this industry and the brand names of its products are as follows:
Denmark, Norway, Switzerland, Sweden, Finland, England and Iran under the name of Leca, Czech and Slovakia, Poland and Russia under the name of Keramzite, France, Belgium and Portugal under the name of Argex, Italy under the name of Laterlite and Germany and Austria under the name of Liapour.

History of Leica in Iran

Leica Iran has been operating since 1352 under the management of the private sector. The initial operation of the first unit of the Lika factory dates back to 1357, and the mass production of the product began in 1360. The production of these seeds in Iran is carried out under the license of Lika International, and currently this factory has 3 light grain production units (industrial pumice) with a total nominal capacity of 750,000 cubic meters per year and 3 light block production units with a total nominal capacity of 35,000 .000 pieces per year.

Also, the special quality control laboratory of this department carefully examines the quality of the products. The development plan of Lika company for the construction of the second unit for the production of light grain (industrial pumice) began in September 2008 and after 2 years of efforts by Iranian experts, it was put into operation in December 2008.

The development plan of the third unit of Lika was started in 2011 and its operation began in 2016. At the same time, the third unit of production of Lika block, which has full automation, was put into operation in 2016.

The development plan of the fourth Lika unit is also in progress with 30% physical progress.

Currently, Leica Iran is the largest Leica manufacturing unit in Central and East Asia.

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Leica in the building

The application of Leica in the building

Each of the materials used in building infrastructure provides a specific function based on the desired properties. Carrying and controlling moisture penetration is one of the mandatory features of a suitable infrastructure. It should be noted that the purpose of damping in the foundation and under the buildings is to prevent the penetration of moisture that is not caused by pressurized water. Considering the sensitivity of the insulation location, all this damping should be equivalent to the useful life of the building. Due to the characteristics of Lika, it can be used to insulate the infrastructure or in the components of load-bearing structures for the foundations of small buildings.

Light application of Lika seeds (Lika industrial pumice)

One of the necessary principles to control moisture infiltration from wet ground to the wall and floor of the building is to cut capillary pipes. One of the most common methods is to use coarse aggregates with sizes of at least 4 mm. For this purpose, a layer of coarse gravel with a height of about 25 to 30 cm should be placed on the ground. Then a mixture of fine and coarse stones is poured on this layer to a height of 20 cm. Therefore, coarse (10-20 mm) lika can be used to create a protective layer against capillarity. Also, in order to level this layer for the next operation of the foundation, a mixture of Lika seeds is used.

For this purpose, 1/1 times the necessary height should be covered with Lika and then the layer should be compacted to reach the appropriate height. This operation is suitable for layers up to 30 cm high. Then, the floor is applied on this layer of concrete. For ease of work, a metal net with 150 mm grids and 4 mm diameter rebars can be used on the grains. In this case, you can walk on the Lika layer before concreting, or place the supports for pipes and structural steels on it.

Due to the harmlessness of Lyca grains from a chemical point of view, installation pipes can also be passed through these layers if necessary.
The lightness of lika grains and as a result the ease of transportation and cost reduction is one of the advantages of using lika instead of ordinary aggregates. Also, due to the fact that lika is heat insulating, in cold regions, the floor of buildings is also protected against the cold of the earth.

Application of Lika concrete

By using Lika concrete with a combination of cement and fine Lika in a volume ratio of 1 to 8, which is made and poured on site, it is possible to seal the floor of the building. The density of this concrete is about 800 cm3/kg and the compressive strength is at least 30 cm²/kg. Therefore, this concrete will also play the role of load distribution, and non-load-bearing walls up to one floor can be placed directly on this concrete. Lika light concrete is poured and compacted in layers of 10 to 15 cm. Then this concrete should be applied for a week. To protect the concrete from possible damage caused by the movement of workers on it and to strengthen the surface of the concrete, slurry mortar – including one part of cement and three parts of fine sand – can be used. 1 to 2 days after concreting, this mortar can be applied on the concrete surface. By using Lika concrete, heat and humidity are controlled together.

Light filler

Due to its light weight, Lika grains (Lika industrial pumice) can be used alone or in combination with other suitable materials to fill empty spaces that are not under pressure.