Talc is crystallized in the formula of Mg3Si4O10 (OH) 2 in the mono-clean system and belongs to the group of minerals of the group of phyllo-silicates. The arrangement of the elements in this mineral is such that the free oxygen of the two layers, or in other words the free vertices of the tetrads, are placed opposite each other. These two layers are connected by elements such as  AL+ or  Mg+ 3, and generally a very strong double network is created. Talc mono-crystals are fine and transparent, and are mostly in the form of scaly, bowl-like grains, fibrous filaments, and generally dense, fine-grained grains. In scaly grains, the excellent separation level of talc is visible and it has a shell polish on the cleavage surface. With a hardness of about one and a low specific gravity (2.8 – 2.7 grams per cubic centimeter), its touch is greasy and affects on the hand. Talc is a colorless, white mass, and its single crystals are pale or blue if coarse. Its mass type is found in impurities in different colors of mud, light yellow and light gray, which is also called Speeskstein talc or oily stone. Due to high heat, its hardness increases to 6.

Ordinary acids are ineffective in talc. Minnesotaite is called talc to replace magnesium with a significant amount of iron. (Fe) where = H 01/3 and is generally colorless or light green. Colorless dense granular talc is also called sewing soap.

Applications of Talc

Porcelain, Ceramic, Tile and Insulator Industries:

The presence of talc in ceramics causes resistance in the products and since talc prevents the formation of small cracks and the tile is crushed over time when the tile is baked, its use in this industry is more welcomed. Other advantages of talc in the ceramic tile industry are high heat or resistance to acids and low volume change in a wide thermal range and greater transparency. Talc is used when glazing requires silica and magnesium and in low grades, about 4% of talc is used as a melting aid and in high grades as refractory and a heat shock regulating agent. Talc is generally used as a melting aid. It is also used in colored slurries from 5 to 15%. Relatively pure talc with a lower percentage is used in the mixture of tile glaze raw materials. The use of talc in ceramics requires uniform physical and chemical properties and must be free of manganese and iron, and for high-frequency insulation more than 5% calcium oxide, 1.5% iron oxide and 4% aluminum oxide is not allowed.


In the United States in 2011, about 26% of talc consumption was related to plastic production. Talc is mainly used as a filler. Plate forms of talc can increase the hardness and thermal resistance of products such as polypropylene, vinyl, polyethylene, nylon and polyester and prevent them from melting.

Paint Production:

Most paints are a suspension of mineral particles in a liquid. Talc is used as a diluent and filler in paints. The plate shapes of talc particles improve the solid suspension, which can help the liquid paint stick to the wall without loosening.

Talc powder is very light white, this makes it a great filler in paint. Because it causes the color to be both white and light at the same time. Talc with low hardness is valuable, because it causes less damage to the spray nozzle and other equipment when painting. In 2011, 16% of talc consumption in the United States was related to paint making.

Paper Making:

Most papers are made from a paste of organic fibers. This paste is made of wood and other organic materials. Essential mineral is added to dough to act as filler. When the dough is rolled into thin sheets of mineral, it fills the spaces between the fibers of the dough, resulting in a paper with a smooth surface for writing. Talc as a filler can improve opacity, brightness, whiteness as well as the ability of paper to absorb ink. In 2011, the paper industry consumed 16% of the talc used in the United States.

Other Uses

Talc is used in chemical warfare agents – floor waxes – shoe waxes and even in peanut polishing.

Compact talc, which is cut into ingots, is used for laboratory tables, washbasins and sewers, acid tanks, electrical switchboards, electronic insulators, stove heaters, as well as household insulation materials. In addition, this type of talc is also used in sculpture.

In addition to the above uses in the soap industry, cosmetics, welding, filtering, health and pharmaceuticals and cosmetics, powder and dentistry, preparation of glossy papers, preparation of dusting materials, colored pencils and waxes, and in the industries of filling asphalt resistant in It is used against heat and mixed with cement.



Perlite is a volcanic glass known in the 3rd century BC.The exact details of the discovery of perlite have been lost over time, and there is disagreement about the rediscovery of perlite as a commercial material. Some scientists believe that perlite is caused by hydration of horseradish and the water in it, is molecular and hydroxyl. The ratio of the amount of these two types of water depends on the amount of calcium and magnesium oxide. Perlites are unstable and begin to crystallize over time and then lose their original properties. Most of high-quality perlites belong to the third and fourth geological periods. If perlite becomes altered, it will converted to montmorillonite, opal and chalcedony.

Prior to World War II, this substance was rarely explored, Overall, it has not been long since perlite was discovered as an industrial material. Until 1928, they only knew that there were some volcanic glasses that would increase in size in the face of sudden temperatures. On 1940 experiments were performed on perlite in Arizona ores, and finally in 1946 perlite processing began for industrial use. In the early years, perlite processing grew rapidly, but gradually continued to grow at a slower rate, with 558,000 tons of perlite mined in 1968.

The discovery of perlite is attributed to a dentist in the United States. Around 1914, while experimenting with tooth enamel, he discovered that perlite had swelled due to rising temperatures. Meanwhile, a geologist at the head of a barite and silver mining company found that the sand had swelled as a result of a fire on the coast of the Greek island of Mylos while pouring beach sand on the fire to put out the fire. Thus the idea of using these volcanic rocks, which formed most of the Greek islands, was conceived.

Preparation of expanded perlite

First, perlite is crushed and then granulated. The granulated perlite is first directed to the preheating section and then guided to the furnace. The furnace temperature is set between 700 and 1100 ° C based on the chemical composition and the amount of perlite water. It expands inside the furnace and is raised by air flow. Wastes falls to the bottom of the furnace.

Applications of expanded perlite

Important uses of expanded perlite include making lightweight concrete and thermal and acoustic insulation, fillers, agriculture, and as a filter and abrasive. Perlite can be mixed with cement in various proportions to make lightweight pieces of concrete. Perlite mortar is lighter than cement one and has less thermal conductivity, and absorbs more sound. Used in painting, plastics, rubber and insulating the empty space of double-walled walls. Perlite sheets can be made with the help of perlite and an adhesive such as gypsum. These panels are light weight and are used as good thermal and sound insulation. Sound-absorbing plates are made from a mixture of perlite and pressed asbestos.

Thermal insulations: A mixture of perlite, asbestos and an adhesive such as gypsum is used as an excellent thermal insulator, which is used to insulate tanks and pipes up to 1000 ° C.

Gardening purposes: There are important benefits to adding perlite, including high water absorption and retention, which prevents water from evaporating and leaving water in the soil for a long time. The constant wetting of the soil reduces the soil’s need for water, thus preventing leaching of soil nutrients. The presence of pores in the perlite in the soil increases the exchange of materials and soil, and the roots of the plants grow easily in the soil.

Ceramic industry: Quartz and feldspar can be substituted for porcelain in order to prepare the silica, alkane and aluminum elements required for ceramics. Perlite can be used in the preparation of colored glazes. In floor tiles and bathrooms, perlite replaces feldspar by 12% to 35%. Perlites have been found to be suitable in electrical ceramics and fiberglass.

Cement industry: Used to produce pozzolanic cement and concrete.

Synthetic Zeolite: Suitable raw material for the preparation of various types of zeolites using thermal solutions.

Abrasives: Perlite with a hardness of 5 to 6 mohs is used as an abrasive.

Metallurgical industries: If raw perlite is applied in layers on the molten material, it prevents the molten material from oxidizing, reducing the temperature rise and collecting slag.

Applications of raw perlite: Raw perlite is used in industries such as ceramics, sieves, electrode fabrication, cement production, explosives, metallurgy, synthetic zeolite production, filters and filters, and glass fiber fabrication.

Perlite in Iran

For the first time in Iran in 1971 J. Eftekharnejad, in the southwest of Ferdows on the Paleogene vulcanites of the area, finds and studies a large layer of obsidian. He later finds out that this area of the wide horizon is being traced And in principle, perlite features are widely evident in this area. During geological surveys in the Miyaneh region, it again observes perlite features in the volcanic areas of this region. In order to explore, groups are sent to the area, and after reviewing the results of the preliminary studies, a wide perlite horizon in the area is finally illuminated. Due to the proximity of this horizon to the sales market, further exploration work on this horizon will lead to the issuance of exploration licenses. Then, in the process of geological surveys in eastern Iran, within the framework of the East Iran project, a pile of perlite is detected within the scope of work of the Geo-metal Company, which is reflected in the Gonabad-Ghaen quadrangle. Meanwhile, in 1976, the first organized research to achieve, organized by experts of the Geological Survey in the Miyaneh region, which discovered large accumulations of this material east of the Miyaneh-Tabriz road, in the Sefidkhaneh area, 46 km northeast Miyaneh and the areas around Tarom village and Abak area in the west of Miyaneh city.



Bentonite is a clay or quasi-clay mineral composed of montmorionite and a small amount of bide lite (a richer type of aluminum bentonite). The term bentonite was first coined in 1898 by Knight to refer to clay extracted from the Benton shale at the time. It is named after Shale Benton, located 400 miles north of the Rock River.

Iranians have known bentonite for a long time and were familiar with some of its properties, such as washing clothes and as a cleaning agent. Ibn Sina also mentioned this mineral as a brittle substance that dissolves well in water. In the past, this substance was used orally in some parts of Iran, which is still very rare in some villages. From a medical point of view, these people are accustomed to eating mud due to calcium deficiency.

Bentonites are formed in two ways, “hydrothermal” and “sedimentary”, the “sedimentary” type is the most important type of bentonite deposits in the world. Bentonite belongs to the family of plate silicates and smectite group and has a three-layer structure in terms of construction. An octagonal aluminum layer is placed between two layers of quadrilateral silica and is mainly on two types of “swollen or sodium” and “non-swollen or calcium”. But industrially, bentonites are classified as follows:

  • Sodium Bentonites
  • Sodium-substituted Bentonites
  • Calcium Bentonites
  • Organophilic Bentonites
  • Acid-activated Bentonites

Application of Bentonite

Due to its soft, swell-able, colloidal and good mixing properties with water, kneading, plasticity, adhesion and adhesion, adsorption, etc., it has numerous uses, including drilling mud, adhesive in casting sands, preventing water penetration From dams, canals and pools, clearing agent for liquids especially fruit juices, clearing water and refining liquids such as paraffin, pelleting minerals such as iron ore, pellets for livestock and domestic animals, paint carriers and other spray materials, fillers in many industries such as paper and paint, etc. Cleaning industries such as soap making, preparing some types of ceramics to complete the body or glaze formula, preparing agricultural pesticides and repelling plant pests, pharmaceutical industries , As a filter, as a catalyst, bleaching of industrial, petroleum and edible oils; Separation of gum from gasoline and acidic sludges from oils, fire, silkworm industry in coal mines to extinguish fires or to cover the walls of the extracted area to prevent air ingress and to prevent coal self-assembly, etc.

Color of Bentonite

In the structure of bentonites, in addition to the main constituent; montmorionite, other elements such as calcium, sodium, iron, aluminum, magnesium, silicon, etc. are also found. The presence of each of these elements and its predominance can affect the color of bentonite. The color of sodium bentonite is usually white, cream or pink and its main feature is the absorption of large amounts of water.



Baryte or natural barium sulfate with the formula BaSO4 is derived from the Greek word (Barus) meaning heavy or dense. This mineral is also called Heavy spar and sometimes Tiff. Barium is the fourteenth most abundant element in the earth’s crust, which makes up about 0.05% of the earth’s crust and 425 grams per ton of sedimentary rocks in the crust.

Barium is a white-silver alkaline earth metal with the symbol Ba, atomic number 56, atomic weight 137.327, specific gravity 3.59 grams per cubic centimeter, hardness of 1.25 on the mouse scale, soft, heavy, boiling point 1898 ° C and melting point 729 ° C. Barium is in group II of the periodic table as an alkaline earth metal and is in period 6. They are usually colorless or milky, but are available in red, brown, yellow, and purple. The color of barite depends on its impurities at the time of crystal formation. This mineral is chemically neutral and insoluble.

Barite is one of the heaviest sulfate minerals and the only mineral in this category that has a higher specific gravity than it is lead (PbSO4). Its crystalline form is mostly in the form of blade crystals, laminates, layers or filaments. In most commercial reserves, nodules, concentrations of rose-like clusters, thin to layered, are observed.

Most barite is extracted from a layer of sedimentary rocks composed of barite deep in the oceans. In some minings, barite is seen in the form of rock veins, in which case a small amount is extracted. Barium sulfate is formed deep in the earth by warm groundwater. In some cases, barite is a by-product of the extraction of materials such as lead, zinc, silver or other metals. There are nine major barite mines in the United States in Missouri, Tennessee, Georgia, and Nevada. Barite production in China is about 10 times higher than in the United States, India has a high production and about 40 other countries in the world produce barite. Many of the world’s reserves are economically viable, but some are not cost-effective because they are mined very cheaply in China.

Applications of Barite:

Barite is used in drilling natural gas and oil wells. In this process, the barite is compressed and mixed with water and other additives are added and then pumped into the well cavity. The high weight of this mixture prevents oil and gas from escaping from the ground under pressure. This prevents explosions of gas and oil released from the ground. It is currently the most widely used barite in the United States for drilling. However, barite consumption varies from year to year, depending on the extraction and price of oil and gas.

Apart from the above-mentioned application, barite is used as an additive in paints, in glazing, plastics, in the production of so-called lead crystals or lead glass, to prevent the radiation of monitors and TVs, and to produce barium sources in chemicals are used.

Barite has the ability to absorb X-rays and gammas, so it is used in medical science for specific X-ray tests for the gut. It is also mixed with cement and used to make containers or chambers for radioactive materials, and more recently for the brake pads and clutches of passenger cars and heavy vehicles.