It has the chemical formula CaMg (Co3) 2 and crystallizes in a hexagonal system. Its structure is similar to calcite. It is also the name of a sedimentary rock that has more than 50% of calcite and dolomite minerals, so that its dolomite content is higher than calcite. One of the most famous types is saddle dolomite. It boils in hot hydrochloric acid. Its color is fleshy pink, sometimes white, gray, green, brown or black and colorless. This substance is named after the famous German chemist Dolumi.

Detection Properties

It is non-flammable. Large pieces are slowly eaten in dilute hydrochloric acid, but boiled in hot hydrochloric acid. Powdered dolomite dissolves easily in cold hydrochloric acid. The crystalline type of dolomite is recognizable by its curved surfaces and fleshy pink color.


Dolomite is found in most parts of the world. Especially in the form of sedimentary layers or in the form of dolomitic marble in metamorphic rocks and by substituting some magnesium instead of calcium in the primary limestones of dolomite is formed secondarily. It is seen in hydrothermal veins, especially in lead and zinc veins that cut limestone.


From its crushed stone for cement components, gravel of roads and railways, etc. as an aid to smelting in melting, refining iron and other metals, as a neutralizer of soil acidity and improving plants in agricultural lands, as a source of lime, to building stone, refractory insulators are used in converters used in the production of alkali steels.


The name Garnet or Grona is derived from the Latin word granatus because the red seeds of this mineral are similar to the seeds of pomegranate fruit.

General Specifications

Garnet is a colorless to reddish-brown, greenish-gray mineral with a specific gravity of 4.2-5.3 g/cm3, a hardness of 6.5-7.5 on a mouse scale, a polish oily or glassy, rough (shell) fracture, crystallubic system, no cracks and fractures. Garnet with the general formula A3B2 [SiO4] 3 in which: A represents CaO, Mn2 +, Mg, Fe2 + and B represents Cr, Al, Fe3 +. Garnet minerals include Almonden, Grossoller, Pyrope, Espartine, Andalusite, and Ouarquite minerals.

Garnet forms an isomorphic series with a complete solid solution. With the exception of chromium-containing grones, the rest of the grones melt more easily and, after melting, produce pearls of different colors. Garnets are characterized by high prominence and their isotropic nature with poor birefringence. Grona ferrous types become magnetic and most grones dissolve in acids. Garnets are converted to chlorite, epidote (Ca types), serpentine (Mg types) and limonite (Fe types).

Major Uses of Garnet

A) Abrasive

Properties such as relatively high melting point (1250 ° C), semi-circular to semi-angular fracture, low or zero free silica and high resistance to chemical and physical attacks, make garnet as a quality abrasive for tools such as sandpaper and Stoning is used.

B) Wind Abrasives

Granulated and soft garnet is used in the production of grain, powder and polishing powder, these materials are used in the final stage of glassmaking, polishing of ceramics and semiconductors. Fixed grain size garnet is used in pneumatic abrasives, which require less air pressure due to their relatively high specific gravity and particle block shape. This method is used to repair ships, locomotives, trucks and cars, aircraft and the construction and maintenance of steel structures such as bridges, oil rigs, power stations, turbines and boilers, tankers, pipelines and smoothing glass and facade stones.

C) Cut with Water Pressure

Garnet is used as an abrasive in this type of cutting. In this method, water with a pressure of 40 mkg /m2 is fired from a narrow opening. It is used for precision cutting of steel, aluminum, wood, plastic, composite, glass, stone, concrete, ceramics and boards.

D) Filtering

The properties of garnet have led to its use in multimedia filter systems (municipal water treatment, separation of wastewater particles). In this type of filters, there are three layers of minerals whose size decreases from top to bottom and their density increases. Garnet resistance to re-contamination during inverse suction of water is one of its most important features.

A common type is: a layer of anthracite with a density of 1.4 and a particle size of 0.5-2.5 mm, silica sand 2.6 and a size of 0.4-1 mm and a layer of garnet 3.8-4.2 and a size of 1.0-1.4 mm and 6-25 mm.

E) Oil Wells

Less common but expanding use of garnet is in sand packages used in oil wells when high pressure oil exits the well.

F) Gemstone

Another use of garnet is as a semi-precious stone. Almandan (purple red) Andradite (black to green) Grossular (pale yellowish green) Hesonite (yellow, brown) Pyrop (light red) Pyrop-Almandan (red) Rhodolite (red-pink) Sparsite (pink-Portuguese), are different types of garnets.

G) Pharmaceutical Uses

It is said about the medicinal properties of garnets that anyone who has it with them is safe from leprosy, epilepsy and colic. Its powder has been used as an eye cream. Some Westerners still believe that having garnet in the first month of the year, January, brings happiness and success in that month.


A) Abrasive Rating

In the first place, almandan is preferred because of its specific gravity, andalusite is the second choice. At least 97% garnet, slightly free silica, in wind abrasives with a particle size of 1-3 mm. Blue cutting effect 0.06-1 mm (half the diameter of the outlet)

B) Water Filtering

Minimum specific gravity 4, circulating particles between 8 and 250 meshes with uniformity coefficient as close as possible to 1%.

C) Oil Well Sand Packages

Requires rounded and separate crystals of almandine garnet.

Recycle: One of the capabilities of garnet in abrasives is that it can be rehabilitated, cleaned, granulated and reused. The higher initial price compared to competing abrasives can be justified by a longer lifespan based on proper recycling.


Abrasives: Bauxite and alumina, magnesium oxide, corundum, diatomite, feldspar, hematite, mannite, nephelinecinite, olivine, perlite, pumice, silica sand, starolite slag, triple, silicon oxide, ilmenite.

Filter: Anthracite, asbestos, cellulose, diatomite, mannite, olivine, perlite, pumice, silica and ilmenite.

Non-slip Surface: Alumina, sanding, silica sand.

Sand Packages of Oil Wells: Calcified bauxite.


Mica is a general term for a group of alumina-silicate minerals. These minerals have a sheet-shaped structure and are composed of various physical and chemical compounds. Mica minerals are plate silicates that include muscovite, biotite, phlogopite, lipidolite and natronite.Muscovite is the most important and abundant plate mineral. Sheet muscovite is found in pegmatites and flakes in granite, pegmatites and schists. Lipedolite is formed in lithium-rich pegmatites. Phlogopite has been reported as streaks and masses in pyroxenites and magnesium-containing skarns.

Minerals of economic importance of Mica Group are classified as follows:

  • Muscovite: Potassium Mica (green or ruby) 3(H2KAl3(SiO4))
  • Biotite: Magnesium Iron Mica (dark color) (Mg, Fe)3Al(SiO4)3)(H2K)
  • Phlogopite: Magnesium Mica  (yellow, dark brown) H2K(Mg)3Al(SiO4)3
  • Vermiculite: Juicy Biotite (bright yellow)
  • Lipidolite: Lithium Mica (pale yellow) (KLiAl(OH,F)2Al(SiO4)3

The crystal system of these minerals is mono-clinic. This group of minerals contains various compounds of aluminum silicate, iron, magnesium and mica. The presence of fluorine, barium, manganese, vanadium have also been reported in these minerals. Among these minerals, muscovite is widely used in industry due to its exceptional physical, chemical, thermal and mechanical properties. Vermiculite and phlogopite are just as important as mica. Biotite is rarely used in industrial applications.

Mineralogically, the minerals of the mica group are divided into three groups, which are:

The main group is mica, the group of brittle mica and the group of chlorite. All minerals in these groups have a mono-clinic structure. The structure of mica is a combination of two layers of tetrahedral silica and one layer of central octahedral.

Among mica minerals, muscovite is widely used in industry due to its exceptional physical, chemical, thermal and mechanical properties. Muscovite is the most common type of scale used to make mica plates. The most common uses of flaky muscovite are: fillers in cement, asphalt and paint, concrete decoration, to prevent drills from getting stuck during drilling, and the very fine-grained type of muscovite used to increase the paint’s resistance to moisture, adhesion and erosion.

Muscovite plate type is used in electronics (capacitors and lamps), making sheet 84 and also due to its dielectric properties in making thermal and electrical insulation devices. Due to its high thermal resistance and transparency, the windows of electric ovens use muscovite. High quality sheet mica, mainly muscovite, is used in many industries, especially in electricity. This is because this mineral has a high dielectric resistance. The use of this mineral also prevents energy loss. Other characteristics of this mineral are high electrical sensitivity and low heat coefficient. In addition to these properties, mica remains resistant to high temperatures.

Windows made of mica mineral have high mechanical strength and prevent energy wastage. Mica types have a dielectric coefficient between 5 and 7. So that it can be used to make capacitors. The high electrical and mechanical properties of mica combined with low adhesion as well as heat dissipate ability have led to its use in the manufacture of transistors, and mica with a thickness of 0.1 mm is used to make coatings for wires. These wires are mostly used in electrical converters, which makes them smaller and lighter.

The high resistance of mica to heat, low density and high mechanical resistance has led to its use in the manufacture of electrical resistors. Mica is also used in the production of helium neon lasers, special optical filters, liners and coatings for glass that must withstand high vapor pressure, diaphragms for oxygen respirators, tracking devices, and heat measuring devices.

Recent research and experiments have shown that mica can be used to make a wide range of devices, such as fan curtains, car dashboards, and flooring. It is also used as a substitute for asbestos in car brakes.

Methods of exploration, extraction and processing

Sheet mica is mined both underground and open.

A) Underground mining: Underground extraction is done by digging a well inside the pegmatite with the appropriate depth and angle. This is done by drilling machines that work with air or by fire. When mica is found, it is carefully transported to the surface without being damaged. Extraction of this type of mica is mostly done in India where labor costs are lower and environmental laws are more flexible.

B) Open pit mining: Currently, grade 1 mica in the United States is derived from pegmatites and aerated mica schists. In this case, mining is done openly. In the case of soft materials, shawls, scrapers and loaders are used to transport materials. In most cases, kaolin, quartz and feldspar are recovered with mica. In the case of extracting mica from hard rocks, drilling and firing operations are required. After the fire operation, the materials obtained are crushed by a mill and then sent by truck to a processing plant to recover mica, quartz and feldspar.

Routine Processing Methods of Mica

Mica can be recovered with high efficiency by gravity concentration methods, while the final concentrate is obtained more by difference in particle shape than by difference in specific gravity. Mica concentrate can be processed both wet and dry. Wet mica is processed in a spiral by a method called zigzag. When the concentrate is dry, the mineral is crushed in two stages by a jaw crusher. After the first crusher, the crushed particles are divided into five different dimensions by the sieve, which are: coarse particles (+165 mm) that these particles return to the crusher for re-crushing. The next three fractions (+ 1.65 mm, 0.8 + 0.4 mm and -0.4 + 0.15 mm) are each processed separately on the table to obtain the final concentrate. The intermediate product obtained from each of the tables is inserted into the second crusher and after crushing, it is sieved again to obtain the desired dimensions. The major mica by-products produced in processing plants are kaolin-quartz and feldspar. In some factories, all of these products are produced, while in others, one or two of them are offered as products. Silica glass can be obtained in most mica processing plants by adding a sufficient amount of quartz.

Types of mica


Vermiculite is the generic name for a group of ferromanganese-containing aluminum silicates that are chemically similar to tri-octahedron smectites and structurally similar to talc. Vermiculites are intermediate between mica and smectite in terms of electrical charge and swelling property. Under the influence of heat shock (about 800 ° C), this mineral increases about 20 to 40 times its initial volume and flakes and shows very good non-combustibility until near the melting point of 1350 ° C.


Application of expanded vermiculite is due to its three important properties, namely lower volumetric mass, heat and sound insulation and high cation exchangeability. Therefore, it is mainly used in the production of construction materials, insulation industries and in the preparation of fertilizers, pesticides and agriculture. Global production of expanded vermiculite in 1995 was equivalent to 606 thousand tons. The United States and South Africa are the largest producers of expanded vermiculite.


Among mica minerals, muscouvite is widely used in industry due to its exceptional physical, chemical, thermal and mechanical properties. Vermiculite and phlogopite are just as important as mica. Biotite is rarely used in industrial applications. Plate Muscovite is used in electronics (capacitors and lamps), in the fabrication of sheet 84, and also in the manufacture of thermal and electrical insulation equipment due to its dielectric properties. Due to its high thermal resistance and transparency, the windows of electric ovens use muscouvite.

Flaky muscouvite is mostly used to make mica plates. The most common uses of flaky muscovite are: fillers in cement, asphalt and paint, concrete decoration, to prevent drills from getting stuck during drilling, and the very fine-grained type of muscovite used to increase the paint’s resistance to moisture, adhesion and erosion.

High quality sheet mica (mostly muscovite) is used in many industries, especially in electricity. This is because this mineral has a high dielectric resistance. The use of this mineral also prevents energy loss. Other characteristics of this mineral are high electrical sensitivity and low heat coefficient. In addition to these properties, mica remains resistant to high temperatures.

Mica windows have high mechanical strength and prevent energy wastage. Mica types have a dielectric coefficient between 5 and 7, So that it can be used to make capacitors. The high electrical and mechanical properties of mica combined with low adhesion as well as the ability to dissipate heat have led to its use in the manufacture of transistors, and mica with a thickness of 0.1 mm is used to make coatings for wires. These wires are mostly used in electrical converters, which makes them smaller and lighter.

The high resistance of mica to heat, low density and high mechanical resistance has led to its use in the manufacture of electrical resistors. Also, due to the high quality in the production of helium-neon lasers, special optical filters, liners and coatings for glasses that have to withstand high vapor pressure, construction of apertures for oxygen respirators, tracking devices as well as devices for measuring heat is used.

Recent research and experiments have shown that mica can be used to make a wide range of devices, such as fan curtains, car dashboards, and flooring. It is also used as a substitute for asbestos in car brakes.

Mica Substitutes

Mica is used in many industrial applications due to its high physical and mechanical properties, and it can be said that there is no alternative to it. But in some cases, sand and talc are used instead. (Such as roofing) Fiberglass is used in limited cases instead of mica in the manufacture of special plastics. The apparent consumption of flake mica in the world increased from 112,000 tons in 1995 to 137,000 tons in 1995-1998, and then the consumption decreased to 119,000 tons in 2000.

Calcium carbonate

Calcium carbonate is known as gypsum, limestone, calcite, aragonite and marble. The chemical formula of calcium carbonate CaCO3, its appearance is pure powder white and its cream is whitish cream. The density of calcium carbonate decomposes from 2.71 to 2.83 g / cm2 at 825 ° C. It has a linear molecular shape and is non-flammable.

Applications of Calcium Carbonate

Paint Industry: In this industry, micronized powder is used as a filler. The specifications of the powder used in this industry are as follows:

Cao content more than 97% and Fe2O3 content less than 1% and its grading more than 500 mesh. Approximately 22% of the consumption of micronized powder in the Iranian paint industry is considered.

Cable and Wire Industry: Micronized powder is used for strength and as a filler in the amount of 20% for cable production and 10% for wire production. The specifications of the powder used should have a purity of 98%, a moisture content of less than 1% and a grain size of about 350 mesh.

Plastics and Rubber Industry: Micronized powder is used in this industry as a filler and product resistance to heat and strength. The specifications of micronized powder in this industry are such that the amount of CaO is at least 98%, the amount of moisture is at most 1%, the amount of Fe2O3 is at most 2%, and the pH is 8.5 to 9.5%.

Food and Pharmaceutical Industry: In these industries, micronized powder is used as a filler and production of antibiotics, antacids, dentistry and is used with 100% purity for the production of cosmetics and as a filler.

Paper Industry: The precipitated calcium carbonate is used as a turbidizer, smoother, filler and also to prevent the ink from spreading on the paper.

Detergent Industry: In this industry, micronized powder is used to prepare bleaching materials with special and soft size.

Oil Drilling industry: In drilling oil wells and in drilling fluid compositions, micronized powder with 85% purity and 325 mesh is used.

Plastic Shoes and Shoe Soles Industry (Suede and Synthetic Leather): In this industry, it is used as a filler of micronized powder with a grain size of a few microns and the outer surface is covered with a type of lubricant, which gives the following properties to the product:

  • Exterior surface polish.
  • Increases resistance to further tearing and stretching.
  • It does not cause jaundice in the body and keeps the white color constant.
  • Reduces elasticity.
  • Fixed against fat.

Health industry: In this industry, micronized powder with 100% purity is used to produce toothpaste. Other applications of micronized powder include the production of machine-made carpets, macaroons, carpets, various types of carpet adhesives and other industries.

The Environment: To control air pollution, lime is used in metal smelters as well as absorbers of toxic gases such as HCl, HF, SO2.

Calcium Carbonate Plaster: One of these dry mortars is calcium carbonate plaster, which is used for indoor plastering. Some of its main properties are as follows:

  • Prevent corrosion of steel parts in the building due to the presence of antioxidants.
  • High initial setting time and the ability to operate the tool within 45 minutes.
  • Hardness much higher than gypsum and comparable to concrete.
  • High adhesion and can be applied on surfaces such as concrete, wood, pottery and 3D Panel.
  • Low specific weight that makes the building light (1060 kg / m3).
  • Fire and direct flame resistance.
  • Resistance to heat and cold transfer, which makes the environment cool in hot seasons and warm in cold seasons.
  • Moisture resistance.
  • Very fast execution on the surfaces so that at least 80 to 120 square meters can be covered in each shift with a shotcrete machine.
  • Fine grain size of 400 mesh and surface smoothness after application.
  • Ability to mix with color pigments.
  • Elimination of gypsum and soil in the building.
  • Low price and competitive with ordinary plastering.
  • Low secondary grip and competitive with conventional plastering.
  • No surface cracks.
  • It is free from any environmental pollution.
  • Absence of adverse effects on the skin of the body at the time of application.
  • High resistance to surface scratches.

Polyvinyl Chloride (PVC) Industry: Micronized powder is used to reinforce rubber objects and also to increase the strength and durability of this type of products, as well as to increase the formability and impact resistance against pressure and impact for hard PVC. It is estimated at approximately 25%. The specifications of micronized powder in this industry are as follows: Cao content more than 97%, Fe2o3 content less than 3% and grading more than 350 mesh.

Other applications include micronized powder, printing ink, glass-making, chimney desulfurization, in the welding and electrode industries, firefighting (preparation of fire extinguishing powders), agriculture, leather making, water treatment industry, sugar factories and Sugar, metallurgy, steel industry, pharmaceuticals, chemical industries as refractories, in food industries as acidity neutralizers and in making chewing gum, for cloud production, in textile and clothing industries, sculpture, false ceilings, and MDF, machine-made carpet production , Macalum, carpet, various types of carpet adhesives and other industries.

In general, the share of each of the consumed calcium carbonate includes: iron and steel 41%, construction industry 32%, environment 3%, chemical industry 6%, in paper making, sugar refining, leather making, agriculture and oil industry 8% And other applications is 10%.


Fluorite with the chemical formula CaF2 is the most important mineral in nature from which fluoride can be obtained. This mineral is yellow, green, pink, blue, purple, colorless and sometimes black and crystallizes in the cubic system. It is semi-transparent and has a glass polish. The specific gravity of this mineral is 3.18 and its hardness is 4.

It usually fills the gaps between other minerals and is mostly observed in nature as streaks and is associated with various minerals such as calcite, quartz, barite, celestine and sulfides. Fluorite, if pure, has 48.7% fluoride and 51.3% calcium.

How fluorite is formed, stored and produced

Fluorite is formed and observed in a wide range of geological conditions. Fluorite deposits can be of sedimentary-carbonate origin or in the form of veins, usually associated with intermediate acidic igneous rocks.

In terms of fluorite reserves, according to a 1998 report by the US Geological Survey, Mexico ranks first with 32 million tonnes, followed by South Africa and China with 30 and 23 million tonnes, respectively. After the above countries are France with 10 million tons and Spain with 6 million tons. According to the Ministry of Industries and Mines, in 2001, there were a total of more than 1.3 million tons of potential reserves and 1.5 million tons of definite fluorine reserves in Iran.

Chemical Application

The most important chemical application of fluorite is in the production of hydrochloric acid, which has a sulfuric effect on fluorite. 454 grams of fluoric acid is made from about one kilogram of fluorite. Hydrofluoric acid has several applications, including in the preparation of fluorocarbons, detergents, surfactants for pharmaceuticals, foaming agents in firefighting, and in the aluminum industry for the production of aluminum fluoride.

Ceramic Industry Application

In the ceramic industry, fluorite is used in the production of white glass and glaze. Fluorite acts as both a melting aid and an opacifier. The use of fluorite in this industry should be used with caution because fluorite causes other reactions with other components of the glaze to spoil these compounds and create needle holes in the glaze.

Metallurgy Application

Due to its melting aid properties, fluorite has many applications in the metallurgical industry. Its applications include the steel industry, cast iron casting and the production of iron alloys.

Optics Industry Application

Fluorite, which can be used in the optics industry, is prepared chemically and with many properties. The crystal of this mineral, due to its low refractive index, transmits ultraviolet rays well. For this reason, it is used as a prism in optical systems and to make object lenses without color interference in the microscope. Fluorite is also used as an optical tool in high-energy laser systems.


Due to its low melting temperature (115 ° C) and strong adhesion, sodium feldspar is used in the preparation of all kinds of clothes and glass, while potassium feldspar is mostly used as a melting aid and the main material for making ceramic structures. Since the consumption of potassium feldspar is at a higher level, its economic value is higher than that of sodium feldspar.

About 65% of alkaline feldspars are used in the glass industry, 30% in the ceramic industry, and another 5% as fillers in the paint, rubber, and other industries. In the glass industry, feldspar is used to supply the silica, aluminum and sodium required by glass, and alkane feldspar is used in the manufacture of various ceramic products. Potassium and sodium feldspars, which together form alkaline feldspars, are among the most widely used materials in the ceramic industry, and there are now many mines in Iran of both, especially the sodium type. In industry, feldspar mines are also referred to as industrial soils. Potash feldspar mines are smaller in number than other types and their soil is sold at a higher price.


Silica or silicon oxide with the chemical formula SiO2 is the most abundant oxide compound in the Earth’s crust. Silica is present in nature in free form or in combination with other oxides. In general, the uses of silica are:

Glassmaking, porcelain, ferrosilicon production, ceramics, lime sand brick production, casting, sodium silicate production, production of other silica materials, as a semiconductor in the electronics industry and glass wool production. Significant amounts of crushed sandstone are used as building materials.

The silica used in each of these industries must have a certain quality.The chemical composition, mineralogical structure and physical properties of silica determine its quality and uses in each of these industries. The chemical composition of silica is actually the percentage of SiO2 in the rock as well as the percentage of each of the other oxides that are usually present with SiO2 in various deposits. If the percentage of each of them exceeds a certain limit, its use in various industries will be limited or impossible.

In addition to the percentage of SiO2, the mineralogical structure of the rock also plays an important role in determining its quality and uses, because SiO2 may be present in the form of various silicates, so this issue will determine the mineralization method and how to remove impurities. The physical properties of silica will also be affected in the same way suitable for crushing, granulating the produced silica powder and determining the uses of the produced powder.

Application of silica in industries

Enameling: Silica is a constituent of glass, it is combined with materials such as feldspar, nepheline syenite, soda, etc. to make different types of silica glass.

Ceramics: Quartz is used in the manufacture of various types of ceramics and sanitary ware.

Casting and Refractory: The resistance of quartz and silica to a temperature of 1470 C has led to its use in the manufacture of metal castings such as steel, ferrous iron, aluminum and copper alloys, as well as as refractories in the manufacture of iron and steel, ceramic, glass and cement furnaces. Other miscellaneous applications include abrasives, polishing powder, filtration, construction sand. Round and quality types are used to open gaps and increase permeability in oil and gas production. Also, by pulverizing it, it can be used as a filler in paint, plastic, rubber, putty and glue.

Types of Silica

Sodium Silicate: Sodium silicate is sold in the form of clear pellets, without water and glass powder or aqueous powder. This material is used in controlling the abrasion of water pipes and the formulation of glaze and enamel. Its various liquid solutions are used in soap making, industrial and general cleaners, adhesives, cementing, paints and coatings, casting molds, ore flotation, peroxide stabilization and corrosion control in water pipes and zeolite-mixed silica precursors.

Sedimented Silica: Sodium silicate reacts with sulfuric acid or hydrochloric acid to produce precipitated silica under certain conditions, due to its high luminosity and low porosity as a fine-grained and non-slip filler in tires (car tires and PVC flooring, poly Olefin, LDPE film and microporous separators for lead batteries, diffusers, carriers and many more are used.

Colloidal Silica: A suspension of fine-grained silica in aqueous medium used for friction on paper and boards, fiberglass refractories, catalysts and chemical precursors.

Silica, Type of Metallurgy: It is made from the reaction of quartz and coke in an electric arc furnace at a high temperature of C’2000 and has 99-98% Si. There are other types of silica and its compounds such as baked silica, silicon chips, silicon nitrate, etc., each of which has its own applications.

Crystal Quartz: Transparent and pleasant types are used for making lenses and cones, jewelry and mineral samples, using its piezoelectric property in electronics.

Triple Silica: Micro-crystalline silica, porous with a specific gravity of 2.65, hardness 7, white to gray, etc., which is used as a filler or pigment in paints, rubber, plastics, abrasives and putties. In addition, it is used in abrasive and polishing powders.

Novacolite Silica: White to gray porous stone, light brown to black, made of dense amorphous quartz grains with excellent abrasive properties: cleaning metals, grinder, refractory and lightweight building materials.

Flint Silica: Hidden chalcedony silica dense crystal (ceramic, bone china, grinder, etc.)

Classification of Silica Types Based on SiO2 Percentage and Consumption:

Grade I

This type of silica has at least 96% SiO2 and is used in glass, glaze, chemical industry, ferrosilicon, fiberglass, sodium silicate, ferrochrome and cement sand test.

Grade II

This type of silica has 85-95% SiO2 and is used in casting sand, sandblast sand, filtration and refractories.

Grade III

This type of silica has 70-85% SiO2 and is used in calcareous sand brick and light brick, cement and light concrete factories.


Zeolites, crystalline mineral aluminosilicates, and hydrates of alkaline and alkaline earth metals are three-dimensional with a lattice and are divided into two major groups, natural such as clinoptilolite, analysium, lamometite, phyllipsite, mordenite, and synthetic or synthetic, e.g. W, ZSM-5, Zeolon, F, Gamma.

In general, three factors such as structure, texture, chemical composition, as well as the economic value of natural zeolites and modified forms, have made them potential sources in various fields, including the following: Use as a catalyst in oil and petrochemical industries, fire industry, agricultural industry as a fertilizer and increase soil moisture, cleaning municipal, industrial and nuclear wastewater from harmful pollutants such as heavy and toxic metals, absorption and desorption of gases and the like.

Major producers of zeolite are China, Cuba, Japan, the United States and Hungary, which together account for more than 3 million tons of zeolite production worldwide. In Iran, zeolite deposits are scattered in areas such as Miyaneh, Taleghan, southeast of Semnan, Roodehen, Rhine Kerman and some other areas.

Zeolites with excellent capacities in absorbing water and some nutrients needed by plants are well able to provide the required water and prevent wastage of nutrients and fertilizers. Zeolites are also used to absorb and remove environmental pollutants, including heavy and harmful metals from polluted water and municipal and industrial wastewater. Wastewater may contain cations of heavy elements such as zinc, cadmium, copper, iron, mercury, and harmful anions such as cyanides, which can cause a great deal of ecological and environmental damage, and zeolites play a key role in the purification of these cations and anions.


Chemical Formula

Discovery Year


Absorption of Hydrocarbons




Absorption of Hydrocarbons








Absorption of Heavy Metals




Absorption of Mercury and Slver – Separation of Alcohol Composition




Absorption of Paraffin and Alcohol

Ca (Al2Si4)O12.4H2O



Lithium Concentrate




Rehabilitation of Contaminated Soils – Nitrogen Uptake

Na6 [(AlO2)6(SiO2)3O].24H2O



The most famous natural zeolites with their chemical formula, the year of their discovery and use

General Properties of Zeolites

Among the unique properties of zeolites, the following can be mentioned:

A) Cation Exchange

This property is related to poorly bonded ions in zeolite that are easily transported by other ions. Different zeolites have a specific order in terms of cation exchange for different cations. In Clinoptilolite, the substitution decreases from Cs to Mg :


In Chabazite, substitution is reduced from K to Ca:


Zeolite is used for the separation of magnesium and calcium ions in cleaners, fertilizers and soil, animal feed and also for the separation of nitrogen in the form of ammonia and heavy metals in aquaculture, pet food, agricultural wastewater and the separation of NH3, H2S, SO2, CO2 from animal waste, excess gases, saline and polluted natural gas.

B) Molecular filter

If the zeolites are heated at 350 to 400 ° C for several hours, water in the ducts and canal space like them is released and dehydrated zeolites are obtained. The diameter of channel-like spaces is determined by the chemical composition of zeolites. The diameters of these spaces in potassium, sodium and calcium zeolites are 4, 3 and 5 angstroms, respectively. Materials whose molecular dimensions are smaller than the diameter of the zeolite space will be absorbed and those that are larger will be discarded.

Using zeolites, hydrocarbon materials can be separated from each other. The adsorption capacity of some zeolites is up to 30% by weight. Substitution of calcium instead of sodium increases the diameter of zeolite channels by 30%, and substitution of potassium instead of sodium reduces the diameter of the channels. Zeolites can absorb toxic or highly interactive substances, thus making it possible to use the absorbed toxic substances. Zeolites are used in the polymerization of polymers and rubbers as well as in color printing.

C) Adsorption and Desorption

Zeolite channels are ready to be used to adsorb other small molecules after draining water. These small molecules are absorbed inwardly, leaving no room for larger molecules. In the process of competing in the adsorption of molecules, polarized molecules that result from electrostatic interactions and the filling of the framework and floating ions are preferred over other molecules. The size of the effective cavities is controlled by the dimensions of the grid. A zeolite may be altered by ion exchange and the type of adsorption. The adsorption capacity as well as the stability of zeolite increase with the extraction of aluminum ions from its framework. The removed aluminum ions are replaced by hydrogen ions. As a result, the resulting structure is similar to the (oH)4 substituted for SiO4 known in the hydro grant. The adsorbed ions can be expelled by increasing pressure or heat, or other ions can be substituted or added to it, so that heat does not damage this interaction.

 D) Water Absorption and Some Organic Compounds

The ability to absorb and lose zeolite water without destroying the matrix can control the moisture level in low humidity areas. By changing the amount of soil moisture, the heat energy of the soil mass also changes significantly. Therefore, temperature fluctuations in wet soils are much less than in dry soils. Zeolites can also carry many insecticides, pesticides and fungicides.

E) Selective absorption

Ionic adsorption and substitution in zeolites is optional. Zeolites absorb molecules that have a constant polar moment in most cases. The radius and geometric shape of the molecule and the voids in the zeolites are important factors in adsorption and substitution. Sodium zeolites can absorb H2O, CO2, SO2, and hydrocarbons that have at least two carbon atoms. Calcium zeolites can also absorb paraffin and alcohol. In Iran, despite the existence of huge resources and reserves of this mineral, so far no significant scientific and research work has been done to investigate the possibility of using them in the various fields mentioned above.

Application of Zeolites in Agriculture

In general, the three factors of chemical structure, frequency and availability, as well as economic value, have provided many applications for zeolites. Despite the abundance of natural zeolites, in many cases it can not compete with artificial zeolites and still the major consumer market is the monopoly of artificial zeolites.

One of the important uses of zeolites is in agriculture; Some zeolites can be added to the soil as ionic fertilizers after ion exchange with the essential nutrient cations needed by plants such as potassium and ammonium. Existing nutrient ions are gradually released from the zeolite phase and made available to plants. In addition to the main nutrient ions, this way the ions needed by plants such as iron, copper, manganese and zinc can be made available to plants. It is possible to use crude zeolites to reduce costs and prices. Zeolites can also be added to fertilizers as diluents and are effective in improving physical condition and maintaining soil moisture.

Zeolites slowly and gradually make fertilizers available to plants through ion exchange reactions or a combination of ion exchange reactions and mineral dissolution reactions. Zeolites such as clinoptilolite can act as a slow release agent to reduce the supply of ammonia fertilizers, as high fertilizers can be toxic to crops and burn their roots. On the other hand, it reduces wastage due to drainage of rainwater. Through the exchange of potassium-saturated clinoptilolite, potassium can be made available to plants with the help of NH4-saturated clinoptilolite.

Recently, it has been found that a mixture of NH4-saturated clinoptilolite; With phosphate rock (apatite) simultaneously and gradually releases N and P and adds to the soil. Zeolites absorb up to 70% of their own weight in water and retain soil moisture without disturbing or sinking.

For plant cultivation, 25% zeolite is added to agricultural soil. For this purpose, approximately 1.5 cm of zeolite is sprinkled on the soil and mixed with the soil with a rake, shovel or any other tool. It has been shown that adding 10% zeolite to agricultural soil leads to soil fertility, aeration and water uptake in the soil. This will lead to sustainable greenery, health and strength of plants. The cost of adding zeolite to the soil will be offset by an increase in crop yields. If chemical or natural fertilizers are mixed with zeolite in a ratio of 50 and dispersed on agricultural lands by fertilizer, it helps to improve soil air conditioning and soil fertility because zeolites place water-soluble fertilizers in their micro-structure and prevent it from coming out of the soil and gradually make it available to the soil again.

Application of Zeolite in Water Treatment

Another use of zeolites is to reduce the hardness of drinking and industrial water. One way to reduce the hardness of water is to change ions, and the most common method is permotite, in which hard water is pressurized through closed filters. In these filters, resin particles are formed from hydrated aluminum silicate -zeolite-, either naturally or artificially(permotite).

Depending on the hardness of the water being treated, zeolites lose their properties over time. In this case, you must continue to work according to the following relationships:

 Na2(Zeolite) + CaCl2 = Ca(Zeolite) + 2NaCl
Mg (Zeolite) + 2 NaCl = Na2 (Zeolite) + MgCl2

With the flow of concentrated brine, the calcium and magnesium silicate obtained in the filter was converted back to efficient and revived zeolite. Such filters are now used in Kerman drinking water treatment plant. Instead of permotite, other compounds such as Wofatite and Lewatite can be used.

Zeolites are mainly natural, inexpensive and available compounds for various uses. Properties such as ion adsorption and repellency as well as water adsorption ability have made these minerals more widely used in agriculture and water and wastewater treatment in the future. Improving the physical properties of soils such as adequate moisture storage, as well as their chemical properties such as changes in soil ion exchange capacity have increased the use of zeolites in agriculture and increased the use of chemical fertilizers. On the other hand, the high capacity of zeolites to absorb cationic pollutants has expanded their use in water and wastewater treatment processes.

According to the results, the use of clinoptilolite in the process of water treatment, including industrial and municipal wastewater, as well as in drinking water treatment, as well as various fields of agriculture and animal husbandry is recommended. Inexpensive, safe for soil and environment and high efficiency in removing pollutants can be among the important factors in choosing this natural mineral as a soil conditioner and purifier of polluted water and wastewater in Iran.