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OCMA Bentonite

OCMA bentonite is an activated grade of sodium bentonite with unique functions. This product contains various features, making it a suitable option for multiple applications. OCMA bentonite may be employed in water-base drilling fluids as a desired chemical for increasing viscosity and decreasing fluid loss. In other words, It is usually used to achieve consistency, fluid-loss control, and filter-cake quality. Moreover, it is frequently used in drilling mud for oil and gas wells as well as boreholes for geotechnical and environmental research because of its excellent colloidal characteristics.

Iran Bentonite Co. is a leading supplier in the bentonite market, supplying products suitable for industrial applications. This OCMA and high yield bentonite supplier ensure their consumers with a well-approved product that meets international requirements. As an in-demand company, you can rely on Iran Bentonite company and its unique products, such as OCMA bentonite and other sodium-based grades like Iran API Bentonite and Iran High Yield Bentonite, to retain competitive advantages relative to your competition.

What is Bentonite?

The term “bentonite” in geology refers to a particular kind of claystone made primarily of montmorillonite. Devitrification of volcanic ash or tuff frequently occurs in marine environments where bentonite develops. As a result, a very soft, porous rock is produced that may still include crystals of harder minerals and feels greasy or soapy to the touch. In contrast, the name “bentonite” is more broadly used in commerce to describe any swelling clay made up primarily of smectite clay minerals, including montmorillonite.

The mineral montmorillonite, which makes up bentonite, is an aluminum phyllosilicate with a low-charge TOT crystal structure. Accordingly, a montmorillonite crystal is built up of layers, each of which is composed of two T sheets joined to either side of an O sheet. The T sheets got their name because they contain four oxygen ions grouped in a tetrahedron around each aluminum or silicon ion. Each aluminum ion in an O sheet is surrounded by six oxygen or hydroxyl ions organized in an octahedron. With a gap of roughly 1 nm between layers, the weak negative electrical charge of the entire TOT layer should be balanced by calcium or sodium cations, which also serve to bind adjacent layers together. Only a tiny portion of the potential cation sites on a TOT layer’s surface contain calcium or sodium since the negative charge is so weak. Between sheets, water molecules can quickly penetrate and fill any empty spaces. This explains the swellable nature of smectite clay minerals like montmorillonite.

The respective major cation is used to identify each of the several forms of bentonite. Sodium and calcium bentonite are the two primary kinds of bentonite recognized for industrial use. Although calcium bentonite is more prevalent, sodium bentonite is more valued. Because this article is allocated to the OCMA Bentonite, which is a grade of activated sodium-based bentonite, below, we only discuss the sodium bentonite and then speak about the OCMA grade, omitting calcium quality.

What is OCMA Bentonite?

OCMA grade, like API bentonite and High Yield Bentonite, is an activated grade of sodium bentonite, so first, we need to make a general understanding of sodium bentonite.

First, we should know that sodium bentonite is introduced as an absorbent aluminium phyllosilicate. When saturated with water, it swells and can absorb up to several times its dry bulk. Since its capacity to swell, sodium bentonite is helpful as a sealant because it creates a low permeability, self-sealing barrier. For instance, it is used to line the bottom of landfills. The backfill used at the Waste Isolation Pilot Project includes bentonite as well. In geoenvironmental applications, specific surface changes to sodium bentonite, including polymers, can enhance some rheological or sealing properties. Sulfur and sodium bentonite can be blended to create fertilizer prills. These enable the gradual oxidation of sulfur to sulfate, a crucial plant nutrient, and prolong the duration of sulfate levels in rainfall-leached soil compared to pure sulfur powder or gypsum. Organic farming has employed sulfur/bentonite pads with additional organic fertilizers.

The acronym OCMA stands for the now-defunct “Oil Company Materials Association,” a group that for many years established standards for mud materials based mainly on the needs of Middle Eastern oil firms. The product, OCMA bentonite, is versatile drilling bentonite that has an excellent price-quality ratio, holds little fluid loss, and is simple to recycle. Due to superior filtering control, OCMA Bentonite offers strong stabilizing qualities. This product can be reused numerous times and is easy to recycle. In water-base drilling fluids, OCMA bentonite increases viscosity and decreases fluid loss. In freshwater and marine mud, it is an affordable way to achieve viscosity, fluid-loss control, and filter-cake quality.

Different grades of OCMA Bentonite

Considering bentonite clay as a type of clay, calling it “dirt” is a little more accurate. However, it merits a more comprehensive explanation. Similar to DE, bentonite clay also contains several trace minerals, but the mineral montmorillonite, which is found in volcanic ash, makes up the majority of the clay. Mined and processed into a light brown, earthy powder are bentonite clay deposits. The two primary types of bentonite clay are food grade and industrial grade.

Additionally, there are various types of bentonite clay with different mineral concentrations. Calcium and sodium bentonite are the two most popular varieties of bentonite clay. In general, sodium bentonite is not a good choice for internal consumption and is typically mined for industrial purposes. Like all types of bentonite clay, sodium bentonite expands when it absorbs moisture, but sodium bentonite clay has a far greater absorption capacity.

OCMA bentonite is an activated grade of sodium bentonite, as mentioned before. Still, this product can be varied due to its purity and components. A chemical Analysis of OCMA Type Bentonite Sample may result in properties below:

  • 16.21 % of Al2O3;
  • 0.45 % of MgO;
  • 47.55% of SiO2;
  • 0.27% of CaO;
  • 1.19 % of FeO;
  • 1.24 % of Fe2O3.


Due to different analyses of OCMA type bentonite samples, the standard type of this product may consist mainly of smectite and montmorillonite. Minor amounts of quartz, kaolinite, mica, cristobalite and illite are also found. Additionally, this product contains minute quantities of chlorite and mixed-layer illite-smectite. The quartz grains in Ocma bentonite were found to be covered in clay mineral layers and aggregated by fine chains of clay mineral particles when analyzed using scanning electron microscopy (SEM). The SEM image also demonstrates the dispersion of clay particles.

Besides chemical features, Iran bentonite may be varied based on its physical properties. OCMA bentonite, as one of the Oil and Gas Drilling Chemicals, holds physical characteristics such as 16 ml of Filtration, 90 bbl of Efficiency, and 10% Humidity. Please remember that you can rely on Iran Bentonite Co. as a respected OCMA Bentonite Manufacturer for a pure product.


OCMA Bentonite production process

As mentioned earlier, OCMA bentonite is widely used in geotechnical and environmental research boreholes and drilling mud because of its excellent colloidal characteristics. Sodium bentonite, or its OCMA grade, is also beneficial in sealing due to its tendency to swell, resulting in a low-permeability, self-sealing barrier. It is a multipurpose product, so it should be produced under particular considerations to achieve the best results. In this case, each OCMA and API Bentonite Manufacturer utilize a specific way to make sodium bentonite that meets international standards.

This section explains how to convert calcium bentonite into sodium bentonite, which can be used as drilling mud or a cement ingredient. The calcium bentonite suspension is continually heated and stirred for up to 24 hours after being added to a prepared soda ash solution at predefined soda ash/bentonite weight ratios. The sodium activation of the bentonite and other rheological properties of the bentonite is enhanced by heating and stirring. As it represents itself, this is a method for producing sodium bentonite, not the OCMA bentonite that is an activated grade of this substance.

Below, we will explain the production process in detail, categorized in various stages so that you can get a better sense of the process.

1st Stage

In the method, sodium carbonate (soda ash) powder or crystals are first dissolved in water (preferably distilled water) to a final sodium carbonate concentration of no more than one wt% (weight percentage based on the total weight of water)

  •  preferably 0.1-1 wt%;
  • more preferably 0.2-0.9 wt%;
  • more preferably 0.3-0.6 wt%;
  • more preferably 0.4-0.5 wt%;
  • most preferably 0.28-0.8.


The sodium carbonate can be employed in anhydrous or hydrated forms (most commonly as monohydrate, decahydrate or crystalline heptahydrate). For an ion exchange procedure with Ca-bentonite, the soda ash solution serves as a source of carbonate and sodium ions so that calcium from Ca-bentonite can precipitate as calcium carbonate. The produced sodium carbonate solution is then supplied with a Ca-bentonite sample until the bentonite concentration is 5–10 weight per cent (weight percentage based on total water weight), preferably 5-8 weight per cent, and even more preferably 6-7 weight per cent. The ratio of sodium carbonate to bentonite in the bentonite suspension ranges from 1:6 to 1:25 (sodium carbonate/bentonite weight ratio), with 1:7 to 1:23 being preferred, 1:10 to 1:23 being preferred, and 1:20 to 1:23 being the most preferred.

Ca-bentonite is a sample of unprocessed, raw bentonite that has been dried to remove water. The moisture content of the Ca-bentonite model is less than 10%, ideally between 0.5 and 10%. A Ca-bentonite sample purified by conventional purification techniques may be employed in certain instances. These purification methods can be combined, including dry-sieving, wet-sieving, dispersion in deionized water with or without hexametaphosphate, and sedimentation. U.S. sieve or mesh sizes for sieves used for dry or wet sieving range from 100 to 400 mesh, including 100, 115, 150, 170, 200, 250, 270, and 400.

2nd Stage

The sodium carbonate solution and the bentonite sample are combined, and the bentonite suspension is then heated and agitated. For at least the following occurrences, heating and stirring are essential:

  • The expansion of the bentonite platelets for enhanced swelling and ion exchange;
  • The movement of sodium ions to the surface of the bentonite layers allowing enhanced Na+ activation and swelling;
  • The increase in Na/Ca ratio;
  • Changes in rheological properties.


The heating temperature should be kept below 100 degrees Celsius, for example, between 60 and 80 degrees or 60 to 75 degrees. The OCMA and High Yield Bentonite Manufacturers should stay outside the water’s boiling point by reducing bentonite suspension evaporation.

3rd Stage

The stirring mechanism can be accomplished using agitation tools, such as but not limited to a magnetic agitator with a tank containing the bentonite suspension and a magnetic bar spinning about a magnetic field placed inside the container. The stirring rotational speed is maintained between 50 and 300 revolutions per minute (rpm), with 100 to 250 preferred. Remember that the continuous heating and stirring must be maintained for at least three hours to get the most remarkable viscosity growth. At 3–24 hours, preferably 6–24 hours, more preferably 9–24 hours, and even more ideally 12–24 hours, the bentonite suspension is constantly heated and stirred.

The final results

The bentonite created after the activation of soda ash, heat processing, and mechanical stirring has a Na/Ca molar ratio of at least 2.5, for instance, 2.8-3.0. The procedure can increase a treated bentonite sample’s Na/Ca ratio by at least 50–65 per cent. More than 90% of the particles fall within the average particle size range (1000-1500 m), which can be increased by more than 500 times, for instance, from 2.5 m to 1000-1500 m. Soda ash activation alone can only increase the average particle size by up to 8 times without ongoing heating and stirring. Dry-sieve or wet-sieve analysis, or any other similar grain size analysis, can be used to determine the particle size distribution and average particle size.

OCMA Bentonite Applications

Various types of bentonites, based on their ingredients, hold multiple utilities. For instance, Calcium bentonites are primarily used in industries, like refining industrial and edible oils, preparing insulation materials and animal feed, adding adhesive additives to the foundry and mould-making industries, and refining industrial and edible oils. Sometimes it is more helpful if different types of this product combine to make a distinct outcome; it happens when Calcium and sodium bentonites are combined to contain cellulose additions, primarily utilized in the concrete and ceramic industries.

OCMA bentonite is an activated grade of sodium-based bentonite, which contains the functions of sodium bentonites and its own applications, too. Sodium bentonites hold various properties that make them perfect choices in the industry, like their role in oil well drilling as Oilfield Drilling Chemicals. The tendency of sodium bentonite to swell is its most well-known property. It has a nearly 5-fold water absorption capacity and, at full saturation, can occupy an area 12 to 15 times larger than its dry bulk. Bentonite maintains a high water absorption rate, making it highly plastic and resistant to breaking or cracking. It’s interesting to note that bentonite can undergo an unlimited number of hydration and drying cycles without losing its ability to swell. Like other materials, it can be repeatedly frozen and thawed without losing its capacity to expand. The sodium bentonite has a large surface area of 600 to 800 square meters per gram due to the uniformly broad and flat particles. Less than 10 grams of bentonite could cover an entire football field if thoroughly disseminated.

OCMA bentonite, as activated sodium bentonite, holds these properties, making it a suitable choice for several functions; it increases viscosity and decreases fluid loss in water-base drilling fluids. In freshwater and marine mud, it is an affordable way to achieve viscosity, fluid-loss control, and filter-cake quality. Despite using OCMA bentonite and other sodium bentonite types as Oilfield Drilling Minerals, they may also carry fungicides, pesticides, and insecticides.

OCMA Bentonite in Drilling Fluids

In drilling fluids, Iran OCMA Bentonite is primarily used to lubricate and cool the cutting tools, clear away cuttings, and lessen the risk of blowouts. The distinctive rheological or “flow” qualities of bentonite contribute significantly to its employment in the drilling and geotechnical engineering industries. A viscous, shear-thinning substance is created when tiny amounts of bentonite are suspended in water. Bentonite suspensions are frequently thixotropic, which increases relative flow inside the solution.

It is also worth mentioning that Bentonite suspensions start to resemble gels, a fluid with a minimum yield strength required to make it move, at high enough concentrations (60 grams of bentonite per litre of liquid). Due to its inclination to aid in the creation of mud cake, it is a frequently utilized ingredient in drilling mud to prevent drilling fluid invasion.

About Iran Bentonite Co’s product

Since OCMA bentonite is a multipurpose product, there is a role for it in various industries. It is mainly used in drilling fluids for different purposes, such as lubricating and cooling. To maintain the highest level of performance in sectors that OCMA bentonite involves, we must supply a high-quality product. Iran Bentonite Co. is a devoted business partner that can serve customers with the quality products they require. This OCMA bentonite supplier enjoys well-equipped factories that allow this company to represent one of the highest quality products in the marketplace. They have strong chemical properties, making them a good choice for industrial use.

When it comes to conducting business with Iran Bentonite Co., a multitude of options are available. As a trustworthy OCMA and API bentonite supplier, this company offers you various options related to selecting the right product and logistics. You are welcome to pick your desired sodium bentonite with your intended purity and other properties. Ultimately, you may decide on your preferred way of packing the product and have it packaged in particular specifications. In this case, please do not hesitate to get in touch with our experts.


Iran OCMA bentonite includes distinct chemical properties that make it a unique product for the market demand. It has thixotropic behavior, which causes it to thin down and become less viscous when swirled with water. Therefore, it behaves as a fluid under mechanical stress, while being shaken or stirred, but becomes solid under static conditions. OCMA bentonite can be produced using various methods and particular tools; in this article, we went into detail about a specific production process that employs Calcium bentonite for this pupose. The outcome of our intended process takes a lead role in several industries due to its pure properties, such as drilling fluids and a pharmaceutical industry.