2 PROPERTIES AND APPLICATIONS Bentonite deposits are normally exploited by Bentonite is a clay generated frequently quarrying. Extracted bentonite is distinctly from the alteration of volcanic ash, solid, even with a moisture content of consisting predominantly of smectite approximately 30%. The material is initially minerals, usually montmorillonite. Other crushed and, if necessary, activated with the smectite group minerals include hectorite, addition of soda ash (Na2CO3). Bentonite is saponite, beidelite and nontronite. Smectites subsequently dried (air and/or forced drying) are clay minerals, i.e. they consist of to reach a moisture content of approximately individual crystallites the majority of which 15%. According to the final application, are <2µm in largest dimension. Smectite bentonite is either sieved (granular form) or crystallites themselves are three-layer clay milled (into powder and super fine powder minerals. form). For special applications, bentonite is purified by removing the associated gangue Depending on the nature of their genesis, minerals, or treated with acids to produce bentonites contain a variety of accessory acid-activated bentonite (bleaching earths), minerals in addition to montmorillonite. or treated with organics to produce These minerals may include quartz, feldspar, organoclays. calcite and gypsum. The presence of these minerals can impact the industrial value of a The main application of natural bentonite deposit, reducing or increasing its value includes: depending on the application. Bentonite Foundry: Bentonite is used as a bonding presents strong colloidal properties and its material in the preparation of molding sand volume increases several times when for the production of iron, steel and non- coming into contact with water, creating a ferrous casting. gelatinous and viscous fluid. The special properties of bentonite (hydration, swelling, Bentonite is used for cat litter, Cat Litter: water absorption, viscosity, thixotropy) due to its advantage of absorbing refuse by make it a valuable material for a wide range forming clumps (which can be easily of uses and applications. removed) leaving the remaining product intact for further use.
2 PROPERTIES AND APPLICATIONS Bentonite is a clay generated frequently from the alteration of volcanic ash, consisting predominantly of smectite minerals, usually montmorillonite. Other smectite group minerals include hectorite, saponite, beidelite and nontronite. Smectites are clay minerals, i.e. they consist of individual crystallites the majority of which are <2µm in largest dimension. Smectite crystallites themselves are three-layer clay minerals. Depending on the nature of their genesis, bentonites contain a variety of accessory minerals in addition to montmorillonite. These minerals may include quartz, feldspar, calcite and gypsum. The presence of these minerals can impact the industrial value of a deposit, reducing or increasing its value depending on the application. Bentonite presents strong colloidal properties and its volume increases several times when coming into contact with water, creating a gelatinous and viscous fluid. The special properties of bentonite (hydration, swelling, water absorption, viscosity, thixotropy) make it a valuable material for a wide range of uses and applications. Bentonite deposits are normally exploited by quarrying. Extracted bentonite is distinctly solid, even with a moisture content of approximately 30%. The material is initially crushed and, if necessary, activated with the addition of soda ash (Na2CO3). Bentonite is subsequently dried (air and/or forced drying) to reach a moisture content of approximately 15%. According to the final application, bentonite is either sieved (granular form) or milled (into powder and super fine powder form). For special applications, bentonite is purified by removing the associated gangue minerals, or treated with acids to produce acid-activated bentonite (bleaching earths), or treated with organics to produce organoclays. The main application of natural bentonite includes: Foundry: Bentonite is used as a bonding material in the preparation of molding sand for the production of iron, steel and non- ferrous casting. Cat Litter: Bentonite is used for cat litter, due to its advantage of absorbing refuse by forming clumps (which can be easily removed) leaving the remaining product intact for further use.
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