Hormite clay

Hormite clay is naturally more susceptible to acid-activation than montmorillo-nite lower levels of acid are required and can be directly applied (i.e., by simple spraying or pugging). Consequently, the slurry technique described above is not required, and the cooking, filtration, and washing steps can be eliminated (31). Data in Table 1 compare the response of hormite and montmorillonite clays with acid-activation. 

The way hormite clay responds to the acid-activation process allows manufacturers to skip certain manufacturing steps that are required when producing acid-activated bentonite. Because of its susceptibility to acid, the activation proceeds... 

Processing differences between bentonite and hormite clays are shown in Figure 3. 

Box 13.10 Kaolin, smectite and hormite clays from ceramics to natural absorbers... 

In addition to their use as absorbents, hormite clays are used as rheological agents. When dispersed in water, their needle-like particles deagglomerate in proportion to the amoimt of energy applied and form a random colloidal lattice. 

In addition to their high absorptive eapacity hormite clays offer useful thickening properties. When dispersed in water they do not swell, as smectites do. Instead, their needle-like colloidal particles deagglomerate in proportion to the amoimt of shear applied and form a random colloidal lattice. This loosely cohesive structure thickens the water and imparts thixotropy, pseudoplasticity, and yield value. Because of their mechanically-based dispersion and colloidal structure building, hormite cl s are largely insensitive to the types and levels of acids, bases, and salts dissolved in the aqueous systems in which they are used. Since their dispersion is mechanically rather than ionically driven, as with smectites, they can be used in nonaqueous applications in much the same... 

In addition to the mineralogical distinction between palygorskite (attapulgite) and sepiolite, hormite clay products are generally classified by function and water content. 

Other uses - Hormite clays are also used as thickeners in grease, polyesters, and vinyl plastisols, odor absorbents, bleaching (decolorizing) agents for petroleum, mineral, and vegetable oils, fdter aids, anticaking agents, pharmaceutical absorbents, acicular fillers in rubber (sepiolite), catalyst supports (sepiolite), and cosmetic/pharmaceutical thickeners and emulsion stabilizers. 

Bleaching clay - Although certain natural smectite and hormite clays are used to deeolorizE oils, die term bleaehing cl most commonly refers to aeid-activated bentonite as described above. 

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