Technological progress in the production and use of natural nanomaterials is based on the improvement of methods for dispersing the ion-covalent structures, as well as the modification of their surface with adsorption layers of special surfactants. Layered aluminosilicates - bentonites, experiencing a real technological renaissance due to involvement in the active development of Russian deposits, are of particular importance among industrially important sedimentary rocks with well-developed structure.
Industrial application of bentonite powders is extremely diverse. They are used in the paper industry, in the manufacture of paints and coatings, for modifying the rheological properties, structuring and providing sedimentation stability of drilling fluids. Due to their catalytic and sorptive properties bentonites are used as carriers for pesticides, adsorbents for animal waste removal, catalysts or catalyst supports, as a brightener in the production of refined oils, and also in pharmacology.
Bentonite’s ability to self-organize to form technologically efficient nanoscale structures is determined by the content of rock-forming mineral montmorillonite (named after Montmorillon, a town in the Poitou-Charentes region, France) in its composition. The equivalent diameter of the particles of montmorillonite can vary from 0.1 micron to 2 microns and an average size is about 0.5 microns. The particles are irregularly shaped. They can have a compact package, but almost always are in laminated state and look like sheets of paper rotated in different directions relative to each other. On the side surfaces of the layered silicates functional groups are located, which are positively charged at low pH and negatively - at high pH of suspension.
A remarkable property of montmorillonite is its ability to split into the separate silicate layers or thin lamellae under the action of salts of lithium and sodium. This explains the phenomenon of sequential swelling and dispersion of bentonite in an aqueous medium to form a structured nano-sol. In a 10% aqueous solution bentonite forms a thixotropic nano-sol, in which the particles mobility is limited by interactions like lateral face – basal plane.
The ability to form nano-sol with high viscosity and structural strength demanded by the industry is inherent to bentonites with particular crystallographic structure characterized by the following features:
The quintessence of Russian bentonite industry is deposit Zyryanskoe (Kurgan region) owned by JSC «Bentonite», combining the highest quality of natural montmorillonite raw materials with advanced methods of bentopowders production. A multistage process of layer by layer excavating raw materials from the opencast mine, aging, drying, modification and fragmentation in its scientific content, complexity and aesthetics resembles the care of the grapevine. The «Kurgan vine» has gained international recognition for many years’ experience in the «cultivation» of deposit Zyryanskoe international: JSC «Bentonite» is the only Russian company licensed to issue bentopowders conforming to «API Specification 13A» OCMA grade (License number 13A-0070 to use the API monogram ).
Due to unique combination of high concentration of montmorillonite mineral base and point contact method of surface activation, allowing to realize the potential of the colloid-chemical raw materials, OCMA grade bentopowders have the following advantages:
OCMA grade bentopowders don’t contain synthetic polymeric thickeners and electrolyte additive that makes the product completely environmentally safe, including using for pitless drilling in conservation areas. The enzyme slurry resulting from utilization of drilling muds based on OCMA bentopowders is suitable for cost-effective biological methods of disposal: bioremediation under the influence of native microflora in a local biogeocenosis.