Delamination and flocculation efficiency of sodium-activated kaolin and montmorillonite

Adsorption of polyamine on clay minerals

“…In the case of clay minerals that bear a structural negative charge, cationic products such as quaternary amine compounds are often used as flocculating agents of clay dispersions [10][11][12][13]. The adsorption of cationic compounds onto clays has then been investigated since the 1950s and most studies reveal that cationic exchange is the major driving force for adsorption (e.g., [14,15]).…”

Incorporation of Rheological Characterization in Grinding and Tailings Slurries to Optimize the CMP Magnetic Separation Plant

“…Kaolinite is a 1:1 clay consisting of alternating layers of silica tetrahedra and aluminum hydroxide octahedral (T-O), which are held tightly together by hydrogen bonding, which explains why kaolinite swelling in water is minor [34]; kaolinite particles have two different surfaces created during particle breakage, i.e., the basal silica-like faces which are negatively charged over a wide range of pH, and the alumina-like edges which are positively charged on the neutral-acidic range of pH [35][36][37][38], which explains the tendency of these particles to aggregate and affect the rheological properties of mineral suspensions. Smectites belong to the 2:1 layer clay minerals, and a single platelet is composed of three layers where one octahedral aluminum-oxygen layer is sandwiched between two tetrahedral silicon-oxygen layers [28,34]. These mineral particles can also be modeled as laminar particles, with faces and edges with the basal silica-like layers carrying a permanent negative charge, and the edges' charge depending on pH [24].…”

Biobased polymers and cationic microfibrillated cellulose as retention and drainage aids in papermaking: Comparison between softwood and bagasse pulps

“…Interactions between bentonites and cationic polymers or colloids result from electrostatic forces and the high surface charge density of the bentonite plays a major role and explains the efficiency of these systems. These interactions are probably affected by the swelling extent of the bentonite and the resulting surface area (Asselman and Garnier, 2001;Burgess et al, 2000;Alince et al, 2001;Cho et al, 2006;Vanerek et al, 2006). More specifically, bentonite based-microparticle systems could improve drainage and retention for non-wood pulps which are often characterized by a poor dewatering but this subject has not been extensively studied (Rainey et al, 2010;Vishtal et al, 2011).…”

“…In water, the resulting negative net charge is compensated by the presence of exchangeable cations on the surface of the plates which are responsible for the penetration of water in the interlayer space and the huge swelling ability of the bentonites. After swelling and delamination, the surface area of montmorillonite can reach 800 m 2 g −1 and the cation exchange capacity, depending on the substituting cations, is usually close to 1 meq g −1 , which corresponds to a high surface charge density of about 0.2 C/m 2 (Hessen and Smit, 2002;Vanerek et al, 2006). In papermaking, bentonites are used with two objectives: for adsorbing contaminants such as wood colloids which can interact with process additives (Asselman and Garnier, 2000) and, as already mentioned, for improving the drainage and retention.…”