Surface modified minerals

The number of surface modified mineral materials described in literature is progressively growing. By now, the methods for fixation of not less than one thousand of individual compounds has been developed. It is not overestimation to say that synthetic methods of surface science allow for covalent immobilization of practically any of chemical compounds or functional groups on a mineral surface. 

J Griffiths, Deputy Editor. Surface modified minerals. Indust Miner 39, 1987. 

Uhy risk the uncertainty of in-process addition of chemicals when surface modified minerals offer so many advantages ... 

Economics Surface modified minerals are among the most cost-effective material investments you can make. 

Improved processability - Surface modified minerals deagglomerate easily and disperse well to maximize mineral-matrix eontact while promoting lower viscosity. This reduces compounding energy requirements and cost. Table 1, for example, shows die dramatie viseosity ehange for various fillers in polyester when pretreated with a methaerylate fimetional silane. 

Griffiths, J.B., 1990, Minerals as Fillers - Modification to Serve Modem Markets , Plastics and Rubber Processing and Applications, Vol. 13, No. 1, pp 3-8 Griffiths, J.B., 1987, Surface Modified Minerals , Industrial Minerals, Oct., pp 23-45 Joslyn, W., 1986, Optimal Pretreatment of Reinforcement Modifiers with New Generation Silanes , C.H. Kline Company Conference on Chemically Modified Minerals, October 9, 1986... 

Kuhn, C.R., Johnston, J., 1995, Surface Modified Minerals-Types of Minetals, Benefits Realized from Their Use and Applications in Industry , SME Annual Meeting, Denver, Colorado, March 6-9,1995... 

Clearly, it is important that there be a large contact angle at the solid particle-solution-air interface. Some minerals, such as graphite and sulfur, are naturally hydrophobic, but even with these it has been advantageous to add materials to the system that will adsorb to give a hydrophobic film on the solid surface. (Effects can be complicated—sulfur notability oscillates with the number of preadsoibed monolayers of hydrocarbons such as n-heptane [76].) The use of surface modifiers or collectors is, of course, essential in the case of naturally hydrophilic minerals such as silica. 

Fig. 6. General geology, mineral occurrences, and diamond drillhole locations In the Long Lake area with a cross section corresponding to the line A-B, Illustrating the general geology beneath the surface (modified from Fyffe Pronk 1985).

Among the surface-modified CNTs materials, a bulk-modified CNT paste (CNTP) has also been reported [126]. The new composite electrode combined the ability of CNTs to promote adsorption and electron-transfer reactions with the attractive properties of the composite materials. The CNTP was prepared by mixing MWCNTs powder (diameter 20-50 nm, length 1-5 jim) and mineral oil in a 60 30 ratio. The oxidation pretreatment [performed in ABS (pH 5.0) for 20 s at 1.30 V, vs Ag/AgCl] proved to be critical in the state of the CNTP surface. Pretreatments improved the adsorption and electrooxidation of both DNA and DNA bases, probably due to the increase in the density of oxygenated groups. 

Beckett and Le, 1989 Tombacz, 2003). The presence of as little as lwt% NOM-modified mineral chemistry surface to the extent that it was concluded to be the controlling factor (Bertsch and Seaman, 1999). 

There are several major areas of interfacial phenomena to which infrared spectroscopy has been applied that are not treated extensively in this volume. Most of these areas have established bodies of literature of their own. In many of these areas, the replacement of dispersive spectrometers by FT instruments has resulted in continued improvement in sensitivity, and in the interpretation of phenomena at the molecular level. Among these areas are the characterization of polymer surfaces with ATR (127-129) and diffuse reflectance (130) sampling techniques transmission IR studies of the surfaces of powdered samples with adsorbed gases (131-136) alumina(137.138). silica (139). and catalyst (140) surfaces diffuse reflectance studies of organo- modified mineral and glass fiber surfaces (141-143) metal overlayer enhanced ATR (144) and spectroelectrochemistry (145-149). 

Surface complexation — is complexation of metal ions by ligands immobilized on the electrode surface (-> electrode surface area). The ligands may be incorporated in the structure of a -> carbon paste electrode, covalently bound to the surface of a chemically modified electrode (-> surface-modified electrodes), or adsorbed (-> adsorption) on the electrode surface etc. Surface complexation is not confined to electrodes. It can occur on many surfaces, e.g., minerals, when in contact with metal ion solutions or solutions containing complexing ions (in the first case, the surface provides the ligand and the solution the metal ion, whereas in the second case, the surface provides the metal ion and the solution the ligand). Surface complexation can be an important step in the dissolution of solid phases [ii]. 

Carbokup. [Malvern Minerals] Surface-modified calcium carbtxiate. 

Micacoat [Nyco Minerals] Chemically surface-modified mica. 

Talc - Talc is a filler made by dry or wet grinding of mineral magnesium silicate. Talc improves stiffness, dimensional stability, flexural modulus, creep resistance, flow, surface smoothness, moisture resistance, tensile strength, and wear resistance of plastics. It also increases heat deflection temperature and decreases vapor permeability. Can be used as a film antiblock agent. Used mainly in polypropylene but also in thermoplastic and unsaturated polyesters and epoxy resins at low levels. Surface-modified grades are available. 

Activators enhance the selectivity action of collectors. These (often surface inactive) substances are primarily the electrolytes, which modify the particle surface, e.g. by ion exchange, and make the adsorption (chemisorption) of collectors easier. One example of an activator is sodium sulfide used to aid the flotation of oxidized non-ferrous minerals. Substances that control the solution pH, and thus create the desired ionization state of the surface of mineral particles also belong to the class of activators. 

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