Calcium titanate mineral

PEROVSKITE. The mineral perovskite is calcium titanate, essentially CaTiCL, with rare earths, principally cerium, proxying for Ca, as do both ferrous iron and sodium, and with colunibiuni substituting for titanium, ll crystallizes in die orthorhombic system, but witli pseudo-isometric character fracture subconchoidal to uneven brittle hardness, 5.5 specific gravity. 4 luster, adamantine color, various shades of yellow to reddish-brown or nearly black transparent to opaque. It is found associated with chlorite or serpentine rocks occurring in the Urals, Baden, Switzerland, and Italy, It was named for Von Perovski. 

As has been mentioned, ternary compounds having polyatomic ions such as NO3-, C032-, NFLt+, and so on often have the same types of structures as binary compounds in which a polyatomic ion occupies a lattice site as a unit. The mineral perovskite, CaTiOs, calcium titanate, however, is a somewhat different type of ternary compound that has the structure shown in Figure 3.8(a). Most ternary compounds are oxides, and the general formula ABO3 corresponds to many compounds because A = Ca, Sr, Ba, and so forth, and B = Ti, Zr, Al,... 

ER fluids are typically are suspensions of 1- to 100- um particles of cornstarch, silica, calcium titanate, or other semiconductors at volume fractions of0.05-0.50 in a hydrophobic liquid, such as mineral oil or com oil. For an electric field E of 50-5000 V/mm, the particles form chains that span the gap between the field-generating electrodes (see... 

The structure is named after the mineral perovskite, calcium titanate, that contains Ti " " in the octahedrally coordinated positions and in the large, 12-coordinate site in the centre of the unit cell. Lithium conductivity has been reported in closely related compounds that replace Ca with various combinations of Li" ", La and cation vacancies that maintain an overall divalent charge per formula unit. The... 

It has been found that compounds of the alkaline earth metals as well as rare earths are suitable for vanadium trapping. Patents relating to the use of titanates of calcium (22), barium (23), and strontium (24) have been issued. Equivalent stannates of calcium and strontium have also been recommended (24,25). Rare earths as separate particles (26) and in the same catalyst particle (27) have been proposed. Naturally occurring minerals such as Sepiolite and Dolomite which are rich in magnesium oxide and calcium oxide have been suggested (28). 

For the polymerization to proceed at a reasonable rate, the use of a transesterification catalyst is needed. Compounds which are usually used as a catalyst for the preparation of polyesters through transesterification can be used here. These include lithium, sodium, zinc, magnesium, calcium, titanium, maganese, cobalt, tin, antimony, etc. in the form of a hydride, hydroxide, oxide, halide, alcoholate, or phenolate or in the form of salts of organic or mineral acids, complex salts, or mixed salts.(10) In this study, tetrabutyl titanate (TBT) in the amount of 1000 ppm was used normally. 

According to well-known theoretical models, inorganic solids with high dielectric constant have a strong electroresponsive fibrous structure. Typical examples include Ti02, calcium, strontium or barium titanate precipitates [26], zeolite or clay-type minerals, and polar-molecule-dominated ERFs (PM-ERFs) [27]. 

Wollastonite siufaces react with water and hydrolyse to form calcium hydroxide. The mineral is attacked by strong mineral acids, especially hydrochloric acid, and by certain organic acids. Siuface treatment can be carried out with silanes, titanates or zircoaluminates. 

Of the various mineral fillers used, calcium carbonate (CaCO ) is one of the most common, due mainly to its availability in readily usable form and low cost [76]. However, the incompatibility of its high energetic hydrophilic surface with the low-energy surface of hydrophobic polymers, e.g., polyethylene (PE) and polypropylene (PP), is a particular problem. For this and other reasons, the surface of calcite is often rendered organophilic by a variety of surface modifiers such as silanes, titanates, phosphates, and stearic acid. 

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