Solid-state reactions calcinations

Calcination temperature. Catalyst 0.7 g in 350 iiiL of water Liglit source 400-W high -pressure mercury lamp. PC stands for polymerizable coin pi ex while SSR stands for solid state reactions. 

Anhydrous calcium sulfoaluminate is formed by calcination of lime, gypsum and bauxite. The active expansive ingredient, C4A3S is formed by solid-state reaction from mixtures of compounds composed of calcium oxide,... 

Solid-State Reactions of Iron Compounds. Black iron oxides obtained from the Laux process (see below) or other processes may be calcined in rotary kilns with an oxidizing atmosphere under countercurrent flow to produce a wide range of different red colors, depending on the starting material. The pigments are ground to the desired particle size in pendular mills, pin mills, or jet mills, depending on their hardness and intended use. 

Coloristic Variations on the Basis of Mica. Mica platelets can be coated with a variety of compounds to produce novel pigments. Solid state reactions and CVD-process enlarge the possibilities for the synthesis of mica pigments. In addition, the calcination of the materials in the presence of inert (e.g. N2, Ar) or reactive gases (e.g. NFI3, H2, hydrocarbons) allows the formation of phases which are not producible by working in air. Table 54 contains a summary of nacreous mica pigments with special coloristic properties. 

Calcination The rate of heat schedule as well as the final temperature employed are important variables. A high enough temperature must be employed to ensure decomposition of the salts used in the preparation. At sufficiently high temperature, some solid-state reactions are engendered. Further, differences can be obtained whether using forced... 

Anhy2drous calcium sulfoaluminate is formed by calcination of lime, gypsum and bauxite. The active expansive ingredient, C A S is formed by solid-state reaction from mixtures of compounds composed of calcium oxide, aluminum oxide, sulfur trioxide gas formed during the calcination of gypsum, and bauxite. Crystal growth of CSAs is encouraged to proceed at a slow rate to preserve the potential force of expansion for extended periods [76],... 

This route is the solid state reaction at temperatures above 1100 °C of a mixture of BaC03 and Ti02 - together with modifiers . The calcination is followed by comminution to reduce the particle size to approximately 1 /an. 

SrFeOx is usually produced via solid state reaction between strontium and iron compounds. This method requires prolong firing at high temperatures (1200°C for about 24 h). This is followed by subsequent grinding and calcination. 

Hydrothermal routes Under ambient conditions, the low reaction temperature and fast precipitation rate have deleterious effect on the crystallization and optical performance of rare earth vanadate nanomaterials. Referring to traditional solid-state reactions, bulk YV04 Eu phosphors require a calcinations temperature above 1300 K, but it is too high for the preparation of nanomaterials. Alternatively, hydrothermal routes could provide the adequate energy for solution phase reactions, which have been widely described in preparation of ceramic powders. The high pressure and temperature largely promote the dissolution-reprecipitation process, so as to decrease the lattice defects of NCs. With fine modulation, this method is also efficient to produce nano-sized crystals. 

Li et al. developed a solid-state reaction process to synthesize perov-skite-type LaCoOs NCs with grain diameters of 15 0 run (Li et al., 2002). In the first step of the preparation, 5 run composite hydroxide NPs were s)mthesized by grinding metal nitrates liquid paste and mixing with KOH. Then the composite powders were calcined at 800 °C, yielding a single-phase oxide. Tien-Thao et al. prepared LaCo Cui J.O3 x < 0.3) by mechano-synthesis (Tien-Thao et al., 2008). The sample has various distinct Co " " ions in the perovskite lattice, which are more reducible. The reduced catalyst surface comprising cobalt and copper atoms is very selective for the hydrogenation of CO. 

Produced by solid-state reaction (yttria added as sintering aid), calcined at 1200°C. 

Calcination is important in these circumstances. Crystallized salt redissolves when the dehydrated catalyst is exposed to moist environments and subsequent process drying may violate optimum conditions. Calcination converts the salt to an oxide or metal and essentially freezes the distribution. Other calcination effects, such as solid state reaction, also take place. 

The synthesis of lithium aluminates for tritium production requires formation of nanostructured phases. These can be made by solid-state reaction, by appropriate mixing of oxide powders [84] or by sol-gel methods [80, 85-87], One technique is the peroxide route where y-Al203 and LiC03 are dissolved in a peroxide (H202) solution. Evaporation of water and calcining the solid residue results in nanophase LiA102. 

The Cu cations introduced by solid-solid reaction were easily accessible for adsorbates such as 2 as was evidenced by the dramatic but reversible change, i.e. loss of intensity, broadening and removal of hyperfine splitting of the ESR signals upon oxygen admission. The amount of Cu " which could be introduced into H-ZSM-5 by solid-state reaction, increased linearly with the A1 content of the framework. Similar results were obtained with H-MOR. However, when Na-MOR was calcined in a mixture with CuO no appearance of the Cu " " ESR signal was observed. 

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