Consolidation chemical process

The metal is isolated commercially by a complex chemical process, the final stage of which is the hydrogen reduction of ammonium ruthenium chloride, which yields a powder. The powder is consolidated by powder metallurgy techniques or by argon-arc welding. 

The solgel process uses a liquid reactive precursor material that is converted to the final product by chemical and thermal means. This precursor is prepared to form a colloidal suspension or solution (sol) which goes through a gelling stage (gel) followed by drying and consolidation. The process requires only moderate temperatures, in many cases less than half the conventional glass or ceramics... 

Solidification and stabilization processes. These immobilize the contaminants through physical or chemical processes. Solidification involves the entrapment of contaminants into a consolidated mass and stabilization is the conversion of contaminants to a chemical form that is less available. 

Aging effects. Diagenetic effects, which, apart from chemical processes (sorption, precipitation, occlnsion, incorporation in reservoir minerals and other geosorbents such as char, soot and ashes), involve enhanced mechanical consolidation of soil and sediment components by compaction, loss of water and mineral precipitations in the pore space, may induce a quite essential redaction of the reactivity of solid matrices (e.g. Lnthy et al., 1997). 

Although consolidation embraces a large range of processes, it is generally considered to be a chemical process the introduction of a liquid substance that solidifies around disintegrated intrinsic materials. Technically,... 

Natural rubber (NR) currently presents a set of consolidated scientific, technological and industrial applications, being of fundamental significance for several sectors of the global economy. Such applications derive from its distinguished mechanical and thermal properties, obtained through thermal and chemical processes e.g. the vulcanization process). In contrast, new fields of application are pursued mainly in sectors traditionally occupied by materials with a nature distinct from polymers, such as ceramic and metallic materials. 

Finally, it may be pointed out that none of the rare metals can be smelted directly from the ore. The concentrate must first be converted to a pure chemical compound which is utilized as the raw material for the production of the metal. The refractory rare metals are often obtained in the form of a powder or sponge. They are consolidated and refined by powder metallurgy techniques or by arc melting or by electron beam melting. In fact, the current refractory rare metals technology has been crucially dependent on the development of vacuum metallurgical techniques and processes. 

The outer crust of earth has provided the solid foundation for the evolution of human beings, who are the prime focus of interest and concern to archaeology. The main components of this crust are minerals and rocks, some consolidated and others occurring as sediments, nonconsolidated deposits, created by weathering processes from the minerals and rocks. All these minerals, rocks, and sediments, as well as everything else in the universe, are made up from just over 100 chemical elements listed in Appendix I. Most of the elements in the crust of the earth occur in extremely low relative amounts, and only a few, listed in Table 1, make up almost 99% of its total bulk (Bloom 1969). 

Since the discovery of alkylation, the elucidation of its mechanism has attracted great interest. The early findings are associated with Schmerling (17-19), who successfully applied a carbenium ion mechanism with a set of consecutive and simultaneous reaction steps to describe the observed reaction kinetics. Later, most of the mechanistic information about sulfuric acid-catalyzed processes was provided by Albright. Much less information is available about hydrofluoric acid as catalyst. In the following, a consolidated view of the alkylation mechanism is presented. Similarities and dissimilarities between zeolites as representatives of solid acid alkylation catalysts and HF and H2S04 as liquid catalysts are highlighted. Experimental results are compared with quantum-chemical calculations of the individual reaction steps in various media. 

---