Dextrins, description

Lead azide is manufactured on a technical scale by the action of sodium azide on an aqueous solution of lead nitrate. According to a description of manufacture in the Wolfratshausen factory in Germany [109], the reaction is conducted in an open reactor of stainless steel, provided with a jacket warmed by hot water and a stirrer which may be lifted out of the reactor (Fig. 49). The reactor is emptied by tilting. Its upper edge is therefore fitted with a spout so that the contents pour easily. The size of the reactor is such that 4.5 kg of lead nitrate in the form of a 9-10% solution can be used in each batch. This solution is poured into the reactor, warmed to 50°C and neutralized with sodium hydroxide to a pH of about 4.0 (in the presence of methyl orange) and 150 g of dextrin mixed with a small amount of water, is added. The suspension or solution of dextrin in water should be decanted before use to separate mechanical impurities, such as sand. 

V)Analysis of Mixtures Containing Lead Azide, Barium Nitrate, Basic Lead Styph-nate and Antimony Sulfide. As an example of such mixts may be cited the NOL No 130 Primer Mixture used in T—32E1 and M47 Detonators LA(dextrinated) 20.0, Ba(NOs)2 20.0, LSt (basic) 40.0, tetracene 5.0, St Sb,S, 15.0/5, Its max moisture content is 0.3%, The method of analysis of such mixts was developed at PicArsn by J.Campisi, ChemLabRept 52—HI—2114(1952) and was incorporated in the Purchase Descriptions PA—PD—202(Rev 1)(1952) and PA-PD-124 (1953)... 

Cyclodextrins, also called Schardinger dextrins, cycloamyloses, or cyclo-glucans, are a family of cyclic oligosaccharides obtained from starch and related compounds by the action of the amylase of Bacillus macerans. They were discovered by Villiers in 1891 [10] and the first detailed description of their properties and isolation was made by Schardinger in 1903 [11-13]. 

The above descriptions show the monomeric structures of starch, dextrin, cellulose, and guar gum. In reality, these polysaccharides can be extracted from different sources and the chain length and configuration, molecular weights, and the contents of impurities may vary considerably. Generally, starches have been used mainly as flocculants or flotation depressants for iron oxide minerals and phosphate minerals while the associated silica is floated. Dextrin has been mainly tested as depressants for inherently hydrophobic minerals such as talc, molybdenite, and coal [96]. Applications of polysaccharides in other mineral systems, both in the laboratory and in commercial processes, have also been frequently reported. As can be seen, the polysaccharides have been used or tested as selective depressants in practically all types of mineral systems, ranging from oxides, sulfides, salt-type, and inherently hydrophobic minerals. 

Chemical Description Gum produced by the incomplete hydrolysis of starch by the enzyme amylase to maltose and the high-molecular-weight residue known as dextrin... 

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