Publisher's Synopsis
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922 Excerpt: ...Further detailed information upon material handling equipment may be obtained from the catalogs of the Jeffrey Mfg. Co., Columbus, Ohio, or from an article in the Chemical Age of Oct. 19, 1921, Vol. 29, p. 427, by R. H. McLain of the General Electric Co. CHAPTER XI. DISSOLVING. (136) The act of bringing substances into solution appears so simple as to require no comment. A little experience shows this to be wide of the mark. In some cases it is difficult to obtain cheaply and rapidly a saturated solution of the material wanted and, inasmuch as a partly saturated solution means more evaporation, it is to be avoided. (137) Salt solutions are almost always heavier than the solvent. If, then, we place the substance to be dissolved in the bottom of the tank, the heavy saturated solution will form and remain just around and over the solid, while the upper part of the tank will contain only solvent with no or only very little dissolved material. If the material to be dissolved is placed in the upper part of the tank in an open sieve or other appropriate support, as fast as the solution forms, it drops to the bottom of the tank and fresh solvent takes its place until the whole amount of liquid becomes saturated. The rapidity of solution and hence the amount of saturated solution to be made in a given time depends upon several factors. 1. Solubility: The more soluble the substance, the more rapidly solution takes place. 2. Surface exposed: The larger the surface, the more rapidly solution takes place. 3. Temperature: Usually, the higher the temperature, the more rapidly solution takes place. Solution is sometimes complicated by reactions which take place when the solute is brought in contact with the solvent. For example, dry sodium carbonate and sulphide in fine po...