STP442A: Chapter 14—Chemical Analysis of Deposits

    Pages: 12    Published: Jan 1978


    Abstract

    Many of the difficulties that arise during the industrial use of water are closely related to water-formed sludges, scales, and corrosion products. These water-formed deposits are the accumulations of insoluble material derived from the water, or are formed by the reaction of water with surfaces in contact with it. The composition of such deposits can be used to diagnose the reason(s) for deposition, to determine preventive treatment of either the water or its environment, and to effect their removal. A thorough and accurate analysis is an important beginning in this process. The analysis of water-formed deposits must be versatile and comprehensive in order to handle the most complex sample. It must also be flexible enough to handle the simplest samples easily and efficiently. The usual quantitative analysis will yield the elemental composition of the major constituents of such deposits. When single elements or simple compounds predominate, such an analysis is probably sufficient. For more complex deposits, however, other tools must be used to determine accurately the combinations of these elements. These include emission spectroscopy, X-ray diffraction, X-ray fluorescence, electron probe microanalysis, flame photometry, atomic absorption, petrographic microscope, and the electron microscope. A method for atomic absorption and spectrographic analysis is outlined in ASTM Testing Water-Formed Deposits (Method D 2331) [1]; a procedure for identification by X-ray diffraction is dealt with in ASTM Test for Identification of Crystalline Compounds in Water-Formed Deposits by X-Ray Diffraction (Method D 934) [1]; X-ray fluorescence is covered in ASTM Analysis of Water-Formed Deposits by X-Ray Fluorescence (Method D 2332) [1]; flame photometry in ASTM Test for Sodium and Potassium Ions in Industrial Water and Water-Formed Deposits by Flame Photometry (Methods D 1428) [1]; and microscopy in ASTM Examination of Water-Formed Deposits by Chemical Microscopy (Method D 1245) [1]; These and other instrumental techniques are also discussed in Chapter 13. It is often possible to determine the source or cause of water-formed deposits from the results of chemical and physical analyses. The treatment for removal or prevention of such deposits can thus be accomplished scientifically instead of by trial and error.


    Paper ID: STP47432S

    Committee/Subcommittee: D19.07

    DOI: 10.1520/STP47432S


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