Significance and Use

Chemical composition of water-formed deposits is a major indicator of proper or improper chemical treatment of process water, and is often an indicator of operational parameters as well, for example, temperature control. This practice allows for rapid determination of constituents present in these deposits, particularly those indications of improper water treatment, since they usually have very distinctive and easily recognized optical properties.

This practice, where applicable, eliminates the need for detailed chemical analysis, which is time-consuming, and which does not always reveal how cations and anions are mutually bound.

Qualitative use of this practice should be limited to those deposits whose control is generally known or predictable, based on treatment and feedwater mineral content, and whose constituents are crystalline, or in other ways optically or morphologically distinctive. If these criteria are not met, other techniques of analysis should be used, such as Practice D2332 or Test Methods D3483 , or both.

Quantitative use of this practice should be limited to estimates only. For more precise quantitative results, other methods should be used (see 5.3).

1. Scope

1.1 This practice describes a procedure for the examination of water-formed deposits by means of chemical microscopy. This practice may be used to complement other methods of examination of water-formed deposits as recommended in Practices D2331 or it may be used alone when no other instrumentation is available or when the sample size is very small.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D887 Practices for Sampling Water-Formed Deposits

D1129 Terminology Relating to Water

D1193 Specification for Reagent Water

D2331 Practices for Preparation and Preliminary Testing of Water-Formed Deposits

D2332 Practice for Analysis of Water-Formed Deposits by Wavelength-Dispersive X-Ray Fluorescence

D3483 Test Methods for Accumulated Deposition in a Steam Generator Tube

Keywords

crystallography; deposits; microchemistry; microscopy; qualitative analysis; refractive index; Chemical analysis--water applications; Crystallography; Microchemistry; Microscopic examination--water; Petrographic analysis; Quantitative analysis/measurement--water; Refractive index; Water-formed deposits; Deposits/deposition;

ICS Code

ICS Number Code 13.060.50 (Examination of water for chemical substances)

DOI: 10.1520/D1245-11

ASTM International is a member of CrossRef.

ASTM D1245