This method is included in NEMI for informational purposes as it is approved by EPA for regulatory use. Detailed information on this method is not currently. eropoly acid. This is reduced to silicomolybdenum blue that is determined pho- tometrically. The method is analogous to APHA SiO2 D+E, ASTM D, . Find the most up-to-date version of ASTM D at Engineering
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Silica removal is commonly accomplished by ion exchange, distillation, reverse osmosis, or by precipitation, usually with magnesium compounds in a hot or cold lime softening process. No other units of measurement are included in this standard. Make up to mL with water and store in a dark, plastic bottle. Under certain conditions, silica forms troublesome silica and silicate scales, particularly on highpressure steam turbine blades.
It is applicable to most d89, but some waters may require filtration and dilution to remove interferences from color and turbidity. Those forms of silica that are molybdate-reactive include dissolved simple silicates, monomeric silica and silicic acid, and an undetermined fraction of polymeric silica.
Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend.
A number in parentheses indicates the year of last reapproval. The CVS is a solution of the method analyte of known concentration mid-calibration range used to fortify reagent water.
Unless otherwise indicated, it is intended that all reagents shall conform to the speci?
ASTM D – 16 – Standard Test Method for Silica in Water
High blanks, nonlinear calibration curves, and poor reproducibility have been observed with some batches of this compound. It may be applied to natural waters and wastewaters following filtration or dilution, or both. The MS should be prepared in accordance with Guide D Current edition approved Feb. Originally approved in Individual reprints single or multiple copies of this standard may be obtained by contacting ASTM at the above address or at phonefaxor service astm.
If non-detects are expected in all the samples to be analyzed, a Matrix Spike Duplicate should be run instead. In solution it can exist as silicic acid or silicate ion, depending upon pH. ASTM D95 – Historical Version s – view previous versions of standard Translated Version s: The upper limit for acceptable precision and the range of acceptable recoveries are detailed below: It is particularly applicable to treated industrial waters.
Phosphate interference is eliminated by the addition of oxalic acid.
Standard Test Method for Silica in Water
This is acceptable when, as frequently occurs, the molybdate-reactive silica is in the milligram per litre concentration range while the nonmolybdate-reactive silica, if present at all, is in the microgram per litre concentration range. Under certain conditions, silica forms troublesome silica and silicate scales, particularly on high-pressure steam turbine blades. It is particularly applicable to treated industrial waters. Axtm concentration of the IRM should be within the scope of the method, as de?
ASTM D859 – 16
It may be applied to natural waters and wastewaters following? The IDP solution contains method analytes of known concentration, prepared from a different source to the calibration standards, used to fortify reagent water. It is found as the oxide in crystalline forms, as in quartz; combined with other oxides and metals in a variety of silicates; and in amorphous 1 This test method is under the jurisdiction of D89 Committee D19 on Water and is the direct responsibility of Subcommittee D Active view current version of standard Translated Standard: NOTE 4—Batch to batch variations in ammonium molybdate have been found to affect results at low concentrations below 0.
The values obtained must fall within the limits speci? Complex silicate residues that do not yield to this treatment are dissolved by alkali fusion and dehydrated with HCl.
Link to Active This link e859 always route to the current Active version of the standard. The LCS is a solution of method analytes of known concentration added to a matrix that sufficiently challenges the Test Method.
Shelf life of this reagent may be extended by refrigeration.