ASTM C25-17 pdf download.Standard Test Methods for Chemical Analysis of Limestone, Quicklime, and Hydrated Lime.
3. Terminology
3.1 Definitions:Definitions—Unless otherwise specified, for definitions of terms used in these test methods refer to Terminology C51.
4. Significance and Use
4.1 These test methods provide accurate and reliable ana- lytical procedures to determine the chemical constituents of limestone, quicklime, and hydrated lime (See Note 1). The percentages of specific constituents which determine a materi- al’s quality or fitness for use are of significance depending upon the purpose or end use of the material. Results obtained may be used in relation to specification requirements.
4.2 Because quicklime and hydrated lime quickly absorb water and carbon dioxide from the air, precision and bias are extremely dependent upon precautions taken during sample preparation and analysis to minimize excessive exposure to ambient conditions. N OTE 1—These test methods can be applied to other calcareous materials if provisions are made to compensate for known interferences.
5. General Apparatus and Materials and Reagents
5.1 General Apparatus and Materials: 5.1.1 Balance—The balance shall be of an analytical type with a capacity not to exceed 200 g. It may be of conventional design or it may be a constant-load, direct-reading type. It shall be capable of reproducing weighings within 0.0002 g with an accuracy of 6 0.0002 g. Rapid weighing devices that may be provided such as a chain, damper, or heavy riders shall not increase the basic inaccuracy by more than 0.0001 g at any reading and with any load within the rated capacity of the balance.
5.1.2 Weights—Weights used for analysis shall conform to Class S-1 requirements of the National Institute of Standards and Technology as described in NIST Circular 547. 4 They shall be checked at least once a year or when questioned, and adjusted to within allowable tolerances for Class S-1 weights. All new sets of weights purchased shall have the weights of 1 g and larger made of stainless steel or other corrosion-resistant alloy not requiring protective coating and shall meet the density requirements for Class S.
5.1.3 Glassware and Laboratory Containers—Standard volumetric flasks, burets, pipets, dispensers, etc., shall be carefully selected precision grade or better and shall be calibrated, if necessary, to meet the requirements of each operation. Standard-type interchangeable ground glass or TFE- fluorocarbon joints are recommended for all volumetric glass- ware. Polyethylene containers are recommended for all aque- ous solutions of alkalies and for standard solutions where the presence of dissolved silica or alkali from the glass would be objectionable.
5.1.4 Desiccators—Desiccators shall be provided with a good desiccant such as anhydrous magnesium perchlorate, activated alumina, sulfuric acid, or phosphoric anhydride. Anhydrous calcium sulfate may also be used provided it has been treated with a color-changing indicator to show when the desiccant has lost its effectiveness. Calcium chloride and silica gel are not satisfactory desiccants for this type of analysis.
5.1.5 Filter Paper—Filter paper shall conform to the re- quirements of Specification E832, Type II (quantitative). Class E shall be used for coarse and gelatinous precipitates. When medium-textured paper is required, Class F filter paper shall be used. When a retentive paper is needed, Class G shall be used.ASTM C25 pdf download.