ASTM C25

ASTM C25 – Standard Test Methods for Chemical Analysis of Limestone, Quicklime, and Hydrated Lime

Description:

Significance and Use

4.1 These test methods provide accurate and reliable analytical procedures to determine the chemical constituents of limestone, quicklime, and hydrated lime (see Note 1). The percentages of specific constituents which determine a material’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.

NOTE 1: These test methods can be applied to other calcareous materials if provisions are made to compensate for known interferences.

Scope

1.1 These test methods cover the chemical analysis of high-calcium and dolomitic limestone, quicklime, and hydrated lime. These test methods are classified as either standard (preferred) or alternative (optional).

1.2 The standard test methods are those that employ classical gravimetric or volumetric analytical procedures and are typically those required for referee analyses where chemical specification requirements are an essential part of contractual agreement between buyer and seller.

1.3 Alternative or optional test methods are provided for those who wish to use procedures shorter or more convenient than the standard methods for the routine determinations of certain constituents. Optional test methods may sometimes be preferred to the standard test methods, but frequently the use of modern and expensive instrumentation is indicated which may not be accessible to everyone. Therefore, the use of these test methods must be left to the discretion of each laboratory.

1.4 The analytical procedures appear in the following order:

	Section
Aluminum Oxide	15
Available Lime Index	28
Calcium and Magnesium Oxide:
Alternative EDTA Titration Method	31
Calcium Carbonate Equivalent	33
Calcium Oxide:
Gravimetric Method	16
Volumetric Method	17
Carbon Dioxide by Standard Method	22
Combined Oxides of Iron and Aluminum	12
Ferrous Iron	Appendix X5
Free Calcium Oxide	Appendix X6
Free Moisture in Hydrated Lime	21
Free Moisture in Limestone	20
Free Silica	29
Insoluble Matter Including Silicon Dioxide:
Standard Method	8
Optional Perchloric Acid Method	9
Insoluble Matter Other Than Silicon Dioxide	11
Loss on Ignition	19
Magnesium Oxide	18
Manganese:
Bismuthate Method	Appendix X4
Periodate (Photometric) Method	27
pH Determination of Alkaline Earth Solutions	34
Phosphorus:
Titrimetric Method	Appendix X3
Molybdovanadate Method	26
Silicon Dioxide	10
Strontium Oxide	Appendix X2
Sulfur Trioxide	23
Total Carbon:
Direct Combustion-Thermal Conductivity Cell       Method	32
Total Carbon and Sulfur:
Combustion/Infrared Detection Method	35
Total Iron:
Standard Method, Potassium Dichromate       Titration	13
Potassium Permanganate Titration Method	Appendix X1
Ortho-Phenanthroline, Photometric Method	14
Total Sulfur:
Sodium Carbonate Fusion	24
Combustion-Iodate Titration Method	25
Unhydrated Oxides	30