ASTM C911-2019 pdf free download

ASTM C911-2019 pdf free download.Standard Specification for Quicklime, Hydrated Lime, and Limestone for Selected Chemical and Industrial Uses
1. Scope
1.1 This specification covers lime and limestone products suitable for the following chemical and industrial uses:1.2 The type designations in Table 1 signify the following:1.3 The buyer shall designate the use, as listed in Table 1, and may specify one or more of the type designations in 1.1. 1.4 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 appro- priate safety and health practices and determine the applicabil- ity of regulatory limitations prior to use. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Chemical Composition
3.1 The requirements for quicklime, hydrated lime, and limestone for the selected end uses are as shown in Table 1, and are on the basis of the weight of sample taken at the place of manufacture, except as noted in footnote B after the require- ment. In this case, the requirement is on a moisture and carbon dioxide-free basis. N OTE 1—Rags are cooked for the manufacture of paper in a digester under steam pressure with lime or with lime and soda ash. They are then washed to eliminate as much of the noncellulose material as possible. A standard composition without rejection limits is specified for the reason that lime of either higher or lower total oxides, available lime, calcium oxide, or calcium hydroxide than the standard, may safely be used under suitable conditions for the purpose herein specified, depending primarily upon economic considerations. In the present state of the art, it is believed that the more serviceable type of specification for the product herein specified is that which defines a reasonable standard rather than one that fixes actual rejection limits. It is generally recognized that, other things being equal, lime meeting this standard is preferable to lime that does not, and lime surpassing the standard should be considered ofpremium quality. N OTE 2—Lime is used in the “milk of lime” or “tank” system of sulfite pulp manufacture for making the cooking liquor. The milk of lime is held in solution or suspension in a series of tanks equipped with suitable agitators. The sulfur dioxide (SO 2 ) is forced or drawn through these tanks successively. In some cases, the tanks are built on top of each other in the form of a tower. The contents of the first tank are drawn off when the liquor has reached a certain strength (3.5 to 6 % total SO 2 ) and the contents of the second and third tanks progress to the first and second tanks respectively. The third tank is again charged with fresh milk oflime. There are other systems of absorption that provide for continuous instead ofintermittent operation. The function ofthe lime is to furnish the base for the formation of the bisulfites of calcium and magnesium. N OTE 3—In the manufacture of silica brick, silica in the form of massive quartzite or quartz conglomerate is ground until the particles are less than 6 mm in size. Lime in the form of either slaked or hydrated lime is then added in quantities varying from 1.5 to 3.0 % calcium oxide (CaO), with sufficient water to produce about 5 to 7 % moisture content, and the shapes are molded and dried. They are then burned in downdraft or tunnel kilns until most of the quartzite has been converted into tridymite or cristobalite. N OTE 4—For most water treatment applications, such as color removal and clarification of water for municipal and industrial supplies, high- calcium lime is preferred. However, for applications involving silica removal from boiler feedwater, dolomitic lime is usually preferred. Drinking water softening and wastewater neutralization are addressed in Specification C1529.