ASTM C911:19 pdf download

ASTM C911:2019 pdf download.Standard Specification for Quicklime, Hydrated Lime, and Limestone for Selected Chemical and Industrial Uses.
NOTE—Rags are cxked 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, availabic lime, calcium oxide, or calcium hydroxide than the standard, may safely be used under suitabic 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 of premium quality.
No-it 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,) 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 theliquor has reached a certain strength (3.5 to 6 % total SO,) and thecontents of the second and third tanks progress to the first and secondtanks respectively. The third tank is again charged with fresh milk of lime.There are other systems of absorption that provide for continuous insteadof intermittent operation.The function of the lime is to furnish the base forthe formation of the bisulfites of calcium and magnesium.
NoTE 3—In the manufacture of silica brick,silica in the form ofmassive quartzite or quartz conglomerate is ground until the particles areless than 6 mm in size. Lime in the form of either slaked or hydrated limeis 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 theshapes are molded and dried. They are then burned in downdraft or tunnelkilns until most of the quartzite has been converted into tridymite orcristobalite.
NoTE 4——For most water treatment applications,such as color removaland clarification of water for municipal and industrial supplies，high-calcium lime is preferred. However, for applications involving silicaremoval from boiler feedwater,dolomitic lime is usually preferred.Drinking water softening and wastewater neutralization are addressed inSpecification C1529.