The chemistry of plant and animal life . Fig- 55-—Decomposition of waterby the use of sodium. CHAPTER XIXCalcium, Magnesium, and Their Compoundsi66. Occurrence of Calcium.—This element is foundwidely distributed in nature in the form of calcium car-bonate, CaCOg, calcium phosphate, Ca^i^FOJ.^, and calciumsulfate, CaSO^, and is a 5^ellowish metal which readilyoxidizes and decomposes water. It enters into the com-position of both plant and animal bodies and takes animportant part in life processes. Its compounds are use-ful in the industries, lime, cement, and mortar being someof the forms in wh
The chemistry of plant and animal life . Fig- 55-—Decomposition of waterby the use of sodium. CHAPTER XIXCalcium, Magnesium, and Their Compoundsi66. Occurrence of Calcium.—This element is foundwidely distributed in nature in the form of calcium car-bonate, CaCOg, calcium phosphate, Ca^i^FOJ.^, and calciumsulfate, CaSO^, and is a 5^ellowish metal which readilyoxidizes and decomposes water. It enters into the com-position of both plant and animal bodies and takes animportant part in life processes. Its compounds are use-ful in the industries, lime, cement, and mortar being someof the forms in which it is employed. Calcium is noteasily separated from its compounds. 167. Calcium Carbonate.—This compound, in the form of limestoneand marble, isfound is soluble toa slight ex-tent in watercharged withcarbon dioxid,and hencemany waters,as stated in Fig. 56. Section of lime kiln. ScctlOU 65, owe their hardness to its presence. Calcium carbonate isused principally for the preparation of quicklime, in the. CALCIUM, MAGNESIUM, ETC. 135 manufacture of glass and in the refining of some of themetals where it is employed as a flux. 168. Calcium Oxid.—When calcium carbonate is sub-jected to heat, as in lime kilns or specially constructedfurnaces, the carbon dioxid is separated and the oxid ob-tained. Layers of limestone and wood are placed alter-nately in the lime kiln, as shown in Fig. 56; the combus-tion of the wood furnishes the necessary heat for the de-composition of the carbonate. Calcium oxid or quick-lime readily combines with both the carbon dioxid andmoisture of the air, forming air-slaked lime. During thisprocess of slaking, there is a material increase in volumeoften resulting in the bursting of the barrels in which thelime is stored. Calcium oxid is used for the preparationof calcium hydroxid and mortar. 169. Calcium Hydroxid.—When water is added to cal-cium oxid or quicklime, the materialundergoes the slaking process and cal-cium hydroxid,
Size: 1773px × 1409px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublishernewyorklondonthema
