Calcium in limestone

Electrons become trapped in the crystal lattice of minerals from adjacent radioactive material and alter the magnetic field of the mineral at a known rate. This technique is used for dating bone and shell, since it does not destroy the material, such as carbonates (calcium) in limestone, coral, egg shells, and teeth, by exposing it to different magnetic fields. 

A At Harvard 1 took a course on quantitative analysis for which we had to do the gravimetric analysis of calcium in limestone. But the instructor told us that we were wasting our time any sensible person would use atomic spectroscopy. I asked what it was and he told me to read a small book written by Gerhard Herzberg, who would later win a Nobel Prize for spectroscopy. 1 did, and that summer at home I made my own carbon arc for taking atomic spectra of various compounds. 

The material source of the watershed fault zone is both from host rock and overlying siliceous rocks. The fault zone is an open system with strong chemical weathering, and alkaline condition. Calcium in limestone is leached, the cohesive force of host rock is reduced and formed smectite. It is easy for feldspar transforms to kaolinite under alkaline condition during faulting. Hence, more geochemistry needed to study in the future, to establish qualitative model between chemical compositions and strength of fault rocks. 

Dolomite—Dolomite consists of carbonate mineral known as magnesium limestone (CaMg(C03)2) and occurs in more or less the same settings as limestone. Dolomite is formed when some of the calcium in limestone is replaced by magnesium. 

Mixed with sand it hardens as mortar and plaster by taking up carbon dioxide from the air. Calcium from limestone is an important element in Portland cement. 

In a similar vein, mean seawater temperatures can be estimated from the ratio of 0 to 0 in limestone. The latter rock is composed of calcium carbonate, laid down from shells of countless small sea creatures as they die and fall to the bottom of the ocean. The ratio of the oxygen isotopes locked up as carbon dioxide varies with the temperature of sea water. Any organisms building shells will fix the ratio in the calcium carbonate of their shells. As the limestone deposits form, the layers represent a chronological description of the mean sea temperature. To assess mean sea temperatures from thousands or millions of years ago, it is necessary only to measure accurately the ratio and use a precalibrated graph that relates temperatures to isotope ratios in sea water. 

Calcium. Soil minerals are a main source of calcium for plants, thus nutrient deficiency of this element in plants is rare. Calcium, in the form of pulverized limestone [1317-65-3] or dolomite [17069-72-6] frequendy is appHed to acidic soils to counteract the acidity and thus improve crop growth. Such liming incidentally ensures an adequate supply of available calcium for plant nutrition. Although pH correction is important for agriculture, and liming agents often are sold by fertilizer distributors, this function is not one of fertilizer manufacture. 

Formation of emissions from fluidised-bed combustion is considerably different from that associated with grate-fired systems. Flyash generation is a design parameter, and typically >90% of all soHds are removed from the system as flyash. SO2 and HCl are controlled by reactions with calcium in the bed, where the lime-stone fed to the bed first calcines to CaO and CO2, and then the lime reacts with sulfur dioxide and oxygen, or with hydrogen chloride, to form calcium sulfate and calcium chloride, respectively. SO2 and HCl capture rates of 70—90% are readily achieved with fluidi2ed beds. The limestone in the bed plus the very low combustion temperatures inhibit conversion of fuel N to NO. ... 

In addition to the principal equations discussed, several others occur which may be of importance, including calcination of calcium carbonate (limestone), which takes place in the upper shaft at 800—870°C,... 

Alumina in combination with siUca is present in limestone chiefly as clay, though other aluminum siUcates in the form of feldspar and mica may be found. When present in appreciable quantities, clay converts a high calcium limestone into a mad or argillaceous stone, which when calcined yields limes with hydrauhc properties. Limestones containing 5—10% clayey matter yield feebly hydrauHc limes those containing 15—30% produce highly hydrauHc limes. 

Kalk. m. lime (equivalent, in old names of salts, to calcium as, phosphorsauerer Kalk, phosphate of lime, calcium phosphate) limestone (Old Chem.) cabc. —. tzender —, caustic lime, quicklime. — gelfischter —, slaked lime. — gebraonter —, quicklime. 

Calcium (sixth most abundant element) is found in limestone, CaC03, and gypsum, CaS04-2H20. Bones are made up of calcium phosphate, Ca PO. ... 

Calcium, D. of - continued in limestone or dolomite, (fl) 813 in presence of barium, (ti) 333 with CDTA, (ti) 333 with lead by EDTA, (ti) 333 with magnesium by EDTA, 328 by EGTA, (ti) 331 by flame emission, (aa) 804 Calcium oxalate, thermal analysis 498 Calcon 318 Calculators 133 Calibration of apparatus, 87 of burettes, 88 of graduated flasks, 88 of pipettes, 88 of weights, 74... 

C04-0134. Calcium carbonate (limestone) reacts with hydrochloric acid to generate water and carbon dioxide gas. In a certain experiment, 5.0 g of CaCO is added to 0.50 L of 0.10 M HCl. (a) Write a balanced net... 

Occurrence. Carbon is distributed very widely in nature as calcium carbonate (limestone). Coal, petroleum and natural gas are chiefly hydrocarbons. Carbon is found as carbon dioxide in the atmosphere of the earth and dissolved in all natural waters. The atmosphere of Mars contains 96% C02. It is plentiful in the sun, stars, comets and the atmospheres of most planets. 

The next major raw material for which we discuss the derived chemicals is calcium carbonate, common limestone. It is the source of some carbon dioxide, but, more importantly, it is used to make lime (calcium oxide) and slaked lime (calcium hydroxide). Limestone, together with salt and ammonia, are the ingredients for the Solvay manufacture of sodium carbonate, soda ash. Soda ash is also mined directly from trona ore. The Solvay process manufactures calcium chloride as an important by-product. Soda ash in turn is combined with sand to produce sodium silicates to complete the chemicals in the top 50 that are derived from limestone. Since lime is the highest-ranking derivative of limestone in terms of total amount produced, we discuss it first. Refer to Fig. 2.1, Chapter 2, Section 1, for a diagram of limestone derivatives. 

The hrst production step involves recovery of the metal from spodumene. The naturahy occurring ore, alpha-spodumene is heated in a brick-lined rotary kiln at a temperature between 1,075 to 1,100°C. This converts the alpha form to a more reactive form, beta-spodumene. The beta form is heated in a rotary kiln at 250°C with an excess of 93% sulfuric acid. The metal reacts with acid forming hthium sulfate. The kiln discharge is leached with water to separate water-soluble hthium sulfate from several impurity metals. Aqueous solution containing excess sulfuric acid is then neutrahzed by treatment with an excess of ground calcium carbonate (limestone). The solution is fdtered to... 

The environmental impact of acid rain depends on local geology, as Figure 10.15 illustrates. In certain regions, such as the midwestern United States, the ground contains significant quantities of the alkaline compound calcium carbonate (limestone), deposited when these lands were submerged under oceans... 

Most chalks are made from calcium carbonate, which is the same chemical found in limestone. The addition of even a weak acid, such as the acetic acid of vinegar, produces hydronium ions that react with the calcium carbonate to form several products, the most notable being carbon dioxide, which rapidly bubbles out of solution. Try this for yourself If the bubbling is not as vigorous as shown here, then the chalk is made of other mineral components. 

The name of calcium was given to the metal hidden in limestone by its discoverer, Humphry Davy, It comes horn calx, the old Latin name for lime. 

The soils of humid regions are commonly low in calcium thus, ground limestone usually is applied tu add the clement, reduce the toxicity uf aluminum and manganese, and correct soil acidity. The soils of dry areas are frequently rich in calcium. There is little evidence to indicate a strung relationship between human nutrition and calcium excesses or deficiencies in the soil. Even wiih farm livestock, most calcium deficiencies are not related to levels of av ailable calcium in the sail. The reason for this anomaly is evident when one examines some of the controls over the movement of calcium in Ihe food chain. 

Scapolite is found in the metamoiphic locks, particularly those, rich in calcium also in contact metamorphic deposits in limestones. It has been found in basic igneous rocks, probably as a secondary mineral. Notable localities are Lake Baikal, Siberia Arendal. Norway and Madagascar. In the United States, it is found in Massachusetts, New York, and New Jersey. Greenville, in the Province of Quebec, Canada is an important locality. Superb transparent yellow gem crystals have recently been found in Brazil and Tanzania. Wernente (scapolite) was named in honor of A.O. Werner, a famous German mineralogist (1749-1817). 

A These downward-growing, icicle-shaped structures called stalactites and the upward-growing columns called stalagmites are formed in limestone caves by the slow precipitation of calcium carbonate from dripping water. 

You have already seen on p. 122 in Table 8.2 that salts are useful substances. Some of the salts shown in that table occur naturally and are mined, for example calcium sulfate (gypsum) and calcium carbonate (limestone). Many of the others must be made by the chemical industry, for example ammonium nitrate, iron(n) sulfate and silver bromide. 

Stalactites and stalagmites are found in underground caverns in limestone areas. They are formed from the slow decomposition of calcium or magnesium hydrogencarbonates in water (Figure 11.34). 

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