Limestone CAS

Muller and colleagues identified four major rock units in the potential homelands of the Iceman on the basis of strontium and lead isotope ratios (Fig. 9.9). These include Eocene basalts (ca. 0.705-0.708), Mesozoic limestones (ca. 0.710-0.714), and Permian volcanics (ca. 0.717-0.719), and a mixed unit of phyllites and gneisses (ca. 0.720-0.724). These last two geological units overlap slightly in their isotope ratios. Strontium isotope ratios in the enamel of the Iceman averaged 0.721 and values in bone were approximately 0.718. These values are most congruent with the... 

Some carbonates are important industrial chemicals. Calcium carbonate occurs naturally in several forms, including limestone, and is used in the production of quicklime, calcium oxide CaO, slaked (or hydrated) lime, calcium hydroxide Ca(OH)2 and cement. 

Except for two countries, there is very fitde world trade in lime. The largest importer is the Netherlands, which is nearly devoid of limestone and thus imports about 10 t aimually from Belgium and Germany. The other net importer of consequence is the United States, which imports ca 150, 000 t/yr or about 1% of U.S. production. About 85% of the U.S. imports are from Canada the balance is from Mexico. 

Time Manufacture. Limestone is consumed at the rate of 32-34 x 10 t/yr in the manufacture of lime. About 75% of the tonnage is captively produced in the United States. The balance is shipped from quarries in northern Michigan and British Columbia in large ore boats or barges. The Hmestone lime ratio is ca 2 1. 

The second most common alkalinity control agent is lime [1305-78-8] normally in the form of calcium hydroxide [1303-62-0], used in both water and oH muds. In the latter, the lime reacts with added emulsifiers and fatty acids to stabHi2e water-in-oH emulsions. Lime is used in brine systems containing substantial quantities of soluble calcium and in high pH lime muds. Concentrations are ca 6—57 kg/m (2—20 lb /bbl) (see Lime AND LIMESTONE). 

Calcium sulfite [10257-55-3] and acid sulfite may be prepared by reaction of SO2 and hydrated lime or limestone. Calcium acid sulfite [13780-03-5] Ca(HS02)2, has been used to remove lignin (qv) from wood pulp in paper manufacture (6) (see Paper Pulp). 

Three demonstrations of the LIMB technology have been carried out. The first was a privately funded project in the 75 MWt Boiler 405 at the No. 4 AC Station of Inland Steel Industries, Inc. (56). By injecting 70 wt % minus 200 mesh (74 -lm) limestone, approximately 40% SO2 removal was achieved at a Ca S ratio of 3. This rose to 50% removal when the Ca S ratio was increased to 4. The second LIMB demonstration was the backup desulfurization system installed by B W as part of the relocation, repowering, and reconfiguration of the PCS power plant (46). 

The chemical formula for limestone is CaCOj and upon burning forms calcium oxide (CaO), which is known as burnt lime. Calcium oxide, when mixed with water, forms calcium hydroxide (Ca(OH)2). Calcium hydroxide is used to treat water as a coagulation aid along with aluminum sulfate. 

The solubility of calcium carbonate is such that in a saturated solution the product of ion concentrations [Ca+2][C0 2] is 5 X I0 B. Though this may seem quite small, it is large enough to be important to man, especially if he lives in a region of the earth where there are extensive limestone deposits. Calcium carbonate can be dissolved in water, especially if it contains much dissolved C02. This is objectionable because soap added to water which contains even traces of Ca+2 forms a precipitate of calcium stearate. This is the ring that is so difficult to remove from the bathtub. 

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

Of the principal minerals of Ca listed in Table 1, the most important ores are the various deposits of CaCOj, especially limestones, which occur as immense sedimentary beds over extensive parts of the earth s surface. Extraction of Ca from CaCOj is a simple and relatively inexpensive process. Although the other Ca-bearing minerals are rarely considered as potential Ca sources, they are widely distributed and extensively mined fluorite and apatite for their fluoride and phosphate content, gypsum and anhydrite for their use in construction. 

The principal minerals of Sr are strontionitc (SrCO,) and celesite (SrS04) those of Ba are barite (BaS04) and witherite (BaCO,). Strontionitc and barite are the usual sources of metallic Sr and Ba, respectively. Traces of both elements occur in nearly all limestones and dolomites and small amounts are usually present in natural limes. Furthermore, although neither element occurs as an independent silicate, traces of each may replace part of the Ca, Pb or K in compounds containing one or more of these elements. 

C-dating of travertines is possible in some instances the initial 14C/12C ratio of speleothem or travertine will generally be less than that of the atmosphere at the time of deposition, due to admixture of dead carbon from the limestone from which the Ca and part of carbonate have been obtained. But, where active... 

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