Limestone impurities

A 5.135 g sample of impure limestone (CaC03) yields 2.050 g of C02 (which was absorbed in a soda-lime tube) when treated with an excess of acid. Assuming that limestone is the only component that would yield C02, calculate the percentage purity of the limestone sample. 

Zoisite occurs in crystalline schists which are products of regional metamorphism of basic igneous rocks rich in plagioclase, the calcium-nch feldspar also in argillaceous calcareous sandstones, thulite from quartz veins, pegmatites, and metamorphosed impure limestones and dolomites. 

Wollastonite is common in thermally metamorphosed impure limestone and can occur in contact-altered calcareous sediments. In most occurrences, it has been formed as a result of the reaction... 

Contact metamorphism produces homfels facies from clay-rich parent rocks such as shale. If the parent rocks are impure limestones, skarn (low- to high-grade metamorphism) is produced. Skarn is a calcium-rich, silicate rock containing a variety of minerals, including garnet. Relatively pure sandstones and limestones do not typically form new minerals due to contact metamorphism. 

CHRONIC HEALTH RISKS no signs of symptoms of chronic exposure to calcium carbonate have been reported similar exposure to impure limestone containing 3% to 20% quartz may pose a silicosis risk. 

Over the centuries, other pozzolanic substances were blended with slaked lime to produce what are now called synthetic (or artificial) hydraulic limes. Both naturally occurring pozzolans (such as trass, found in Germany), and synthetic pozzolans (such as ground blast furnace slag) have been, and still are used. It was also found that some impure limestones, containing silica and alumina, produced slaked limes with a range of hydraulic properties. Such natural hydraulic limes were widely used in construction and building for mortar and concrete. 

Viscous acid fracturing uses viscous acid systems such as gelled, emulsified, and foamed acid, or chemically retarded adds, to both create the fracture and differentially etch the fracture face. Treatments with viscous acid are applicable in heterogeneous carbonates such as dolomites or impure limestones. 

Limestones are rarely pure and often contain alumino-silicate components. When these impure limestones are calcined, dicalcium silicate (2Ca0.Si02) may form as well as lime. This hydrates on contact with water to form CSH gel. Many archaeological lime-based mortars are therefore likely to have originally contained small amounts of gel. 

Wollastonite is a naturally occurring, nondurable calcium silicate derived from metamorphosed impure limestone. It rarely occurs in pure form and is most commonly associated with calcite, quartz, garnet, and diopside. Morphologically, wollastonite can be found as a coarse-bladed, acicular or fibrous structure. Wollastonite was first mined for the production of mineral wool. Current uses of... 

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