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Gypsum is a common mineral, with thick and extensive evaporite beds in association with sedimentary rocks. Deposits are known to occur in strata from as far back as the Archaean eon. [16] Gypsum is deposited from lake and sea water, as well as in hot springs, from volcanic vapors, and sulfate solutions in veins.
Gypsum materials consist of calcium sulfate dihydrate (CaSO 4 ·2H 2 O). Sulfate-reducing bacteria convert sulfates to toxic hydrogen sulphide gas; they are killed by exposure to air, but the moist, airless, carbon-containing environment in a landfill is a good habitat for them.
The National Council for Cultural Heritage, an organization under the Ministry of Culture and Information of Vietnam (now the Ministry of Culture, Sports and Tourism) recommended the Vietnamese prime minister that Phong Nha-Kẻ Bàng National Park be submitted to UNESCO second time for recognition as a world natural heritage for biodiversity ...
It is mainly composed of gypsum (CaSO 4 ·2H 2 O). Although gypsum is a widely used material in the construction industry , phosphogypsum is usually not used, but is stored indefinitely because of its weak radioactivity caused by the presence of naturally occurring uranium (U) and thorium (Th), and their daughter isotopes radium (Ra), radon (Rn ...
The Truong Son and Luang Prabang structures converge in northern Laos, bordered by northwest trending fault-bounded structures such as Phu Hoat Massif. The Song Ma Anticlinorium near Vietnam exposes Proterozoic basement rock at the surface. The Yunnan-Malay fold belt originated from closure of two sedimentary basins and is a prominent feature.
National Gypsum Company is a company based in Charlotte, North Carolina, that produces drywall gypsum boards in the US. It has 17 gypsum board plants in the US and presents itself as a fully integrated building products manufacturer. [ 1 ]
A gypsum block is made of gypsum plaster and water. The manufacturing process [1] is automated at production plants where raw gypsum (CaSO 4 ·2H 2 O) is ground and dried, then heated to remove three-quarters of the bound water and thus transformed into calcium sulfate hemihydrate (CaSO 4 ·½H 2 O), also known as gypsum plaster, stucco, calcined gypsum or plaster of Paris.
There are also 270 coral species spread over an area of 1,000 hectares (2,500 acres). In addition, the marine fauna and flora are of 1,323 species including 44 species in the Red Data Book of Vietnam. The park has the richest diversity of 153 species of mollusc species, reported to be the highest for any island in Vietnam.