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Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO 4 ·2H 2 O. [4] It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster , drywall and blackboard or sidewalk chalk .
The disposal of gypsum-based materials can become a problem if they are accepted at normal cells in non-hazardous landfills, as the sulphate content of gypsum mixed with organic waste can break down under certain conditions into hydrogen sulfide gas.
Gypsum recycling is the process of turning gypsum waste (from construction) into recycled gypsum, thereby generating a raw material that can replace virgin gypsum raw materials in the manufacturing of new products.
The main sources of calcium sulfate are naturally occurring gypsum and anhydrite, which occur at many locations worldwide as evaporites. These may be extracted by open-cast quarrying or by deep mining. World production of natural gypsum is around 127 million tonnes per annum. [17]
The most common method of handling collected leachate is on-site treatment. When treating leachate on-site, the leachate is pumped from the sump into the treatment tanks. The leachate may then be mixed with chemical reagents to modify the pH and to coagulate and settle solids and to reduce the concentration of hazardous matter.
If you’re stuck on today’s Wordle answer, we’re here to help—but beware of spoilers for Wordle 1257 ahead. Let's start with a few hints.
2)) present in the hardened cement paste to give gypsum: H 2 SO 4 + Ca(OH) 2 → CaSO 4 · 2H 2 O. When concrete is carbonated by atmospheric carbon dioxide (CO 2), or if limestone aggregates are used in concrete, H 2 SO 4 reacts with calcite (CaCO 3) and water to also form gypsum while releasing CO 2 back to the atmosphere: H 2 SO 4 + CaCO 3 ...
Hints and the solution for today's Wordle on Thursday, November 28.