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K2MgCa2(SO4)4·2H2O A sulfate mineral usually found in fibrous brick-red masses due to iron.



a mineral, a hydrated sulfate of potassium, calcium, and magnesium with composition K2Ca2Mg[SO4]4 · 2H2O. It contains 15.62 percent K2O, 18.60 percent CaO, 6.69 percent MgO, 53.11 percent SO3, and 5.98 percent H2O. Polyhalite crystallizes in the triclinic system, forming granular aggregates and, more rarely, fibrous or columnar aggregates. Tabular and elongated crystals with distinct cleavage are rare. Polyhalite is colorless, gray, pink, or brick-red. It has a hardness of 2.5–3.5 on Mohs’ scale and a density of 2,720–2,780 kg/m It decomposes upon the action of water to precipitate gypsum.

Polyhalite is widely distributed in commercial salt deposits, where it is most often associated with rock salt and anhydrite, as well as with sylvite, carnallite, and kieserite. It may be used in the preparation of potassium fertilizers.

References in periodicals archive ?
Once the move to polyhalite production occurs, ICL UK will remain a signifi-cant employer, but it is unlikely to be at the same level as in the past.
Customer with this deal will be able to distribute polyhalite via, its wide networks of local and regional companies to allow for servicing a greater range of farmers.
Uni-axial compressive strength for the polyhalite, as well as minerals above and below the ore line and
The Salado Formation, or main salt, consists of thick halite intervals with interbedded anhydrite, siltstone and polyhalite.
We're incredibly positive about the future prospects of the York Potash Project and polyhalite extraction in the area, although of course that will not offer immediate consolation to those affected by this announcement.
Sirius CEO and managing director Chris Fraser said : "This agreement continues to extend the global sales reach of polyhalite and means we are now partnered with an organisation that controls a substantial proportion of the Central American crop input market.
CPL, a UK company owned by ICL Fertilizers, will begin implementing a [pounds sterling]38 million investment programme designed to increase production capacity and mining of Polyhalite to around 600,000 tonnes per year, compared to its current production level of approximately 130,000 tonnes.
3 billion tonnes of polyhalite discovered below the Yorkshire coast.
3bn tonnes of polyhalite, which is processed to make premium potash fertiliser, below the protected coastline.
Mined in the UK at ICL's Boulby Mine, this naturally occurring fertilizer is found in the polyhalite layer of rock over 1,000 meters below the ground under the North Sea off the coast of North Yorkshire.
The proposed development is the construction, operation and maintenance of a Harbour facility at Bran Sands, Teesside for the export of polyhalite bulk fertilizer which will be linked by conveyor to a material handling facility ("MHF") located within the Wilton International complex.
By extracting polyhalite from deep beneath the North York Moors, this project is set to generate 2,000 direct and indirect jobs and to pump billions into the economy.