作者：I.Wilson

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刊名：refractories worldforum

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出版年：2013-03-01

卷：5

期：1

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语种：英文

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内容简介

Magnesite (MgCO3) is the most abundant mineral source for magnesia products such as FM, DBM and CCM. The world's resources of natural magnesite are estimated at 13 billion t of which China, North Korea and Russia account for 70 %. There are two main types of magnesite, namely macrocrystalline/sparry type which is generally coarse-grained and microcrystalline/cryptocrystalline which is very fine particle sized. The sparry type accounts for 92,6 % of the resources with just 7,4 % for the cryptocrystalline magnesite. However, quality of the cryptocrystalline material (associated with alteration of ultrabasic rocks such as serpentine) is generally higher than sparry type with lower SiO2 Fe2O3 and CaO. The main producing area for magnesia is China controlling an overall 49 % of the total market. Supply to the world has been dramatically affected during the last decade by the imposition of a quota system, which has restricted exports and forced the prices up. This quota system and additional taxes in China has encouraged the rest of the world to develop their own resources by expanding capacity and even totally new production units. This paper explains the current situation with resources, production and how the rest of the world has reacted to the changing situation forced by the Chinese imposing an export quota system. For a large company such as RHI they have acquired other companies in their ambition to become more self-sufficient in supplying their own refractory plants with magnesia and not relying so much on China for sourcing CCM, DBM and FM.