Research on the influence of thermal decomposition of magnesium chloride hexahydrate on the preparation of magnesium oxide and hydrated magnesium hydroxide

Magnesium chloride hexahydrate is an important intermediate product in magnesite processing. In order to promote the efficient utilization of magnesite resources, based on the pyrolysis interval of magnesium chloride hexahydrate, the relationship between magnesium oxide with different physicochemical properties and the apparent properties of hydrated magnesium hydroxide was studied. The results show that the effect of temperature on magnesium oxide sintering is stronger than that of holding time. With the increase of calcination temperature and the extension of holding time of magnesium chloride hexahydrate, the calcined product magnesium oxide was sintered into large particle size with the characteristic particle size D50 of 33.89 μm. The crystal was distorted, the chemical activity deteriorated, and the color development time was up to 407 s. When hexahydrate magnesium chloride was calcined at 480 °C with 2 h, it decomposed almost completely. The product, magnesium oxide, consisted of uniformly distributed small coral rod-like particles with strong chemical reactivity and a color development time of 115 s. The particles were small and evenly distributed, with a characteristic particle size D50 of 1.36 μm, and the highest specific surface area reached 7.292 m2/g. The hydrated magnesium hydroxide particles had well-defined edges and corners, with a characteristic particle size D50 of 1.59 μm and a uniform particle size distribution.

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Opracowanie rekordu ze środków MNiSW, umowa nr POPUL/SP/0154/2024/02 w ramach programu "Społeczna odpowiedzialność nauki II" - moduł: Popularyzacja nauki (2025).