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US 4,944,928 AGranted
Process for producing pure magnesium oxide
AssigneeVeitscher Magnestiwerke-Actien-Gesellschaft
InventorsMichael Grill, Gerhard Graf
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AssigneeVeitscher Magnestiwerke-Actien-Gesellschaft
InventorsMichael Grill, Gerhard Graf
Estimating the term…
A process for the preparation of pure magnesium oxide, especially suitable for the preparation of refractory products, from magnesium silicate and magnesium hydrosilicate materials such as olivine, serpentine, garnierite, or the like, the starting material being decomposed (digested) with hydrochloric acid, the residues being separated from the decomposition slurry and the sesquioxides to be regarded as contaminants and other contaminants being precipitated from the crude brine thus obtained by the addition of crude serpentine as a pH increasing substance, the precipitates being separated and the magnesium chloride solution thus obtained being subjected to thermal decomposition, particularly by spray calcination, whereby magnesium oxide is obtained and hydrogen chloride is recovered.
A process for the preparation of pure magnesium oxide from starting materials selected from the group consisting of magnesium silicate and magnesium hydrosilicate materials comprising dissolving the starting material in hydrochloric acid to form a slurry comprising crude brine and residues, separating the residues from the slurry, adding finely ground crude serpentine having a grain size of between 0 and 1mm to the brine as the pH increasing substance for precipitating oxides of iron and aluminum, separating the precipitates and thermally decomposing the magnesium chloride solution thus obtained to obtain magnesium oxide and hydrogen chloride.
A process for the preparation of refractory product grade pure magnesium oxide from starting materials selected from the group consisting of magnesium silicate and magnesium hydrosilicate materials comprising dissolving the starting material in hydrochloric acid to form a slurry comprising crude brine and residues, separating the residues from the slurry, adding finely ground crude serpentine having a grain size of between 0 and 1mm to the brine as the pH increasing substance for precipitating oxides of iron and aluminum, separating the precipitates and thermally decomposing the magnesium chloride solution thus obtained to obtain said pure magnesium oxide and hydrogen chloride.
Dependencies are inferred from the claim text.