Obtaining magnesia and periclase refractories from bischofite from the volgograd deposits

Abstract

The demand for periclase and refractories made from magnesium oxide with a purity of 98-99% is rather high. It is possible to use Volgograd bischofite as a highly effective raw material for the production of magnesia of this purity.The Volgograd deposits of bischofite (MgCI2*6H20) constitute unique sources, both in terms of reserves, and also the quality of the magnesium chloride (95-98%). Moreover, it has a high concentration of bromine, 5-8 kg per m 3 of ore [i]. Note has been made of the need for all-round development of the bischofite with the production, primarily, of bromine and magnesia. The density of the liquhrs of the underground solution of bischofite is 1.29- The organization of large-tonnage production should be preceded by a range of investigational work in order to develop the technology and equipment specifications of the process.In this article we describe the results of obtaining, by the thermohydrolysis method, from Volgograd bischofite that has not been debrominized, magnesium oxide and periclase refractories based on it.The Combine received two cisterns of bischofite liquor (78. Magnesium, calcium, and iron were determine according to GOST 844-79, GOST 25423.4-80, and GOST 844-79, the alkaline elements --with the atomic-absorption method on the flame spectrophotometer "Saturn"; the sulfates were determined according to GOST 844-79, the chlorides using the Folgardt method [2], the silicon dioxide --according to GOST 24523.1-80. the residues insoluble in HCI (inorganic) according to GOST 844-79, and the boron by the volumetric method [3].

Proposals for developing raw-material base for magnesia production

“…The chief impurities of magnesite are calcium, silicon, iron and aluminum oxides. Volgograd bischofite has low concentrations of these impurities and a high content of chlorine, bromine, and alkalis, with almost the same content of the basic substance [5]. Therefore, in the combined process it is not necessary to remove bromine and boron from the solution of bischofite, since the final product has slight amounts of these impurities (measured in a few thousandths of one percent).…”

“…The production technology for obtaining magnesia from bischofite by the thermohydrolysis method has been tested on experimental plant at the Crimean Production Association "Iodobrom," and in prototype conditions at the Magnezit Combine [5]. However, in the treatment of magnesite by thermohydrolysis, the HCI obtained as a result of the hydrolysis of magnesium chloride is directed to the initial stage of the process used for decomposing new portions of magnesite, and is a consumable reagent due to the incomplete absorption of the hydrogen chloride and other production losses, whereas during the treatment of the bischofite solution for each tonne of magnesia, we obtain about i0 tonnes of dilute (20%) hydrochloric acid, which is difficult to market.…”