Process for preparing calcined dolomite from magnesium chloride of chloride type by-product of potassium-extracting from salt lake

Abstract

The invention provides a method for preparing a composed calcined dolomite by taking the byproduct of brine ( a saturated liquor which is mainly magnesium chloride ) after potassium extraction or the bischofite separated out from the brine by naturally evaporating as the materials to react with excess lime to prepare the floccule mixture of magnesium hydrate and calcium hydroxide; then the mixture is calcined and dehydrated under the temperature of 400 to 1200 DEG C after the mixture is deposited, filtered, washed, dried and cracked. The materials of the invention are easily obtained and cheap; the production process is simply and easily controlled; no carbon dioxide is discharged; besides, the invention basically has no corrosion to a device. The mol ratio of MgO to CaO in the composed calcined dolomite is within the range of 1:0.8 to 1:1.2; the activity of water is 25 to 36 percent; the composed calcined dolomite is applicable for the areas rich in the resource of magnesium chloride to use a Pidgeon process to produce the metal of magnesium.

Description

technical field

[0001] The invention belongs to the field of light metal smelting, and relates to a preparation method of magnesium-calcium oxide (commonly known as calcined white) for magnesium smelting by silicothermal method, in particular to a method of using magnesium chloride as a raw material, which is a by-product after potassium extraction from chloride salt lakes, through transformation, Calcination and other processes, the production of calcined white method for silicon thermal magnesium smelting. technical background

[0002] The production methods of metal magnesium can be summarized into two methods, namely ferrosilicon thermal reduction method (Pidgeon method) and electrolysis method. The electrolytic method is to electrolyze molten anhydrous magnesium chloride to decompose it into metallic magnesium and chlorine gas. According to the raw materials used and the methods of processing raw materials, they can be subdivided into the following specific methods: Do...