Magnesium and magnesium alloys are widely studied as the \”green engineering materials of the 21st century\”. Magnesium compounds (later referred to as magnesium salts) are a class of inorganic salts of great importance, and are one of the most important products exported by China, bringing a certain economic value to the national income every year. Among them, magnesite is usually used as a very precious high-magnesium metal ore to extract magnesium because it is rich in magnesium element, which has important application value. In the process of manufacturing oriented silicon steel sheet, the black powder is rich in magnesium oxide, how to recycle it and reuse it to make special magnesium products is a very meaningful thing for resources and environmental protection. The special series of magnesium oxide is usually divided into a wide range, generally including: active magnesium oxide, silicon steel grade magnesium oxide, nano magnesium oxide, heavy magnesium oxide, high-purity magnesium sand, magnesium oxide for medicine and so on these types of magnesium oxide.
This thesis is divided into three parts, the first two parts are mainly based on hydromagnesite as the raw material, one of them adopts one-step direct calcination method to produce high activity magnesium oxide, this method is simple and easy, and green economy and environmental protection; the other part without any auxiliary additives, NaOH as precipitant, direct precipitation to prepare capsule-like heavy magnesium oxide; the black powder shed in the process of producing oriented silicon steel sheet is recycled, to The black powder shed during the production of oriented silicon steel sheet was recycled and the ultra-fine flake magnesium hydroxide and small spherical magnesium oxide particles were prepared by hydrothermal method with ammonia as precipitant.
The main research contents are described as follows: The preliminary investigation of the one-step direct calcination of magnesite to produce high active magnesium oxide in industry, the current preparation of active magnesium oxide is usually obtained by precipitation of precursors and then calcination of precursors, eliminating the precipitation process of precursors, directly using ground magnesite as precursors, using muffle furnace direct one-step calcination to prepare high active magnesium oxide.