Reburned magnesite It is a kind of raw material with medium alkalinity and chemical activity, which is not only used as refractory and cementitious material, but also used in other industrial fields. In addition, the development of converter slag splashing technology has further expanded the application range of light burned magnesia powder. At present, slag splashing furnace protection technology mostly uses light burned magnesia powder to form balls, including light burned magnesia powder balls, carbon containing light burned magnesia sub balls and carbon containing calcium containing light burned magnesia powder balls. Light burned magnesia powder Light burned magnesium powder It is an active magnesium oxide obtained by calcining magnesite, brucite and magnesium hydroxide extracted from seawater or brine at about 800~1000 ℃. Light burned magnesium powder is yellowish and brownish powder, with particle size mostly below 100 mesh. Magnesite crystal is very small, with a density of 3.07~3.22g/cm3. It has large lattice constant, many lattice defects, brittle texture, porous structure, high reactivity, easy to conduct solid phase reaction or sintering, and hardens with water to generate Mg (OH) 2.
Selecting calcination mode and controlling light calcination temperature are important means to obtain good activity. With the increase of calcination temperature, the specific surface area of MgO decreased significantly. When the temperature is higher than 1000 ℃, the recrystallization rate of MgO accelerates, the dispersion degree drops sharply, and the activity becomes worse. The use of different calcination methods and calcination equipment at the same temperature is also an important factor affecting the activity of MgO. If fluidized bed furnace and suspension furnace are used for calcination, the light burned magnesia powder with maximum activity can be obtained by rapidly decomposing it in an instant. The tunnel kiln and the reflection kiln are used to calcine large blocks for a long time, which often causes the surface to overheat and the interior to burn, which will reduce the activity of light burned magnesia powder. If the rotary kiln is used to calcine granular magnesite, the situation is between the two, and the light burned magnesia powder obtained can also maintain good activity.
1 The weight of each batch of finished products shall not exceed 120 t.
2. Samples for particle size determination shall be sampled before batch forming, and samples for chemical analysis shall be sampled after batch forming. Take one sample from each 20 small bags (25kg) and one sample from each large bag (1000kg). After fully mixing the particle size samples obtained, measure the particle size by sampling 10-20g. The test sample after mixing is reduced to 200g and sent to the laboratory for analysis. 3 In case of any unqualified or abnormal chemical composition in the inspection result, take twice as many samples from the same batch of products for re inspection, and the re inspection result shall be the final inspection result of the batch of products.
