Production Process of Magnesia Calcium Brick
October 19, 2018
Production process of magnesia Calcium brick
(1) Preparation of magnesium-calcium brick raw materials. The production of clean steel and ultra-clean steel requires magnesium-calcium refractories containing high free CaO. For this purpose, it is necessary to prepare high-calcium-magnesium-calcium bricks with synthetic magnesium-calcium sand with a CaO content of 40% to 60% or higher. As the CaO content increases, the production becomes more difficult and the yield decreases. At present, China usually produces magnesia-calcium bricks with a CaO content of 20% or 30%, which is widely used and compared.
(2) Breaking and crushing of magnesium-calcium brick raw materials. Generally, a jaw crusher, a roll crusher, a cone crusher and a mill are used to obtain four kinds of particle sizes. When using magnesium-calcium sand fine powder to make bricks, consider the problem of fine powder hydration, and use it with the grinding.
(3) Ingredients for magnesia-calcium bricks. Generally, it is compounded according to the above four kinds of particle sizes. In order to improve the shortcomings of the thermal shock resistance of the brick, the critical particle size is appropriately increased according to the actual size of the brick type, the bulk density of the brick is increased, and the rate of cold cracking in the firing process is reduced.
(4) Mixed training. The binder is made of paraffin or anhydrous resin, first coarse, medium granules, and then paraffin. After thorough mixing, add fine powder, and the mixing time is more than 20 minutes.
(5) Forming. The brick density is controlled at 2.98 ~ 3.05g / cm3, due to the shrinkage of the product during the firing process, need to be placed on the ruler.
(6) Calcination of magnesia-calcium bricks. The formed bricks do not need to be dried, and the bricks are required to be fired into the kiln within 8 hours after molding. When the code bricks are coded, the fire path is uniform, which is beneficial to the rapid elimination of the bonding agent. The firing temperature is between 1550 and 1620 ° C, and the holding time is not less than 5 hours.
(7) Hydration treatment. The burnt magnesia-calcium brick needs to be waterproofed. The usual method is dipping wax, plastic packaging, surface coating, etc., so that it can be stored for at least 6 months at room temperature.