Design and application practice of refractory materials in lead metallurgy industry
Furnace Bottom Design
After years of practical production experience, for lead smelting, the metallurgical furnaces used include dozens of metallurgical furnaces that process various lead materials, but the refractory linings of metallurgical furnaces mainly use magnesia-chrome bricks, high-alumina bricks, high-alumina Quality refractory ramming material, etc.
(1) The permanent layer area at the bottom of the furnace
In the design of the furnace lining, each position in the furnace body is different, and the selection of refractory materials also changes accordingly. Taking the fixed horizontal metallurgical furnace body as an example, the furnace bottom generally uses magnesia-chrome bricks, high-alumina bricks, aluminum-chromium spinel, high-alumina ramming materials, magnesia ramming materials, etc., and some use high-strength ramming materials. The anti-seepage ramming material is also composed of Al₂O₃-SiO₂ series, and the content of Al₂O₃ is >75%. The specific gravity of liquid lead is 10.6g/cm³, and the permeability is extremely strong. Therefore, the refractory material at the bottom of the furnace should not only have the function of heat dissipation, but also have a high ability to prevent seepage of lead.
At present, the widely used practice is to first lay high-alumina bricks on the steel plate of the furnace bottom. A layer of refractory material with resistance to lead penetration should be provided on the upper part of the cushion. Currently, there are magnesium ramming materials or high-strength anti-seepage ramming materials (high aluminum), both of which can play the role of a barrier. The ratio of magnesia ramming material is: magnesia: magnesium powder = 7:3, with brine, magnesia particle size: 0.2~0.5mm70%, 1.5~3.0mm 30%; the composition of high-strength anti-seepage ramming material It is: high-aluminum aggregates and bone powder of various particle sizes are configured. After baking at high temperature, the aggregates of various particle sizes are expanded and tightly combined to achieve the ideal anti-seepage lead purpose.
It must be noted that after the magnesium and magnesium-chromium ramming materials are rammed, they need to be baked at a low temperature. After baking out free water, the expansion joints are filled with fine magnesium powder to ensure the strength and compactness of the ramming layer. sex. The thickness of the ramming material is recommended to be 150~300mm, which is not only easy to complete the ramming process at one time, but also completes the baking more uniformly, forming an overall layer with better anti-seepage effect.