Refractory for flash furnace

Flash smelting technology is one of the most advanced copper smelting technologies in today's mines. This method was first applied to industrial production in 1949 in Harya Valta copper smelting plant of Otto Kumpu Company in Finland. In 1952, Inco horizontal type was built at the Copper-Scarp smelter of Inco, Canada. The furnace uses industrial oxygen and the process is completely self-heating. Flash smelting has developed rapidly worldwide since 1965 because of its many advantages, and is now widely used in the smelting of copper and cu-Ni sulphide concentrates, as well as in the treatment of lead sulphide and pyrite concentrates. Flash smelting (Flash smelting) system will be dry, flux of sulfide ore concentrate with oxygen-enriched air or oxygen or preheat air into hot, supply the chamber of a stove or furnace under high temperature, the burden on the state of suspension under rapid reactions such as oxidation desulfurization, melting, slagging, after the formation of the melt into the tank to further complete the slagging process, and the enrichment of separated into metal and slag. The heat required to maintain the reaction in the flash furnace is mainly from the oxidation reaction of sulfur in the concentrate, which is a kind of autothermal smelting. The copper smelting technology combines the roasting and part of the smelting operation in the same equipment to complete continuously, which has a high smelting strength.

The chemical reaction of flash furnace process is intense, the speed is fast, the thermal strength is high, the atmosphere inside the furnace is complex, the lining of the furnace is demanding to the refractory material. China has introduced many flash furnaces since the 1980s, among which the ones of Guixi Smelting Plant and Jinchuan Nonferrous smelting Company are the most famous ones. According to the different furnace type, there are two types of flash melting: Outokumpu flash melting and Inco flash melting. Among them, Finland otto - Kuenpu type is widely used.

The main body of the flash furnace is composed of a cylindrical reaction tower, a settling basin and a cylindrical flue.

A reaction tower

The reaction tower is the most important component of the flash furnace. The gas-solid two-phase flow containing concentrate is injected from the top of the tower at high speed, and the chemical reaction is completed instantly at the top of the tower and the melt flow moves downward at high speed into the settling pool. Therefore, gas-solid two-phase and high temperature and high speed melt have serious erosion, erosion and wear on the lining of the tower. The lining of the reaction tower is generally made of magnesia-Chrome brick, and the steel shell of the tower is cooled by water pouring. The upper part of the reaction tower has a low temperature of about 900~1100℃ and a high partial pressure of oxygen. The wall of the tower has formed a protective layer of Fe3O4. The lining is lined with directly combined magnesium-chrome brick. The lower part of the furnace has a high temperature of 1350~1550℃ and is subject to the rapid flow and erosion of melt along the surface. The lining is easy to be worn and corroded. The lining is mostly made of fused magnesium-chrome brick and protected by water-cooled copper sleeve. The top of the tower is hung with magnesia-chrome brick.

B sedimentation tank

The sedimentation tank is a rectangular molten pool with a height of 2.5~5m and a width of 3~10m. The main function of the sedimentation tank is to further complete the slagging reaction and precipitate and separate the melt. The working environment of refractory materials in the sedimentation tank is also very bad. The end walls and side walls of the sedimentation tank at the bottom of the reaction tower are subject to the erosion and erosion by the high-speed falling high temperature airflow and melt, and the working conditions are similar to those of the reaction tower wall. The furnace wall in the slag line area is the most damaged part due to the constant fluctuation of the molten pool level. The mg-Cr refractory material in this part is required to have good anti-sulfur permeability and slag erosion. According to the side wall and the top of the furnace to bear the erosion and erosion of the high temperature flue gas with slag and soot, the bottom of the furnace bears the weight and suffers high temperature and chemical erosion. In addition to the recombined magnesia-chrome brick masonry, these parts are equipped with horizontal copper plate water jacket and cooling copper pipe, and inclined copper water jacket is set on the outside of the firebrick near the slag line. The top of the sedimentation tank is also subjected to severe erosion by high temperature airflow. Usually, finned water-cooled copper pipe is outfitted with refractory castable in the axial direction, and the upper part is "H" water-cooled beam of cooling water sandwiched in magnesia-Chrome brick on the top of the furnace to prevent the axial deformation of the sedimentation tank top.

C discharges flue

The flue duct is mainly subjected to the erosion and erosion of high temperature flue gas with slag and smoke, and is generally constructed by direct combination of magnesia-Chrome brick. The refractories used in the initial construction of the copper flash furnace in a domestic smelter were imported from Japan, and the fused cast magnesia-Chrome bricks with excellent slag resistance were selected in the slag line area of the side wall and lower part of the reaction tower and the sedimentation tank at a price equal to 10 times of the sintered brick. The upper side wall of the reaction column and the flow area of the sedimentation tank were directly combined with magnesia-Chrome bricks fired at high temperature, and the other parts were common magnesia-Chrome bricks. High quality magnesia-Chrome castable is selected for some special parts with complex structure.