Refractories from Noranda Furnace

Founded in Horn smelter, Nolanda, Canada, began research and development in 1964. The ø5.2m*21.3m Nolanda furnace for industrial production was completed and put into production in March 1973.

Nolanda furnace is a horizontal cylindrical melting tank smelting furnace. The furnace body rotates forward and backward under the drive of the transmission device. One end of the furnace body is fed, one end of the slag is discharged, and the bottom side of the deposit area is open with matte outlet.

Copper concentrates, copper-containing materials, fluxes and petroleum coke used as fuel are mixed and thrown into the furnace by a high-speed feeder. The oxygen-enriched air is pumped into the furnace from the tuyere, so that the molten pool is in a stirring state, and the material is desulphurized and slagging in the furnace, and about 70% copper containing matte is produced.

Nolanda furnace has strong adaptability to raw materials, large treatment capacity, high smelting efficiency and high SO2 concentration in flue gas to meet the requirements of acid preparation. At the same time, it is a self-heating smelting technology with low energy consumption. China's Daye smelter is using the furnace to produce copper and sulfur, production capacity.

The process of drying, roasting, melting and blowing slag making is completed in a reaction furnace. The melting strength is large and the mixing of the molten pool is intense. In order to ensure the smooth progress of the process and the life of the furnace, high requirements are put forward for the lining design and refractories. The vulnerable parts of Nolanda furnace are the top of the furnace tube corresponding to the tuyere area, the furnace mouth, the feeding end burner and the slag discharge end burner, as well as the upper and lower circular walls and slag end walls of the slag line in the sedimentation area. Due to a large amount of oxygen-enriched air entering the melt, intense stirring and splashing, severe chemical reaction, serious erosion, frequent thermal shock caused by alternating changes in furnace temperature, heat and cold, and mechanical scour caused by piercing the air hole, The tuyere lining is damaged quickly, so the life of Nolanda furnace is determined. The furnace mouth is also easily damaged by the scour of high temperature flue gas and the impact of mechanical cleaning furnace slagging. Because of the high temperature zone and the frequent fluctuation of slag layer, the serious erosion of slag and the scour of high temperature flue gas are also easy to damage. Because of the entry of moisture and cold air in the charging end wall, the lining around the charging port is deformed, and the circumferential lining of the top of the furnace corresponding to the flame of the burner at the feeding end and the slag discharge end is mainly directly washed by the flame.

According to the production conditions of Nolanda furnace, high purity, good slag resistance, high strength, scour resistance, wear resistance and good thermal stability are required. In the past, two kinds of brick masonry were mainly used in furnace lining: one is molten cast magnesium chromium brick, which is built in vulnerable parts, and the other parts are directly combined with magnesium chromium brick masonry. Fused magnesium chromium brick accounts for 30%~40% of the total. With the improvement of furnace design, the damage degree of some vulnerable parts is greatly improved, and the quality of refractory brick is improved. Now, melt-grained and magnesium-chromium brick has been used instead of fused-cast magnesium-chromium brick. The melt-cast brick is wear-resistant, erosion-resistant and mechanical scour-resistant, but it has poor resistance to cold and heat and is expensive.