Noranda Furnace Refractory

Noranda furnace is formerly called Noranda reactor, it is horizontal cylindrical bath smelting furnace. Copper concentrate ore, copper containing material, flux and fuel are proportionally mixed and loaded into furnace by thrower. Oxygen rich air are blasted into furnace from tuyere, which makes the molten bath in a stirring state, raw material can have desulfurization reaction and slag making reaction, and produce matte with about 70% copper content.

Noranda furnace has strong adaptation to raw material, large capacity and high efficiency, flue gas SO2 concentration is high and can meet the requirement of sulfate acid making. It is also self heating smelting furnace, with low energy consumption. Noranda furnace copper smelting belongs to oxygen-rich bath smelting. It can realize drying, sintering, smelting and blowing smelting slag making at the same time, with high smelting intensity, intense bath agitating. To ensure the smooth going of smelting process and the service life of furnace, furnace lining refractory should have very high performance.

The most vulnerable parts of Noranda furnace are tuyere, furnace mouth, material loading-end combustor and furnace cylinder top corresponded to slag discharging end combustor, sediment zone slag line upper and lower part wall and slag-end wall. 

At tuyere zone, large amount of oxygen enriched air enters into furnace, accompanied with fierce agitating and spraying, chemical reaction is intense, corrosion is severe, meanwhile, furnace temperature will fluctuate frequently and cause thermal shock, mechanical abrasion is also happened when poking tuyere. So the working atmosphere is very harsh, damage speed is quick. It directly determined the service life of Noranda furnace. Furnace mouth would suffer high temperature smoke current scouring, mechanical impaction during cleaning slag, is also easy to be damaged.
Sediment zone slag line upper and lower cylindrical wall and slag-end wall are exposed in high temperature, and as slag layer will frequently change position during slag discharging and copper discharging, this part will suffer severe erosion and high temperature current scouring, is also vulnerable.

Material loading end wall and loading mouth. As material is water containing, cold air will also enter furnace from loading mouth, the furnace lining of material loading mouth will deform and form bump.

Feeding end combustor and slag discharging end combustor surrounding furnace top lining mainly suffer the direct scouring of flame, local thermal load is overlarge and with the coaction of large amount cold air, thermal shock is very severe.

According to the production condition of Noranda furnace, refractory materials used in it should have high purity, good slag corrosion resistance, high mechanical strength, good scouring resistance, abrasion resistance, good thermal stability. Earlier, furnace lining where suffers severe damage is mainly built by fused cast magnesia chrome bricks, other parts are built by direct bonded magnesia chrome bricks. The quantity of fused cast magnesia chrome bricks accounts for 30%~40% of the total firebricks consumption. With the improvement of furnace design, the damage degree of the damage tending parts is greatly reduced, along with the enhancement of firebrick quality, now fused grain rebonded magnesia chrome bricks have replaced fused cast magnesia chrome bricks. Although fused cast bricks have good abrasion resistance, erosion resistance and mechanical scouring resistance, their thermal shock resistance is poor and it is also expensive. The rest parts still use direct bonded magnesia chrome bricks.