The input quantity
Each input quantity of blast furnace depends on the furnace size,large furnace can reach 1~3.5t ,small furnace just can reach 100~500kg.Feeding time interval usually be 10 ~ 20 min, material surface wave can not more than 0.5 m before and after feeding.
The stock column height
Lead blast furnace has two operation methods-- with high stock column (3.6 ~ 6.0 m) and with low stock column (2.5 ~ 3 m), generally we use the former one. When any of the following special circumstances, we can consider to use low stock column operation: (1) sintering block has higher lead grade (more than 50%), high residual S;(2) low sintering block strength;(3) to obtain a higher hearth efficiency 80~90t/(m2?d-1);(4) small blast furnace smelting.
Blast volume and air pressure
In production, when we use high stock column operation,blast strength is 25 ~ 35 m3?m-2?min-1; when we use low stock column operation,blast strength is 40 ~ 60 m3?m-2?min-1.The blast pressure of blast furnace mainly depends on the resistance of stock column in furnace, and fluctuates according to the furnace condition. When high stock column operations, generally it is about 11 ~ 20 kpa;when low stock column operations, generally it is about 6.7 ~ 11 kpa.When the blast furnace has a larger tuyere zone width or small outlet, we should take higher blast pressure, conversely take lower blast pressure.
Liquid lead, slag discharge temperature and furnace top pressure
Lead liquid discharge temperature is 800 ~ 1000 ℃, slag temperature is 1100 ~ 1200 ℃.In order to prevent roof smoke and a lot of air leakage, we should control the negative pressure operation, top pressure is commonly l0 ~ 50 pa.
Coke rate
When we take high stock column operations, we control coke rate to be general 10% ~ 13%;When low stock column,we control coke rate to be 7.50 ~ 10%.
Blast furnace water jacket supply water
Water jacket cooling way has two kinds-- water cooling and evaporative cooling.When we take water cooling, for water supply,it has the following requirements:
(1) the general water temperature at the outlet is 60 ~ 80 ℃, take lower limit when the water hardness is bigger, conversely take the ceiling;
(2) when the water temperature difference between import and export is 40 ~ 60 ℃, the water consumption of unit water jacket area is 16 l/m2 (min), also can estimate according to 2~4m3 water consumption per ton burden.
Be controled by lead liquid surface and slag surface in furnace hearth
When the blast pressure is 13.3 ~ 17.3 kPa,the lead liquid level of siphon lead well generally higher than the lead level in furnace hearth in 100 ~ 250 mm. The lead level in well is controlled by mud weir of lead chute. If the lead liquid level is too high, partial lead will be taken out through the discharge of slag and matte;If it is too low, matte can not discharge in time, it is easy to form furnace accretion. When the blast pressure is 11-17.3 kPa, throat bottom below the siphon well lead level 50 ~ 100 mm;the throat mouth slag dam height is generally 350 ~ 450 mm.
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