There are many major risk factors in steelmaking, and improper control is likely to cause serious accident consequences, such as ladle falling off, gas poisoning, nitrogen suffocation, explosion, etc.
According to the steelmaking process, the major risk factors and control measures of nine major dangerous links are listed, and I hope it will be helpful to everyone.
1. Mixing molten iron
Larger risk factor: improper operation or misoperation of the hoisting personnel for adding molten iron.
Types of prone accidents: scalding
Main precautions:
(1) Command the crane to lift the molten iron at the specified safety station.
(2) The crane commander who holds the qualification certificate directs the crane to hoist the molten iron from the molten iron waiting position to the converter platform to exchange the molten iron according to the standard whistle, gesture or special walkie-talkie.
(3) Do not hang the small hook for tipping the molten iron tank before mixing the molten iron.
(4) Close the explosion-proof door in front of the window of the operating room before adding molten iron.
(5) Command all other personnel to evacuate from the converter platform site; no one should pass in front of the furnace when pouring molten iron.
(6) When adding molten iron, the molten iron tank cannot be pressed against the furnace’s mouth.
2. Add scrap steel
Major risk factors: there is water in scrap steel, there is damp waste, and there is a closed container in the furnace.
Types of accidents prone to occur: other explosions
Main precautions:
(1) Check that the scrap steel is free of water and moisture before lifting, otherwise, take drying measures or stop using it.
(2) Before adding steel scrap, check whether there are closed containers, explosives, and harmful metals in the raw materials.
3. Converter smelting
Larger risk factors 1: Leakage of steel, and water on the ground within the area.
Types of accidents prone to occur: other explosions
Main precautions:
(1) Check before smelting to confirm that there is no water on the ground in the area.
(2) Regularly check the wall thickness of the furnace lining.
(3) Repair the furnace in time according to the furnace repair plan.
Larger risk factor 2: Oxygen or auxiliary gun leaks into the furnace.
Types of accidents prone to occur: other explosions
Main precautions:
(1) Before smelting, check whether the safety chain of the oxygen lance system is intact; check whether the oxygen lance nozzle, sub-lance, and fume hood are leaking.
(2) When the auxiliary gun is lowered, the oxygen lance stops blowing or raises the oxygen lance; observe the oxygen lance at any time, and if the flow rate of the water in and out is poor, and it is greater than the safe value, the gun must be lifted to stop processing and inspection.
(3) When water leaks, press the emergency stop, and immediately raise the oxygen gun and auxiliary gun to cut off the water source.
(4) It is strictly forbidden to shake the furnace to prevent foreign matter (fume hood, oxygen lance, sub-lance sticky slag) from falling into the furnace.
4. Gas recovery
Major risk factor: gas leakage during smelting.
Types of prone accidents: poisoning and suffocation
Main precautions:
(1) The oxygen lance hole and feeding port on the flue should be equipped with reliable nitrogen seals; all platforms above the converter furnace cross furnace mouth should be equipped with gas detection and alarm devices; personnel should not stay for a long time on the above platforms.
(2) When the converter gas is recovered, the fan room is a Class B production plant and a second-level dangerous place. Its design should adopt fire prevention and explosion prevention measures and be equipped with fire fighting equipment, fire alarm signals, communication, and ventilation facilities.
(3) Gas recovery should be equipped with continuous measurement of carbon monoxide and oxygen content and an automatic control system; the oxygen content of recovered gas should not exceed 2%; automatic switching valves should be used for recovery and release of gas. The upper part should be equipped with an ignition device.
(4) For the converter gas recovery system, facilities such as explosion venting, venting, and purging should be reasonably set up.
5. Electric furnace smelting
Larger risk factor 1: Water leakage from the cooling water system of the electric furnace enters the furnace.
Types of accidents prone to occur: other explosions
Main precautions:
(1) The cooling water flow distribution of each cooling part meets the requirements, the inlet water temperature and pressure are normal, and the flow difference between the inlet and outlet of the cooling water is observed at any time.
(2) Do not switch cooling water pump stations during work.
(3) During smelting and after tapping, carefully observe the water cooling block. If water leakage is found, stop smelting immediately, press the tight stop button, and it is strictly forbidden to shake the furnace.
Larger risk factors 2: steel leakage due to improper operation, and water on the ground in the area.
Types of accidents prone to occur: other explosions
Main precautions:
(1) Check before smelting to confirm that there is no water on the ground in the area.
(2) Regularly check the wall thickness of the furnace lining, the condition of the oxygen lance, and the refractories on both sides of the furnace door.
6. Temperature measurement and sampling
Larger risk factors: artificial temperature measurement and sampling in front of the furnace, the speed of furnace shutdown being too fast, the operation of furnace shutdown being out of control, and steel being poured.
Types of accidents prone to occur: other explosions, scalding.
Main precautions:
(1) Manual temperature measurement and sampling to observe the pressure in the furnace and slowly reverse the furnace.
(2) Stand on the side of the fire door for manual temperature measurement and sampling, and wear protective clothing.
(3) Check before smelting to confirm that there is no water on the ground in the area.
7. Tapping
Larger risk factors: the molten steel tanker is not aligned and pours steel, and there is water on the ground.
Types of accidents prone to occur: other explosions
Main precautions:
(1) Check and confirm that the molten steel tank car is aligned and tapped.
(2) Slowly shake the oven.
8. Discharging the slag
Major risk factors: the slag tank is not in place, and there is water or damp waste in the slag dumping tank.
Types of accidents prone to occur: other explosions
Main precautions:
(1) Check to make sure that the slag tanker moves to the slag discharge position of the converter, and that the alignment is accurate.
(2) Check to make sure that there is no water or moisture in the slag tank
(3) Check to make sure that the slag tunnel has no water and no tidal waste.
9. Furnace protection by splashing slag
Major risk factor: nitrogen leakage.
Types of prone accidents: poisoning and suffocation
Main precautions:
(1) Check the valve position and joints of the nitrogen system for no leakage.
(2) Check that the nitrogen valve room has ventilation facilities and there is no leakage.
(3) Before entering the nitrogen and argon valve room for the inspection, it must be ventilated and checked with an oxygen detector before entering.
How Steel Mill Automation Can Improve Safety?
There are also many problems in the process of steel production that restrict the development of the steel industry, the most important of which is safety.
Automation control technology makes use of advanced science and technology to replace human labour with the operation of machinery and equipment, so that more employees can not directly participate in the highly hazardous production process, thereby greatly reducing the number of accidental injuries to employees, reducing the incidence of work-related injuries and even death probability, which greatly improves the safety of steel production. In line with the people-oriented concept, it is also conducive to the sustainable development of the steel industry. The solution to safety issues in production workshops in the iron and steel industry depends on advanced technology, and automation control technology as an advanced technology meets its requirements, which makes the two linked.
