Submerged Arc Furnace Nickel Pig Iron
Nickel pig iron in submerged arc furnaces can generally be divided into high-grade ferronickel (10 and above), medium-grade ferronickel (ranging from 4-9), and low-grade ferronickel according to the content of nickel pig iron. The smelting of nickel pig iron mainly uses submerged arc furnaces and blast furnaces. Generally, submerged arc furnaces produce high-grade ferronickel, and blast furnaces produce medium and low-grade ferronickel. Nickel pig iron is mainly used by steel mills (Baosteel, Pohang, etc.) to smelt stainless steel, such as 300 series and 200 series stainless steel.
The production process of ferronickel is also varied and complicated. According to the smelting equipment, it can be divided into the rotary kiln-electric furnace (RKEF), blast furnace, electric furnace, and other processes. At present, RKEF is the mainstream process for smelting laterite nickel ore.
The RKEF process, that is, the rotary kiln-submerged arc furnace process, has mature technology, simple and easy-to-control equipment, and high production efficiency. However, its disadvantages are that the smelting temperature (about 1500°C) is high, it needs to consume a lot of metallurgical coke and electric energy, the production cost is high, and there is dust pollution. Moreover, the grade of nickel contained in the ore has a great influence on the production cost of the pyrotechnic process. For every 0.1% reduction in the nickel grade of the ore, the production cost will increase by about 3-4%. This process is suitable for treating type A magnesia silicate laterite ore and type C1 and C2 intermediate laterite ore. And the Ni grade is >1.6%, preferably 1.8%, which is conducive to saving production costs.
The RKEF process flow is ore batching—rotary kiln drying—rotary kiln roasting—furnace smelting crude ferronickel—LF furnace refining (or mechanical stirring desulfurization)—refined ferronickel water quenching—outputting qualified ferronickel particles.
Fuan Dingxin Ferronickel Co., Ltd., invested in and constructed by Tsingshan Group, was the first company in China to adopt the RKEF process of producing ferronickel with a large rectangular submerged thermal electric furnace. Φ4.8×100m rotary kiln, four 33000KVA round submerged arc furnaces. So far, these two RKEF production lines have stable production, good indicators, and the lowest cost in China.