rotary kiln for nickel

Processing of nickel rotary kiln

The investment costs and operational difficulties vary for different nickel ore processing techniques. The impact of rotary kilns on the overall energy consumption and product quality in the nickel-iron smelting process also varies. Therefore, as nickel-iron production scales up, it is worth analyzing which nickel ore pretreatment method to choose.

1. Firstly, we introduce the processing of a normal rotary kiln for nickel calcination. This type of processing has some advantages compared to RKEF Nickel process, such as: less fuel cost, because it use cheap coal, not coke or electricity; more selection of raw materials; finished nickel ferro (containing about 20% Ni) can be directly used as raw material for stainless steel production; It can be used as coolant in molten steel smelting.

1. The working zone of a rotary kiln for nickel ore can be divided into three sections: drying section, heating section, and roasting section.
2. In the rotary kiln, the nickel ore is calcined and dehydrated, resulting in a weight reduction of approximately 30%.
3. At the same time, nickel oxide and some iron are reduced by the reducing agent in the furnace charge.
4. A sealed discharge device is located at the discharge end of the rotary kiln, and the nickel slag is discharged at a temperature of 600-900°C, while being insulated, and then sent to the insulated feeding bin of the ore hot furnace for insulation. It is then uniformly distributed into the ore hot furnace through a sealed pipe-like feeding device.
5. The ratio of diameter to length of the rotary kiln varies depending on the treatment method of the furnace charge.
6. The burner structure of the rotary kiln is important for effectively adjusting the length and stiffness of the flame to ensure that the temperature in the three working zones of the kiln is within the required range.
7. Additionally, the utilization of the rotary kiln’s flue gas for drying the raw materials should be fully considered for energy conservation.

2. Secondly, RKEF Nickel is another hot processing on the market we can’t ignore. The RKEF process for nickel can be generally divided into these steps: Ore blending – Rotary kiln drying – Rotary kiln roasting – Electric furnace smelting of crude nickel-iron – LF furnace refining (or mechanical stirring desulfurization) – Water quenching of refined nickel-iron – Production of qualified nickel-iron granules.

• The RKEF process is mature, highly efficient in production, and has a relatively high nickel recovery rate (about 95%).
• It is easy to achieve automated control, can achieve higher smelting temperatures, and can handle refractory materials.
• Due to the high process smelting temperature (around 1500°C), a large amount of coke and electrical energy are required, resulting in high comprehensive energy consumption.
• The nickel grade of the ore has a significant impact on production costs, with approximately a 3-4% cost increase for every 0.1% decrease in nickel grade.
• From an economic perspective, it is suitable for processing medium to high-grade laterite nickel ores (with a nickel content greater than 2% and cobalt content less than 0.05%), and it requires high-quality coal and abundant local power or fuel supply.