Nickel oxide deposits upper limonite ore is laterite ore type, generally adapted to hydrometallurgical processing, a lower quality of a magnesium nickel silicate (serpentine based), are more suitable for pyrometallurgical smelting, while the intermediate layer Suitable for both methods. The three grades have some differences in nickel grade, chemical composition and mineral composition. The chemical composition of the different layers of the nickel oxide deposit and the corresponding extraction processes are listed in Table 1. However, with the development of hydrometallurgical technology, the leaching process of nickel oxide ore will break through the above positioning and play a more important role in the future nickel extraction industry.
Table 1 Chemical composition of different layers of nickel oxide deposits and applicable extraction methods
Layer position | chemical composition | Applicable extraction method | ||||
Ni | Co | Fe | Cr 2 O 3 | MgO | ||
surface layer | <0.8 | <0.1 | >50 | <1 | <0.5 | Discarding stockpiles |
Limonite layer | 0.8 to 1.5 | 0.1 to 0.2 | 40~50 | 2 to 5 | 0.5 to 5 | Hydrometallurgy |
Transition layer | 1.5 to 1.8 | 0.02~0.1 | 25~40 | 1 to 2 | 5~15 | Fire method or wet method |
Serpentine formation | 1.8~3 | 0.02~0.1 | 10~25 | 1 to 2 | 15～35 | Pyrometallurgy |
( olive rock ) bedrock | 0.25 | 0.01 to 0.02 | 5 | 0.2 to 1 | 35～45 | Not mining |
There are currently four main metallurgical processes for producing commercial nickel from nickel oxide ore:
1. The production process of nickel-iron alloy is mainly based on electric furnace smelting. It is the mainstream process for processing nickel oxide ore in various countries around the world. The principle flow is: ore → crushing and batching → drying → rotary kiln reduction roasting → electric furnace smelting → crude nickel iron → refining and decontamination → ferronickel → adding ferrosilicon or aluminum deoxidation → commercial nickel iron, the recovery rate of nickel is about 85% ~90%, iron is about 50%. The ferronics produced by various manufacturers have different specifications, and the chemical composition meets the international ISO6501 standard. There are five groups, each with 5 grades. Nickel-iron is mainly used in steelmaking, and the utilization of cobalt is not high. In the best case, it is only used as a substitute for nickel.
2. Production process of sputum (vulcanization to obtain high nickel bismuth). The principle flow is: ore → screening → rotary kiln reduction vulcanization roasting → electric furnace smelting → converter blowing → water quenching → high nickel bismuth. Add sulfur powder as a vulcanizing agent. The main metal components of high nickel niobium are: 78% Ni, 2% Co and 3% Fe, the balance being sulfur. The high nickel bismuth produced is often shipped to a nickel sulphide refinery for further processing into nickel and cobalt final products.
3. Reduction roasting - ammonia leaching (Caron) process. The main production process involves placing 90% less than 200 mesh ore in a multi-hearth furnace for selective reduction roasting: all nickel in the ore is reduced to metallic nickel, and ferric iron is reduced to form magnetite and partially reduced to a metallic state. The calcination is leached with ammonia-ammonium carbonate mixed solution, treated by a thickener, overflowed into a rich liquid, purified and evaporated to produce a nickel carbonate slurry, which is dried and calcined by a rotary kiln to obtain a nickel oxide product (76.5%). Ni, 0.6% Co). The nickel-cobalt recovery of this process is not high, nickel is about 75% to 80%, and cobalt is less than 60%.
4. High pressure acid leaching (PAL) process. The main feature of the process is that the oxidized slurry is leached by sulfuric acid at 240-270 ° C under high pressure conditions, and the products of nickel and cobalt are produced from the immersion liquid after solid-liquid separation. The leaching rate of nickel and cobalt can reach more than 95%, and the total yield is over 90%.
The processes associated with hydrometallurgy are the latter two, namely the reduction roasting-ammonia leaching process and the high pressure acid leaching process.
The plants used to treat nickel-containing laterite ore by reduction roasting-atmospheric ammonia leaching process include Nicro Nickel Smelter, Yabulu Refinery, and Surigao Nickel Plant. The production plants and production plants of the Sukinda Plant in India and the Sered Plant in Slovakia are listed in Table 2.
Table 2 Typical manufacturers and products of reduction roasting-ammonia leaching process
Factory name | Production capacity /(万t·a) | Ore grade | Brief process | product |
Yabru factory | 2.5 | 1.57% Ni 0.12% Co | Reduction roasting → ammonium carbonate leaching → H 2 S precipitation sulfide → nickel carbonate precipitation → reduction calcination | Nickel oxide (90% Ni) Sulfide (39% Ni, 13% Co) |
Niagara Plant 1943 | 2.3 (Ni+Co) | 1.3% to 1.4% Ni 33% to 37% Fe | Reduction roasting → ammonia leaching → nickel carbonate → reduction calcination | Nickel oxide (76.5% Ni), sintered nickel oxide (88.9%, Ni) |
Cuban New Nickel Plant 1985 | 3.0 (Ni+Co) | 1.3% Ni 39%Fe | Nicaro Factory | Nickel oxide (76.5% Ni), sintered nickel oxide (88.9%, Ni) |
Sheridan Nickel Factory | 0.2Ni 0.01Co | 1.3% Ni 51.3% Fe | Reduction roasting→Ammonia leaching→purification→separation of cobalt→steamed ammonia nickel carbonate→sulphuric acid dissolution→electrolysis | Electrolytic nickel, electrolytic cobalt, nickel powder, etc. |
Table 3 Main technical parameters of high-pressure acid leaching nickel laterite ore production plant
Factory name | Production capacity /(万t·a) | Ore grade | Brief process | product |
Maua | 2.3Ni 0.2Co | 1.35% Ni 47.6% Fe | Preparation→High-pressure acid leaching→solid-liquid separation→solution neutralization (iron, aluminum, chromium )→H 2 S pressurized nickel-cobalt | Sulfide concentrate (55% Ni, 5.9% Co) |
Mullin Mullin | 4.5Ni 0.3Co | 1.02% Ni 0.06% Co | Preparation→High-pressure acid leaching→Solid-liquid separation→H 2 S-sinking Ni, Co→sulfide precipitation, pressurized oxidizing acid leaching→Cyanex272 extraction cobalt→reverse extraction cobalt-oxygen reduction to obtain cobalt powder; raffinate hydrogen reduction to nickel powder | Cobalt powder, nickel powder |
Cowes | 0.9Ni | 0.98%Ni 0.08% Co | Preparation→High-pressure acid leaching→Solid-liquid separation→MgO-sinking nickel, cobalt→carbon ammonium solution re-dissolving→purification→Lix84A nickel extraction→reverse liquid electrowinning electrowinning nickel; raffinate H 2 S cobalt | Electro-nickel, cobalt sulfide |
Bulong | 0.9Ni | 0.70% Ni 0.04% Co | Preparation→High-pressure acid leaching→Solid-liquid separation→Cyanex272 extraction cobalt→Separation solution purification, electrowinning electrowinning cobalt; raffinate alkanecarboxylic acid extraction nickel→reverse extraction electrowinning electrowinning nickel | Electro-nickel, electro-cobalt |
Popcorn Maker,Hot Air Popcorn Popper,Microwave Popcorn Maker,Nostalgia Popcorn Machine
CIXI XINPU JIANKE ELECTRIC APPLIANCE FACTORY , https://www.cxjianke.com