Selective laterite nickel ore by pressurized acid leaching in Maawan Bay, Cuba

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A nickel-wool factory Bay in Cuba pressurized Magnesium acid leaching of nickel laterite ore containing suboxide, is the world's only high-temperature high-pressure direct acid leaching laterite nickel and cobalt extraction plant. The plant adopts advanced technology, compact factory layout, small floor space and clean environment.
The process flow is shown in Figure 6.
Figure 6 Process of the Maawan Bay Nickel Plant in Cuba
The plant treated with nickeliferous laterite Ni Jialuo different plants belonging to the type of limonite ore, if the sulfuric acid leaching solution, it is present in large amounts of iron ore (iron oxide mine containing 68%) at atmospheric pressure and room temperature Easy access to solutions containing nickel and cobalt. However, with the same concentration of sulfuric acid solution, leaching at high temperature and high pressure (246 ° C, 3.6 MPa), only a small amount of iron entered the solution and the leaching rate of nickel and cobalt exceeded 95%. The content of alkaline oxidation in the ore is quite low, and it is not necessary to consume a large amount of sulfuric acid to neutralize the alkaline oxide in the ore.
The amount of pressurized leaching sulfuric acid is 22.5% per ton of dry concentrate. The leaching residue contains 51% iron and can be used as a raw material for iron making. The leachate is sent to a precipitation autoclave (118-121 ° C, pressure 1 MPa), and sulfide precipitates such as nickel, cobalt and copper are precipitated by hydrogen sulfide. A sulphide concentrate containing 55% Ni, 5.9% Co, and 1.0% Cu is produced and sent to a refinery for further refining.
The main equipment structure and process parameters and related material composition and indicators used in the Ma'awan Nickel Plant are shown in Tables 1 and 2.
Table 1 Process equipment structure and process parameters of hot-pressed sulfuric acid leaching method in Ma'awan Nickel Plant
Device name
Quantity
Standard sizes
structure
Process parameters
Steam heating leaching autoclave
16 units
Vertical Φ3.05, H15.8m steam agitation, 4 columns in parallel
Steel shell lining 6.4mm Pb leather +76mm acid-resistant brick + carbon brick
246 ° C, 3.6Mpa, 112min, solid concentration 45% ~ 33%, ore particle size <20 mesh, H 2 SO 4 dosage = 22.5% dry ore, 4 series
Slurry cooler after leaching
4 sets
Beam tube type Φ1.22, L5.35m beam tube Φ71mm
Countercurrent, the slurry passes through the inner tube, the temperature is from 246 ° C → 135 ° C, generating steam 0.1 Mpa
Slurry flash tank
2 sets
Φ2.2, H3.1, level 1 nozzle Φ20mm
Level 2 nozzle Φ17mm
Steel shell lining 4.5mm rubber + 115mm carbon brick ceramic nozzle (Al 2 O 3 80% ~ 95% + SiO 2 3.76%)
From 135 ° C → ≤ 100 ° C, two parallel, each set of 2 nozzles in series
Slurry washing thickener
6 sets
Φ68.5m, 6-level series
Countercurrent, washing ratio 2/1, efficiency 99%
Overflow neutral tank
4 sets
Within Φ 4.27, H4m
Wooden, 4 series
Effective volume grooves 45.5m 3, PH 2.5 ~ final 2
Nickel-cobalt pressure autoclave
4 sets
Horizontal three-chamber Φ3.5, L9.91m, one 45kW turbine agitation per chamber
Carbon steel shell, lined with 4.75 glue + 114mm acid-resistant brick
118 ~ 121 ℃, P total = 1Mpa, P H2 s0.8Mpa, three rooms are sequentially residence time (min) 6.2,5.7,5.1; Q solution = 3.64m3 · min - 1
Sulfide slurry flash tank
4 sets
Φ2.13, H4.26m
Same pulp flash tank
Solution Q = 3.64m 3 · min - 1
Table 2 Material composition and process indicators of the hot-press acid leaching process in Ma'aowan Nickel Plant
composition
ore/%
Leaching
Leach rate /%
Neutralization solution / (g·L - 1 )
H 2 S precipitation
Liquid / (g·L - 1 )
Slag /%
Concentrate /%
Washing liquid
/(g·L - 1 )
Recovery rate/%
Ni
1.35
5.95
0.06
96
4.15
55.1
0.037
99
Co
0.146
0.64
0.008
96
0.45
5.9
0.007
98.1
Cu
0.02
0.1
~100
0.08
1.0
~100
Zn
0.04
0.2
~100
0.1
1.7
~100
Fe
47.5
0.8
51
0.4
0.6
0.3
0.5
4
Mn
0.8
2.0
0.4
57
1.4
+
1.2
0
Cr(Cr 2 O 3 )
(2.9)
0.3
(3.0)
3.0
0.2
0.4
0.15
13.1
SiO 2
3.7
2
3.5
12
++
Mg(MgO)
(1.7)
2
(0.7)
60
1.9
1.7
0
Al(Al 2 O 3 )
(8.5)
(8.1)
11
1.6
0.02
1.4
0.1
SO 4 2 -
67
8.1
27
S 1 so4 2 - 0.06
twenty four
CaO
H 2 O combination
12.5
3.2
Pb100
H 2 SO 4 (pH)
28
(2.4)
7
1 Sulfide contains 35.5% sulfur; +-Pb 0.003%; ++-Ca 0.1g/L.

Iron Based Alloy Powder

Iron-based alloy powder is commonly used in plasma transfer arc welding (PTAW) due to its excellent mechanical properties and high resistance to corrosion and heat. This type of powder is typically composed of iron as the base metal, along with various alloying elements such as nickel, chromium, molybdenum, and tungsten.

The specific composition of the iron-based alloy powder may vary depending on the desired properties and application requirements. For example, adding nickel can increase the strength and toughness of the weld, while chromium enhances the corrosion resistance. Molybdenum and tungsten are often added to improve the high-temperature strength and creep resistance of the weld.

Iron-based alloy powders for PTAW are available in various particle sizes, typically ranging from a few micrometers to several hundred micrometers. The powder is usually fed into the plasma arc through a powder feeder, which ensures a controlled and consistent supply of powder during the welding process.

During PTAW, the powder is melted and deposited onto the workpiece, forming a weld bead. The high energy plasma arc provides the heat necessary to melt the powder and the base metal, creating a strong and durable weld joint.

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