Chemical Engineering March 2022 - 32

FEED
TABLE 2. PRODUCT PURITY FOR DIFFERENT TYPES OF FEEDS TO NICKEL SULFATE CRYSTALLIZERS
CURRENT CRYSTALLIZER TECHNOLOGY
Design parameters
Ni in feed, g/L
Purge, % of feed
Entrainment, % w/w
Wash efficiency, %
Feed type
Impurity in feed relative to NiSO4·6H2O,
mg/kg
Impurity in feed relative to Nickel, mg/kg
Impurity in feed , mg/L
Crystallizer performance
Ratio of impurity in feed to that in product
Product purity
Impurity in product relative to NiSO4·6H2O,
mg/kg
Impurity in product as mg per 100 mg
Purity of product NiSO4·6H2O, % w/w
Product purity designation
180
5
5
80
Poor
2,000
8,951
1,611
10
200
0.020
99.980
3 nines
crystallizer will operate with a purge
flow that is set to no more than 5%
of the desired product and wash efficiency
on the centrifuge that dilutes
the entrained mother liquor by a factor
of five or more. These limiting
values were used to determine the
predicted amount of impurity in the
product versus the average diameter
of the crystals. The results plotted
in Figure 5 show that as the crystal
diameter decreases below 1 mm diameter,
the amount of impurity in the
product increases relatively quickly.
Continual improvement is key
Crystallization is critical to meeting
the benchmark for purity in battery
chemicals. However, if crystallization
is to be an acceptable part of the supply
chain for electric vehicle makers, it
must also meet the benchmarks for
sustainability and value. Tesla has set
benchmarks for the industry, which
have been widely endorsed by other
electric vehicle and battery makers:
* Purity - Battery chemicals must
be free from impurities to allow high
energy density to be safely achieved.
* Sustainability - The sustainability
of producing battery chemicals
must be consistent with the " green "
credentials of the vehicles that the
chemicals will help power.
* Value - The ratio of performance
to cost must increase
with time to help drive increased
32
Typical
1,000
4,475
806
10
100
0.010
99.990
4 nines
Good
100
448
81
10
10
0.001
99.999
5 nines
consumer demand.
When used well, it is clear that crystallization
technology achieves the
high degree of purity that is required
to maximize energy in lithium-ion batteries.
To stay at the forefront, batterychemical
producers, the minerals
processing industry, and their technology
partners must continue to realize
efficiencies that lower costs and
deliver increasing value. They must
also leverage green energy sources to
offer a lower carbon footprint for how
to build and operate the plant. ■
Edited by Mary Page Bailey
References
1.
Samant,
K.D. and O'Young,
L.,
Understanding Crystallizers
and Crystallization, Chem. Eng. Progress, pp. 28-37,
October 2006.
2. Shah, N. M., Bradbury, D.S., Rogans, D. M. and Warner, J.J., Design
of Battery Grade Purity Nickel and Cobalt Sulphate Crystallisation
Plants, ALTA Conference Proceedings, May 2019.
3. Urwin, S.J., Levilain, G., Marziano, I., others, A Structured Approach
to Cope with Impurities during Industrial Crystallization
Development, Org. Process Res. Dev., 24, 8, pp. 1,443-
1,456, July 2020.
4. Shah N. M., Bradbury, Warner, J.J., Market Outlook for Battery
Grade
Nickel
Sulphate
Product Specifications,
November 2020.
and
Implications
of Varying
ALTA Conference Proceedings,
5.Warner, J.J., Bradbury, D.S., Shah N. M., The Production of High
Purity Nickel Sulphate Hexahydrate Suitable for Lithium-Ion Batteries
by Evaporative Crystallisation, ALTA Conference Proceedings,
May 2018.
Authors
John Warner is the managing director
at JordProxa (Unit 28/63
Knutsford Ave, Rivervale WA
6103 Australia; Email: jwarner@
jordproxa.com). Since the joint
venture was established in 2018,
Warner has led JordProxa in its
growth to become a leading supplier
of crystallizers to the battery
chemical market, with major projExcellent
50
224
40
10
5
0.001
99.9995
5
nines
Poor
2,000
8,951
1,611
40
50
0.005
99.995
4 nines
Typical
1,000
4,475
806
40
25
0.003
99.998
4 nines
180
10
3
85
Good
100
448
81
40
2.50
0.000
100.000
5 nines
Excellent
50
224
40
40
1.25
0.000
100.000
5 nines
ect references in Australia, Europe and the Middle East.
Prior to the formation of JordProxa, he designed and
sold process plant equipment (often in modular form) for
Jord International, and he was instrumental in introducing
new products into the company's portfolio to serve
leading global companies. Warner has worked extensively
on clean air and clean water projects in both the
research and corporate sectors in Australia, the U.S.,
Korea, India and Chile. These projects have included the
application of evaporation and crystallization technology
to achieve zero liquid discharge solutions. He holds a
B.S.Ch.E. and a Ph.D. in chemical engineering from the
University of Melbourne in Australia.
Nipen Shah is the head of sales at
JordProxa (40 Oxley St, St Leonards
NSW 2065 Australia; Email:
nshah@jordproxa.com), a company
specializing in the recovery of
pure solids from liquid solutions
using evaporation and crystallization.
Shah oversees the design,
costing, proposals, sales and business
development activities for the
supply of crystallization and evaporation plants for applications
involving battery-grade nickel sulfate, cobalt
sulfate and lithium hydroxide, ammonium sulfate and
zero liquid discharge (ZLD). Shah has a Ph.D. in chemical
engineering with specialization in process optimization
from Monash University in Australia.
Further reading
For more information on crystallization, please read the
following articles:
1. Crystallization: Contributing to Circularity, Chem.
Eng., March 2021.
2. Moisture Measurement in Solid Materials, Chem.
Eng., January 2021.
3. A Simplified Approach to Crystallization Mass Balances,
Chem. Eng., July 2020.
4. Nucleation Phenomena in Crystallization, Chem.
Eng., May 2020.
5. Industrial Crystallization for the CPI, Chem. Eng.,
November 2017.
6. Confronting Issues in Industrial Crystallization,
Chem. Eng., November 2017.
OPTIMIZED CRYSTALLIZER TECHNOLOGY
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
MARCH 2022
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