U.nited States Patent [19]
Lowenhaupt et al.
[11]
[45]
Patent Number:
Date of Patent:
4,541,994
* Sep. 17, 1985
11 Claims, No Drawings
OTHER PUBLICATIONS
"Freeport Nickel's Moa Bay Puts Cuba Among Ranking
Ni-Producing Nations", Engineering and Mining
Journal, vol. 160, No. 12, Dec. 1959, pp. 84-92.
Primary Examiner-John Doll
Assistant Examiner-Robert L. Stoll
Attorney, Agent, or Firm-Sheridan, Ross & McIntosh
3,737,307 6/1973 Fitzhugh, Jr. et al. 75/109
3,773,891 11/1973 O'Neill 423/139
3,793,430 2/1974 Weston 423/36
3,793,432 2/1974 Weston 423/143
3,804,613 4/1974 Zundel et al. 75/101 R
3,809,549 5/1974 Opratko 75/101 R
3,991,159 11/1976 Queneau et a1. 423/150
4,012,484 3/1977 Lussiez 423/53
4,044,096 8/1977 Queneau et al. 423/150
4,065,542 12/1977 Subramanian et al. 423/35
4,097,575 6/1978 Chou et al. 423/150
4,098,870 7/1978 Fekete et al. 423/123
4,195,065 3/1980 Duyvesteyn 423/150
4,410,498 10/1983 Hatch et al. 423/150
According to the present invention, Ni- and Co-rich,
low Mg fines may be advantageously separated from
the coarse fractions of lateritic ores by atmospheric or
low pressure leaching. In particular, the process of the
present invention comprises contacting a lateritic ore or
ore fraction at temperatures from about 20· C. to about
200· C. and pressures from about atmospheric to about
200 psig with an aqueous acid solution to form a leach
liquor, a leach residue and a fines fraction. The fines
fraction which can be separated from the residue with
the leach liquor by conventional means such as cycloning
is found to be richer in Ni and Co and lower than the
remainder of the residue.
[57] ABSTRACT
[54] METHOD OF LIBERATING NICKEL- AND
COBALT-ENRICHED FINES FROM
LATERITE
[75] Inventors: E. Harris Lowenhaupt, Gasquet,
Calif.; John E. Litz, Lakewood;
Dennis L. Howe, Broomfield, both of
Colo.
[73] Assignee: California Nickel Corporation,
Crescent City, Calif.
[ *] Notice: The portion of the term of this patent
subsequent to Sep. 17,2002 has been
disclaimed.
[21] Appl. No.: 516,237
[22] Filed: Jul. 22, 1983
[51] Int. Cl.4 COIG 53/00; COIG 55/00;
C22B 3/00
[52] U.S. Cl. 423/150; 423/123;
423/128; 423/131;423/141;423/146; 423/159;
423/161; 423/166; 75/101 R; 75/108; 75/115;
75/119; 75/121
[58] Field of Search 423/123, 128, 140, 131,
423/141, 146, 159, 150, 161, 155, 166; 75/101
R, 108, 115, 121, 119
[56] References Cited
u.s. PATENT DOCUMENTS
2,842,427 7/1958 Reynaud et a1. 23/183
2,872,306 2/1959 Morrow 75/101
2,971,836 2/1961 Hall 75/119
3,093,559 6/1963 White 204/123
3,293,027 12/1966 Mackiw et al. 75/119
3,333,924 8/1967 Hazen et al. 23/165
3,365,341 1/1968 Fitzhugh, Jr. et al. 75/119
3,466,144 9/1969 Kay 23/183
3,473,920 10/1969 Fitzhugh, Jr. et al. 75/109
3,720,749 3/1973 Taylor et al. 423/141
SUMMARY OF THE INVENTION
DETAILED DESCRIPTION OF A PREFERRED
EMBODIMENT
2
enriched fraction has been obtained, with or without
grinding.
It has now been discovered that the secondary leach
at low or atmospheric pressure liberates a Ni- and Co-
5 enriched fine fraction which is lower in Mg. If the leach
residue is separated, e.g. by cycloning, the overflow
stream containing the liberated enriched fine fraction
can be sent to high pressure leach, while the underflow
fraction which is high in Mg and low in Ni and Co can
be discarded.
By discarding the high Mg underflow, sulfuric acid
consumption in the high pressure leach can be reduced,
with resulting savings in capital and operating costs of
producing the acid. Because of the unexpected discovery
of a method of liberating enriched fines, undue loss
ofNi and Co with the discarded residue is avoided if the
fines are separated and sent to high pressure leach.
According to the present invention, Ni- and Co-rich
low Mg fines may be advantageously separated from
the coarse fractions of lateritic ores by atmospheric or
low pressure leaching. In particular, the process of the
25 present invention comprises contacting a lateritic ore or
ore fraction at temperatures from about 20· C. to about
200· C. and pressures from about atmospheric to about
200 psig with an aqueous acid solution to form a leach
liquor, a leach residue and a fines fraction. The fines
fraction which can be separated from the residue with
the leach liquor by conventional means such as cycloning
is found to be richer in Ni and Co and lower in Mg
than the remainder of the residue.
The present invention provides a method for liberating
and separating Ni- and Co-rich fines from the coarse
fractions of a laterite ore. In particular, the process
provides for leaching the ore fractions at ambient or
low temperature and thereafter separating the Ni- and
Co-rich fines liberated by such leaching along with the
leach liquor.
As described hereinbefore, there are a number of
processes wherein nickel and cobalt may be recovered
from lateritic ores by a sequence of steps including at
, least one sulfuric acid leach whereby the nickel and
cobalt are solubilized into the pregnant leach liquor and
recovered therefrom by conventional means. Typical of
50 such processes are those described in U.S. Pat. Nos.
4,044,096,4,195,065 and 3,466,144 the details of which
are incorporated herein by reference.
The process of the present invention wherein the ore
fractions to be subsequently processed is first leached to
liberate low-magnesium fines may advantageously be
used in conjunction with any such processes. By liberating
the Ni and Co-rich 10w-Mg fmes according to the
present invention, the ore subsequently processed has a
higher proportion of nickel and cobalt relative to magnesium
resulting in a lower consumption of acid. In
addition, since nickel and cobalt recovery processes
using sulfuric acid leaching require that the acid subsequently
be neutralized, this acid can be used to liberate
fines while it is being neutralized.
In one method of leaching lateritic or limonitic nickel
ore using sulfuric acid as the leach reagent the ore is
cumminuted to a suitable degree of fineness by grinding,
crushing, classifying and the like, to from about -48
4,541,994
1
FIELD OF INVENTION
BRIEF DESCRIPTION OF THE PRIOR ART
METHOD OF LIBERATING NICKEL- AND
COBALT-ENRICHED FINES FROM LATERITE
This invention relates to methods of recovering
nickel and cobalt from lateritic ores and, in particular,
to a method of separating nickel and cobalt-rich fines
from the coarse fractions of the ore prior to recovery of
the desired metal values. 10
A wide variety of processes are known for the recovery
of nickel and/or cobalt from various nickel-bearing
ores including laterite and serpentine ores. Basic to one 15
type of recovery processing is the solubilizing of the
nickel and/or cobalt by sulfuric acid leaching followed
by neutralization. In general, it is known that process
economics are advantageously altered by minimizing
the amount of acid consumption during leaching by 20
non-essential alkaline elements of the ore such as magnesium.
In addition, advantages are known to be
achieved through the use of acid-consuming ore fractions
as part or all of the neutralizing agent utilized
subsequent to the acid leach step.
The acid-consuming ore fractions are generally the
coarser particles of greater than about 100 mesh. These
particles are high in acid-consuming magnesium, and
are often lower in nickel and cobalt than the finer portion
of the ore. In the prior art practice, these coarser 30
particles are often separated from the ore feed by for
example a cyclone.
The fine fraction, smaller than about 100 mesh, which
is lowest in magnesium, is sent to high pressure sulfuric
acid leach, where the nickel and cobalt are extracted at 35
high recoveries, typically in excess of 90% of each
metal. In order to achieve this high yield, sufficient
H2S04 must be added to leave a residual concentration
of acid in the product liquor from the high pressure
leach. 40
This acid is known to be neutralized by contacting it
with the high acid consuming coarser fractions in a
secondary downstream lower temperature leach, where
some of the magnesium, nickel, and cobalt in these
coarse fractions are leached while the acid is neutral- 45
ized. Because relatively low extractions of Ni and Co
are obtained in the secondary leach, the residue containing
unrecovered Ni and Co is then sent to the primary
high pressure leach along with the minus 100 mesh fines
fraction from the original ore separation.
In the primary high pressure leach, the unrecovered
Ni and Co from the secondary leach residue are extracted
at high yield, but with the detrimental effect of
also extracting much of the residual magnesium. This
represents an unwanted consumption of H2S04, which 55
in some cases makes the process uneconomical.
Thus it would be advantageous to eliminate some of
the magnesium in the coarse fractions before sending
them to high pressure leach, without also eliminating
unacceptable amounts of the Ni and Co. This would be 60
possible if a new fraction which is relatively high in Ni
and Co, and relatively low in Mg could be liberated
from the coarse fractions.
Liberation of such a fraction has proved impossible in
prior art practice. All known beneficiation techniques, 65
including flotation, gravity separation, magnetic separation,
selective flocculation, classification, and the like
have been tried. No significant liberation of a Ni and Co
EXAMPLES
4-
geously be contacted with H2 to reduce the cobalt present
to its elemental state.
The following examples are provided by way illustration
and not by way of limitation.
A series of tests were conducted to assess the amount
and distribution of nickel, cobalt and magnesium present
in various mesh sizes of the solid residue remaining
after leach tests generally conducted according to the
process of the present invention. The size of the particles
of the initial feed materials, the amount of each
material used and temperatures and pressures employed
varied among the tests. For purposes of the laboratory
tests the feed materials were filtered and washed after
treatment and the solids were separated by sizing into
the various fractions for analysis of metal content.
Analysis of metal components was done by the
atomic absorption method. The analysis of feed material
used, initial size distribution of the solids and the specific
parameters of the individual test conditions are
given in the tables reporting each test series.
EXAMPLE 1
5
A laterite ore coarse fraction was leached in three
separate tests with an acid-containing evaporate solution
prepared by the evaporation of water from a solution
recovered from a previous laterite ore fines fraction
high temperature leach. The evaporate contained: 5.92
gil Ni, 0.662 gil Co, 37.7 gil Mg, 19.79 b/I Fe, 5.1 g/I
A and 20 gil H2S04. The amount of evaporate utilized
varied in each of three tests, while the amount of the
feed material remained constant. The low temperature/
pressure leach was conducted at a pressure of
300 psi for 40 minutes at 180· C. followed by 20 minutes
at 160· C. For Tests #1 and #3 bleed was 100 cc/min.
For Test #2 bleed was 500 cc/min.
Particle sizes of the coarse fractions, analysis of the
particle sizes within the feed, acid-content of the evaporate
and metallurgical data for both feed and evaporate
are given in Table I.
Table 2 shows the results of secondary low pressure
leach tests on this material, with the buildup of Ni- and
Co-enriched, low-Mg fines in the -200 mesh fines frac45
tion.
4,541,994
3
mesh, most preferably - 28 mesh to about 90% less than
325 mesh and formed into an aqueous slurry or pulp of
suitable consistency, typically from about 20 to about 50
weight percent solids and more preferably from about
40 to about 45 weight percent solids.
The slurried ore is then typically preheated to a
leaching temperature of between about 200· C. and
about 300· C., directly or indirectly as by injection of
live steam. The preheated slurry is then typically fed to
an autoclave or other reactor suitable for acid leaching 10
with H2S04.
In the practice of the present invention the ore or
slurry, before or in lieu of preheating, is pre-leached by
contact with sulfuric acid at ambient or low temperatures
and pressures, i.e. a temperature of from about 20· 15
C. to about2oo· C. ancJ a pressure below about 300 psig,
to liberate the nickel- and cobalt-enriched, magnesiumdepleted
fines fraction. The amount of sulfuric acid
required to liberate fines from coarse laterite ore is not
critical, and will depend on the source of the ore, the 20
amount of fines liberation desired, and the amount of
attendant magnesium dissolution desired. As will be
recognized by those skilled in the art, there will for any
particular ore be a quantity of acid which will cause
extensive fines liberation without undue dissolution of 25
the low grade magnesium containing fraction. The preleach
liquor along with the liberated fines, typically 90
percent less than about 100 mesh, frequently 90 percent
less than 200 mesh in size, are separated from the remainder
of the residue by conventional means such as 30
cycIoning.
The primary H2S04 leach is typically at temperatures
between 200· and 300· C. and pressures of about 400 to
about 850 psig for a time sufficient to solubilize a substantial
amount of the Ni and Co from the ore and form 35
a slurry of Co- and Ni-containing pregnant liquor and
leach residue. The slurry is then neutralized by the
addition of MgO or other acid neutralizing agent. The
liquor is separated from the neutralized residue and the
metal values recovered therefrom by conventional 40
means. Typically, the pregnant liquor is contacted with
H2S to precipitate nickel sulfide. The remaining liquor
is then separated from the precipitate and may advanta-
TABLE I
Analysis of Feed Material
for Low Pressure Leach Tests
Metallurgical Data
Solids +20-mesh 17.01 0.47 14.36 0.05
#1478-75 20 X 48 16.22 0.50 14.72 0.06
i X 48 X 100 21.33 0.50 19.31 0.07
325 mesh 100 X 200 28.13 0.58 29.11 0.09
-200 17.31 0.72 22.50 0.10
Total 100.00 0.56 100.00 0.08
Evaporate Volume:
Test #1 - 670 mls
Test #2 - 830 mls
Test #3 - 1000 mis
Feed to Test 1-3
Ni
dist % % Disl. % %
Co Mg
Disl. % % Disl. %
10.74 8.20 14.18
12.80 9.02 14.87
20.48 11.20 24.28
33.66 11.00 31.45
22.31 8.65 15.22
100.00 9.84 100.00
TABLE 2
Results of Low Pressure Leach Tests
Metallurgical Data
Ni Co Mg Fe Al
Test #1
Filtrate Volume
Wash Volume
465 mls
1050 mls
6.17 gil
1.28 gil
.926 gil
.193 gil
60.4 gil
11.2 gil
.9 402 1.2
0.22
5
4,541,994
6
TABLE 2-continued
Results of Low Pressure Leach Tests
Metallurgical Data
Ni Co Mg Fe AI H2SO4
dist Dist. Dis!. Dis!.
Residue Weight % % % grams % % grams % % grams
+20-mesh 46.1 11.65 .502 11.76 0.23 .042 13.56 0.02 7.67 13.05 3.54
20 X 48 52.6 13.30 .351 • 9.39 0.18 .029 10.68 0.02 9.35 18.15 4.92
48 X 100 65.2 16.48 .308 10.21 0.20 .026 11.87 0.02 9.79 23.56 6.38
100 X 200 71.6 18.10 .363 13.21 0.26 .029 14.54 0.02 8.04 21.25 5.76
-200 160.1 40.47 .681 - 55.43 1.09 .044 49.34 0.07 4.06 23.99 6.50
Total 395.60 59.53 0.50 100.00 1.97 0.04 100.00 0.14 6.85 100.00 27.09
Dissolution, % 11.48 543.05 31.15
Balance (out/in X 100) 99.86 103.79 103.60
Acid Consumption (Includes acid produced by Fe and Al precipitation and excludes acid consumed by MgO addition) Iblton 305
Test H2
Filtrate Volume 640mls 7.01 gil .977 gil 67.9 gil 1.64 1.34 5.4
Wash Volume 1000 mls 1.03 gil .015 gil 9.57 gil 0.76
dist Dis!. Dis!. Dis!.
Residue Weight % % % grams % % grams % % grams
+20-mesh 50.9 12.95 .423 16.22 0.22 .037 19.35 0.02 7.19 12.35 3.66
20 X 48 42.5 10.81 .288 9.22 0.12 .025 10.92 0.01 8.70 12.48 3.70
48 X 100 52.9 13.46 .206 8.21 0.11 .018 9.78 0.01 9.56 17.07 5.06
100 X 200 66.8 16.99 .281 14.14 0.19 .020 13.73 0.01 8.06 18.17 5.38
-200 180 45.79 .385 52.21 0.69 .025 46.23 0.05 6.57 39.92 11.83
Total 393.10 54.21 .338 100.00 1.33 .025 100.00 0.10 7.54 100.00 29.62
Dissolution, % 40.27 67.99 24.72
Balance (out/in X 100) 95.91 86.42 117.00
Acid Consumption (includes acid produced by Fe and Al precipitation) Iblton 399
Test H3
Filtrate Volume 815 mls 6.25 gil .874 gil 53.4 gil 1.78 1.91 7.2
Wash Volume 990 mls 1.05 gil .156 gil 9.02 gil 1.22
dist Dis!. Dis!. Dis!.
Residue Weight % % % grams % % grams % % grams
+20-mesh 45.6 11.49 .423 12.03 0.19 .037 14.41 0.02 7.18 13.57 3.27
20 X 48 40.8 10.28 .292 7.43 0.12 0.25 8.71 0.01 8.17 13.81 3.33
48 X 100 59.7 15.04 .194 7.22 0.12 .019 9.69 0.01 9.6 23.75 5.73
100 X 200 74.0 18.64 .3 13.85 0.22 .025 15.80 0.02 7.79 23.88 5.76
-200 176.9 44.56 .539 59.47 0.95 .034 51.38 0.06 3.41 24.99 6.03
Total 397.00 55.44 0.40 100.00 1.60 0.03 100.00 0.12 6.08 100.00 24.14
Dissolution, % 27.85 61.51 38.67
Balance (out/in X 100) 95.02 101.83 99.39
Acid Consumption (Includes acid produced by Fe and Al precipitation and excludes acid consumed by MgO addition) Iblton 382
the feed material varied from 5% to 15% were conducted.
The particle size distribution of the solid feed
material, volume and acid content of the evaporate and
metallurgical data for each of the tests are reported in
Tables 3, 4 and 5. Once again, the build-up of Ni- and
Co-enriched, low Mg fines is shown in the - 200 mesh
fines fraction.
EXAMPLE 2
The sands from +325 mesh laterite ore feed containing
0.42%; Ni, 0.05% Co and 8.72% Mg were leached
with evaporate containing 6.11 gil Ni, 0.65 gil Co, 38.1
gil Mg, 20 gil Fe and 5.43 gil Al for 8 hours at atmo- 45
spheric pressure and a temperature of 60· C. Three
separate tests (Nos. 4-6) wherein the percent of solids of
TABLE 3
Analysis of Feed and Results of Atmospheric Pressure Leach
Metallurgical Data - 5% solids
Ni Co Mg Fe Al
Test H4
dist Dis!. Dist. Dis!.
Weight % % % grams % % grams % % grams gil gil
Feed +20-mesh 66.57 44.38 0.483 50.96 0.32 .050 44.39 0.03 8.34 42.45 5.55
Solids 20 X 48 47.77 31.85 0.403 30.51 0.19 .051 32.42 0.02 8.44 30.82 4.03
48 X 100 22.11 14.74 0.285 9.99 0.06 .042 12.38 0.01 10.50 17.75 2.32
100 X 200 8.04 5.36 0.288 3.67 0.02 .048 5.15 0.00 9.96 6.13 0.80
-200 5.51 3.67 0.558 4.87 0.03 .077 5.66 0.00 6.78 2.86 0.37
Total 150 100.00 0.421 100.00 0.63 .050 100.00 0.07 8.72 100.00 13.08
Evaporate Volume 3000 mls 6.11 gil .65 gil 38.1 gil 20 5.43
Filtrate Volume 3000 mls 5.89 gil .66 gil 38.6 gil 20.9 5.43
Wash Volume 600 mls .17 gil .018 gil 1.2 gil
dist Dist. Dis!. Dis!.
Residue Weight % % % grams % % grams % % grams
+20-mesh 37.8 32.50 0.434 46.52 0.16 .032 37.03 0.01 4.82 25.79 1.82
20 X 48 35.4 30.44 0.217 21.78 0.08 .022 23.84 0.01 6.66 33.37 2.36
48 X 100 22.5 19.35 0.150 9.57 0.03 .022 15.15 0.00 8.19 26.09 1.84
100 X 200 11.4 9.80 0.285 9.21 0.03 .034 11.87 0.00 6.34 10.23 0.72
gil
36
14.71
0.46
4,541,994
7 8
TABLE 3-continued
Analysis of Feed and Results of Atmospheric Pressure Leach
Metallurgical Data - 5% solids
Ni Co Mg Fe Al H2SO4
-200 9.2 7.91 0.495 12.91 0.05 .043 12.11 0.00 3.47 4.52 0.32
Total 116.30 92.09 0.303 100.00 0.35 .028 100.00 0.D3 6.07 100.00 7.06
Dissolution, % 44.11 56.44 45.99
Balance. (out/in X 1(0) 95.59 99.92 97.02
Acid Consumption Ib/ton 848
TABLE 4
Analysis of Feed and Results of Atmospheric Pressure Leach
Metallurgical Data - 10% solids
Ni Co Mg Fe Al H2SO4
Test #5
dist Dis!. Dist. Dis!.
Weight % % % grams % % grams % % grams gil gil gil
Feed +20-mesh 133.15 44.38 0.483 50.96 0.64 .050 44.39 0.07 8.34 42.45 11.10
Solids 20 X 48 95.54 31.85 0.403 30.51 0.39 .051 32.42 0.05 8.44 30.82 8.06
48 X 100 44.21 14.74 0.285 9.99 0.13 .042 12.38 0.02 10.50 17.75 4.64
100 X 200 16.09 5.36 0.288 3.67 0.05 .048 5.15 0.01 9.96 6.13 1.60
-200 11.02 3.67 0.558 4.87 0.06 .077 5.66 0.Ql 6.78 2.86 0.75
Total 300 100.00 0.421 100.00 1.26 .050 100.00 0.15 8.72 100.00 26.16
Evaporate Volume 3000 mls 6.11 gil .65 gil 38.1 gil 20 5.43 36
Filtrate Volume 3000 mls 5.96 gil .66 gil 39.4 gil 23.2 5.45 11.7
Wash Volume 600 mls .39 gil .043 gil 2.7 gil 0.80
dist Dist. Dist. Dis!.
Residue Weight % % % grams % % grams % % grams
+20-mesh 90.1 37.26 0.431 47.92 0.39 .035 42.58 0.03 5.86 35.08 5.28
20 X 48 72.2 29.86 0.225 20.05 0.16 .025 24.37 0.02 6.78 32.52 4.90
48 X 100 34.3 14.19 0.144 6.09 0.05 .019 8.80 0.01 8.41 19.16 2.88
100 X 200 11.9 4.92 0.166 2.44 0.02 .025 4.02 0.00 7.79 6.16 0.93
-200 33.3 13.77 0.572 23.50 0.19 .045 20.23 0.01 3.2 7.08 1.07
Total 241.80 86.23 0.335 100.00 0.81 .031 100.00 0.07 6.23 100.00 15.05
Dissolution, % 35.78 50.62 42.46
Balance (out/in X 1(0) 96.59 99.04 96.02
Acid Consumption Ib/ton 483
TABLE 5
Analysis of Feed and Results of Atmospheric Pressure Leach
Metallurgical Data - 15% solids
Ni Co Mg Fe AI H2SO4
Test #6
dist Dis!. Dist. Dis!.
Weight % % % grams % % grams % % grams gil gil gil
Feed +20-mesh 99.86 44.38 0.483 50.96 0.48 .050 44.39 0.05 8.34 42.45 8.33
20 X 48 71.65 31.85 0.403 30.51 0.29 .051 32.42 0.04 8.44 30.82 6.05
48 X 100 33.16 14.74 0.285 9.99 0.09 .042 12.38 0.01 10.50 17.75 3.48
100 X 200 12.07 5.36 0.288 3.67 0.D3 .048 5.15 0.01 9.96 6.13 1.20
-200 8.26 3.67 0.558 4.87 0.05 .077 5.66 0.01 6.78 2.86 0.56
Total 225 100.00 0.421 100.00 0.95 .050 100.00 0.11 8.72 100.00 19.62
Evaporate Volume 1500 mls 6.11 gil .65 gil 38.1 gil 20 5.43 36
Filtrate Volume 1450 mls 6.09 gil .67 gil 40.7 gil 21.6 5.6 10.3
Wash Volume 600 mls .29 gil .031 gil 2.02 gil 0.51
dist Dis!. Dist. Dis!.
Residue Weight % % % grams % % grams % % grams
+20-mesh 69.30 39.99 0.362 46.66 0.25 .033 45.44 0.02 6.04 35.19 4.19
20 X 48 50.80 29.31 0.251 23.71 0.13 .024 24.23 0.Ql 7.60 32.46 3.86
48 X 100 23.70 13.68 0.162 7.14 0.04 .020 9.42 0.00 9.74 19.41 2.31
100 X 200 7.50 4.33 0.222 3.10 0.02 .023 3.43 0.00 8.8 5.55 0.66
-200 22.00 12.69 0.474 19.39 0.10 .040 17.49 0.01 4.0 7.40 0.88
Total 173.30 87.31 0.310 100.00 0.54 .029 100.00 0.05 6.86 100.00 11.89
Dissolution, % 43.19 55.26 39.37
Balance (out/in X 100) 94.37 95.67 93.95
Acid Consumption Ib/ton 345
EXAMPLE 3
Classifier sands stage laterite ore was ground to pass
through a 20 mesh screen and was then further screened
65
and separated into smaller particle sizes. An analysis of
the relevant metallic components of the ore according
to particle sizes is given in Table 6.
9
4,541,994
10
TABLE 6
Classifer Sands Stage Laterite Ore Ground to Pass 20-Mesh
Screen Analysis and Distribution of Values
Weight Nickel Cobalt Iron Magnesium
Size % % Distr % Distr % Distr %
Mesh % Retain Pass %Ni % Pass %Co % Pass % Fe % Pass %Mg % Pass
35 36.56 36.56 63.44 0.432 33.88 66.12 0.044 32.81 67.19 27.7 37.58 62.42 8.97 34.31 65.69
48 16.80 53.36 46.64 0.432 15.57 50.56 0.044 15.08 52.11 27.7 17.27 45.15 8.97 15.77 49.93
65 12.98 66.33 33.67 0.402 11.19 39.37 0.043 11.38 40.73 22.9 11.03 34.12 11.1 15.07 34.86
100 8.41 74.74 25.26 0.402 7.25 32.12 0.043 7.38 33.35 22.9 7.15 26.98 11.1 9.76 25.09
150 5.50 80.24 19.76 0.447 5.28 26.84 0.048 5.39 27.97 23.9 4.88 22.10 10.8 6.22 18.88
200 2.15 82.39 17.61 0.447 2.06 24.78 0.048 2.10 25.87 23.9 1.90 20.20 10.8 2.42 16.45
-200 17.61 100.00 0.00 0.656 24.78 0.00 0.072 25.87 0.00 30.9 20.20 0.00 8.93 16.45 0.00
Calculated Head 0.47 0.049 26.9 9.56
Weight Manganese Chromium Aluminum
Size % % Distr % Distr % Distr %
Mesh % Retain Pass %Mn % Pass %Cr % Pass %AI % Pass
35 36.56 36.56 63.44 0.329 36.72 63.28 1.96 28.59 71.41 3.25 37.21 62.79
48 16.80 53.36 46.64 0.329 16.87 46.41 1.96 13.14 58.28 3.25 17.10 45.69
65 12.98 66.33 33.67 0.272 10.78 35.63 4.02 20.81 37.46 3.08 12.52 33.18
100 8.41 74.74 25.26 0.272 6.98 28.65 4.02 13.49 23.98 3.08 8.11 25.06
150 5.50 80.24 19.76 0.292 4.90 23.74 4.22 9.26 14.71 3.28 5.65 19.41
200 2.15 82.39 17.61 0.292 1.91 21.83 4.22 3.61 11.10 3.28 2.20 17.21
-200 17.61 100.00 0.00 0.406 21.83 0.00 1.58 1l.10 0.00 3.12 17.21 0.00
Calculated Head 0.33 2.51 3.19
30
EXAMPLE 4
Four samples of the - 20 mesh ore fraction of Example
3 were leached at atmospheric pressure for 2 hours
at a temperature of 80· C. with a high pressure leach
evaporate containing 22.7 gil Fe, 4.99 gil AI, 35 gil 35
H2S04, 5.82 gil Ni, 0.674 gil Co, and 41.9 gil Mg. For
each of Test Nos. 7, 8, 9 and 10 the solids were 9.1,7.7,
6.3 and 4.8% by weight.
The residue of these atmospheric leaches were analyzed
for metallic content after the leach and demon- 40
'.. strate that Mg was rejected in the +200 mesh fraction,
whereas Ni and Co were concentrated in the -200
mesh fractions. Results of the screen analysis are given
in Table 7.
TABLE 7-continued
Distribution of Values in Leached Residue
Iron, % 25.1 31.4 25.1 30.8
Distr, % 73.8 75.2
Magnesium, % 8.94 6.27 8.63 6.00
Distr, % 83.4 84.3
Manganese, % 0.16 0.18 0.16 0.17
Distr, % 76.5 76.9
Chromium, % 2.97 1.57 2.80 1.65
DistT, % 87.1 86.3
Aluminum, % 3.52 3.54 3.37 3.37
Distr, % 78.0 78.9
EXAMPLES
The amount of each solid material varied in the three
tests while the amount of evaporate remained constant
65 at 1000 mls. An analysis ofthe metallurgical data for the
feed, the residue and the evaporate or leach filtrate
before low pressure leaching and results after the leaching
are shown in Tables 8, 9 and 10.
TABLE 7
Distribution of Values in Leached Residue
Test No. 7
Screen Size +200 -200 +200 -200
Weight, % 76.4 77.1
Nickel, % 0.26 0.43 0.30 0.43
Distr, % 66.1 68.2
Cobalt, % 0.021 0.033 0.024 0.034
DistT, % 68.4 66.7
Iron, % 23.2 30.4 26.3 30.9
Distr, % 71.2 74.1
Magnesium, % 9.09 6.59 8.95 6.53
Distr, % 81.7 82.1
Manganese, % 0.15 0.16 0.16 0.17
Distr, % 75.0 77.3
Chromium, % 3.02 1.71 3.04 1.59
Distr, % 85.2 86.4
Aluminum, % 3.54 3.56 3.53 3.54
Distr, % 76.3 77.0
Test No. 9 10
Screen Size +200 -200 +200 -200
Weight, % 77.9 78.8
Nickel, % 0.28 0.43 0.29 0.43
Distr, % 69.7 70.8
Cobalt, % 0.023 0.036 0.023 0.034
Distr, % 66.7 72.5
50
Solids:
55
Evaporate:
Test
60 Conditions:
Pressure:
+325 Classifier Overflow
0.63% Ni 0.09% Co 10.31% Mg
-200 mesh Atmospheric Leach Residue
0.53% Ni 0.04% Co 4.69% Mg
32.00% Fe 3.41% Al
Atmospheric Leach Filtrate
5.92 gil Ni .71 gil Co 45.9 gil Mg
21.3 gil Fe 4.97 gil Al
Tinie one 40 min Temperature one 180' C.
Time two 20 min Temperature two 160' C.
300 psig Bleed 500 cc/min
4,541,994
11 12
TABLE 8
Low Pressure Leach of Fine Particle Feed
Metallurgical Data
Ni Co Mg Fe Al H2SO4
dist Dis!. Dis!. Dist.
Weight % % % grams % % grams % % grams gil gil gil
Feed + 65-mesh 84.50 16.9 0.619 16.51 0.523 0.083 15.36 0.070 10.90 17.86 9.21
Solids . 65 X 150 212.00 42.4 0.597 39.94 1.266 0.090 41.79 0.191 11.00 45.23 23.32
+325 150 X 270 179.50 35.9 0.662 37.50 1.188 0.096 37.75 0.172 9.64 33.56 17.30
-270 24.00 4.8 0.799 6.05 0.192 0.097 5.10 0.023 7.19 3.35 1.73
Total 500 100.00 0.634 100.00 3.169 0.091 100.00 0.457 10.31 100.00 51.56
Atmos. 38.0 0.53 0.20 0.04 0.02 4.69 1.78
Residue
Weight
-200
Evaporate Volume 1000 mls 5.92 gil .71 gil 45.9 gil 21.3 4.97 15
Filtrate Volume 640 mis 6.07 gil 1.15 gil 66.9 gil 1.4 .23 .31
Wash Volume 1060 mls 1.89 gil .24 gil 17.2 gil 0.08
dist Dis!. Dis!. Dis!.
Residue Weight % % % grams % % grams % % grams
+ 65-mesh 41.3 7.65 0.447 5.71 0.185 0.031 6.31 0.013 11.10 13.31 4.58
65 X 150 126.7 23.46 0.390 15.28 0.494 0.028 17.49 0.035 9.69 35.64 12.28
150 X270 138.9 25.72 0.478 20.54 0.664 0.029 19.86 0.040 7.26 29.27 10.08
-270 233.1 43.17 0.811 58.47 1.890 0.049 56.33 0.114 3.22 21.79 7.51
Total 540.00 100.00 0.599 100.00 3.233 0.038 100.00 0.203 6.38 100.00 34.45
Dissolution, % 4.05 57.15 35.41
Balance (out/in X 100) 98.19 100.84 96.23
Acid Consumption (Includes acid generated by Fe and Al precipitation) Iblton 336
TABLE 9
Low Pressure Leach of Fine Particle Feed
Metallurgical Data
Ni Co Mg Fe AI H2SO4
dist Dis!. Dis!. Dist.
Weight % % % grams % % grams % % grams gil gil gil
Feed +65-mesh 76.05 16.9 0.619 16.51 0.471 0.083 15.36 0.063 10.90 17.86 8.29
Solids 65 X 150 190.80 42.4 0.597 39.94 1.139 0.090 41.79 0.172 11.00 45.23 20.99
+325 150 X 270 161.55 35.9 0.662 37.50 1.069 0.096 37.75 0.155 9.64 33.56 15.57
-270 21.60 4.8 0.799 6.05 0.173 0.097 5.10 0.021 7.19 3.35 1.55
Total 450 100,00 0.634 100.00 2.852 0.091 100.00 0.41 I 10.31 100.00 46.40
Atmos. 34.0 0.53 0.18 0.04 0.01 4.69 1.59
Residue Weight
-200
Evaporate Volume 1000 mls 5.92 gil .71 gil 45.9 gil 21.3 4.97 15
Filtrate Volume 670 mls 6.67 gil 1.15 gil 72 gil .75 .46 1.01
Wash Volume 1070 mls 1.64 gil .24 gil 14.2 gil 0.20
dist Dist. Dist. Dis!.
Residue Weight % % % grams % % grams % % grams
+ 65·mesh 38.1 7.77 0.383 5.66 0.146 0.031 6.51 0.012 11.10 13.99 4.23
65 X 150 112.7 23.00 0.340 14.88 0.383 0.028 17.40 0.032 9.24 34.44 10.41
150 X 270 129.5 26.42 0.440 22.12 0.570 0.032 22.86 0.041 7.00 29.98 9.07
-270 209.8 42.81 0.704 57.34 1.477 0.046 53.23 0.097 3.1 I 21.58 6.52
Total 490.10 100.00 0.526 100.00 2.576 0.037 100.00 0.181 6.17 100.00 30.23
Dissolution, % 15.04 57.42 37.01
Balance (out/in X 100) 98.30 106.41 99.75
Acid Consumption (Includes acid generated by Fe and Al precipitation) Iblton 371
TABLE 10
Low Pressure Leach of Fine Particle Feed
Metallurgical Data
Ni Co Mg Fe AI H2SO4
dist Dist. Dis!. Dis!.
Weight % % % grams % % grams % % grams gil gil gil
Feed +65-mesh 67.60 16.9 0.619 16.51 0.418 0.083 15.36 0.056 10.90 17.86 7.37
Solids 65 X 150 169.60 42.4 0.597 39.94 1.013 0.090 41.79 0.153 11.00 45.23 18.66
+325 150 X 270 143.60 35.9 0.662 37.50 0.951 0.096 37.75 0.138 9.64 33.56 13.84
-270 19.20 4.8 0.799 6.05 0.153 0.097 5.10 0.019 7.19 3.35 1.38
Total 400 100.00 0.634 100.00 2.535 0.091 100.00 0.365 10.31 100.00 41.25
Atmos. 30.0 0.53 0.16 0.04 0.01 4.69 1.41
Residue Weight
-200
Evaporate Volume 1000 mls 5.92 gil .71 gil 45.9 gil 21.3 4.97 15
Filtrate Volume 835 mls 6.67 gil 1.02 gil 64.3 gil 1.72 .73 1.4
13
4,541,994
14
TABLE lO-continued
Low Pressure Leach of Fine Particle Feed
Metallurgical Data
Ni Co
dist Dis!.
Residue Weight % % % grams %
Iblton 398
Mg Fe Al H2SO4
4.2 gil 0.09
Dis!.
% % grams
0.008 11.00 14.61 3.76
0.022 8.38 31.79 8.19
0.028 6.96 28.22 7.27
0.076 3.36 25.38 6.54
0.134 5.98 100.00 25.75
39.63
94.32
grams
5.61
16.76
21.03
56.59
100.00
.016 gil
Dis!.
%
0.022
0.023
0.027
0.039
0.031
64.58
91.99
0.115
0.326
0.408
1.196
2.045
5.60
15.95
19.96
58.49
100.00
Wash Volume 972 mls .49 gil
+ 65-mesh 34.2 7.94 0.335
65 X 150 97.7 22.68 0.334
150 X 270 104.4 24.23 0.391
-270 194.5 45.15 0.615
Total 430.80 100.00 0.475
Dissolution, % 24.07
Balance (out/in X 100) 93.93
Acid Consumption (Includes acid generated by Fe and AI precipitation)
2. The improvement according to claim 1 wherein
said acid leach solution comprises sulfuric acid.
3. A method according to claim 2 wherein said leach
solution further contains at least one species selected
from the group consisting of Fe, AI, Ni, Mg and Co.
4. A method according to claim 1 wherein said separating
is by cycloning.
5. A method according to claim 1 wherein 90 percent
25 of said fines are no larger in size than about 100 mesh.
6. The improvement according to claim 1 wherein
said coarse, magnesium-rich fraction is leached at a
pressure of from atmospheric to about 300 psig.
7. A method according to claim 6 wherein said pressure
is atmospheric and said temperature is below 800 C.
8. A method according to claim 7 wherein said temperature
is about 600 C.
9. A method according to claim 7 wherein said temperature
is ambient.
10. A method according to claim 1 wherein about 90
percent of said fines fraction comprises about -200
mesh size fines.
11. A method according to claim 1 wherein about 90
percent of said fines fraction comprises from about
- 100 to about - 200 mesh size fines.
* * * * *
Although the foregoing invention has been described 20
in some detail by way of illustration and example for
purposes of clarity of understanding, it will be obvious
that certain changes and modifications may be practiced
within the scope of the invention, as limited only by the
scope of the appended claims.
What is claimed is:
1. A method of extracting nickel and cobalt from
nickel; cobalt and magnesium-containing laterite ore
comprising classifying said ore into a coarse, magnesium-
rich fraction and a less coarse cobalt- and nickel- 30
rich fraction, solubilizing said nickel and cobalt from
said less coarse fraction into a pregnant liquor by a
primary high pressure acid leach at a temperature of
from about 2000 C. to about 3000 C., neutralizing said
pregnant liquor and recovering said nickel and cobalt 35
from said neutralized liquor, the improvement comprising
leaching said coarse, magnesium-rich fraction at a
temperature of below about 200" C. to liberate magnesium-
depleted, nickel- and cobalt-enriched fines, separating
said fines from the remainder of said coarse fraction 40
and advancing said fines to said high pressure leach.
45
50
55
60
65