US006733564B1

(12) United States Patent

Sahu et al.

(10) Patent N0.: (45) Date of Patent:

US 6,733,564 B1 May 11,2004

(54)

PROCESS FOR RECOVERY OF NICKEL FROM SPENT CATALYST

Radhanath Prasad Das; Production of Nickel and Cobalt

from Secondary Sourcesthe Indian Experience; ErZmet

(75) Inventors: Kamala Kanta Sahu; Jamshedpur (IN);

Banshi Dhar Pandey; J amshedpur

all; 2001; pp. 450454; vol. 54; No. 9; published by Regional Research Laboratory; Orissa; India; (Publication No.

(IN); Prem Chand; Jamshedpur (IN)

XP001082739).
Alex P. et al.; Reduction RoastingSulphuric Acid Leach ing of Nickel From A Spent Catalyst; Metals Materials and

(73) Assignee:

Council of Scienti?c and Industrial

Research, New Delhi (IN)

Processes; 1991; pp. 8191; vol. 3; No. 2; published by Meshap Science Publisher; Bombay; India; (Publication No.

(*)

Notice:

Subject to any disclaimer, the term of this patent is extended or adjusted under 35

XP002217885).
Takaishi KaZuyuki; Method for Recovering Nickel Sulfate From NickelContaining Sludge; Patent Abstracts of

U.S.C. 154(b) by 0 days.

(21) Appl. No.: 10/095,526 Mar. 13, 2002 (22) Filed: (51) Int. Cl.7 ................................................. .. B22F 9/24 (52) US. Cl. ...................... .. 75/353; 75/374; 423/1502;
502/24

Japan; Sep. 18; 2001; (Publication No. 2001253719).

Database WPI; Sibe Sibtsvetmetnii; Jul. 23; 1982; published by DerWent Publications Ltd.; London; Great Britain; (Pub lication No. XP002217886).
* cited by examiner

(58) (56)

Field of Search .............. .. 75/353; 374; 423/1502;

502/24
References Cited
U.S. PATENT DOCUMENTS

Primary ExaminerGeorge WysZomierski

(74) Attorney, Agent, or FirmBurns; Doane; SWecker &
Mathis L.L.P.

(57)

ABSTRACT

2,576,314 A 3,891,521 A 4,474,735 A

11/1951 Forward 6/1975 Carlin

10/1984 Rastas et al.

The present invention relates to a process for recovery of

nickel and alumina from spent catalyst by direct leaching

With sulphuric acid in presence of small amount of an additive. The invention is useful for recovery of both nickel and sources of nickel and therefore important from the vieW of environmental protection; resource recycling and conser vation.

FOREIGN PATENT DOCUMENTS

JP
60-102945 * 6/1985

OTHER PUBLICATIONS

International Search Report for PCT/IN02/00061; ?led Mar. 21; 2002; 7 pages.

5 Claims, N0 Drawings

US 6,733,564 B1
1
PROCESS FOR RECOVERY OF NICKEL FROM SPENT CATALYST
FIELD OF THE INVENTION
The present invention relates to a process for recovery of

2
major problems for the subsequent processing steps of ?nal
product recovery. Neutralisation of highly acidic leach liquor requires high amount of alkali and Will generate huge
quantity of Waste cake Which Will add cost to the process,

besides creating environmental problem.

Thought several attempts have been made to recover

nickel from spent catalyst. The present invention also relates

to a process for the recovery of nickel from spent catalyst Wherein alumina is also recovered as an important by-product. The present invention particularly relates to a process for recovery of nickel and alumina from spent
10

nickel by various processes involving pre-treatment such as

roasting, reduction/alkali/chlorination roasting etc. folloWed by acid/alkali/neutral leaching, hoWever, there are rarely any
attempt made to accelerate the metal dissolution process by adding additive such a persulphate salts of ammonium,

catalyst by direct leaching With sulphuric acid in presence of

small amount of an additive. The invention is useful for recovery of both nickel and sources of nickel and therefore

sodium, potassium, etc.

OBJECTS OF THE INVENTION
15

important from the vieW of environmental protection,

resource recycling and conservation.
BACKGROUND OF THE INVENTION

The main object of the present invention is to provide a process for extraction of nickel from spent catalyst Which
obviates the draWbacks as detailed above.

The consumption of nickel in India is about 20,000 MTPY (metric tonnes per year Which is entirely imported. Though several by-products/Wastes such as nickel sludge

20

generated during the pickling of stainless steel, grinding

Waste of AlNiCo magnets, and spent catalyst from the

Another object of the present invention is to provide a leaching process for extraction of nickel from spent nickel catalyst in presence of little amount of catalytic established processes and avoids requirement of high strength acid for selective and quantitative dissolution of nickel from this
resource.

fertiliser, petrochemical and hydrogenation plants are

exploited commercially. Therefore, to meet the ever groWing demand, the effort has been made to provide an
innovative and cost effective process for recovery of both

Still another objective of the present invention is to

available, at present none of such sources are being 25 develop a suitable process for the recovery of alumina from

spent catalyst as a valuable by-product suitable for special

grade refractories or for reuse as supports for catalyst.
SUMMARY OF THE INVENTION
30

nickel and alumina from the nickel spent catalyst of the fertiliser plants, besides producing alumina as a by-product

thereby generating minimal Waste for disposal.

Nickel based catalysts are the catalysts of choice in several industries due to their loW cost competing substi tutes. Such catalysts use alumina and silica as supports. Deactivated nickel catalysts are not considered to be regen

Accordingly, the present invention provides a process for extraction of nickel from spent nickel catalyst Which com
prises

eratable by ordinary techniques and also pose a signi?cant Waste disposal problem. Hence, it is necessary to develop neW extraction techniques for processing of such spent
catalyst to obtain pure metal for re-reuse. Considerable efforts have been made to recover nickel

35

i) adding a persulphate based additive along With ?ne siZed nickel catalyst in the sulphuric acid solution and stirring by a magnetic needle/glass stirrer and main
taining the solid liquid ratio in the range of 1/21/10

(Wt./vol.),
ii) keeping the temperature of the slurry obtained in
40

from spent catalyst by hydrometallurgical processes. In most

of the earlier Work the spent catalyst had to undergo pre

step(i) in the range of 40 to 100 C. for a period of 0.5 to 6 h,

iii) alloWing the slurry to settle and then ?ltering the slurry
to obtain leach liquor containing nickel and alumina as

treatment step to processing (Inooka Masayoshi, Japan, Kokai, Yokyo, Koho 7811621, 11 Oct. 1978; Telly, George
L., US. Pat. No. 4,721,600, 20 Jan. 1988; Giurea et al Rom

solid residue, iv) Washing the solid residue to remove entrapped liquor
45

R0 85578, 29 Sep. 1984). In general chlorination (Gravey,

G., LeGroff J. and Gonin C., Jan. 8, 1980, US. Pat. No.

and drying at 110120 C. to get a by-product contain

4,182,747), pressure leaching With ammonium hydroxide

ammonium carbonate or sodium hydroxide (Gutnikov G. Mar. 2, 1971, US. Pat. No. 3,567,433; Millsap W. A. and

ing high alumina,

v) purifying the said leach liquor by precipitating iron and
other impurities using lime and ?ltering to obtain pure
50

Reisler N., 1978, Eng. and Min 1., Vol. 179 (5), p. 105. ) and sodium carbonate roasting (Castange H., Gravey G. and
Roth A, Feb. 21, 1978, US. Pat. No. 4,075,277 Were

nickel sulphate solution,

vi) crystallising or precipitating the leach liquors to obtain nickel sulphate crystal or nickel hydroxide, vii) reducing nickel hydroxide to obtain nickel metal
poWder or nickel oxide. In an embodiment of the present invention the spent

applied. After a pre-treatment spent catalyst is directly is leached With Water/acid/alkali. Reduction roasting folloWed

by sulphuric acid leaching of a spent catalyst from hydro genation plant to produce nickel oxide reported only 83% of overall recovery (P. Alex, T. K. Mukherjee and M.
Sundaresan, 1991, Metals Materials and processes, Vol.

nickel catalyst used is selected from nickel catalyst having

particle siZe in the range of 211 to +38 pm and has a

composition in range:

3(2), P.-81). Roasting folloWed by selective chlorination at 400 C. of spent catalyst under Cl2+air, Cl2+N2 and Cl2+N2
Was investigated and maximum recovery of only 80% Was

Ni: 520%, Fe 0.11%, A1203: 7090% SO21 06%

60

reported (Gaballah I. and Dona M., 1993, the Paul E. Queneau Int. Symp. on Extractive Metallurgy of Copper, Nickel and Cobalt, Vol. 1, p. 1253, Ed. R. G. Reddy and R. N. WeiZenbach, minerals, Metals and Material Society). Direct leaching of a spent catalyst has several disadvantages
such as requirement of high strength acid as high as 2030%
and poor nickel dissolution of other metal ions Which are the

In another embodiment of the present invention the spent nickel catalyst used is selected from persulphate salts of sodium, potassium and ammonium and has concentration in the range of 0.254% (W/W).
In still another embodiment of the present invention the

65

sulphuric acid is of commercial grade and has concentration in the range of 212% (v/v). This acid concentration is obtained after mixing With the Wash solution generated from the leaching step earlier and is used for further leaching.

US 6,733,564 B1
3
In still another embodiment of the present invention the

4
stirring, the samples are collected at different time intervals, ?ltered and analyZed for nickel. Extraction data at different time intervals are incorporated in Table 2. Recovery of nickel increases With leaching time and a maximum of 50.390% nickel recovery is achieved in 6 h.
TABLE 2

pulp density of leaching is in the rage of 10100%. The

higher pulp density leaching generates concentrated leach

solution requiring loW capital investment and energy.
DETAILED DESCRIPTION OF THE INVENTION

In the process of present invention the leach slurry is ?ltered and the residue is Washed With very dilute sulphuric acid solution. The Wash liquor containing 1030 g/L Ni is

Recovery of nickel at different time intervals.

10

recycled for the leaching of the fresh spent catalyst is in

oxide phase and dissolution in sulphuric acid occurs as:
15
Parameters 0.25 h

Percentage recovery
0.5 h
9.44

1 h

2 h

4h

6 h

T:90, Acid: 3%, ADS: Nil NC: 50 g, S/L: A (Wt/vol.)

15.42 23.30 41.70 50.39

The iron free leach liquor is evaporated crystalliZe nickel as nickel sulphate. The puri?ed leaching liquor can also be precipitated as nickel hydroxide and nickel metal from this can be obtained by knoWn method called hydrogen/ carbothermic reduction process. Alternatively nickel metal poWder can be produced by the knoWn process by aqueous

T(temp): C., and acid: vol. H2SO4, NC: nickel catalyst, ADS: additive

EXAMPLE 3
20

hydrogen reduction of puri?ed leach liquor.

Novelty of the present invention is the use of a catalytic additive Which has not been used earlier for direct leaching of nickel catalyst to recover nickel and alumina simulta

200 ml of Water containing 3 vol. % of concentrated

sulphuric acid in a conical ?ask is kept over a thermostati

cally controlled hot plate ?tted With a magnetic stirrer. After maintaining the temperature of the solution at 70 C., 50 g
25

neously. Another feature of the invention is complete nickel dissolution (99.9%) from the spent catalyst Without any prior treatment such as roasting, reduction/alkali/
chlorination roasting etc. Which are necessary steps in earlier

development. The complete dissolution of nickel in the leaching stage produces very bright coloured alumina as a valuable by-product, Which may ?nd applications as high alumina refractoriness and a support for catalyst.

30

of nickel catalyst of composition: 9.70% Ni, 0.31% Fe, 81.3% A1203, and 3.77% SiO2 and 0.5 g of persulphate salt are added. Temperature of the slurry is maintained through out the leaching experiment. Leaching is carried out by agitating the slurry. Samples collected at different time
intervals are ?ltered and leach liquor is analysed for nickel.
The recovery data at different time intervals are incorporated in Table 3. A Maximum of 97.50% of nickel recovery is

The folloWing examples are given by Way of illustration

and should not be construed to limit the scope of invention.
EXAMPLE-1
35

achieved in 6 h of leaching time as compared to only 11.95% nickel recovery in absence of additive.
TABLE 3
Effect of additive on the percentage nickel recovery at different time intervals.

A conical ?ask containing 200 ml 3 vol % sulphuric acid is kept over a thermostatically controlled hot plate ?tted With

stirring arrangement by a magnetic needle. The temperature

of the solution is maintained at 70 C. 50 g of nickel catalyst

40

Percentage recovery
Parameters 0.25 h
6.2

of composition: 9.70% Ni, 0.31% Fe, 81.3% A1203, and 3.77% SiO2 is added to the ?ask With stirring. Samples
collected at different time intervals are ?ltered and analyZed for nickel content. Recovery of nickel increases With leach ing time. Recovery data at different time intervals are

0.5 h
19.5

1 h
74.6

2 h
92.3

4h
95.3

6 h
97.5

T:70, Acid: 3%, ADS:

45 0.25% NC: 50 g, S/L: A

(Wt/vol.)

incorporated in Table 1. A maximum of 11.95% nickel recovery is achieved in 6 h.

TABLE 1
Percentage nickel recovery at different time intervals.

T(temp): C., and acid: vol. H2SO4, NC: nickel catalyst, ADS: additive

50

EXAMPLE 4

Percentage recovery
Parameters 0.25 h 0.5 h
3.83

A solution containing 200 ml of Water With 3 vol. % concentrated sulphuric acid in a conical ?ask is kept over a
4 h 6 h

1 h
4.91

2h
6.14

55

T:70, Acid: 3%, ADS: Nil NC: 50 g, S/L: A (Wt/vol.)

9.1 11.95

T(temp): C., and acid: vol. H2SO4, NC: nickel catalyst, ADS: additive

thermostatically controlled hot plate ?tted With a magnetic stirring system. The solution temperature is raised to 70 C. and 50 g of spent nickel catalyst of composition: 9.70% Ni, 0.31% Fe, 81.3% A1203, and 3.77% SiO2 and 1.0 g of
persulphate salt are added to the system. The above tem

EXAMPLE-2

60

perature is maintained While stirring through out the leach ing experiment. Very fast reaction occurs in presence of
additive. Samples collected at deferent time intervals are

A conical ?ask containing 200 ml of 3vol. % of concen trated sulphuric acid is kept over a thermostatically con

?ltered and the leach liquor analysed for nickel. Recovery

65

trolled hot plate ?tted With a magnetic stirrer. Temperature of the solution is raised to 90 C. and 50 g of nickel catalyst

of composition: 9.70% Ni, 0.31% Fe, 81.33% Al2O3 and 3.77% SiO2 is added. Once the leaching proceeded With

data at different time intervals are incorporated in Table4. About 98% of nickel recovery is achieved Within 2 h of leaching and a maximum of 99.6% nickel recovery is achieved in 6 hours of leaching.

US 6,733,564 B1
5
TABLE 4
Effect of higher dose of additive on % nickel recovery at different time intervals.
Percentage recoverv
Parameters 0.25 h 0.5 h 1 h 2h 4h 6 h

6
The Major Advantages of the Present Invention are: 1. Elimination of pre-treatment step Which is carried out at

higher temperature, prior to leaching as required in the developed process, results in cost and energy saving.
2. With no gas emission, the process is much eco-friendly. 3. The process requires only little excess to the stoichiomet ric amount of acid in presence of additive for complete dissolution of nickel. 4. Bright White coloured leach alumina residue obtained is
10

T270, Acid: 3%, ADS: 0.5% NC: 50 g, S/L: A (Wt/

9.1

54.24 85.42 98.15 98.80

99.6

a high value by-product.

5. The process operates at very loW temperature and loW acid concentration, and therefore special material of construc tion is not required. 6. The process requires less amount of alkali in the puri? cation step and generates less amount of residue, and therefore account for loW loss of metal values at this

vol.)
T(temp): C., and acid: vol. H2SO4, NC: nickel catalyst, ADS: additive

EXAMPLE 5

15

The temperature of a solution containing 200 ml of 3 vol. % of concentrated sulphuric acid in a conical ?ask is maintained at 90 C. by a thermostatically controlled hot

stage. 7. High pulp density leaching generates concentrated leach

20

plate ?tted With a magnet6ic stirring arrangement. 50 g of

nickel catalyst of composition: 9.70% Ni, Fe. 81.3% A1203,

and 3.77% SiO2 and 1 g of persulphate salt are added to the

solution and requires less heat energy for crystallisation and less capital cost.
8. The process is much less corrosive a compared to chlo

steps. time intervals are ?ltered and leach solution is analysed for nickel content. Nickel recovery at different time intervals 25 10. The process requires much less capital investment and can be operational in medium and small scale. summarised in Table 5. About 99% of nickel recovery is We claim: achieved Within 1 h of leaching.
1. A process for extraction of nickel from spent nickel
TABLE 5
Effect of higher temperature in presence of additive
on the nickel recoverv.

system. Temperature of the reaction is maintained through out the leaching experiment. Samples collected at different

rination roasting often followed.

9. The process is very simple and involves lesser number of

catalyst Which comprises

i) adding a persulphate-based additive along With ?ne
sized nickel catalyst in a sulphuric acid solution and

Percentage recoverv
Parameters
T:90, Acid: 3%, ADS:

0.1 h
83.4

0.25 h
93.3

0.5 h
96.7

1 h
99.6

2 h

4h

35

stirring by a magnetic needle/glass stirrer and main taining the solid liquid ratio in the range of 1/z1/i0 (Wt. in grams/vol. in mL) to obtain a slurry, ii) keeping the temperature of the slurry obtained in step
(i) in the range of 40 to 100 C. for a period of 0.5 to

0.5% NC: 50 g, S/L: A (Wt/

vol.)
T(temp): C., and acid: vol. H2SO4, NC: nickel catalyst, ADS: additive
40

6 h, iii) alloWing the slurry to settle and then ?ltering the slurry
to obtain (a) a leach liquor containing nickel and (b) an
alumina as a solid residue,

EXAMPLE 6

iv) Washing the solid residue to remove entrapped liquor

and drying at 110120 C. to get a by-product contain

2L of 6 vol. % sulphuric acid solution in a 3L beaker is kept over a hot plate and temperature is maintained at 80 C.

ing high alumina,

45

v) purifying the leach liquor by precipitating iron and

other impurities using lime and ?ltering to obtain a pure

It is kept under stirring With the help of a glass stirrer ?tted to a motor. 1 kg of spent catalyst of composition: 9.70% Ni, 0.31% Fe, 81.3% A1203, and 3.77% SiO2 and 15 g of
persulphate salt are added to the acid solution under stirring

nickel sulphate solution,

vi) crystalliZing or precipitating the leach liquors to obtain nickel sulphate crystal and nickel hydroxide, and vii) reducing nickel hydroxide to obtain nickel metal
poWder or nickel oxide. 2. A process as claimed in claim 1 Wherein the spent

While maintaining the pulp density of 59%. After 2 h of leaching the slurry is kept for settling, Within 2 h about 70%
of the slurry settles. The clear supernatant is taken out and the thick slurry is ?ltered. The leach liquor, Wash solution and residue analysis is given in Table 6. Residue basis nickel
recovery obtained is more than 99.9%. The dried residue

50

nickel catalyst used is selected from nickel catalyst having

particle siZe in the range of 38 pm211 pm and has a
55

containing 96.2% A1203, With 3.85% SiO2 and 0.0093% Ni is suitable for various applications.
TABLE 6
Results of leaching experiment on 1 Kg scale.

composition in range Ni:520%, Fe 0.11%, A1203: 7090%, and S02: 06%.

3. A process as claimed in claim 1 Wherein the

persulphate-based additive is selected from persulphate salts

of sodium, potassium and ammonium and has a salt to

catalyst concentration in the range of 0.254% (W/W).

60

No.
1
2
3

Component
Leach liquor
Wash solution
Leach residue (dry)

Quantity
1.65 l
0.61 l
0.855 kg

Analysis
Ni51.2 g/l
Ni19.75 g/l
Al2O3 96.1%; SiO2 3.85%
Ni - 0.0093%

4. Aprocess as claimed in claim 1 Wherein the sulphuric acid is of commercial grade and has concentration in the

range of 212% (v/v).

5. A process as claimed in claim 1 Wherein the concen
65

tration of the pulp in the slurry in step 10100%.

is in the range of