US20020006370A1 - Method for leaching nickeliferous laterite ores - Google Patents

Method for leaching nickeliferous laterite ores Download PDF

Info

Publication number
US20020006370A1
US20020006370A1 US09/433,110 US43311099A US2002006370A1 US 20020006370 A1 US20020006370 A1 US 20020006370A1 US 43311099 A US43311099 A US 43311099A US 2002006370 A1 US2002006370 A1 US 2002006370A1
Authority
US
United States
Prior art keywords
ore
leach
leaching
nickel
saprolite
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
US09/433,110
Other versions
US6379636B2 (en
Inventor
J. Carlos Arroyo
James D. Gillaspie
David A. Neudorf
Erik M. Weenink
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BHP Minerals International LLC
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=23718891&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=US20020006370(A1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Individual filed Critical Individual
Priority to US09/433,110 priority Critical patent/US6379636B2/en
Assigned to BHP MINERALS INTERNATIONAL, INC. reassignment BHP MINERALS INTERNATIONAL, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ARROYO, J. CARLOS, GILLASPIE, JAMES D., NEUDORF, DAVID A., WEENINK, ERIK M.
Priority to AU24697/01A priority patent/AU779844B2/en
Priority to KR1020027005702A priority patent/KR100727720B1/en
Priority to PCT/US2000/041511 priority patent/WO2001032944A1/en
Priority to AT00988492T priority patent/ATE256203T1/en
Priority to DE60007175T priority patent/DE60007175T2/en
Priority to JP2001535622A priority patent/JP4895454B2/en
Priority to BR0015305-2A priority patent/BR0015305A/en
Priority to ES00988492T priority patent/ES2213066T3/en
Priority to CA002389653A priority patent/CA2389653A1/en
Priority to EP00988492A priority patent/EP1232290B1/en
Priority to CO00083211A priority patent/CO5190741A1/en
Priority to GT200000192A priority patent/GT200000192A/en
Priority to DO2000000087A priority patent/DOP2000000087A/en
Publication of US20020006370A1 publication Critical patent/US20020006370A1/en
Priority to ZA200203242A priority patent/ZA200203242B/en
Publication of US6379636B2 publication Critical patent/US6379636B2/en
Application granted granted Critical
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B23/00—Obtaining nickel or cobalt
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B23/00—Obtaining nickel or cobalt
    • C22B23/04—Obtaining nickel or cobalt by wet processes
    • C22B23/0407—Leaching processes
    • C22B23/0415—Leaching processes with acids or salt solutions except ammonium salts solutions
    • C22B23/043—Sulfurated acids or salts thereof
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B23/00—Obtaining nickel or cobalt
    • C22B23/04—Obtaining nickel or cobalt by wet processes
    • C22B23/0453—Treatment or purification of solutions, e.g. obtained by leaching
    • C22B23/0461—Treatment or purification of solutions, e.g. obtained by leaching by chemical methods
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • the present invention relates to the hydrometallurgical processing of nickeliferous ores and, in particular, to an improved method for leaching nickel values from the high-magnesium or saprolite fraction of such ores in combination with high pressure and temperature leaching of the limonite fraction of the ore.
  • the efficient recovery of nickel and cobalt in substantially pure form from the high pressure leach liquor often requires the prior removal of impurities such as ferric iron, aluminum, and chromium, which dissolve to a greater or lesser extent during pressure leaching. These impurities may interfere in downstream nickel and cobalt recovery processes if not removed from the solution.
  • the removal can be effected by raising the pH of the leach liquor to effect the hydrolysis and precipitation of these impurities as hydroxide or hydroxysulfate compounds.
  • this hydrolysis often produces voluminous precipitates that are difficult to separate from the pregnant liquor by conventional settling and filtration techniques.
  • a further disadvantage is the co-precipitation and subsequent loss of significant quantities of the nickel and cobalt values during this hydrolysis step.
  • Taylor et al. (U.S. Pat. No. 3,720,749) teach the precipitation and removal of iron and aluminum by the addition of a soluble neutralizing agent, e.g. magnesia, to the leach liquor at a temperature in excess of 130° C. thereby precipitating the iron and aluminum in an easy to separate form.
  • a soluble neutralizing agent e.g. magnesia
  • the preferred temperature for the neutralization step ranges from 140° to 200° C. and requires the use of autoclaves to maintain the elevated temperature and pressure.
  • the patent also describes a method where high magnesium ore is contacted at atmospheric pressure and temperatures less than the boiling point, with the leach solution from the pressure leach step, before the low-pressure leach step. Nickel extraction is very low in the atmospheric leach step (only 33-44%) and the low-pressure leach is still required to achieve adequate nickel extraction and to precipitate iron and aluminum in an easy to settle and filter form.
  • U.S. Pat. No. 4,097,575 teaches the use of high magnesium ore that has been previously roasted to neutralize acid present in a leach slurry resulting from the high-pressure acid leach of a low magnesium ore.
  • the high magnesium ore is thermally treated at 500°-750° C. under oxidizing conditions prior to the neutralization step to increase the neutralization capacity of the ore.
  • the pH of the final liquor is taken above 2, but the neutralization residue containing unleached high magnesium ore is recycled to the autoclave to obtain higher nickel recovery.
  • rejected iron and aluminum are in the form of hydroxides, which are difficult to deal with. This process suffers from the high capital cost needed for roasting facilities and disadvantages associated with injection of high magnesium ore atmospheric leach slurry into the high pressure autoclave.
  • U.S. Pat. No. 4,410,498 teaches a method to leach high magnesium laterite ore with sulfuric acid at a controlled pH of 1.5 to 3.0 while adding a reducing agent to maintain the redox potential between 200 and 400 mV (vs. saturated calomel reference electrode).
  • the addition of a reducing agent increases the reactivity of the serpentine in the ore and results in maximum extraction of nickel consistent with minimum extraction of iron and magnesia and minimum acid consumption.
  • the process has the disadvantages of the additional cost of the reducing agent, the need for electrochemical potential control, and the need for equipment to control the leaching atmosphere and prevent external discharges in the case of toxic, gaseous reductants such as sulfur dioxide.
  • the above methods are aimed at utilizing both the high and low magnesium fractions of the nickeliferous laterite ore in order to fully utilize the ore body, maximize the nickel and cobalt extraction and minimize the iron and/or aluminum content of the final leach liquor. All of these methods require the use of one of the following to leach the high magnesium ore effectively: a) elevated temperature and pressure; b) pretreatment by calcination or roasting, or; c) addition of a reducing agent with controlled pH.
  • pH adjustment of the leach slurry causes the precipitation of metal hydroxides, including the hydroxides of ferric iron, chromium and aluminum, which are separated from the leach solution in the subsequent liquid/solid separation.
  • metal hydroxides including the hydroxides of ferric iron, chromium and aluminum
  • nickel and cobalt co-precipitate with the metal hydroxides and reduce the metals recovery.
  • Another important consideration is the efficiency of the liquid/solid separation process.
  • hydroxides produced at atmospheric pressure are colloidal and difficult to filter or settle, thus requiring very large equipment for effective separation.
  • alkali metal or ammonium jarosite is crystalline, which makes it easier to filter and settle.
  • ferric iron In the presence of an alkali metal or ammonium ion and in a certain range of pH, ferric iron will form jarosite, a basic sulfate compound of the formula M[Fe 3 (SO 4 ) 2 (OH) 6 ] where M is sodium, lithium, potassium or ammonium.
  • the loss of nickel and cobalt by precipitation as metal hydroxides is minimized, resulting in maximum metals recovery, while an easier to settle iron compound is formed.
  • the present invention provides a process for the efficient leaching of both the low magnesium and high magnesium fractions of nickel laterite ore.
  • the low magnesium fraction of the ore is leached at high temperature and pressure, as in other processes previously described. No special reductants, pretreatment steps or high pressure steps are required to leach the high magnesium fraction of the ore, representing substantial simplification over the prior art.
  • the current invention also provides for the removal of iron by the formation of alkali metal jarosite, e.g. sodium jarosite, to produce a low iron solution suitable for nickel and cobalt recovery.
  • FIG. 1 is a flow sheet of one embodiment of the process of the present invention.
  • FIG. 2 shows another embodiment of the process of the present invention.
  • FIG. 3 is a graph showing the rate of nickel extraction from high magnesium containing ore, or saprolite, as a function of sulfuric acid concentration.
  • FIG. 4 is a graph showing the rate of nickel extraction as a function of time during atmospheric leaching of saprolite ore with sulfuric acid at 90° C.
  • the present invention provides a novel method for combining the leaching of the high magnesium fraction of nickeliferous laterite ore with the high pressure leaching of the low magnesium fraction of the ore, while maximizing the extraction of nickel and cobalt.
  • laterite ore is separated into two fractions 10 .
  • This separation can be based on selective mining or on size classification by, for example, screening.
  • One fraction is finer than the other and has a lower magnesium content.
  • This low magnesium laterite, or so-called limonite is mixed with water to provide an aqueous pulp.
  • This pulp is leached with sulfuric acid at elevated temperature (at least about 200° C.) and pressure.
  • sulfuric acid at elevated temperature (at least about 200° C.) and pressure.
  • most metals in the ore are completely or partially solubilized.
  • the pressure leach slurry Upon completion of the leaching reaction, typically within 30 to 45 minutes, the pressure leach slurry is discharged to atmospheric pressure and cooled to a temperature at or near the normal boiling point of the leach solution. Steam is “flashed” off during this step.
  • the leach slurry, or leach liquor after solid/liquid separation to remove the pressure leaching residue is now contacted 30 at atmospheric pressure with the other laterite fraction.
  • the high magnesium laterite or saprolite is used to neutralize the free acid in the leach liquor at a temperature of 80° to 98° C., preferably above 90° C. This temperature is conveniently the temperature of the low magnesium ore leach slurry after flashing to atmospheric pressure.
  • the free sulfuric acid concentration in the pressure leach solution is typically 20 to 100 g/L H 2 SO 4 .
  • the quantity of high magnesium ore or saprolite added is calculated based on the pre-determined acid consumption properties of the saprolite and the quantity of free acid in the pressure leach solution. It is not necessary to control the pH of the leach slurry, unlike the teaching of U.S. Pat. No. 4,410,498. In fact, the relatively low pH, typically ⁇ 1.0, or high acidity of the pressure leach solution is advantageous in that the rate of saprolite leaching is higher at lower pH. Surprisingly, it is also unnecessary to add a reducing agent to control the oxidation/reduction potential (see FIG. 3 in U.S. Pat. No. 4,410,498) of the slurry in order to effect rapid leaching of the saprolite at the higher acid concentration prevailing in the pressure leach slurry or solution.
  • a high nickel extraction from the high magnesium ore is possible in this process, without the need of ore pretreatment or the use of any other reagents to increase the reactivity of the ore.
  • the high magnesium fraction of the laterite ore is first leached 60 with additional sulfuric acid.
  • the quantity of acid to be added is calculated from the pre-determined acid consumption properties of the saprolite ore, the quantity of free acid in the pressure leach solution and the desired limonite to saprolite processing ratio. In this process, nickel and other metals will be solubilized.
  • This embodiment of the invention allows the ratio of limonite to saprolite ore to be varied while maintaining high overall nickel and cobalt extractions and minimal iron extraction.
  • the terminal acidity of the slurry after neutralization with saprolite is advantageously 5-10 g/L free sulfuric acid. If the free acid to saprolite ratio in the overall feed to the saprolite neutralization step is too low, the leach extraction will be lowered. On the other hand, if the free acid to saprolite ratio is too high, there will be excess acid in the final neutralization slurry that requires neutralization prior to iron precipitation.
  • the saprolite neutralization step is carried out continuously in a series of agitated tanks.
  • the number and size of the tanks is chosen to maximize the rate of leaching and minimize the overall retention time required to achieve the desired nickel extraction from the saprolite.
  • Multiple tanks are used in order to carry out the leaching process at the highest average acidity possible. This increases the rate of reaction because the leaching rate increases as the sulfuric acid concentration increases.
  • a precipitating agent selected from the group consisting of alkali metal ions, ammonium ions or mixtures thereof can be added to the process.
  • the precipitating agent is a source of sodium ions.
  • One method is to recycle sodium sulfate solution from the downstream recovery process. This is the filtration product in the formation of a metal carbonate precipitate.
  • the formation of iron jarosite is advantageously carried out at temperatures of about 90° C. to 100° C. under atmospheric pressure for at least two hours and at a pH of 1.6 to 2.0 (preferably at 1.8).
  • the acid that is produced from the iron hydrolysis can be neutralized with any neutralizing agent to maintain the desired pH.
  • Examples of the neutralizing agent include but are not limited to limestone, lime or magnesia.
  • more high magnesium laterite can be added to neutralize the acid that is produced by the formation of jarosite. Jarosite precipitation occurs at much lower pH values than iron hydroxide precipitation and virtually eliminates the problem of co-precipitation of nickel and cobalt and their subsequent loss.
  • the leach slurry proceeds to the liquid/solid separation process 50.
  • This is preferably a counter current decantation circuit, which produces a solids residue virtually void of nickel and cobalt, and a clear leach liquor to proceed to the metals recovery.
  • This example illustrates the atmospheric leaching of saprolite ore with sulfuric acid solutions at constant acid concentration and at temperatures between 80° and 90° C.
  • Saprolite ore was pulped at 15% solids in deionized water and agitated in a well-sealed kettle with sulfuric acid at either 80° or 90° C. The concentration of sulfuric acid was kept constant during the tests. Samples of liquid were taken at different times during the test for analysis. The solids at the end of the tests were filtered, washed, dried and split for chemical analysis. Table 1 shows the final leaching results for each test. TABLE 1 Results of saprolite atmospheric leach tests conducted at constant sulfuric acid concentration Acid (Acid consumption) conc. Temp.
  • This example illustrates the atmospheric leaching of saprolite ore with a fixed amount sulfuric acid solution at 90° C.
  • Saprolite ore was pulped at 15% solids in deionized water and agitated in a well-sealed kettle with sulfuric acid at 90° C. for 3 hours.
  • the initial sulfuric concentration varied from 106 to 114 g/L in the 4 tests described. Samples of liquid taken at different times during the test for analysis. The solids at the end of the tests filtered, washed, dried and split for chemical analysis.
  • Table 2 shows the final leaching results for each test and FIG. 4 shows the kinetics of nickel dissolution from saprolite ore.
  • This example illustrates the atmospheric leaching of saprolite ore with the product leach slurry from pressure leaching of low magnesium, or limonite, ore.
  • Limonite ore was first leached in a titanium autoclave for 30 minutes at an acid to ore ratio of 0.38, 270° C. and 40 wt % solids. After leaching and pressure letdown, saprolite ore was added as a 50 wt % slurry to neutralize the remaining free acid in the autoclave discharge that results from the bisulfate shift at low temperatures.
  • the saprolite to limonite ratio when leaching saprolite in this manner, was about 0.17 (tests 1 and 2).
  • This example shows a method of iron control by precipitation of jarosite after leaching of limonite ore at high pressure and temperature and neutralization of the remaining acid with saprolite ore at 90° C.
  • Limonite ore was first leached in a titanium autoclave for 30 minutes at an acid to ore ratio of 0.38, 270° C. and 40 wt % solids. After leaching and pressure letdown, saprolite ore was added as a 50 wt % slurry to neutralize the remaining free acid in the autoclave discharge slurry (ACD) at atmospheric pressure and 90° C.
  • ACD autoclave discharge slurry
  • Concentrated sulfuric acid was also added to the ACD to be able to leach more saprolite ore and increase the saprolite to limonite ratio to 0.4.
  • Sodium sulfate was added to the saprolite slurry before addition to the ACD to provide a source of alkali ions for jarosite formation.
  • the final step, after saprolite leaching, consisted of precipitating the iron in solution as natro-jarosite. This was achieved by maintaining the free acid concentration at around 5 g/l H 2 SO 4 (pH ⁇ 1.5) and the temperature at about 95° C. for an additional 3 hours.
  • the free acid concentration was kept at the mentioned level by periodic additions of CaCO 3 slurry after 200 minutes of leaching.
  • This example illustrates the continuous processing of limonite ore under high-pressure acid leach (HPAL) conditions followed by the processing of saprolite ore under atmospheric leach (AL) conditions.
  • HPAL high-pressure acid leach
  • AL atmospheric leach
  • a limonite ore slurry at 38.5 wt. % solids was leached at high pressure and temperature (270° C. and 820 psi) at an acid to ore ratio of 0.4 tonnes acid/tonne ore in a continuous autoclave.
  • Limonite was processed at a rate of 0.8 dry tonnes/day yielding an autoclave retention time of 30 minutes.
  • the discharge from the autoclave consisted of HPAL residue and leach solution containing metals and free sulfuric acid (92 g/L).
  • the compositions of the ore fed to the autoclave and the discharge residue, as well as the calculated metal extractions, are shown in Table 7. TABLE 7 High pressure acid leaching (HPAL) results.
  • the autoclave discharge slurry was mixed with saprolite ore (at 46 wt. % solids) in the proportion of 0.3 tonnes saprolite/tonne limonite.
  • Sodium was added as sodium sulfate to the water used to prepare the saprolite ore slurry.
  • Sulfuric acid was added to the mixture in the proportion of 0.46 tonnes concentrated acid/tonne saprolite.
  • the concentrated acid combined with the residual acid from the HPAL yielded an acid to saprolite ratio of 0.96 tonnes acid/tonne saprolite.
  • the overall concentrated acid to ore ratio was 0.41 tonnes acid/tonne ore (limonite plus saprolite).
  • the atmospheric leach circuit consisted of 3 tanks in series with an overall retention time of 4.2 hours (1.4 hours/tank). This circuit was followed by a jarosite precipitation circuit (JP) consisting of 2 tanks in series with an overall retention time of 5.9 hours (first tank 1.4 hours, second tank 4.5 hours). Limestone slurry was added to the jarosite precipitation tanks to control the slurry pH.
  • This example illustrates the continuous processing of limonite ore under high pressure acid leach (HPAL) conditions followed by the processing of saprolite ore under atmospheric leach (AL) conditions.
  • HPAL high pressure acid leach
  • AL atmospheric leach
  • a limonite ore slurry at 35 wt. % solids was leached at high pressure and temperature (270° C. and 820 psi) at an acid to ore ratio of 0.34 tonnes acid/tonne limonite in a continuous autoclave.
  • Limonite was processed at a rate of 0.8 dry tonnes/day yielding an autoclave retention time of 30 minutes.
  • the discharge from the autoclave consisted of HPAL residue and leach solution containing metals and free acid (102 g/L).
  • the autoclave discharge slurry was mixed with saprolite ore (at 51 wt. % solids) in the proportion of 0.38 tonnes saprolite/tonne limonite.
  • Sodium was added as sodium sulfate to the water used to prepare the saprolite ore slurry.
  • Sulfuric acid was added to the mixture in the proportion of 0.23 tonnes concentrated acid/tonne saprolite.
  • the concentrated acid combined with the residual acid from the HPAL yielded an acid to saprolite ratio of 0.59 tonnes acid/tonne saprolite.
  • the overall concentrated acid to ore ratio was 0.31 tonnes acid/tonne ore (limonite plus saprolite).
  • the atmospheric leach circuit consisted of 4 tanks. Half the saprolite was added to the first tank (1 hour retention) along with the concentrated sulfuric acid, while the other half was added to the second tank (1.4 hour retention) along with the autoclave discharge slurry. The first tank overflowed into the second tank, which then overflowed into 2 tanks in series (1.4 hour retention each).
  • This circuit was followed by a jarosite precipitation circuit (JP) consisting of 2 tanks in series with an overall retention time of 5.9 hours (first tank 1.4 hours, second tank 4.5 hours). Limestone slurry was added to the jarosite precipitation tanks to control the slurry pH.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Compounds Of Iron (AREA)
  • Extraction Or Liquid Replacement (AREA)

Abstract

A process is provided for the leaching of both the “limonite” (Fe approx. ≧25% and Mg approx. ≦6%) and “saprolite” (Fe approx. <20% and Mg approx. ≧10%) fractions of typical nickel and cobalt bearing laterite ore. The low magnesium fraction of the laterite ore is leached with sulfuric acid at high pressure and temperature to solubilize the metal values while precipitating most of the solubilized iron as hematite or other iron compounds and a portion of the dissolved aluminum as alunite or other aluminum compounds. After reducing the pressure of the leach slurry to approximately atmospheric pressure, the pregnant leach slurry or solution is contacted with the high magnesium fraction of the ore to solubilize most of the nickel contained in the high-magnesium ore fraction while dissolving only a small portion of the iron content of the high magnesium ore fraction. Further neutralization of the leach slurry in the presence of an alkali metal or ammonium ion will allow the precipitation of iron-bearing jarosite at ambient pressure. This process for incorporating the leaching of saprolite in the high pressure leaching process for limonite ores requires neither high temperature and pressure, nor special treatment of the saprolite ore fraction, nor the addition of special reagents, e.g. reducing reagents.

Description

    FIELD OF THE INVENTION
  • The present invention relates to the hydrometallurgical processing of nickeliferous ores and, in particular, to an improved method for leaching nickel values from the high-magnesium or saprolite fraction of such ores in combination with high pressure and temperature leaching of the limonite fraction of the ore. [0001]
    • BACKGROUND OF THE INVENTION
  • The high pressure and temperature leaching of the limonite portion of nickeliferous laterite ores with sulfuric acid is well known, having been practiced commercially at Moa Bay in Cuba since 1959 (Boldt and Queneau, “The Winning of Nickel,” Longmans Canada Ltd., Toronto, pp. 437-449). The quantity of sulfuric acid required to leach the major portion (approx. ≧90%) of the contained nickel and cobalt and variable portions of several impurity elements in the ore, e.g. magnesium, manganese, iron, aluminum, chromium, is in excess of that required to form the corresponding water-soluble metal sulfate compounds. This is because sulfuric acid only dissociates to the single proton (H[0002] +) and the bisulfate (HSO4 −) ion at the high temperature used in this leaching step, typically ≧200° C. The bisulfate ion dissociates on cooling of the leach slurry to sulfate (SO4 2) ion, releasing an additional proton. Thus, the cooled leach slurry inevitably contains excess sulfuric acid in addition to the dissolved metal values and impurity elements. This excess acid must be neutralized before recovery of the dissolved nickel and cobalt values, as would be apparent to anyone skilled in the art. The cost of the excess sulfuric acid that must be added to the leaching step and the cost of neutralizing agents required to neutralize excess sulfuric acid in the final leach liquor are significant disadvantages of this process.
  • Furthermore, the efficient recovery of nickel and cobalt in substantially pure form from the high pressure leach liquor often requires the prior removal of impurities such as ferric iron, aluminum, and chromium, which dissolve to a greater or lesser extent during pressure leaching. These impurities may interfere in downstream nickel and cobalt recovery processes if not removed from the solution. The removal can be effected by raising the pH of the leach liquor to effect the hydrolysis and precipitation of these impurities as hydroxide or hydroxysulfate compounds. Unfortunately, when carried out at atmospheric pressure and temperatures below the solution boiling point, this hydrolysis often produces voluminous precipitates that are difficult to separate from the pregnant liquor by conventional settling and filtration techniques. A further disadvantage is the co-precipitation and subsequent loss of significant quantities of the nickel and cobalt values during this hydrolysis step. [0003]
  • A variety of methods have been developed to deal with the above-mentioned disadvantages and problems of the high pressure leaching process. [0004]
  • Taylor et al. (U.S. Pat. No. 3,720,749) teach the precipitation and removal of iron and aluminum by the addition of a soluble neutralizing agent, e.g. magnesia, to the leach liquor at a temperature in excess of 130° C. thereby precipitating the iron and aluminum in an easy to separate form. [0005]
  • An improvement of the neutralization process was patented by Lowenhaupt et al. (U.S. Pat. No. 4,548,794). This patent teaches the recovery of nickel and cobalt from laterite ore by using a low-pressure leach of high magnesium ore, after high pressure leaching of low magnesium ore, to precipitate aluminum and iron. A size separation of the laterite ore feed is made to produce low and high magnesium ore fractions for the process. The finer, low magnesium fraction is leached at high temperature and pressure and, after separating the pressure leach liquor form the leach residue, contacting the liquor with the coarser, high magnesium fraction of the ore at greater than atmospheric pressure and high temperature such that iron and aluminum precipitate in crystalline forms, e.g. hematite, alunite. This aids the subsequent settling and filtration of the precipitated iron and aluminum, while also dissolving additional nickel units from the high magnesium fraction of the ore. The preferred temperature for the neutralization step ranges from 140° to 200° C. and requires the use of autoclaves to maintain the elevated temperature and pressure. The patent also describes a method where high magnesium ore is contacted at atmospheric pressure and temperatures less than the boiling point, with the leach solution from the pressure leach step, before the low-pressure leach step. Nickel extraction is very low in the atmospheric leach step (only 33-44%) and the low-pressure leach is still required to achieve adequate nickel extraction and to precipitate iron and aluminum in an easy to settle and filter form. [0006]
  • Other methods for using the high magnesium fraction of the ore to neutralize the high-pressure leach liquor have been patented. U.S. Pat. No. 3,991,159 teaches the use of high magnesium ore to neutralize acid resulting from the high-pressure acid leach of a low magnesium ore. This is accomplished by coordinating the leaching of the low magnesium fraction with the leaching of the high magnesium fraction at high temperature and pressure. In this method, leaching of the high magnesium fraction is carried out at high temperature (150°-250° C.) and pressure for effective iron and aluminum rejection, but with relatively low nickel extraction from the high magnesium ore. Again, this process has the disadvantage of requiring relatively high temperature and pressure for the neutralization step. [0007]
  • In U.S. Pat. No. 3,804,613, a method to conduct high-pressure acid leaching of high magnesium ore at relatively low acid/ore ratios is disclosed. This is accomplished by preconditioning the high magnesium ore with leach liquor from the high-pressure leach step, before a high-pressure leach of the conditioned high magnesium ore. The high magnesium ore must still be submitted to a high pressure leaching step following the atmospheric pressure conditioning step. [0008]
  • U.S. Pat. No. 4,097,575 teaches the use of high magnesium ore that has been previously roasted to neutralize acid present in a leach slurry resulting from the high-pressure acid leach of a low magnesium ore. The high magnesium ore is thermally treated at 500°-750° C. under oxidizing conditions prior to the neutralization step to increase the neutralization capacity of the ore. The pH of the final liquor is taken above 2, but the neutralization residue containing unleached high magnesium ore is recycled to the autoclave to obtain higher nickel recovery. Furthermore, rejected iron and aluminum are in the form of hydroxides, which are difficult to deal with. This process suffers from the high capital cost needed for roasting facilities and disadvantages associated with injection of high magnesium ore atmospheric leach slurry into the high pressure autoclave. [0009]
  • U.S. Pat. No. 4,410,498 teaches a method to leach high magnesium laterite ore with sulfuric acid at a controlled pH of 1.5 to 3.0 while adding a reducing agent to maintain the redox potential between 200 and 400 mV (vs. saturated calomel reference electrode). The addition of a reducing agent increases the reactivity of the serpentine in the ore and results in maximum extraction of nickel consistent with minimum extraction of iron and magnesia and minimum acid consumption. The process has the disadvantages of the additional cost of the reducing agent, the need for electrochemical potential control, and the need for equipment to control the leaching atmosphere and prevent external discharges in the case of toxic, gaseous reductants such as sulfur dioxide. [0010]
  • The above methods are aimed at utilizing both the high and low magnesium fractions of the nickeliferous laterite ore in order to fully utilize the ore body, maximize the nickel and cobalt extraction and minimize the iron and/or aluminum content of the final leach liquor. All of these methods require the use of one of the following to leach the high magnesium ore effectively: a) elevated temperature and pressure; b) pretreatment by calcination or roasting, or; c) addition of a reducing agent with controlled pH. [0011]
  • It is an object of the current invention to combine the leaching of the high magnesium fraction of the ore with the high pressure leaching of the low magnesium portion of the ore, without the use of elevated temperature and pressure, calcination pretreatment, or addition of reducing agents, and still achieve high nickel and cobalt recoveries, relatively short leaching time, low iron extraction to solution and good solid/liquid separation properties. [0012]
  • In most practices, pH adjustment of the leach slurry causes the precipitation of metal hydroxides, including the hydroxides of ferric iron, chromium and aluminum, which are separated from the leach solution in the subsequent liquid/solid separation. During this process, nickel and cobalt co-precipitate with the metal hydroxides and reduce the metals recovery. Another important consideration is the efficiency of the liquid/solid separation process. In general, hydroxides produced at atmospheric pressure are colloidal and difficult to filter or settle, thus requiring very large equipment for effective separation. On the other hand, alkali metal or ammonium jarosite is crystalline, which makes it easier to filter and settle. In the presence of an alkali metal or ammonium ion and in a certain range of pH, ferric iron will form jarosite, a basic sulfate compound of the formula M[Fe[0013] 3(SO4)2(OH)6] where M is sodium, lithium, potassium or ammonium.
  • It is a further object of this invention to provide a solution that is very low in iron by the formation of jarosite at atmospheric pressure in the presence of alkali metal or ammonium ions. The loss of nickel and cobalt by precipitation as metal hydroxides is minimized, resulting in maximum metals recovery, while an easier to settle iron compound is formed. [0014]
    • SUMMARY OF THE INVENTION
  • The present invention provides a process for the efficient leaching of both the low magnesium and high magnesium fractions of nickel laterite ore. The low magnesium fraction of the ore is leached at high temperature and pressure, as in other processes previously described. No special reductants, pretreatment steps or high pressure steps are required to leach the high magnesium fraction of the ore, representing substantial simplification over the prior art. The current invention also provides for the removal of iron by the formation of alkali metal jarosite, e.g. sodium jarosite, to produce a low iron solution suitable for nickel and cobalt recovery.[0015]
    • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 is a flow sheet of one embodiment of the process of the present invention. [0016]
  • FIG. 2 shows another embodiment of the process of the present invention. [0017]
  • FIG. 3 is a graph showing the rate of nickel extraction from high magnesium containing ore, or saprolite, as a function of sulfuric acid concentration. [0018]
  • FIG. 4 is a graph showing the rate of nickel extraction as a function of time during atmospheric leaching of saprolite ore with sulfuric acid at 90° C.[0019]
    • DETAILED DESCRIPTION OF THE INVENTION
  • The present invention provides a novel method for combining the leaching of the high magnesium fraction of nickeliferous laterite ore with the high pressure leaching of the low magnesium fraction of the ore, while maximizing the extraction of nickel and cobalt. [0020]
  • Referring to FIG. 1, laterite ore is separated into two [0021] fractions 10. This separation can be based on selective mining or on size classification by, for example, screening. One fraction is finer than the other and has a lower magnesium content. This low magnesium laterite, or so-called limonite, is mixed with water to provide an aqueous pulp. This pulp is leached with sulfuric acid at elevated temperature (at least about 200° C.) and pressure. During this leaching process 20, most metals in the ore are completely or partially solubilized.
  • Upon completion of the leaching reaction, typically within 30 to 45 minutes, the pressure leach slurry is discharged to atmospheric pressure and cooled to a temperature at or near the normal boiling point of the leach solution. Steam is “flashed” off during this step. The leach slurry, or leach liquor after solid/liquid separation to remove the pressure leaching residue, is now contacted [0022] 30 at atmospheric pressure with the other laterite fraction. The high magnesium laterite or saprolite is used to neutralize the free acid in the leach liquor at a temperature of 80° to 98° C., preferably above 90° C. This temperature is conveniently the temperature of the low magnesium ore leach slurry after flashing to atmospheric pressure. The free sulfuric acid concentration in the pressure leach solution is typically 20 to 100 g/L H2SO4. The quantity of high magnesium ore or saprolite added is calculated based on the pre-determined acid consumption properties of the saprolite and the quantity of free acid in the pressure leach solution. It is not necessary to control the pH of the leach slurry, unlike the teaching of U.S. Pat. No. 4,410,498. In fact, the relatively low pH, typically <1.0, or high acidity of the pressure leach solution is advantageous in that the rate of saprolite leaching is higher at lower pH. Surprisingly, it is also unnecessary to add a reducing agent to control the oxidation/reduction potential (see FIG. 3 in U.S. Pat. No. 4,410,498) of the slurry in order to effect rapid leaching of the saprolite at the higher acid concentration prevailing in the pressure leach slurry or solution.
  • A high nickel extraction from the high magnesium ore is possible in this process, without the need of ore pretreatment or the use of any other reagents to increase the reactivity of the ore. [0023]
  • Referring to FIG. 2, in another embodiment of this invention, the high magnesium fraction of the laterite ore is first leached [0024] 60 with additional sulfuric acid. The quantity of acid to be added is calculated from the pre-determined acid consumption properties of the saprolite ore, the quantity of free acid in the pressure leach solution and the desired limonite to saprolite processing ratio. In this process, nickel and other metals will be solubilized. This embodiment of the invention allows the ratio of limonite to saprolite ore to be varied while maintaining high overall nickel and cobalt extractions and minimal iron extraction. Addition of the additional sulfuric acid directly to the hot, pressure leach slurry prior to the addition of saprolite causes redissolution of iron compounds that were precipitated during the pressure leaching step. The iron redissolution is largely avoided by mixing the additional acid with all or a portion of the saprolite ore prior to mixing with the pressure leach slurry.
  • The terminal acidity of the slurry after neutralization with saprolite is advantageously 5-10 g/L free sulfuric acid. If the free acid to saprolite ratio in the overall feed to the saprolite neutralization step is too low, the leach extraction will be lowered. On the other hand, if the free acid to saprolite ratio is too high, there will be excess acid in the final neutralization slurry that requires neutralization prior to iron precipitation. [0025]
  • In another embodiment of the process, the saprolite neutralization step is carried out continuously in a series of agitated tanks. The number and size of the tanks is chosen to maximize the rate of leaching and minimize the overall retention time required to achieve the desired nickel extraction from the saprolite. Multiple tanks are used in order to carry out the leaching process at the highest average acidity possible. This increases the rate of reaction because the leaching rate increases as the sulfuric acid concentration increases. [0026]
  • During any step prior to the [0027] jarosite formation 40, a precipitating agent selected from the group consisting of alkali metal ions, ammonium ions or mixtures thereof can be added to the process. Preferably, the precipitating agent is a source of sodium ions. One method is to recycle sodium sulfate solution from the downstream recovery process. This is the filtration product in the formation of a metal carbonate precipitate. The formation of iron jarosite is advantageously carried out at temperatures of about 90° C. to 100° C. under atmospheric pressure for at least two hours and at a pH of 1.6 to 2.0 (preferably at 1.8). The acid that is produced from the iron hydrolysis can be neutralized with any neutralizing agent to maintain the desired pH. Examples of the neutralizing agent include but are not limited to limestone, lime or magnesia. Alternatively, more high magnesium laterite can be added to neutralize the acid that is produced by the formation of jarosite. Jarosite precipitation occurs at much lower pH values than iron hydroxide precipitation and virtually eliminates the problem of co-precipitation of nickel and cobalt and their subsequent loss.
  • After the formation of jarosite, the leach slurry proceeds to the liquid/[0028] solid separation process 50. This is preferably a counter current decantation circuit, which produces a solids residue virtually void of nickel and cobalt, and a clear leach liquor to proceed to the metals recovery.
  • The following examples illustrate, but do not limit, the present invention. Unless otherwise indicated, all parts and percentages are by weight. [0029]
    • EXAMPLE 1
  • This example illustrates the atmospheric leaching of saprolite ore with sulfuric acid solutions at constant acid concentration and at temperatures between 80° and 90° C. Saprolite ore was pulped at 15% solids in deionized water and agitated in a well-sealed kettle with sulfuric acid at either 80° or 90° C. The concentration of sulfuric acid was kept constant during the tests. Samples of liquid were taken at different times during the test for analysis. The solids at the end of the tests were filtered, washed, dried and split for chemical analysis. Table 1 shows the final leaching results for each test. [0030]
    TABLE 1
    Results of saprolite atmospheric leach tests
    conducted at constant sulfuric acid concentration
    Acid (Acid consumption)
    conc. Temp. Sample Wt Composition Extraction (%) Kg/tonne Kg/Kg
    (g/L) (° C.) ID (g) Ni Fe Mg Ni Fe Mg ore Ni
    100  80 Ore 50 1.92 8.01 14.10 94 84.2 79.7 599 32.26
    Residue 30.2 0.192 2.1 4.75
    50 80 Ore 50 1.87 7.14 13.59 89.7 66.2 77.7 — —
    Residue 31.1 0.309 3.89 4.87
    25 80 Ore 50 1.87 7.35 13.91 77.6 38.7 66.4 529.6 34.89
    Residue 34.6 0.606 6.51 6.77
    10 90 Ore 233.5 1.91 7.31 16.07 70.1 31.6 71.8 625.0 45.50
    Residue 192.6 0.693 6.06 5.49
  • These results show that saprolite ore is effectively leached with sulfuric acid at temperatures close to the boiling point at atmospheric pressure without the need of any ore pre-treatment or additional reagents during leaching. The data also show that at lower acid concentrations the kinetics of iron dissolution lag behind those of nickel and magnesium dissolution resulting in a high nickel extraction and low iron extraction. This is an important criterion since iron poses a problem in the downstream recovery of nickel by means known to those skilled in the art. A process in which high nickel and low iron dissolution from saprolite ore can thus be devised by leaching the ore with acid concentrations below about 50 g/L The nickel extraction as a function of time is illustrated in FIG. 3, which shows that the rate of nickel extraction is a strong function of the sulfuric acid concentration. [0031]
    • EXAMPLE 2
  • This example illustrates the atmospheric leaching of saprolite ore with a fixed amount sulfuric acid solution at 90° C. Saprolite ore was pulped at 15% solids in deionized water and agitated in a well-sealed kettle with sulfuric acid at 90° C. for 3 hours. The initial sulfuric concentration varied from 106 to 114 g/L in the 4 tests described. Samples of liquid taken at different times during the test for analysis. The solids at the end of the tests filtered, washed, dried and split for chemical analysis. Table 2 shows the final leaching results for each test and FIG. 4 shows the kinetics of nickel dissolution from saprolite ore. [0032]
    TABLE 2
    Results of saprolite atmospheric leach with sulfuric acid at 90° C.
    Initial Acid consumption
    Test [H2SO4] Sample Wt Composition Extraction (%) Kg/Kg
    No. (g/L) ID (g) Ni Fe Mg Ni Fe Mg Kg/ton Ni
    1 106 Ore 107.8 1.91 7.45 15.90 86.7 28.7 86.6 559 33.6
    Residue 71.8 0.38 7.98 3.19
    2 106 Ore 165.9 1.11 9.10 14.60 76.2 36.4 65.6 512 60.5
    Residue 103.5 0.42 9.28 8.07
    3 114 Ore 167 2.04 8.54 15.30 84.1 46.3 76.3 565 32.9
    Residue 104.7 0.51 7.27 5.73
    4 101 Ore 164 1.28 11.40 16.10 73.7 33.3 69.6 507 53.8
    Residue 112.4 0.50 11.20 7.21
  • The variation of final nickel extraction between the various tests is due mostly to the different amount of acid used in each test and to the variation of composition of the samples. Metal and free acid concentrations in solution as a function of time are shown in Table 3. Approximate metal extractions were calculated from the solution assays over time. These data show that most of the nickel dissolves within the first 15 minutes of leaching when the acid concentration is higher. After this time, saprolite continues to react at much slower rates until most of the acid is consumed. Since saprolite ore was leached at acid concentrations under 50 g/l for most of the test period, the final iron dissolution was relatively low. [0033]
    TABLE 3
    Solution composition as a function of time during the
    atmospheric leaching of saprolite ore at 90° C. (Test 3)
    Time Solution concentration (g/L) Extraction %
    (min) Ni Fe Mg H2SO4 Ni Fe Mg
     0 0 0 0 114 0 0 0
     5 2.37 4.4 11.4 34.4 65.9 29.4 42.2
    15 2.82 5.4 14.9 21.6 79.3 36.5 55.7
    30 2.91 5.6 16.1 16.7 82.6 38.1 61.0
    45 2.72 5.4 15.5 13.7 78.6 37.4 59.5
    60 2.80 5.6 16.4 12.3 81.7 39.1 63.6
    90 2.67 5.2 15.5 9.3 79.1 36.9 61.1
    120  2.69 5.1 15.9 7.8 80.5 36.9 63.2
    150  2.68 5.4 16.6 6.9 81.3 38.7 66.4
    180  2.85 5.5 17.4 6.9 86.9 40.3 70.3
    • EXAMPLE 3
  • This example illustrates the atmospheric leaching of saprolite ore with the product leach slurry from pressure leaching of low magnesium, or limonite, ore. Limonite ore was first leached in a titanium autoclave for 30 minutes at an acid to ore ratio of 0.38, 270° C. and 40 wt % solids. After leaching and pressure letdown, saprolite ore was added as a 50 wt % slurry to neutralize the remaining free acid in the autoclave discharge that results from the bisulfate shift at low temperatures. The saprolite to limonite ratio, when leaching saprolite in this manner, was about 0.17 ([0034] tests 1 and 2). In some cases, concentrated sulfuric acid was added to the leach slurry in order to leach more saprolite ore and increase the saprolite to limonite ratio (tests 3-5). Saprolite leaching was carried out in an agitated tank at 90° C. for 3 hours. The results from each test are shown in Table 4.
    TABLE 4
    Results of saprolite atmospheric leaching with autoclave
    discharge at 90° C. Additional sulfuric acid was added to tests 3-5.
    Test Sample Wt Composition (%) Extraction (%)
    No. ID (g) Ni Fe Mg from Ni Mg
    1 Limonite 738 1.95 37.5 3.55
    ore
    HPAL 650 0.13 43.7 0.9 Limonite 94.2 76.5
    residue
    Saprolite 110 1.91 7.6 15.6 Saprolite 70.8 66.0
    ore
    Final 722 0.20 40.1 1.7 Overall 91.2 72.3
    residue
    2 Liminite 721 1.89 36.4 3.35
    ore
    HPAL 634 0.09 44.1 0.9 Limonite 95.8 77.5
    residue
    Saprolite
    120 1.91 7.6 15.6 Saprolite 66.1 64.4
    ore
    Final 724 0.19 40.1 1.7 Overall 91.5 71.8
    residue
    3 Liminite 802 1.97 37.9 3.44
    ore
    HPAL 705 0.11 41.0 1.0 Limonite 95.3 75.6
    residue
    Saprolite 335 1.91 7.6 15.6 Saprolite 80.4 66.0
    ore
    Final 897 0.22 33.8 2.7 Overall 91.0 69.3
    residue
    4 Liminite 658 1.88 36.5 3.46
    ore
    HPAL 579 0.13 41.7 0.9 Limonite 93.7 76.0
    residue
    Saprolite 245 1.91 7.6 15.6 Saprolite 76.1 67.2
    ore
    Final 741 0.26 34.6 2.4 Overall 88.9 70.5
    residue
    5 Liminite 790 2 36.9 3.66
    ore
    HPAL 695 0.14 41.60 0.96 Limonite 94.0 76.8
    residue
    Saprolite 315 1.91 8.25 15.00 Saprolite 74.9 73.2
    ore
    Final 927 0.27 32.90 2.09 Overall 88.7 74.6
    residue
  • These results demonstrate that saprolite ore can be used to neutralize the free acid in the autoclave discharge from a high-pressure acid leach of limonite ore, while obtaining high nickel extractions from this high magnesium ore fraction. The results also show that it is possible to vary the saprolite to limonite ratio by adding extra sulfuric acid to the autoclave discharge. [0035]
    • EXAMPLE 4
  • This example shows a method of iron control by precipitation of jarosite after leaching of limonite ore at high pressure and temperature and neutralization of the remaining acid with saprolite ore at 90° C. Limonite ore was first leached in a titanium autoclave for 30 minutes at an acid to ore ratio of 0.38, 270° C. and 40 wt % solids. After leaching and pressure letdown, saprolite ore was added as a 50 wt % slurry to neutralize the remaining free acid in the autoclave discharge slurry (ACD) at atmospheric pressure and 90° C. Concentrated sulfuric acid was also added to the ACD to be able to leach more saprolite ore and increase the saprolite to limonite ratio to 0.4. Sodium sulfate was added to the saprolite slurry before addition to the ACD to provide a source of alkali ions for jarosite formation. The final step, after saprolite leaching, consisted of precipitating the iron in solution as natro-jarosite. This was achieved by maintaining the free acid concentration at around 5 g/l H[0036] 2SO4 (pH˜1.5) and the temperature at about 95° C. for an additional 3 hours. The free acid concentration was kept at the mentioned level by periodic additions of CaCO3 slurry after 200 minutes of leaching. Results from this test are shown in Tables 5 and 6.
    TABLE 5
    Results of saprolite atmospheric leaching with
    autoclave discharge at 90° C. followed by jarosite precipitation.
    Test Sample Wt Composition (%) Extraction (%)
    No. ID (g) Ni Fe Mg from Ni Mg
    6 Limonite 355 1.92 35.7 4.9
    ore
    HPAL 312 0.13 40.7 1.4 Limonite 94.1 73.9
    residue
    Saprolite
    140 1.91 7.3 16.1 Saprolite 75.3 69.7
    ore
    Final 448 0.24 32.6 2.5 Overall 88.8 71.5
    residue
  • [0037]
    TABLE 6
    Kinetics of saprolite atmospheric leaching with
    autoclave discharge at 90° C. followed by jarosite precipitation.
    Time Solution concentration (g/L) Extraction (%)
    (min) H2SO4 Ni Fe Mg Na Ni Mg
     0 76 0 0 0 4.2 0 0
     20 46.6 7.42 3.66 15.9 4.15 33.5 24.6
     60 15.7 7.96 4.82 21.4 3.87 63.5 56.9
    120 10.3 7.75 4.52 22.1 3.97 57.9 62.0
    180 10.1 7.48 3.70 22.1 4.03 49.6 63.5
    230 3.0 7.78 1.00 22.8 3.93 68.0 69.1
    280 5.2 7.81 0.92 23.4 3.81 73.5 73.8
    330 4.4 7.83 0.56 22.6 3.78 76.5 70.8
  • These results, once again, show that saprolite was effectively used to neutralize the acid in the autoclave discharge and to leach a high proportion of the nickel contained within the saprolite ore. At the end of the atmospheric leach step, iron in solution decreased from a maximum of about 5 g/l by the formation of jarosite until the iron concentration in solution reached about 0.5 g/l. The low nickel assay of the final residue after jarosite precipitation was achieved despite the precipitation of approx. 5 g/L iron as jarosite. [0038]
    • EXAMPLE 5
  • This example illustrates the continuous processing of limonite ore under high-pressure acid leach (HPAL) conditions followed by the processing of saprolite ore under atmospheric leach (AL) conditions. [0039]
  • A limonite ore slurry at 38.5 wt. % solids was leached at high pressure and temperature (270° C. and 820 psi) at an acid to ore ratio of 0.4 tonnes acid/tonne ore in a continuous autoclave. Limonite was processed at a rate of 0.8 dry tonnes/day yielding an autoclave retention time of 30 minutes. The discharge from the autoclave consisted of HPAL residue and leach solution containing metals and free sulfuric acid (92 g/L). The compositions of the ore fed to the autoclave and the discharge residue, as well as the calculated metal extractions, are shown in Table 7. [0040]
    TABLE 7
    High pressure acid leaching (HPAL) results.
    Al Co Cr Fe Mg Mn Ni
    (%) (%) (%) (%) (%) (%) (%)
    Limonite 2.82 0.125 1.47 34.4 3.72 0.71 1.63
    feed
    HPAL 2.62 0.000 1.54 39.5 0.93 0.17  0.075
    residue
    Extraction 20.0% 100.0% 9.5% 1.1% 78.4% 79.7% 96.0%
  • The autoclave discharge slurry was mixed with saprolite ore (at 46 wt. % solids) in the proportion of 0.3 tonnes saprolite/tonne limonite. Sodium was added as sodium sulfate to the water used to prepare the saprolite ore slurry. Sulfuric acid was added to the mixture in the proportion of 0.46 tonnes concentrated acid/tonne saprolite. The concentrated acid combined with the residual acid from the HPAL yielded an acid to saprolite ratio of 0.96 tonnes acid/tonne saprolite. The overall concentrated acid to ore ratio was 0.41 tonnes acid/tonne ore (limonite plus saprolite). [0041]
  • The atmospheric leach circuit (AL) consisted of 3 tanks in series with an overall retention time of 4.2 hours (1.4 hours/tank). This circuit was followed by a jarosite precipitation circuit (JP) consisting of 2 tanks in series with an overall retention time of 5.9 hours (first tank 1.4 hours, second tank 4.5 hours). Limestone slurry was added to the jarosite precipitation tanks to control the slurry pH. Average conditions of these tanks over the test duration of approximately 70 hours are presented in Table 8: [0042]
    TABLE 8
    Atmospheric Leach and Iron Precipitation Conditions
    Tank pH Free Acid (g/L) Temperature (° C.)
    AL1 37.7 97
    AL2 33.5 92
    AL3 27.1 94
    JP1 1.5 10.5 94
    JP2 1.9  5.9 92
  • The compositions of the residues resulting from the consecutive operations and the calculated metal extractions from saprolite in atmospheric leaching and the overall extractions from HPAL followed by atmospheric leaching are given in Table 9. [0043]
    TABLE 9
    Ore and Leach Residue Compositions and Metal Extractions for Each Stage
    Al (%) Co (%) Cr (%) Fe (%) Mg (%) Mn (%) Ni (%)
    Limonite ore 2.82 0.125 1.47 34.4 3.72 0.71 1.63
    Saprolite ore 1.58 0.085 0.85 11.4 14.83  0.48 1.31
    HPAL residue 2.62 0.000 1.54 39.5 0.93 0.17  0.075
    AL residue 2.45 0.027 1.38 32.9 2.00 0.23 0.13
    JP residue 2.04 0.007 1.19 29.2 1.53 0.18  0.092
    Extraction from 17.6% 82.6% 13.9% −5.4% 73.3% 38.8% 85.6%
    saprolite
    Extraction from 20.0% 97.5% 10.3%  0.6% 75.6% 72.8% 94.1%
    limonite and saprolite
  • The solutions resulting from the leaching and precipitation stages show the increase in nickel and cobalt content as well as the decrease in free acidity. The Fe content initially increased during the atmospheric leaching stage, but subsequently decreased during jarosite precipitation, as shown in Table 10. [0044]
    TABLE 10
    Solution Compositions after Each Stage
    Al Co Cr Fe Mg Mn Ni Free
    (mg/ (mg/ (mg/ (mg/ (mg/ (mg/ (mg/ Acid
    L) L) L) L) L) L) L) (g/L)
    HPAL 2741 695 491  2463 16847 3791  9826 92
    solution
    AL 3728 825 768 13715 33066 4472 12084 27
    solution
    JP 2819 820 587  1417 35663 4500 12591 5.9
    solution
    • EXAMPLE 6
  • This example illustrates the continuous processing of limonite ore under high pressure acid leach (HPAL) conditions followed by the processing of saprolite ore under atmospheric leach (AL) conditions. [0045]
  • A limonite ore slurry at 35 wt. % solids was leached at high pressure and temperature (270° C. and 820 psi) at an acid to ore ratio of 0.34 tonnes acid/tonne limonite in a continuous autoclave. Limonite was processed at a rate of 0.8 dry tonnes/day yielding an autoclave retention time of 30 minutes. The discharge from the autoclave consisted of HPAL residue and leach solution containing metals and free acid (102 g/L). The compositions of the ore fed to the autoclave and the discharge residue, as well as the calculated metal extractions, are shown in Table 11. [0046]
    TABLE 11
    High pressure acid leaching (HPAL) results
    Co (%) Fe (%) Mg (%) Ni (%)
    Limonite feed 0.11 40.33 2.79 1.66
    HPAL residue 0.004 43.8 0.82 0.091
    Extraction 96.1% 1.2% 70.5% 94.8%
  • The autoclave discharge slurry was mixed with saprolite ore (at 51 wt. % solids) in the proportion of 0.38 tonnes saprolite/tonne limonite. Sodium was added as sodium sulfate to the water used to prepare the saprolite ore slurry. Sulfuric acid was added to the mixture in the proportion of 0.23 tonnes concentrated acid/tonne saprolite. The concentrated acid combined with the residual acid from the HPAL yielded an acid to saprolite ratio of 0.59 tonnes acid/tonne saprolite. The overall concentrated acid to ore ratio was 0.31 tonnes acid/tonne ore (limonite plus saprolite). [0047]
  • The atmospheric leach circuit (AL) consisted of 4 tanks. Half the saprolite was added to the first tank (1 hour retention) along with the concentrated sulfuric acid, while the other half was added to the second tank (1.4 hour retention) along with the autoclave discharge slurry. The first tank overflowed into the second tank, which then overflowed into 2 tanks in series (1.4 hour retention each). This circuit was followed by a jarosite precipitation circuit (JP) consisting of 2 tanks in series with an overall retention time of 5.9 hours (first tank 1.4 hours, second tank 4.5 hours). Limestone slurry was added to the jarosite precipitation tanks to control the slurry pH. Average conditions of these tanks over the test duration of approximately 82 hours are presented in Table 12: [0048]
    TABLE 12
    Atmospheric Leach and Iron Precipitation Conditions
    Tank pH Free Acid (g/L) Temperature (° C.)
    AL1 54.4 71
    AL2 21.5 92
    AL3 20.3 91
    AL4 14.7 91
    JP1 1.7  7.6 94
    JP2 2.1  6.5 93
  • The compositions of the residues resulting from the consecutive operations and the calculated metal extractions from saprolite in atmospheric leaching and the overall extractions from HPAL followed by atmospheric leaching are given in Table 13. [0049]
    TABLE 13
    Ore and Leach Residue Compositions
    and Metal Extractions for Each Stage
    Co (%) Fe (%) Mg (%) Ni (%)
    Limonite feed 0.11 40.33 2.79 1.66
    Saprolite ore 0.088 11.4 14.2 1.30
    HPAL residue 0.004 43.8 0.82 0.091
    AL residue 0.016 36.7 1.83 0.147
    JP residue 0.018 33.0 1.83 0.132
    Extraction from saprolite 42.9% -4.7% 62.7% 76.5%
    Extraction from limonite and 83.6% 0.6% 69.9% 91.8%
    saprolite
  • The solutions resulting from the leaching and precipitation stages show the increase in metals content as well as the decrease in free acidity. The Fe content initially increased during the atmospheric leaching stage, but subsequently decreased during jarosite precipitation, as shown in Table 14. [0050]
    TABLE 14
    Solution Compositions after Each Stage
    Al Co Cr Fe Mg Mn Ni Free
    (mg/ (mg/ (mg/ (mg/ (mg/ (mg/ (mg/ Acid
    L) L) L) L) L) L) L) (g/L)
    HPAL 4391 764 719 3820 17220 4264 12030 102
    solution
    AL 3261 698 640 6618 32628 3982 11228 14.7
    solution
    JP 3343 757 547 1568 35399 4279 12185  6.5
    solution
  • While there have been described what are presently believed to be the preferred embodiments of the invention, those skilled in the art will realize that changes and modifications may be made thereto without departing from the spirit of the invention. It is intended to claim all such changes and modifications that fall within the true scope of the invention. [0051]

Claims (19)

What is claimed:
1. A hydrometallurgical sulfuric acid leaching process for the extraction of nickel and cobalt from nickeliferous laterite oxide ore that comprises:
a. providing an aqueous pulp of nickeliferous oxide ore at a low magnesium content;
b. leaching the aqueous pulp at an elevated temperature (at least 200° C.) and pressure with an addition of sulfuric acid at least sufficient stoichiometrically to effect the leaching of contained nickel and cobalt and thereby provide a pregnant solution of nickel sulfate, cobalt sulfate and a leach residue; and
c. atmospheric pressure leaching of high magnesium containing nickeliferous oxide ore with the pregnant solution from step (b) by adding controlled quantities of raw, untreated high magnesium ore to the pregnant solution at temperatures of from 80° C. up to the normal boiling point of the solution and providing sufficient agitation and time to effect the extraction of nickel and cobalt from the high magnesium ore and form a final leach slurry.
2. The process of claim 1 wherein the pregnant solution and leach residue of step (b) are not separated before atmospheric pressure leaching of the high magnesium containing nickeliferous oxide ore.
3. The process of claim 1 further comprising leaching a portion of the high magnesium laterite ore at atmospheric pressure with sulfuric acid before adding it to the pregnant solution from step (b).
4. The process of claim 1 further comprising neutralizing the pregnant solution from step (b) with a portion of the high magnesium laterite ore.
5. The process of claim 3 further comprising neutalizing the pregnant solution from step (b) with a portion of the high magnesium laterite ore.
6. The process of claim 1 further comprising neutralizing the final leach slurry by the adding a neutralization agent selected from the group consisting of alkali and alkaline earth oxides, hydroxides, carbonates, or mixtures thereof.
7. The process of claim 5 further comprising neutralizing the leach slurry by adding a neutralization agent selected from the group consisting of alkali and alkaline earth oxides, hydroxides, carbonates, or mixtures thereof.
8. The process of claim 1 further comprising neutralizing the final leach slurry by adding high magnesium laterite ore.
9. The process of claim 5 further comprising neutralizing the leach slurry by adding high magnesium laterite ore.
10. The process of claim 6 further comprising providing a sufficient amount of a precipitating agent selected from the group consisting of alkali metal ions, ammonium ions, and mixtures thereof, to precipitate ferric iron as jarosite.
11. The process of claim 7 further comprising providing a sufficient amount of a precipitating agent selected from the group consisting of alkali metal ions, ammonium ions, and mixtures thereof, to precipitate ferric iron as jarosite.
12. The process of claim 8 further comprising providing a sufficient amount of a precipitating agent selected from the group consisting of alkali metal ions, ammonium ions, and mixtures thereof, to precipitate ferric iron as jarosite.
13. The process of claim 9 further comprising providing a sufficient amount of a precipitating agent selected from the group consisting of alkali metal ions, ammonium ions, and mixtures thereof, to precipitate ferric iron as jarosite.
14. The process of claim 1 further comprising subjecting the leach slurry to a solid/liquid separation step to produce a final pregnant leach liquor suitable for recovery of nickel and cobalt and a final leach residue.
15. The process of claim 6 further comprising subjecting the leach slurry to a solid/liquid separation step to produce a final pregnant leach liquor suitable for recovery of nickel and cobalt and a final leach residue.
16. The process of claim 7 further comprising subjecting the leach slurry to a solid/liquid separation step to produce a final pregnant leach liquor suitable for recovery of nickel and cobalt and a final leach residue.
17. The process of claim 8 further comprising subjecting the leach slurry to a solid/liquid separation step to produce a final pregnant leach liquor suitable for recovery of nickel and cobalt and a final leach residue.
18. The process of claim 9 further comprising subjecting the leach slurry to a solid/liquid separation step to produce a final pregnant leach liquor suitable for recovery of nickel and cobalt and a final leach residue.
19. The process of claim 1 further comprising grinding the high magnesium containing nickeliferous ore before adding it to the pregnant solution from the pressure leaching step.
US09/433,110 1999-11-03 1999-11-03 Method for leaching nickeliferous laterite ores Expired - Lifetime US6379636B2 (en)

Priority Applications (15)

Application Number Priority Date Filing Date Title
US09/433,110 US6379636B2 (en) 1999-11-03 1999-11-03 Method for leaching nickeliferous laterite ores
KR1020027005702A KR100727720B1 (en) 1999-11-03 2000-10-25 Nickel Iron Laterite Ore Extraction Method
BR0015305-2A BR0015305A (en) 1999-11-03 2000-10-25 Method for leaching nickel laterite ores
EP00988492A EP1232290B1 (en) 1999-11-03 2000-10-25 Method for leaching nickeliferous oxide ores of high and low magnesium laterites
PCT/US2000/041511 WO2001032944A1 (en) 1999-11-03 2000-10-25 Method for leaching nickeliferous oxide ores of high and low magnesium laterites
AT00988492T ATE256203T1 (en) 1999-11-03 2000-10-25 LEACHING PROCESS FOR OXIDE ORES CONTAINING NICKEL-IRON, ESPECIALLY. LATERITE ORES WITH LOW OR HIGH MAGNESIUM CONTENT
DE60007175T DE60007175T2 (en) 1999-11-03 2000-10-25 LAUGHING PROCESS FOR OXIDE ORES CONTAINING NICKEL IRON, IN PARTICULAR. LATERITE ORE WITH LOW OR LOW HIGH MAGNESIUM CONTENT
JP2001535622A JP4895454B2 (en) 1999-11-03 2000-10-25 Nickel-containing laterite ore leaching method
AU24697/01A AU779844B2 (en) 1999-11-03 2000-10-25 Method for leaching nickeliferous laterite ores
ES00988492T ES2213066T3 (en) 1999-11-03 2000-10-25 PROCEDURE FOR LIXIVING MINERALS OF NICKEL OXIDES OF HIGH AND LOW LATERITES CONTAINED IN MAGNESIUM.
CA002389653A CA2389653A1 (en) 1999-11-03 2000-10-25 Method for leaching nickeliferous laterite ores
CO00083211A CO5190741A1 (en) 1999-11-03 2000-11-01 METHOD FOR LIXIVIATING LETTERS FROM NICKEL LATERITE
GT200000192A GT200000192A (en) 1999-11-03 2000-11-03 METHOD TO REMOVE THE MINERAL LATERITA DEL FERRONIQUEL.
DO2000000087A DOP2000000087A (en) 1999-11-03 2001-11-03 METHOD TO REMOVE THE MINERAL OF LATERITA DEL FERRONIQUEL
ZA200203242A ZA200203242B (en) 1999-11-03 2002-04-24 Method for leaching nickeliferous oxide ores of high and low magnesium laterites.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US09/433,110 US6379636B2 (en) 1999-11-03 1999-11-03 Method for leaching nickeliferous laterite ores

Publications (2)

Publication Number Publication Date
US20020006370A1 true US20020006370A1 (en) 2002-01-17
US6379636B2 US6379636B2 (en) 2002-04-30

Family

ID=23718891

Family Applications (1)

Application Number Title Priority Date Filing Date
US09/433,110 Expired - Lifetime US6379636B2 (en) 1999-11-03 1999-11-03 Method for leaching nickeliferous laterite ores

Country Status (15)

Country Link
US (1) US6379636B2 (en)
EP (1) EP1232290B1 (en)
JP (1) JP4895454B2 (en)
KR (1) KR100727720B1 (en)
AT (1) ATE256203T1 (en)
AU (1) AU779844B2 (en)
BR (1) BR0015305A (en)
CA (1) CA2389653A1 (en)
CO (1) CO5190741A1 (en)
DE (1) DE60007175T2 (en)
DO (1) DOP2000000087A (en)
ES (1) ES2213066T3 (en)
GT (1) GT200000192A (en)
WO (1) WO2001032944A1 (en)
ZA (1) ZA200203242B (en)

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050118082A1 (en) * 2001-12-21 2005-06-02 Mohamed Buarzaiga Chromium removal from leach liquors produced during high pressure acid leaching of lateritic ores
US20050226797A1 (en) * 2002-04-29 2005-10-13 Houyuan Liu Atmospheric pressure leach process for lateritic nickel ore
US20060002835A1 (en) * 2004-06-28 2006-01-05 David Neudorf Method for nickel and cobalt recovery from laterite ores by reaction with concentrated acid and water leaching
EP1922423A4 (en) * 2005-08-09 2009-09-30 Murrin Murrin Operations Pty Hydrometallurgical method for the extraction of nickel and cobalt from laterite ores
US20100098608A1 (en) * 2006-09-06 2010-04-22 Agin Jerome Process for the hydrometallurgical treatment of a lateritic nickel/cobalt or and process for producing nickel and/or cobalt intermediate concentrates or commercial products using it
AU2006279255B2 (en) * 2005-08-09 2011-04-21 Murrin Murrin Operations Pty Ltd Hydrometallurgical method for the extraction of nickel and cobalt from laterite ores
US20120186398A1 (en) * 2010-04-01 2012-07-26 Search Minerals, Inc. Low acid leaching of nickel and cobalt from lean iron-containing nickel ores
CN102628100A (en) * 2012-04-13 2012-08-08 宁波金田铜业(集团)股份有限公司 Device and method for extracting zinc through acid leaching by using acid cyclically
US20130266493A1 (en) * 2010-12-17 2013-10-10 Outotec Oyj Method for separating nickel from material with low nickel content
CN104611555A (en) * 2014-12-31 2015-05-13 金川集团股份有限公司 Method for extracting nickel, cobalt, iron, silicon and magnesium from limonite
CN104611554A (en) * 2014-12-31 2015-05-13 金川集团股份有限公司 Method for extracting nickel, cobalt and iron from limonite
CN104789765A (en) * 2014-12-31 2015-07-22 金川集团股份有限公司 A method of recovering nickel, iron and silicon from limonite by a combined leaching process
US20160076121A1 (en) * 2013-04-23 2016-03-17 Sumitomo Metal Mining Co., Ltd. Hydrometallurgical process for nickel oxide ore
EP2553129A4 (en) * 2010-04-01 2016-11-30 Search Minerals Inc Low acid leaching of nickel and cobalt from lean iron-containing nickel ores
CN108396157A (en) * 2018-03-15 2018-08-14 李宾 A kind of method of laterite nickel ore by sulfuric acid leaching liquid and silica gel chelating resin purification production sulfuric acid nickel cobalt
CN113526576A (en) * 2021-05-31 2021-10-22 金川集团股份有限公司 A kind of preparation method of nickel sulfate solution with high nickel, low acid and low sodium
CN115821063A (en) * 2022-12-09 2023-03-21 中国恩菲工程技术有限公司 Method for purifying magnesium from serpentine
WO2025020124A1 (en) * 2023-07-26 2025-01-30 青美邦新能源材料有限公司 Oxygen pressure leaching method for low-grade nickel matte mixed with laterite-nickel ore
EP4337802A4 (en) * 2021-05-13 2025-08-06 Commw Scient Ind Res Org PRODUCTION OF HIGH-PURITY NICKEL AND COBALT COMPOUNDS

Families Citing this family (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7220394B2 (en) * 2002-10-30 2007-05-22 Council Of Scientific And Industrial Research Process for simultaneous recovery of chromium and iron from chromite ore processing residue
AU2003903632A0 (en) * 2003-07-14 2003-07-31 Qni Technology Pty Ltd Process for recovery of nickel and cobalt by heap leaching of low grade nickel or cobalt containing material
JP4525428B2 (en) * 2004-05-13 2010-08-18 住友金属鉱山株式会社 Method for hydrometallizing nickel oxide ore
EP1777304B1 (en) * 2004-05-27 2013-11-13 Pacific Metals Co., Ltd. Method of recovering nickel or cobalt
CA2572420A1 (en) * 2004-08-02 2006-03-23 Skye Resources Inc. Method for nickel and cobalt recovery from laterite ores by combination of atmospheric and moderate pressure leaching
EP1825010A4 (en) 2004-11-17 2009-08-19 Bhp Billiton Ssm Tech Pty Ltd Consecutive or simultaneous leaching of nickel and cobalt containing ores
ES2394915T3 (en) * 2005-02-14 2013-02-06 Bhp Billiton Ssm Development Pty Ltd Procedure for improved acid leaching of laterite minerals
JP5060033B2 (en) * 2005-09-15 2012-10-31 大平洋金属株式会社 Method for recovering nickel or cobalt
BRPI0505544B1 (en) 2005-11-10 2014-02-04 COMBINED Leaching Process
AU2007219059B2 (en) * 2006-02-24 2010-08-26 Murrin Murrin Operations Pty Ltd Hematite precipitation at elevated temperature and pressure
US20070240341A1 (en) * 2006-04-12 2007-10-18 Esco Corporation UDD dragline bucket machine and control system
AU2011218755B9 (en) * 2006-09-06 2014-05-15 Eramet Process for the hydrometallurgical treatment of a lateritic nickel/cobalt ore and process for producing nickel and/or cobalt intermediate concentrates or commercial products using it
CN101311281B (en) * 2007-05-24 2010-05-26 东北大学 Metallurgical method for comprehensive utilization of nickel laterite ore
FI123646B (en) * 2010-02-25 2013-08-30 Outotec Oyj Method for streamlining solid-particle liquid separation in connection with leaching of laterites
EP2640861A1 (en) * 2010-11-19 2013-09-25 Murrin Murrin Operations Pty Ltd Method for the leaching of a metal sulfide
CN104789763A (en) * 2014-12-31 2015-07-22 金川集团股份有限公司 A method of recovering nickel, cobalt and iron from limonite
CN104611553A (en) * 2014-12-31 2015-05-13 金川集团股份有限公司 Method for recovering nickel, cobalt, iron, silicon and magnesium in limonite
CN105154669A (en) * 2014-12-31 2015-12-16 金川集团股份有限公司 Method for recovering Ni, Co, Fe, Si and Mg from laterite
JP6036875B2 (en) 2015-02-24 2016-11-30 住友金属鉱山株式会社 Method for hydrometallizing nickel oxide ore
JP6589950B2 (en) 2017-08-16 2019-10-16 住友金属鉱山株式会社 Leaching treatment method, nickel oxide ore hydrometallurgy method
JP6977458B2 (en) * 2017-09-29 2021-12-08 住友金属鉱山株式会社 Hydrometallurgical method for nickel oxide ore
JP6969262B2 (en) * 2017-09-29 2021-11-24 住友金属鉱山株式会社 Hydrometallurgical method for nickel oxide ore
JP7285427B2 (en) * 2019-07-16 2023-06-02 住友金属鉱山株式会社 Nickel oxide ore leaching method
CN112080636B (en) * 2020-08-17 2022-11-15 广东邦普循环科技有限公司 Method for producing battery-grade nickel sulfate salt by using laterite-nickel ore
JP7628014B2 (en) * 2020-09-01 2025-02-07 ピーティー． ハイドロテック メタル インドネシア Process for recovering nickel, cobalt and other metals from lateritic nickel ore
JP7607760B2 (en) * 2020-10-14 2024-12-27 エルジー エナジー ソリューション リミテッド Method for producing high nickel positive electrode active material
CN112538574A (en) * 2020-12-09 2021-03-23 金川集团股份有限公司 Leaching method for improving nickel ion concentration of laterite leaching solution

Family Cites Families (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA618826A (en) 1958-04-21 1961-04-25 S. Simons Courtney Recovery of nickel, cobalt and other valuable metals
US3466144A (en) * 1967-07-03 1969-09-09 American Metal Climax Inc Treatment of nickeliferous oxidic materials for the recovery of nickel values
US3720749A (en) 1970-08-26 1973-03-13 American Metal Climax Inc Treatment of nickel leach liquor
US3804613A (en) 1971-09-16 1974-04-16 American Metal Climax Inc Ore conditioning process for the efficient recovery of nickel from relatively high magnesium containing oxidic nickel ores
US4042474A (en) 1973-08-02 1977-08-16 Pako Corporation Separating nickel, cobalt and chromium from iron in metallurgical products
US3991159A (en) 1975-01-09 1976-11-09 Amax Inc. High temperature neutralization of laterite leach slurry
US4044096A (en) * 1975-12-11 1977-08-23 Amax Inc. Sulfuric acid leaching of nickeliferous laterite
US4097575A (en) 1976-11-05 1978-06-27 Amax Inc. Roast-neutralization-leach technique for the treatment of laterite ore
CA1171287A (en) 1980-11-05 1984-07-24 William R. Hatch Acid leaching of lateritic nickel ores
US4541868A (en) 1983-07-22 1985-09-17 California Nickel Corporation Recovery of nickel and cobalt by controlled sulfuric acid leaching
US4548794A (en) 1983-07-22 1985-10-22 California Nickel Corporation Method of recovering nickel from laterite ores
JP3203707B2 (en) * 1991-10-09 2001-08-27 大平洋金属株式会社 Method for recovering valuable metals from oxide ore
US5378262A (en) 1994-03-22 1995-01-03 Inco Limited Process for the extraction and separation of nickel and/or cobalt
CA2137124C (en) * 1994-12-01 1999-03-16 Tao Xue Pressure leaching of nickel and cobalt sulphides with chlorine under controlled redox potential conditions
US5535992A (en) * 1995-03-07 1996-07-16 Goro Nickel S.A. Apparatus and method for acidic leaching of lateritic ores
WO1996041025A1 (en) 1995-06-07 1996-12-19 Pacific Nickel Corp. Process for extraction of nickel and cobalt from laterite ores
FI98073C (en) * 1995-08-14 1997-04-10 Outokumpu Eng Oy Process for the hydrometallurgical recovery of nickel from two different types of nickel stone

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7318914B2 (en) * 2001-12-21 2008-01-15 Falconbridge Limited Chromium removal from leach liquors produced during high pressure acid leaching of lateritic ores
US20050118082A1 (en) * 2001-12-21 2005-06-02 Mohamed Buarzaiga Chromium removal from leach liquors produced during high pressure acid leaching of lateritic ores
US20050226797A1 (en) * 2002-04-29 2005-10-13 Houyuan Liu Atmospheric pressure leach process for lateritic nickel ore
US7416711B2 (en) 2002-04-29 2008-08-26 Qni Technology Pty. Ltd. Atmospheric pressure leach process for lateritic nickel ore
US20060002835A1 (en) * 2004-06-28 2006-01-05 David Neudorf Method for nickel and cobalt recovery from laterite ores by reaction with concentrated acid and water leaching
EP1922423A4 (en) * 2005-08-09 2009-09-30 Murrin Murrin Operations Pty Hydrometallurgical method for the extraction of nickel and cobalt from laterite ores
AU2006279255B2 (en) * 2005-08-09 2011-04-21 Murrin Murrin Operations Pty Ltd Hydrometallurgical method for the extraction of nickel and cobalt from laterite ores
US8287827B2 (en) 2006-09-06 2012-10-16 Eramet Process for the hydrometallurgical treatment of a lateritic nickel/cobalt ore and process for producing nickel and/or cobalt intermediate concentrates or commercial products using it
US20100098608A1 (en) * 2006-09-06 2010-04-22 Agin Jerome Process for the hydrometallurgical treatment of a lateritic nickel/cobalt or and process for producing nickel and/or cobalt intermediate concentrates or commercial products using it
EP2553129A4 (en) * 2010-04-01 2016-11-30 Search Minerals Inc Low acid leaching of nickel and cobalt from lean iron-containing nickel ores
US8361191B2 (en) * 2010-04-01 2013-01-29 Search Minerals, Inc. Low acid leaching of nickel and cobalt from lean iron-containing nickel ores
US20120186398A1 (en) * 2010-04-01 2012-07-26 Search Minerals, Inc. Low acid leaching of nickel and cobalt from lean iron-containing nickel ores
US20130266493A1 (en) * 2010-12-17 2013-10-10 Outotec Oyj Method for separating nickel from material with low nickel content
US8974755B2 (en) * 2010-12-17 2015-03-10 Outotec Oyj Method for separating nickel from material with low nickel content
CN102628100A (en) * 2012-04-13 2012-08-08 宁波金田铜业(集团)股份有限公司 Device and method for extracting zinc through acid leaching by using acid cyclically
US20160076121A1 (en) * 2013-04-23 2016-03-17 Sumitomo Metal Mining Co., Ltd. Hydrometallurgical process for nickel oxide ore
CN104789765A (en) * 2014-12-31 2015-07-22 金川集团股份有限公司 A method of recovering nickel, iron and silicon from limonite by a combined leaching process
CN104611554A (en) * 2014-12-31 2015-05-13 金川集团股份有限公司 Method for extracting nickel, cobalt and iron from limonite
CN104611555A (en) * 2014-12-31 2015-05-13 金川集团股份有限公司 Method for extracting nickel, cobalt, iron, silicon and magnesium from limonite
CN108396157A (en) * 2018-03-15 2018-08-14 李宾 A kind of method of laterite nickel ore by sulfuric acid leaching liquid and silica gel chelating resin purification production sulfuric acid nickel cobalt
EP4337802A4 (en) * 2021-05-13 2025-08-06 Commw Scient Ind Res Org PRODUCTION OF HIGH-PURITY NICKEL AND COBALT COMPOUNDS
CN113526576A (en) * 2021-05-31 2021-10-22 金川集团股份有限公司 A kind of preparation method of nickel sulfate solution with high nickel, low acid and low sodium
CN115821063A (en) * 2022-12-09 2023-03-21 中国恩菲工程技术有限公司 Method for purifying magnesium from serpentine
WO2025020124A1 (en) * 2023-07-26 2025-01-30 青美邦新能源材料有限公司 Oxygen pressure leaching method for low-grade nickel matte mixed with laterite-nickel ore

Also Published As

Publication number Publication date
JP2003514110A (en) 2003-04-15
JP4895454B2 (en) 2012-03-14
EP1232290A1 (en) 2002-08-21
WO2001032944A1 (en) 2001-05-10
KR100727720B1 (en) 2007-06-13
KR20020070275A (en) 2002-09-05
DE60007175D1 (en) 2004-01-22
CO5190741A1 (en) 2002-08-29
AU779844B2 (en) 2005-02-17
DOP2000000087A (en) 2002-07-15
ATE256203T1 (en) 2003-12-15
GT200000192A (en) 2001-10-19
EP1232290B1 (en) 2003-12-10
DE60007175T2 (en) 2004-08-26
WO2001032944B1 (en) 2001-11-22
AU2469701A (en) 2001-05-14
ZA200203242B (en) 2002-11-26
US6379636B2 (en) 2002-04-30
CA2389653A1 (en) 2001-05-10
BR0015305A (en) 2002-10-08
ES2213066T3 (en) 2004-08-16

Similar Documents

Publication Publication Date Title
US6379636B2 (en) Method for leaching nickeliferous laterite ores
US6261527B1 (en) Atmospheric leach process for the recovery of nickel and cobalt from limonite and saprolite ores
US4410498A (en) Acid leaching of nickel from serpentinic laterite ores
AU740712B2 (en) Chloride assisted hydrometallurgical extraction of nickel and cobalt from sulphide or laterite ores
US20070297960A1 (en) Extraction of Nickel and Cobalt from a Resin Eluate Stream
AU751862C (en) Selective precipitation of nickel and cobalt
US20120186398A1 (en) Low acid leaching of nickel and cobalt from lean iron-containing nickel ores
AU2006100870B4 (en) Method for leaching nickeliferous laterite ores
US4594102A (en) Recovery of cobalt and nickel from sulphidic material
US9057116B2 (en) Method for enhancing solid-liquid separation in conjunction with laterite leaching
US6949232B2 (en) Producing cobalt (III) hexammine sulfate from nickel cobalt sulfides
WO2002048042A1 (en) Hydroxide solids enrichment by precipitate contact
JP3407738B1 (en) Method for recovering nickel and cobalt from oxide ore
GB2086872A (en) Acid Leaching of Lateritic Nickel Ores
AU2002221333A1 (en) Hydroxide solids enrichment by precipitate contact

Legal Events

Date Code Title Description
AS Assignment

Owner name: BHP MINERALS INTERNATIONAL, INC., NEVADA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ARROYO, J. CARLOS;GILLASPIE, JAMES D.;NEUDORF, DAVID A.;AND OTHERS;REEL/FRAME:010508/0932

Effective date: 20000105

STCF Information on status: patent grant

Free format text: PATENTED CASE

FPAY Fee payment

Year of fee payment: 4

FPAY Fee payment

Year of fee payment: 8

FPAY Fee payment

Year of fee payment: 12