JP3430973B2 - Method for recovering nickel and scandium from oxidized ore - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for recovering nickel and scandium from an oxide ore containing nickel and scandium.

[0002]

2. Description of the Related Art Scandium is an encapsulant for metal halide lamps used in gymnasiums and hotels as a high color rendering lamp, an additive for laser single crystals as a solid-state laser oscillation source, and a long afterglow orange for CRT display tubes. It is used for color phosphors, ferroelectric materials, piezoelectric materials, etc. Further, in recent years, the use as a Lewis acid catalyst is also promising,
There are great expectations for scandium compounds as new catalysts for the next generation.

On the other hand, scandium as a resource is contained in the crust in an amount of about 5 to 10 ppm, but there is almost no ore that can be industrially used alone as a scandium source. Currently, industrially, the content is only a few pp
Refining residues of tin, titanium, tungsten, uranium, tantalum, niobium, bauxite, etc. of m to several tens of ppm are used as scandium-containing raw materials.

As a method of recovering scandium from such a raw material, conventionally, after the scouring residue is acid-leached under atmospheric pressure, impurities other than scandium are removed by various methods such as solvent extraction, chelate extraction, and ion exchange. It is separated and recovered by removing it. Such a scandium recovery method has the following problems. During acid leaching, a large amount of iron, aluminum, etc. other than scandium are leached at the same time, and at the same ratio as scandium. Therefore, the concentration of iron and aluminum in the leachate is several hundred times that of scandium, and the subsequent liquid treatment becomes complicated. For example, when iron or aluminum is removed from the acid leaching solution as a hydroxide, the hydroxide becomes a gel-like substance and is very difficult to remove. When iron or aluminum is removed from the acid leachate by solvent extraction, chelate extraction, or ion exchange, it is necessary to dilute the concentration of iron or aluminum, and not only the liquid treatment amount becomes very large, but finally iron or aluminum is removed. Must be treated as waste liquid. If scandium is to be leached at a high rate, iron, aluminum, etc., which are contained in a large amount in addition to scandium, are also leached at the same ratio as scandium, so a large amount of acid is required.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and provide a novel method for recovering nickel and scandium. In particular, it is an object of the present invention to provide a novel method for recovering nickel and scandium from an oxide ore containing nickel and a trace amount of scandium at the same time.

[0006]

The present inventors have found that the amount of Clark's number in the nickel-containing oxide ore is 2 to 5 although it is a trace amount.
It was discovered that 20 times more scandium was present, and as a result of various studies to efficiently recover this scandium, the temperature was 150 to 300 ° C and the pressure was 5 to 60 kg /
It was discovered that acid leaching under high temperature and high pressure of cm ² (gauge pressure) suppresses leaching of iron and aluminum in the oxide ore, while almost all nickel and scandium are selectively and efficiently leached. .

The acid leaching solution has a low content of impurities such as iron and aluminum, and it has been found that nickel and scandium can be recovered as a high-concentration precipitate simply by adjusting the pH of the leaching solution. is there.

That is, the present invention is characterized by recovering scandium and nickel from the nickel-containing oxide ore by sequentially treating the nickel-containing oxide ore in the following steps (1) to (4). is there.

The gist is as described in claim 1 of the claims. (1) The oxide ore is heated at a temperature of 150 to 300 ° C. and a pressure of 5 to 5.
A leaching step of leaching with acid under high temperature and high pressure of 60 kg / cm ² (gauge pressure) to obtain a leaching solution containing nickel and scandium, and (2) adding a neutralizing agent to the leaching solution to adjust the pH to a range of 2 to 4. A first neutralizing step of removing iron and aluminum in the leachate as a precipitate by adjusting, (3) a neutralizing agent is added to the solution after removing the precipitate in the first neutralizing step. In addition, a second neutralization step of recovering scandium in the solution as a precipitate by adjusting the pH to a range of more than 4 to 7.5, and (4) further adding a neutralizing agent to a pH of more than 7.5. The third neutralization step of recovering nickel in the solution as a precipitate by adjusting In addition, the method of the present invention is carried out by changing the combination of the first, second and third neutralization steps when there are reasons such as the composition of the nickel-containing oxide ore, the omission of manufacturing equipment, etc. It is also possible.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. In the present invention, nickel-containing oxide ore is used as the scandium recovery raw material. Mineralogically known laterites and garnierites are known as nickel-containing oxide ores.
5-4.0%, iron 15-50%, aluminum 2-
About 5% is included, and 0.0010 to 0.01
It contains 0% scandium.

In the present invention, such nickel-containing oxide ore is first leached with an acid in the leaching step.

In the acid leaching, in order to use the acid efficiently and to facilitate the treatment process of the leachate in the subsequent step, scandium and nickel are preferentially dissolved from the oxide ore to be oxidized. Iron and aluminum contained in ores should be left in the leach residue as much as possible. This is because the amount of acid used is reduced, and the leachate has a low content of iron and aluminum, which facilitates post-treatment of the leachate.

Therefore, the leaching step is carried out at high temperature and high pressure using an autoclave. The temperature is 150-300 ° C,
The pressure is 5 to 60 kg / cm ² (gauge pressure, the same applies below),
Preferably, the temperature is 220 to 260 ° C. and the pressure is 24 to 4
It is carried out in the range of 8 kg / cm ² . This is because if the temperature is less than 150 ° C. and the pressure is less than 5 kg / cm ² , the leaching rate of nickel and scandium may be low, and the iron and aluminum contents of the leaching solution may be high. If the temperature exceeds 300 ° C and the pressure exceeds 60 kg / cm ² , the leaching speed of nickel and scandium will increase, but the equipment and equipment will become large and the cost will increase, and operating costs such as the use of extra energy will increase. Is also higher.

Such high temperature and high pressure is achieved by blowing pressurized steam into the autoclave. The blowing of the pressurized steam also has the effect of stirring the leachate, and therefore has the effect of promoting the leach reaction and shortening the leach time. It should be noted that the leaching reaction can be completed within 1 hour by simultaneously performing stirring with an impeller in addition to the pressurized steam blowing.

The acid used in the leaching step may be sulfuric acid, hydrochloric acid or nitric acid. The amount of acid used is such that the pH of the leaching solution obtained by acid leaching under high temperature and high pressure is 0.5 to 0.5 at room temperature. It is preferable to adjust it to 2. If the pH of the leachate is as low as less than 0.5, the contents of iron and aluminum in the leachate will be high, and a large amount of neutralizing agent will be used for neutralization in the subsequent step, which is not preferable. On the other hand, when the pH of the leachate is a high value of 2 or more, the leaching rate of nickel and scandium is low, which is not preferable.

When acid leaching is carried out under the above conditions, nickel and scandium are leached at 95% or more, while the leaching rates of iron and aluminum are suppressed to 5% or less and 10% or less, respectively.

The leachate obtained in this way from the leach step contains iron and aluminum in addition to nickel and scandium. In the method of the present invention, the first leach step is the middle leach solution. Add a solvating agent to adjust the pH to the range of 2 to 4.

In this first neutralization step, iron and aluminum in the leachate are preferentially neutralized and precipitate to give nickel,
Separated from scandium. As the neutralizing agent, it is easiest to use an alkali compound, but if available, ores containing an alkali compound can also be used. As the alkaline compound, magnesium, calcium, oxides of sodium, magnesium, calcium,
Carbonates of sodium and ammonia, or hydroxides of magnesium, calcium, sodium and ammonia can be used. When the pH is less than 2, the neutralization precipitation of iron and aluminum is not complete, and when the pH is more than 4, nickel and scandium precipitates are also generated in addition to iron and aluminum. It is necessary to adjust the pH to the range of 2-4.

The iron and aluminum precipitates thus produced in the first neutralization step are separated and removed by a known method such as filtration to obtain a first neutralization solution as a residual liquid.

Iron and aluminum are removed from the first neutralization solution obtained from the first neutralization step, and nickel and scandium are contained. In the method of the present invention, the neutralizing agent is then added to the first neutralizing solution to adjust the pH to
A second neutralization step is performed, adjusting to a range of ultra to 7.5.

In this second neutralization step, scandium in the first neutralization solution is preferentially neutralized, precipitates, and is separated from nickel. As the neutralizing agent, as in the case of the first neutralizing step, magnesium, calcium, sodium oxide, magnesium, calcium, sodium, ammonia carbonate, or magnesium, calcium, sodium, ammonia hydroxide, etc. Alkalineized inclusions can be used. If PH is less than 4, neutralization precipitation of scandium is not complete, and if PH is more than 7.5, nickel precipitation is also generated in addition to scandium. Therefore, in the second neutralization step, PH is more than 4 It is necessary to adjust to the range of ~ 7.5.

The scandium precipitate thus produced in the second neutralization step is separated and recovered by a known method such as filtration to obtain a second neutralization solution as the residual liquid. The concentrated precipitate of scandium collected here is in the form of hydroxide or carbonate of scandium, and the concentration ratio of scandium to the hydroxide or carbonate of scandium is the same as that of the original oxide ore. Scandium 4
It becomes 0 to 2000 times.

The concentrated precipitate of scandium obtained in the second neutralization step is easily dissolved in an acid when used as a main raw material for purification and recovery of scandium, and iron, aluminum, etc. A high-concentration scandium-containing liquid containing less impurities can be obtained. Therefore, the high-purity scandium can be easily obtained by the conventional solvent extraction, chelate extraction or ion exchange, and its technical and economic effects are great.

On the other hand, the second neutralization solution obtained from the second neutralization step is free of iron, aluminum and scandium and contains nickel. In the method of the present invention, a third neutralizing step is carried out in which a pH of more than 7.5 is adjusted by further adding a neutralizing agent to the second neutralizing solution.

In this third neutralization step, nickel in the second neutralization solution is neutralized and precipitates. As the neutralizing agent, magnesium, calcium, sodium oxide, carbonate,
Alternatively, an alkali compound such as hydroxide can be used. Note that if the pH is 7.5 or less, the neutralization precipitation of nickel will not be complete, so it is necessary to adjust the pH to more than 7.5 in the third neutralization step.

The nickel precipitate thus produced in the third neutralization step is separated by a known method such as filtration,
It collects and a third neutralization solution is obtained as a residual liquid. The nickel concentrated precipitate collected here is in the form of nickel hydroxide or carbonate, and the concentration ratio of nickel to this nickel hydroxide or carbonate is the same as that of the original oxide ore. 10 to 1000 times.

Since the third neutralizing solution separated from the nickel concentrated precipitate in the third neutralizing step does not contain any metal other than magnesium, calcium or sodium, particularly heavy metal, the third neutralizing solution is discharged into the water such as the ocean. However, since there is no problem in terms of pollution, it can be discharged as it is, or when an ammonia compound is used as a neutralizing agent in the first to second neutralization steps, ammonia can be separated and recovered before being discharged.

As described above, according to the present invention, useful nickel and scandium can be recovered from an oxide ore containing nickel and scandium by a relatively simple process.

The method of the present invention can also be used for recovering scandium from the refining residue such as tin, titanium, tungsten, uranium, tantalum, niobium and bauxite.

Further, in the method of the present invention, the combination of the first, second and third neutralization steps is changed when there are reasons such as the composition of the nickel-containing oxide ore, the omission of the production equipment and the like, such as economy. It is also possible to carry out.

For example, when the content of iron or aluminum in the nickel-containing oxide ore is low, nickel, scandium, iron and aluminum are simultaneously precipitated in one neutralization step without dividing the neutralization step. It is also possible to collect. In this case, an alkali compound such as magnesium, calcium, sodium oxide, carbonate, or hydroxide is used as a neutralizing agent, and PH is 7.5.
Adjust to super.

Further, for example, in order to make the nickel compound recovered from the nickel-containing oxide ore into a form suitable for the existing nickel recovery step, among the components contained in the nickel-containing oxide ore, scandium, iron and aluminum coexist. It is also possible to recover as a precipitate and nickel as a separate precipitate. In this case, PH first
In the range of 2 to 7.5 to precipitate scandium, iron and aluminum, and to separate the generated precipitate,
Next, PH may be adjusted to more than 7.5 to precipitate nickel. In this case, nickel can be recovered not only by neutralization with a neutralizing agent but also by known methods such as sulfurization and hydrogen reduction.

Further, for example, when the nickel content in the nickel-containing oxide ore is low and the scandium content is high, after the iron and aluminum are neutralized with a neutralizing agent and washed, scandium and nickel coexist. It is also possible to collect it as a precipitate. In this case, first, the pH is adjusted to a range of 2 to 4 to precipitate iron and aluminum, and then the pH is adjusted to more than 7.5 to simultaneously neutralize and precipitate nickel and scandium.

Further, the leachate itself is directly subjected to solvent extraction,
It is also possible to supply to processes such as chelate extraction and ion exchange.

Specific examples of the present invention will be described below. In addition, when displaying% in the examples, all are% by weight (Wt%).

[0036]

Example 1 Garnierite ore (Ni: 1.6%, S
c: 0.003%, Fe: 30.5%, Al: 2.0
%) To a 25% slurry concentration, 240 g of 98% sulfuric acid was added to 1 kg of ore, and the mixture was leached with an autoclave at a temperature of 240 ° C. and a pressure of 35 kg / cm ² for 1 hour, and then the pressure of the autoclave was reduced to atmospheric pressure.

The pH of this leachate at room temperature is 0.95,
Ni: 7.9 g / l, Sc: 0.015 g / l, Fe:
A leachate having a concentration of 1.3 g / l and Al: 0.3 g / l was obtained. At this time, the leaching rates of Ni and Sc were both 95%, and the leaching rates of Fe and Al were suppressed to 0.8% and 3.0%. The leaching rate is a percentage of the weight of leached Ni and Sc with respect to the weight of Ni and Sc contained in the ore. The same applies to the leaching rates of Fe and Al.

Calcium carbonate was added to this leachate to obtain PH.
Was set to 3.5, and Fe and Al were precipitated and removed as carbonates. The precipitation removal rates of Fe and Al at this time are 95% each.
And 87%. The precipitation rate of Sc is 5%,
That of i was 0.3%. The precipitation removal rate is based on the weight of Fe and Al contained in the leachate,
It is the percentage by weight of Fe and Al that have been precipitated and removed.

Next, sodium carbonate was added to the solution after removing Fe and Al by precipitation to adjust the pH to 5.8, and Sc was recovered as a carbonate by precipitation recovery. The precipitation recovery rate of Sc at this time was 98%. The precipitation rate of Ni was 2.8%.
Also, the precipitation recovery rate of Sc is the percentage of the weight of Sc recovered by precipitation with respect to the weight of Sc contained in the leachate, and the precipitation rate of Ni is the Ni content contained in the leachate. Is the percentage of the weight of precipitated Ni relative to the weight of.

The content of this carbonate is Ni: 29.3%,
Sc: 1.86%, Fe: 8.6%, Al: 5, 2%
So, Sc is 62 against that of the original garnierite ore.
It was concentrated 0 times.

Magnesium oxide was added as a neutralizing agent to the liquid after recovering Sc as carbonate to adjust pH to 8.0 and Ni as hydroxide was recovered. At this time, the recovery rate of Ni into the precipitate was 100%, and a hydroxide of Ni: 45.3% was obtained as a precipitate. Ni was enriched 28 times with respect to Ni of the original garnierite ore. As described above, in this embodiment, Fe and Al contained in the leachate are first precipitated and removed.
The precipitate of Ni and Ni has an effect of obtaining high purity.

[0042]

Example 2 Laterite ore (Ni: 1.1%, Sc:
0.005%, Fe: 45.2%, Al: 2.8%) to 30% slurry concentration with water, 98% sulfuric acid ore 1
145g was added to kg and the temperature was set to 2 by autoclave.
After leaching at 40 ° C. and a pressure of 35 kg / cm ² for 1 hour, the pressure of the autoclave was reduced to atmospheric pressure.

The pH of this leachate at room temperature is 1.02,
Ni: 5.4 g / l, Sc: 0.025 g / l, Fe:
A leachate having a concentration of 1.2 g / l and Al: 0.4 g / l was obtained. At this time, the leaching rates of Ni and Sc were both 95%, and the leaching rates of Fe and Al were suppressed to 0.5% and 2.8%.

Aqueous ammonia was added to this leachate as a neutralizing agent to adjust the pH to 5.5, and Sc, Fe and Al were precipitated as hydroxides to be separated and recovered. Sc, F at this time
e and Al precipitation recovery rates are 98% and 100%, respectively
And 100%. The Ni precipitation rate was 0%. The component of this hydroxide is Sc: 0.67%, F
e: 32.2% and Al: 10.7%. Sc was 134 times that of the original laterite ore.

Sodium hydroxide was added to the liquid after recovering Sc, Fe and Al as hydroxides to adjust the pH to 8.2 and Ni was precipitated as hydroxides. At this time, the Ni precipitation recovery rate was 100%, and a hydroxide of Ni: 48.6% was obtained. The Ni content was 44 times that of the original laterite ore. In this embodiment, Sc, Fe, and Al contained in the leachate are first precipitated and recovered as hydroxides, and only Ni needs to be recovered in the subsequent steps, so that processing equipment and processing steps can be omitted. effective.

[0046]

Example 3 To the leachate obtained in Example 2, sodium carbonate was added as a neutralizing agent to adjust the pH to 7.8, and Ni, Sc, F
The whole amount of e and Al was precipitated as a carbonate and separated and collected.

The content of this carbonate is Ni: 32.3%,
Sc: 0.15%, Fe: 7.2%, Al: 2.4%
Then, Ni and Sc were both concentrated 30 times with respect to Ni and Sc of the original laterite ore. This actual example is a method of precipitating and recovering all of Sc, Fe, Al, and Ni contained in the leachate as hydroxides. Compared with Example 2, further processing equipment and processing steps are omitted. There is an effect that can be done.

[0048]

INDUSTRIAL APPLICABILITY As described above, the present invention provides a method for recovering useful nickel and scandium in high yield from oxide ores containing nickel and scandium by a relatively simple technical means. , Its technical and economic effects are extremely large.

Continuation of the front page (56) Reference JP-A-9-143588 (JP, A) JP-A-63-83234 (JP, A) JP-A-51-149117 (JP, A) JP-A-9-143589 (JP , A) JP-A-9-194211 (JP, A) JP-A-9-176756 (JP, A) JP-A-2000-234130 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) ) C22B 1/00-61/00

Claims (4)

(57) [Claims] 1. A method for recovering nickel and scandium from an oxide ore containing nickel and scandium, comprising: (1) a temperature of 150 to 300 ° C. and a pressure of 5 to 60 for the oxide ore.
Leaching step of leaching with acid under high temperature and high pressure of kg / cm ² (gauge pressure) to obtain leachate containing nickel and scandium, and (2) adding neutralizing agent to leachate to adjust pH to a range of 2 to 4. By doing so, a first neutralizing step of removing iron and aluminum in the leachate as a precipitate, and (3) a solution after removing the precipitate in the first neutralizing step, a neutralizing agent is added to adjust the pH. A second neutralization step of recovering scandium in the solution as a precipitate by adjusting the pH in the range of more than 4 to 7.5, and (4) further adjusting the pH to more than 7.5 by adding a neutralizing agent. The method for recovering nickel and scandium from oxide ore, which comprises a third neutralization step of recovering nickel in the solution as a precipitate. 2. A method for recovering nickel and scandium from an oxide ore containing nickel and scandium, comprising: (1) temperature of the oxide ore at 150 to 300 ° C .;
Leaching step to obtain leachate containing nickel and scandium by leaching with acid under high temperature and high pressure of kg / cm ² (gauge pressure), (2) Add neutralizing agent to leachate to adjust pH to more than 7.5 A method for recovering nickel and scandium from oxide ore, which comprises a neutralization step of recovering nickel, scandium, iron, and aluminum in the leachate as a precipitate by adjusting. 3. A method of recovering nickel and scandium from an oxide ore containing nickel and scandium, comprising: (1) temperature of the oxide ore at 150 to 300 ° C .;
Leaching step of leaching with acid under high temperature and high pressure of kg / cm ² (gauge pressure) to obtain a leachate containing nickel and scandium, and (2) adding a neutralizing agent to the leachate to adjust pH to a range of 2 to 7.5. The neutralization step of recovering scandium, iron and aluminum in the leachate as a precipitate by adjusting to (3) a solution after recovering the precipitate in the neutralization step, and further adding a neutralizing agent to the solution. A method for recovering nickel and scandium from oxide ore, which comprises a neutralization step of recovering nickel in the solution as a precipitate by adjusting the pH to more than 7.5. 4. A method for recovering nickel and scandium from an oxide ore containing nickel and scandium, comprising: (1) temperature of the oxide ore at 150 to 300 ° C .;
Leaching step of leaching with acid under high temperature and high pressure of kg / cm ² (gauge pressure) to obtain leachate containing nickel and scandium, and (2) adding neutralizing agent to leachate to adjust pH to a range of 2 to 4. By doing so, a neutralizing step of removing iron and aluminum in the leachate as a precipitate, and (3) a neutralizing agent is further added to the solution after removing the precipitate in the neutralizing step to adjust the pH to 7. A method for recovering nickel and scandium from oxide ore, which comprises a neutralization step of recovering nickel and scandium in the solution as a precipitate by adjusting the ratio to more than 5.