JP5446226B2 - Method for hydrometallizing nickel oxide ore - Google Patents

Description

  The present invention relates to a method for hydrometallizing nickel oxide ore, and more particularly, high-pressure acid leaching including an ore treatment process, a leaching process, a solid-liquid separation process, a neutralization process, a zinc removal process, a sulfidation process, and a final neutralization process. In the hydrometallurgical method for recovering nickel and cobalt from nickel oxide ore by the method, the wear of piping, pumps and other equipment due to ore slurry produced from the ore processing step is suppressed, and durability is improved. Reduce the amount of final neutralization residue produced from the final neutralization step, and achieve the task of reducing costs and environmental risks by compressing the capacity of the tailing dam that stores waste leach residue, neutralized residue, etc. In addition, the present invention relates to a method for hydrometallizing nickel oxide ore capable of separating and recovering impurity components that can be recycled and effectively utilized.

  In recent years, raw materials costs in metal smelting have increased significantly due to the increasing oligopoly of mining rights in mineral resources such as coal, iron, copper, nickel, cobalt, chromium and manganese. Therefore, in metal smelting, as a measure for cost reduction, technical development has been carried out in order to use low-grade raw materials that have not been targeted since they are disadvantageous in terms of cost. For example, in nickel smelting, a material having excellent corrosion resistance under high temperature and high pressure has been developed. Wet smelting based on a high pressure acid leaching method in which nickel oxide ore is acid leached under pressure with sulfuric acid. Refining methods are attracting attention.

  This high-pressure acid leaching method differs from the conventional dry smelting method that is a nickel oxide ore smelting method and is advantageous in terms of energy cost because it does not include dry processes such as a reduction process and a drying process. Is considered to be a promising technology for smelting low-grade nickel oxide ore. For this reason, various proposals for improving the leaching rate of nickel and cobalt, purifying the leachate, reducing the amount of operating materials, etc., focusing on the leaching process under high temperature and pressure, in order to increase the degree of completion as a smelting process Has been made.

By the way, as a process using leaching under high temperature and pressure, for example, in recovering the metal from oxide ore containing valuable metals such as nickel, cobalt, manganese, etc., the following steps (a) to (c) A method (for example, refer to Patent Document 1) for recovering valuable metals from the oxidized ore is proposed.
Step (a): Oxidized ore that has been slurried in advance is subjected to atmospheric pressure leaching under the acidic condition of sulfuric acid with the pressure leaching solution obtained in step (b) to obtain an atmospheric pressure leaching solution and an atmospheric pressure leaching residue.
Step (b): The atmospheric leaching residue obtained in the step (a) is reacted with sulfuric acid in an oxidizing atmosphere at high temperature and high pressure to obtain a pressurized acid leaching solution.
Step (c): A neutralizing agent is added to the atmospheric leachate obtained in step (a) to neutralize it, and then an alkali sulfide compound is added to recover nickel and cobalt in the leachate as sulfides.

  In this method, the nickel leaching rate from the ore is obtained by performing two-stage leaching, in which ore slurry is subjected to atmospheric leaching (step (a)) and then pressure leaching residue is pressurized acid leaching (step (b)). At the same time, excess acid contained in the leaching solution of pressurized acid leaching is neutralized by the alkali component contained in the atmospheric leaching residue, and the load of the neutralization step (step (c)) is reduced. is there. However, because of the two-stage leaching, there is a problem that the number of facilities increases and the cost and labor are increased, and that the processing of a large amount of thin liquid generated when washing the leaching residue requires a cost.

In order to solve these problems, as another process using leaching under high temperature and pressure, a method including the following steps (1) to (4) (for example, see Patent Document 2) is proposed. ing.
(1) Leaching step: Slurry nickel oxide ore, add sulfuric acid, and stir at a temperature of 220-280 ° C. to form a leaching slurry.
(2) Solid-liquid separation step: The leaching slurry is washed using a multi-stage thickener and separated into a leaching solution containing nickel and cobalt and a leaching residue.
(3) Neutralization step: Adjusting the pH to be 4 or less using calcium carbonate while suppressing oxidation of the leachate to produce a neutralized precipitate containing trivalent iron. Separate into slurry and nickel recovery mother liquor. And (4) Sulfurization step: Hydrogen sulfide gas is blown into the nickel recovery mother liquor to produce a sulfide containing nickel and cobalt, which is separated from the poor solution.

Here, the outline | summary of the practical plant based on the said method (patent document 2) is demonstrated using figures. FIG. 2 is a smelting process diagram showing an example of a practical plant based on a nickel oxide ore hydrometallurgical method (Patent Document 2).
In FIG. 2, nickel oxide ore 8 is first mixed with water in ore processing step 1, and then foreign matter removal and ore particle size adjustment are performed to form ore slurry 9. Next, the ore slurry 9 is subjected to high-temperature pressure leaching using sulfuric acid in the leaching step 2 to form a leaching slurry 10. The leaching slurry 10 is subjected to the solid-liquid separation step 3 and subjected to multistage cleaning, and then separated into a leaching solution 11 containing nickel and cobalt and a leaching residue slurry 12. The leachate 11 is subjected to a neutralization step 4 and separated into a neutralized precipitate slurry 13 containing a trivalent iron hydroxide and a mother liquid (1) 14 for recovering nickel. The mother liquor (1) 14 is subjected to a zinc removal step 5 in which a sulfurizing agent is added, and is separated into a zinc sulfide residue 15 containing zinc sulfide and a mother liquor (2) 16 for recovering nickel. Next, the mother liquor (2) 16 is subjected to a sulfiding step 6 and separated into a mixed sulfide 17 containing nickel and cobalt and a poor liquid 18 from which nickel or the like has been removed. The poor liquid 18 is used as washing water for the leaching residue in the solid-liquid separation step 3.
Finally, the leaching residue slurry 12 is subjected to the neutralization process 7 together with the excess poor solution 18 and neutralized, and the final neutralization residue 19 is stored in the tailing dam 20.

  As a feature of this method, it is possible to reduce the amount of neutralizing agent consumed and the amount of residue in the neutralization step and to increase the true density of the leach residue by washing the leach slurry in multiple stages in the solid-liquid separation step. Therefore, the solid-liquid separation characteristics can be improved, and further, the process can be simplified by performing the leaching process only by high-temperature pressure leaching, and there are advantages over the above-described method (Patent Document 1). It is said that there is. In addition, if a poor liquid is used as the cleaning liquid used in the solid-liquid separation process, nickel adhering to the leaching residue can be leached and recovered using the remaining sulfuric acid, and effective and efficient water repetition It is said that it can be used. Furthermore, if the neutralized precipitate slurry is sent to the solid-liquid separation step, nickel loss can be reduced, which is more advantageous.

However, the practical plant according to this method has the following problems.
(1) Suppression of equipment wear: Nickel oxide ore is transported between each process as a slurry, but the wear of equipment materials is remarkably promoted, especially in equipment such as piping and pumps in the leaching process, which is frequently repaired and maintained. This was a major cause of increased costs and reduced plant availability. In other words, chromite contained in nickel oxide ore is particularly hard and is a component that remarkably promotes wear of pipes, pumps, etc. in a hydrometallurgical plant that involves the transfer of slurry. It is desirable to remove.

(2) Increase in solid content of ore slurry: Generally, the higher the solid content of the nickel oxide ore slurry, the less liquid is handled and the equipment such as piping and tanks can be simplified. Although it is preferable to concentrate the ore slurry to such an extent that there is no hindrance or pipe clogging occurs, there is a limit associated with the sedimentation property of the ore slurry.

(3) Reduction of the content of impurity elements in the ore slurry: In the leaching process, impurity elements such as magnesium and aluminum contained in the ore slurry greatly affect the amount of sulfuric acid used. The lower one is preferable.

(4) Reduction of the amount of final neutralization residue: The leaching residue obtained in the solid-liquid separation step is united with the excess poor liquid produced from the sulfidation step, and neutralized by adding limestone slurry or slaked lime slurry to this. Detoxified. The final neutralization residue produced from this final neutralization process (hereinafter sometimes referred to as final neutralization process) is stored in a tailing dam. However, since the final neutralization residue contains impurities such as hematite, chromite, silica mineral, and silicic acid ore in the leach residue, it also contains gypsum formed by the neutralization treatment. There was a big cost burden for management. For this reason, it is expected that impurity components such as hematite, chromite, silica mineral, and siliceous ore in the leaching residue are effectively recycled. For example, chromite is expected to be used as a raw material for producing ferrochrome used as an additive element of stainless steel. However, for the production of ferrochrome, it is desired to collect it as a concentrate having a chromium quality of, for example, 5% by mass or more from the viewpoint of processing efficiency and cost. Hematite is expected to be used as a raw material for steel. However, many components other than hematite are contained in the leaching residue, and separation from these is desired. In particular, sulfur has problems such as the generation of sulfurous acid gas in the steelmaking process, and it is desired that sulfur is not contained as much as possible. The allowable upper limit of sulfur quality varies depending on the factory receiving and treating it as a steel raw material, but it is generally required to have a content of about 2 to 3% by mass or less.

(5) Repeated treatment of neutralized residue slurry: As described above, the treatment in the solid-liquid separation step of the neutralized residue slurry is effective for improving nickel recovery. The iron hydroxide is also redissolved, eventually increasing the consumption of neutralizing agent and increasing the amount of leach residue. Therefore, the fewer neutralization precipitates that are repeated in the solid-liquid separation step, the better.

  Under the circumstances as described above, a solution for the above problem has been demanded in a practical plant using the hydrometallurgical method based on the high pressure acid leaching method. Furthermore, in order to effectively and economically solve the above problems, it is an effective means to efficiently separate and recover the impurity components contained in the ore or the leaching residue. It was also required to utilize it.

JP-A-6-116660 (first page, second page) JP-A-2005-350766 (first page, second page)

  The object of the present invention is to provide a high-pressure acid leaching method including an ore processing step, a leaching step, a solid-liquid separation step, a neutralization step, a zinc removal step, a sulfidation step, and a final neutralization step in view of the above-mentioned problems of the prior art. In the hydrometallurgical method for recovering nickel and cobalt from nickel oxide ore, the wear of pipes, pumps, etc. due to ore slurry produced from the ore treatment process is suppressed, and durability is improved, solidity of the ore slurry To increase the rate, simplify the equipment for the ore processing process, reduce the amount of final neutralization residue produced from the final neutralization process, and store waste leach residue, neutralized residue, etc. It is possible to achieve the task of reducing cost and environmental risk by compressing the capacity of the tailing dam, and to separate and recover the impurity components that can be recycled and effectively used To provide a hydrometallurgical method for nickel oxide ore.

  In order to achieve the above object, the inventors of the present invention have carried out nickel oxidation by a high pressure acid leaching method including an ore treatment process, a leaching process, a solid-liquid separation process, a neutralization process, a zinc removal process, a sulfidation process, and a final neutralization process. In the hydrometallurgical method for recovering nickel and cobalt from oxide ore, as a result of earnest research on the solution of the above problem, silica mineral, chromite or siliceous ore in the ore slurry produced from the ore treatment process is obtained. From the step (A) of separating and recovering the contained particles by a specific method, the step of (B) separating and recovering the hematite particles in the leach residue produced from the solid-liquid separation step, or the neutralization step When at least one step selected from the step (C) of separately neutralizing the produced neutralized slurry is carried out, it is found that it is effective as a solution to the above problem, Invention has been completed.

That is, according to the first invention of the present invention, nickel oxidation is performed by a high pressure acid leaching method including an ore treatment process, a leaching process, a solid-liquid separation process, a neutralization process, a zinc removal process, a sulfidation process, and a final neutralization process. In the hydrometallurgical method for recovering nickel and cobalt from ore,
There is provided a method for hydrometallurgy of nickel oxide ore comprising at least one step selected from the following steps (A) to (C).
(A) The particle | grains containing the at least 1 sort (s) chosen from the silica mineral in the ore slurry produced from the said ore processing process, a chromite, or a siliceous clay ore are separated and collect | recovered by a physical separation method.
(B) The hematite particles in the leach residue slurry produced from the solid-liquid separation step are separated and recovered by a physical separation method.
(C) The neutralized residue slurry produced from the neutralization step is subjected to final neutralization separately from the leaching residue produced from the solid-liquid separation step.

Further, according to the second invention of the present invention, in the first invention, when the step (C) is included, in the step (C), the zinc sulfide precipitate slurry produced from the zinc removal step in the step (C), Provided is a method for hydrometallizing nickel oxide ore, characterized in that final neutralization is performed simultaneously with the neutralized slurry.

  Moreover, according to the third invention of the present invention, in the first or second invention, the ore treatment step is a step of performing foreign matter removal and ore particle size adjustment of the mined raw material ore to form an ore slurry, The leaching step is a step of adding sulfuric acid to the ore slurry and stirring it under high temperature and high pressure to form a leaching slurry comprising a leaching residue and a leaching solution. The solid-liquid separation step is a step of leaching the leaching slurry in multiple stages. Washing to obtain a leachate containing nickel and cobalt and a leach residue slurry, wherein the neutralization step is to add calcium carbonate to the leach liquor, and neutralize residue slurry containing trivalent iron and nickel The zinc removal step is a step of blowing hydrogen sulfide gas into the mother liquor to form a zinc sulfide deposit slurry and a mother liquor for recovering nickel and cobalt. The sulfurization step is a step of blowing hydrogen sulfide into the nickel and cobalt recovery mother liquor to produce a mixed sulfide containing nickel and cobalt and a poor solution, and the final neutralization step is performed on the leaching residue slurry. There is provided a method for wet smelting of nickel oxide ore, which is a step of adding a surplus poor solution and adjusting the pH to about 8 to 9 to obtain a final neutralized residue.

  According to a fourth invention of the present invention, in the third invention, in the ore treatment step, the ore particle size adjustment is subjected to a sieving treatment with a particle size of 2 mm or less, and the wet wet nickel oxide ore A smelting method is provided.

According to a fifth invention of the present invention, in any one of the first to fourth inventions, when the step (A) is included, in the step (A), the ore slurry is subjected to sieving classification or centrifugal classification. A method for hydrometallurgy of nickel oxide ore is provided, characterized in that it is subjected to a physical separation method by the method, and the classified coarse particles are recovered as a concentrate of silica mineral, chromite or siliceous ore. .

Moreover, according to the sixth invention of the present invention, in the fifth invention, when subjected to the physical separation method by sieving classification or centrifugal classification, the classification particle size is selected from the range of 20 to 850 μm. A method for hydrometallizing nickel oxide ore is provided.

According to the seventh invention of the present invention, in the fifth invention, when the physical separation method by sieving classification or centrifugal classification is used, the classification particle size is selected from a range of 850 μm or more and a range of 20 to 850 μm. First, the coarse part classified in the former range of particle size is recovered as a concentrate of silica mineral or siliceous ore, and then the coarse part classified in the latter range of particle size is recovered. There is provided a method for hydrometallizing nickel oxide ore, which is recovered as a chromite concentrate.

Moreover, according to the eighth invention of the present invention, in any one of the first to fourth inventions, when the step (B) is included, in the step (B), the leaching residue slurry or a final medium containing it Provided a method for hydrometallurgy of nickel oxide ore, characterized in that the Japanese residue slurry is subjected to a physical separation method by sieving classification or centrifugal classification, and at that time, the classified fine particles are recovered as a hematite concentrate. Is done .

Further, according to the ninth invention of the present invention, in the eighth invention, when subjected to the physical separation method by sieving classification or centrifugal classification, the classification particle size is selected from the range of 20 to 100 μm. A method for hydrometallizing nickel oxide ore is provided .

According to a tenth aspect of the present invention, in any one of the first to fourth aspects of the invention, when the step (B) is included, in the step (B), the leaching residue slurry or a final medium containing it There is provided a method for wet smelting of nickel oxide ore, wherein the sum residue slurry is subjected to a physical separation method by magnetic separation, and the magnetic deposit is recovered as a hematite concentrate .

  The hydrometallurgical method of nickel oxide ore according to the present invention comprises an ore treatment step, a leaching step, a solid-liquid separation step, a neutralization step, a zinc removal step, a sulfidation step and a final neutralization step. In the hydrometallurgical method for recovering nickel and cobalt from ore, the above problems can be solved as follows by adopting the steps (A) to (C), and thus the industrial value is extremely large.

  If the process of (A) is adopted, by separating and recovering particles containing silica minerals, chromite and siliceous ore in the ore slurry produced from the ore treatment process, piping of the ore slurry, equipment such as pumps, etc. While suppressing wear, the solid content of the ore slurry can be increased. Furthermore, if these impurity components are separated, the amount of the final neutralization residue can be reduced due to the decrease in the amount of leaching residue, and further, the content of the impurity element that greatly affects the amount of sulfuric acid used is also achieved. Here, these impurity components, particularly chromite, can be effectively utilized.

  In addition, if the step (B) is employed, the amount of the final neutralization residue produced from the final neutralization step is reduced and discarded by separating and recovering the hematite in the leach residue produced from the solid-liquid separation step. Cost and environmental risk can be reduced by compressing the capacity of the tailing dam that stores leach residue, neutralized debris, etc., and hematite that can be effectively used as iron resources can be separated and recovered.

  In addition, if the step (C) is adopted, the neutralized residue slurry produced from the neutralization step is separated from the final neutralization step and separately neutralized to reduce the amount of the final neutralization residue. In particular, it is advantageous when separating and recovering hematite in the leach residue.

The hydrometallurgical method of nickel oxide ore according to the present invention comprises an ore treatment step, a leaching step, a solid-liquid separation step, a neutralization step, a zinc removal step, a sulfidation step and a final neutralization step. In the hydrometallurgical method for recovering nickel and cobalt from ore,
It includes at least one step selected from the following steps (A) to (C).
(A) The particle | grains containing the at least 1 sort (s) chosen from the silica mineral in the ore slurry produced from the said ore processing process, a chromite, or a siliceous clay ore are separated and collect | recovered by a physical separation method.
(B) The hematite particles in the leach residue slurry produced from the solid-liquid separation step are separated and recovered by a physical separation method.
(C) The neutralized residue slurry produced from the neutralization step is subjected to final neutralization separately from the leaching residue produced from the solid-liquid separation step.

In the method of the present invention, it is important for solving the problem to include at least one step selected from the steps (A) to (C).
Here, if the step (A) is adopted, by separating and recovering particles containing silica minerals, chromite and siliceous ore in the ore slurry produced from the ore processing step, piping or pumps using the ore slurry It is possible to suppress wear of the equipment and the like and to increase the solid rate of the ore slurry. In other words, by separating chromite or siliceous clay (magnesium silicate) ore, which is generally contained in nickel oxide ore and having extremely high hardness, it suppresses wear and is generally contained in nickel oxide ore. By preventing low density cristobalite (amorphous silica), viscous agglomerates (eg, montmorillonite: iron, aluminum hydrosilicate) that have an adverse effect on sedimentation, the increase in solid content of ore slurry is prevented. One of the factors can be eliminated. Furthermore, if these impurity components are separated, the amount of the final neutralization residue can be reduced due to the decrease in the amount of leaching residue, and further, the content of the impurity element that greatly affects the amount of sulfuric acid used is also achieved. By the way, these impurity components, particularly chromite, can be effectively utilized. Since chromite is a valuable mineral containing chromium, which is a component of stainless steel, it can be used as an effective resource if it is separated and recovered. Here, when using it as a raw material for the production of ferrochrome used as an additive element for the production of stainless steel, it is preferable to separate it with a chromium quality of, for example, 5% by mass or more from the viewpoint of processing efficiency and cost.

  In addition, if the step (B) is adopted, the amount of the final neutralization residue produced from the final neutralization step is reduced by separating and recovering the hematite in the leach residue produced from the solid-liquid separation step. The cost and environmental risk can be reduced by compressing the capacity of the tailing dam that stores the leach residue, neutralized residue, etc., and hematite that can be effectively used as an iron resource can be separated and recovered. That is, iron in the nickel oxide ore is hydrolyzed at a high temperature in the leaching process, so that it is contained in the form of hematite in the final neutralization residue. However, since the final neutralized residue contains gypsum formed by neutralization in addition to chromite, silicic acid ore, etc. in the leach residue, its iron grade is as low as 30-50% by mass, producing Considering efficiency and cost, it has been difficult to effectively use as it is as an iron-making raw material or the like, which is generally preferred to have a grade of 60% by mass or more. This is because sulfur, chromium, silicon, and the like are components that affect the distribution of trace components in pig iron, the quality of steel products, and the like, and it is required to suppress the inclusion of these impurity elements.

  If the step (C) is adopted, the neutralized residue slurry produced from the neutralization step is separated from the final neutralization step and separately neutralized to obtain the final neutralization residue amount. This is particularly advantageous when separating and recovering hematite in the leach residue. That is, in the treatment in the solid-liquid separation process of the neutralized residue slurry which has been repeated conventionally, the consumption of the neutralizing agent is to be increased.

First, an embodiment of the method for hydrometallizing nickel oxide ore of the present invention will be described with reference to the drawings.
FIG. 1 is a smelting process diagram showing an example of an embodiment of the nickel oxide ore wet smelting method according to the present invention.
In FIG. 1, nickel oxide ore 8 is first mixed with water in ore processing step 1, and then foreign matter removal and ore particle size adjustment are performed to form ore slurry 9. At this time or thereafter, the ore slurry 9 is subjected to the newly provided step 21 of (A), and silica minerals, siliceous oresite or chromite 22 are separated and recovered. The ore slurry 9 is subjected to the leaching process 2. Here, in the ore slurry 9, valuable components such as nickel and cobalt are leached with sulfuric acid using an autoclave or the like, and the leaching slurry 10 is formed. The leaching slurry 10 is subjected to a solid-liquid separation step 3 using a multistage thickener or the like, and separated into a leaching solution 11 containing nickel and cobalt and a leaching residue slurry 12.

  Subsequently, the leachate 11 is subjected to a neutralization step 4 and separated into a neutralization residue 13 mainly composed of trivalent iron hydroxide and a mother liquid (1) 14 containing nickel. The mother liquor (1) 14 is subjected to a zinc removal step 5 in which a sulfurizing agent is added, and is separated into a zinc sulfide residue 15 containing zinc sulfide and a mother liquor (2) 16 for recovering nickel. Next, the mother liquor (2) 16 is subjected to a sulfiding step 6 in which a sulfiding agent is added, and separated into a mixed sulfide 17 containing nickel and cobalt and a poor liquid 18. The poor liquid 18 is used as washing water for the leach residue in the solid-liquid separation process 3 and as washing water for the neutralized residue slurry 13 produced in the neutralization process 4.

  Finally, the leaching residue slurry 12 is subjected to a neutralization process by being subjected to the final neutralization step (1) 7 together with the excess poor solution 18. At that time, or after that, it is applied to the newly provided step 23 of (B) and separated into the final neutralization residue (1) 19 and the hematite residue 24. Further, the neutralized residue slurry 13 is subjected to a final neutralization step (2) 25 corresponding to the newly provided step (C) together with the zinc sulfide precipitate 15. The obtained final neutralization residue (2) 26 and final neutralization residue (1) 19 are stored in the tailing dam 20.

Below, each process is demonstrated in detail.
(1) Ore processing step and step (A) The ore processing step is a step of performing foreign matter removal and ore particle size adjustment to form an ore slurry. Here, the nickel oxide ore is sieved with a wet sieve or the like to separate foreign matter that cannot be leached in the leaching process, ore with a particle size that is difficult to flow with a pump. Here, the sieving particle size is usually about 2 mm, preferably 1.4 mm, and the ore having a particle size larger than that is crushed. A slurry is formed by the ore that has passed through the pulverization-sieving treatment, and then, the slurry is settled and concentrated to prepare an ore slurry in which the solid concentration (slurry concentration) in the slurry is adjusted. The slurry concentration is usually adjusted to about 25 to 45% by mass.

  The nickel oxide ore is mainly so-called laterite ore such as limonite ore and saprolite ore. The nickel content of the laterite ore is normally 0.8 to 2.5% by mass, and nickel is contained as a hydroxide or a hydrous silicic clay (magnesium silicate) mineral. The iron content is 10 to 50% by mass and is mainly in the form of trivalent hydroxide (goethite), but partly divalent iron is contained in the hydrous silicic clay. . The silicic acid content is contained in silica minerals such as quartz and cristobalite (amorphous silica) and hydrous silicic clay. Further, most of the chromium content is contained as a chromite mineral containing iron or magnesium. Further, the magnesia content is contained in hydrous silicic clay minerals as well as silicic clay minerals that are unweathered and contain almost no nickel which has high hardness. As described above, in the laterite ore, the silica mineral, the chromite mineral, and the siliceous clay mineral are so-called gangue components that hardly contain nickel.

Therefore, ore slurries produced from the above ore processing processes generally include cristobalite, which has a negative effect on sedimentation when raising the solid concentration, and chromite and silica, which have a great influence on the wear of equipment such as piping and pumps in the leaching process. Silica mineral containing low-nickel content, including magnesium, which consumes sulfuric acid in the leaching process.
For this reason, it is desirable to separate and collect silica minerals such as cristobalite, chromite and siliceous ore in advance in the ore processing step from the ore slurry prepared in the ore processing step.

Here, the distribution state of each component in the ore particle which comprises an ore slurry is demonstrated.
In the EPMA observation of nickel oxide ore, the portion with high chromium, silicon, and magnesium content has a high ratio that exists as a single phase independent of the portion with high iron content and has a particle size of 20 to 1000 μm There are many. This means that minerals containing chromium, silicon, and magnesium are mostly contained in particles of about 20 μm or more, while minerals containing nickel and iron are contained in particles of about 20 μm or less. Show.

  Therefore, in order to effectively separate and collect silica minerals, chromite and siliceous ore from the ore slurry, the ore after removing the coarse mass is slurried and the nickel oxide ore in the ore slurry is appropriately used. It is important to break up to a suitable particle size and to set an appropriate classification particle size. The pulverization particle size is determined in consideration of the original purpose of forming the ore slurry and the properties of the ore, but is preferably 2 mm or less, more preferably 1.4 mm or less.

Tables 1 and 2 show examples of the ore particle size distribution of the ore slurry and the quality of each component in each particle size classification. Note that the ores used in Tables 1 and 2 differ in the deposits produced.
Table 1 shows an example of the ore particle size distribution of the ore slurry obtained by crushing to a particle size of 2 mm or less and the quality of each component in each particle size classification. From Table 1, the coarse particle part of 75 μm or more is shown. It can be seen that chromium, silicon, magnesium and the like are concentrated in each particle size category, and in particular, silicon, magnesium and the like are concentrated in each particle size category of the coarse particle portion of 355 μm or more.

  Table 2 shows an example of the ore particle size distribution of the ore slurry obtained by crushing to a particle size of 1.4 mm or less and the quality of each component in each particle size classification. From Table 2, 75 μm or more is shown. It can be seen that chromium, silicon, magnesium and the like are concentrated in each particle size category of the coarse portion, and that silicon, magnesium and the like are particularly concentrated in each particle size category of the coarse particle portion of 1000 μm or more. Table 3 shows the average analysis values when the particle size classifications in Table 2 are summarized for each predetermined particle size range.

Based on the above results, the particles containing chromium, silicon, and magnesium at a high content are coarser than the particles containing iron at a high content. And a coarse grain part containing magnesium in a high content and a fine grain part containing nickel and iron in a high content. Here, the coarse-grained portion can be dispensed out of the system, purified in a separate process, and recovered as a resource such as chromium.
In the coarse part, particles containing silicon and magnesium at a high content are distributed more on the coarse particle side than particles containing chromium at a high content. And the concentrate which improved the chromium content can be collect | recovered by isolate | separating the particle | grains containing magnesium and a high content.

  The step (A) is a step of separating and recovering at least one selected from silica mineral, chromite or siliceous ore in the ore slurry produced from the ore treatment step. In addition, the process of (A) can be included in the said ore processing process, or can be implemented following it.

The method of the step (A) is not particularly limited, and methods using various physical separation means for separating silica mineral, chromite or siliceous ore from the ore slurry are applied. Among these, physical analysis by wet methods such as sieving classification, sedimentation classification, centrifugal classification, etc., from which analysis of the distribution state of each component in the ore particles constituting the ore slurry can be separated and recovered. The method is convenient and preferable as a rough separation means.
For example, the ore slurry is subjected to a physical separation method by sieving classification or centrifugal classification, and at that time, a method of recovering the classified coarse particles as a concentrate of silica mineral, chromite or siliceous ore is adopted. . That is, in the classification, goethite and hydrous siliceous clay containing gangue components such as silica mineral, chromite, and silicic acid ore in the classified coarse-grained portion, while nickel is contained in the classified fine-grained portion. The ore is distributed.

  In the classification, the classification particle size is not particularly limited, and is preferably 20 to 850 μm, more preferably 20 to 300 μm, particularly considering the properties of the raw ore and the nickel yield to the fine-grained portion. Preferably it is chosen from the range of 75-100 micrometers. That is, the lower limit of the classification point that can be industrially implemented is approximately 20 μm, and if the classification particle size is less than 20 μm, the concentration of silica mineral, chromite, and silicic clay is insufficient in the coarse part. The nickel in the ore slurry used in the leaching process is lost. On the other hand, when the classified particle size exceeds 850 μm, removal of silica minerals, chromite and silicic clay is insufficient at the fine-grained portion.

  Moreover, when recovering the concentrate with improved chromium content from the silica mineral, chromite or siliceous coarse-grained portion, the classified particle size is selected from a range of 850 μm or more and a range of 20 to 850 μm. Two particle sizes are used. Here, first, the coarse particles classified with a particle size in the former range are recovered as a concentrate of silica mineral or siliceous ore, and then the coarse particles classified with a particle size in the latter range are collected into silica minerals or Recovered as chromite concentrate with reduced contamination of silicic clay. Alternatively, it is possible to first obtain a coarse part classified with a particle size in the latter range and to separate the coarse part classified with a particle size in the former range. That is, the concentrate of silica mineral or siliceous ore is separated by selecting an appropriate particle size between 850 μm and the ore cracking particle size as the classified particle size. On the other hand, the chromite concentrate is efficiently separated by selecting an appropriate particle size in the range of preferably 20 to 850 μm, more preferably 20 to 300 μm, and particularly preferably 75 to 100 μm as the classified particle size.

(2) Leaching step In the leaching step, sulfuric acid is added to the ore slurry obtained in the ore treatment step and the step (A), and the mixture is stirred at a temperature of 220 to 280 ° C. Forming a leach slurry. In this process, a preheater, an autoclave, and a flash tank are used as main equipment.

  In the leaching step, leaching as sulfates such as nickel and cobalt and leaching iron sulfate as hematite by leaching reaction and high-temperature thermal hydrolysis reaction represented by the following formulas (1) to (5) Immobilization is performed. However, since the fixation of iron ions does not proceed completely, the leaching slurry obtained usually contains divalent and trivalent iron ions in addition to nickel and cobalt.

[Leaching reaction]
MO + H ₂ SO ₄ ⇒ MSO ₄ + H ₂ O (1)
(In the formula, M represents Ni, Co, Fe, Zn, Cu, Mg, Cr, Mn, etc.)
2Fe (OH) ₃ + 3H ₂ SO ₄ ⇒ Fe ₂ (SO ₄ ) ₃ + 6H ₂ O (2)
FeO + H ₂ SO ₄ ⇒ FeSO ₄ + H ₂ O (3)

[High temperature thermal hydrolysis reaction]
2FeSO ₄ + H ₂ SO ₄ + 1 / 2O ₂ ⇒ Fe ₂ (SO ₄ ) ₃ + H ₂ O (4)
_{Fe 2 (SO 4) 3 +} 3H 2 O⇒ Fe 2 O 3 + 3H 2 SO 4 (5)

  As temperature used at the said leaching process, it is 220-280 degreeC, and 240-270 degreeC is preferable. That is, by performing the reaction in this temperature range, iron is fixed as hematite. Here, when the temperature is less than 220 ° C., since the rate of the high-temperature thermal hydrolysis reaction is slow, iron remains dissolved in the reaction solution, so that the load of the liquid for removing iron increases and separation from nickel occurs. It becomes very difficult. On the other hand, when the temperature exceeds 270 ° C., the high-temperature thermal hydrolysis reaction itself is promoted, but it is not only difficult to select the material of the container used for the high-temperature pressure leaching, but it is not possible because the steam cost for the temperature rise increases. Is appropriate.

  The amount of sulfuric acid used in the leaching step is not particularly limited, and is slightly more than the chemical equivalent required for the iron in the ore to be leached and transformed into hematite, for example, per ton of ore. 300-400 kg is used. That is, if the amount of sulfuric acid added per ton of ore exceeds 400 kg, the sulfuric acid cost and the neutralizing agent cost in the subsequent process increase, which is not preferable.

  The amount of sulfuric acid used is not particularly limited, and the concentration of free sulfuric acid at the end of leaching is preferably 25 to 50 g / L, and more preferably 35 to 45 g / L. This increases the true density of the leach residue and stably produces a high density leach residue and improves the solid-liquid separation property of the slurry. it can. That is, when the concentration is less than 25 g / L, when the slurry containing the leaching residue is settled, the sediment concentration of solids becomes incomplete, and the suspended solids remain in the supernatant. This is because the reaction rate of high-temperature thermal hydrolysis is slow, the dehydration of iron hydroxide does not proceed sufficiently, and hematite with a low true density is formed. On the other hand, if the concentration exceeds 50 g / L, it is necessary to improve the durability of the leaching equipment, and the amount of neutralizing agent used for neutralizing the acid is remarkably increased. It will be disadvantageous.

(3) Solid-liquid separation process The said solid-liquid separation process is a process of wash | cleaning the leaching slurry formed at the said leaching process multistage, and obtaining the leaching liquid and leaching residue containing nickel and cobalt. As a result, nickel or the like that adheres to the leaching residue and is discarded is recovered in the leaching solution.

(4) Neutralization step In the neutralization step, calcium carbonate is added so that the pH is 4 or less, preferably 3.2 to 3.8, while suppressing oxidation of the leachate obtained in the leaching step. This is a step of forming a neutralized precipitate slurry containing trivalent iron and a mother liquor for nickel recovery. Thus, the excess acid used in the leaching step is neutralized and trivalent iron ions remaining in the solution are removed. That is, when the pH exceeds 4, the generation of nickel hydroxide increases.
The obtained neutralized residue slurry is sent to the final neutralization step (2) corresponding to the newly provided step (C) for processing.

(5) Zinc removal step In the zinc removal step, prior to the step of separating nickel and cobalt as sulfides, hydrogen sulfide gas is blown into the mother liquor to produce sulfide containing zinc, and zinc sulfide deposit slurry and It is a step of forming a mother liquor for nickel and cobalt recovery. This suppresses the speed of the sulfidation reaction by creating weak conditions during the sulfidation reaction, and selectively removes zinc by suppressing the coprecipitation of nickel, which has a higher concentration than zinc. is there.
The obtained zinc sulfide slurry can be sent to the final neutralization step (2) and processed in the same manner as the neutralized slurry obtained in the neutralization step.

(6) Sulfurization step The sulfidation step is a step in which hydrogen sulfide is blown into the mother liquor for nickel and cobalt recovery obtained in the dezincing step to produce a mixed sulfide containing nickel and cobalt and a poor solution.
Here, the obtained poor solution has a pH of about 1 to 3 and contains a slight amount of nickel and cobalt, which are recovery losses, in addition to impurities such as iron, magnesium, and manganese contained without being sulfided. It is used as washing water for leaching residues in the solid-liquid separation process and as washing water for neutralization residues produced in the neutralization process.

(7) Steps of final neutralization step (1) and (B) In the final neutralization step (1), an excess poor solution is added to the leaching residue slurry, and a limestone slurry and slaked lime slurry are added thereto to adjust the pH. Is adjusted to about 8 to 9, and the metal ions in the liquid are precipitated as neutralized precipitates to obtain a final neutralized residue (1) containing the leaching residue.
The leaching residue contains hematite as a main component, and contains gangue components such as quartz, chromite, and siliceous ore that have not been leached in the leaching step.

Here, the analysis of the distribution state of each component in the ore particles constituting the leaching residue slurry will be described.
First, Table 4 shows the ore particle size distribution of the leaching residue obtained when the ore slurry (see Table 1) obtained by pulverization to a particle size of about 2 mm or less and the grade of each component in each particle size category. An example is shown.

  From Table 4, it can be seen that iron is concentrated in the fine grain part of 75 μm or less, and silicon is separated in this part. In addition, the analysis of the leaching residue was performed on the leaching residue slurry washed with water to remove the attached sulfuric acid.

  Next, using a leaching residue (iron quality: 47.6 mass%, chromium quality: 2.6 mass%, silicon quality: 7.1 mass%) different from the above, iron, chromium and silicon for each particle size are used. The quality or distribution rate was determined. 3 and 4 show the relationship between the particle size and the grade or distribution rate of iron, chromium and silicon. From the figure, it can be seen that the finer the particle size, the higher the iron quality and the higher the distribution ratio to fine particles compared to chromium and silicon.

  From the above results, utilizing the fact that particles containing a high content of iron are finer than particles containing a high content of chromium, silicon, etc., it is possible to remove chromium, silicon, etc. by sorting means such as a classification method. It can be separated from the coarse portion containing a high content and discharged out of the system to recover hematite as a resource.

  The step (B) is a step of separating and recovering hematite particles in the leaching residue produced from the solid-liquid separation step by a physical separation method. In addition, the process of (B) can be implemented as a process which is included in the said last neutralization process (1), or follows it. In order to avoid the inclusion of gypsum which will be described later, it is desirable to introduce the step (B) before neutralization, but there is a problem that a large amount of water is required for washing to remove the attached sulfuric acid. .

The method of the step (B) is not particularly limited, and can be separated from the ore slurry by various wet methods such as sieving classification, sedimentation classification, centrifugal classification, and magnetic separation. A method using physical separation means is applied.
For example, the leaching residue slurry or the final neutralization residue slurry containing it is subjected to a physical separation method by sieving classification or centrifugal classification, and at that time, a method of recovering the classified fine particle portion as a hematite concentrate is adopted. .
That is, in the classification, hematite is distributed in the classified fine-grained portion, while the gangue component is distributed in the classified coarse-grained portion.

  In the classification, the classification particle size is not particularly limited and is preferably selected from the range of 20 to 100 μm. Here, the classified particle size is determined in consideration of the iron quality and yield of the hematite porcelain. However, if the classified particle size is less than 20 μm, the amount of leachable residue in this particle size category decreases, so that the iron recovery In this respect, efficiency deteriorates. On the other hand, when the classified particle size exceeds 100 μm, the concentration of hematite to fine particles, that is, the increase in iron quality is insufficient.

Here, the analysis of the distribution state of each component in the ore particles constituting the final neutralization residue will be described.
Table 5 shows the ore particle size distribution of the final neutralization residue obtained by leaching and neutralizing the ore slurry (see Table 4) obtained by crushing to a particle size of about 2 mm or less. An example of the quality of each component is shown.

  From Table 5, it can be seen that iron is concentrated in a fine particle part of 75 μm or less, and silicon, calcium and the like are lowered. That is, it can be seen that the gangue component and hematite are separated in this portion. The presence of calcium is due to the fact that gypsum was generated and mixed during the neutralization in the final neutralization step (1), and it can be seen that this gypsum is distributed to the coarse particles.

  Based on the above results, when hematite is separated and recovered from the final neutralized residue slurry including the leach residue slurry, it is utilized that the hematite particles are finer than other leach residue components and gypsum produced by the neutralization reaction. As in the case of the leaching residue slurry, physical separation means using various wet methods such as sieving classification, sedimentation classification, and centrifugal classification are used, and the fine granule portion containing hematite, other leaching residue components, and the coarse portion containing the gypsum are used. It can be separated into grain parts. Here, the fine-grained portion can be taken out of the system and purified in a separate process to recover hematite as an iron resource. In addition, a coarse grain part is stored by a tailing dam as a final neutralization residue (1).

  In addition, as the method of the step (B), a magnetic separation method using magnetic separation can be applied. In particular, as a means for improving the separation of the above-mentioned gypsum, it can be used in combination with the classification method. it can. That is, in the magnetic separation method, hematite is a weak magnetic material, while gypsum is a non-magnetic material, and therefore, separation is performed by utilizing the difference in properties.

  In order to fundamentally prevent calcium from being mixed into the recovered hematite deposit, a method of washing the leaching residue slurry with water having a low calcium concentration before the treatment in the final neutralization step (1). By adopting it, it is effective to remove the attached sulfuric acid and reduce the sulfur grade to about 1% by mass or less, but depending on the location conditions, it is not always possible to secure abundant water with low calcium concentration. There is a problem.

(8) Final neutralization step (2)
In the final neutralization step (2), the neutralized precipitate slurry obtained in the neutralization step or, if necessary, the zinc sulfide precipitate slurry obtained in the zinc removal step is added to the limestone slurry. And slaked lime slurry is added to adjust the pH to about 8 to 9, and the metal ions in the liquid are precipitated as neutralized precipitates to obtain the final neutralized residue (2). The final neutralization residue (2) obtained is stored in a tailing dam.

  Conventionally, the neutralized precipitate slurry obtained in the neutralization step has been sent to the solid-liquid separation step as necessary. For this reason, while increasing the amount of neutralizing agent consumed, the amount of leaching residue Was supposed to increase. When the hematite is separated and recovered from the leaching residue as in the method of the present invention, the neutralized slurry is preferably treated in a separate system in order to increase the hematite content in the leaching residue.

  EXAMPLES The present invention will be described in more detail below with reference to examples of the present invention, but the present invention is not limited to these examples. In addition, the analysis method of the metal used in the Example was performed by the fluorescent X ray analysis method or the ICP emission analysis method.

Example 1
In the step (A), silica mineral, chromite, and silicic clay were concentrated and separated from the ore slurry by centrifugal classification.
Using a Nelson concentrator (manufactured by Nelson Engineering and Manufacturing Division) having a centrifugal force of a maximum of 100 G as a classification device, the ore slurry shown in Table 1 was classified.
Here, the slurry concentration was 15 mass%, and the liquid temperature was normal temperature.
The results obtained are shown in Table 6.

From Table 6, in the coarse part obtained by centrifugal force classification, chromium, silicon and magnesium are 5.3 mass% with respect to 2.7 mass% of chromium in the supply, and silicon 6.6 in the supply It increased to 12.5% by mass with respect to mass% and 4.6% by mass with respect to 2.0% by mass of magnesium in the supply, while iron was an iron grade of 45.7% in the supply. % To 34.4% by mass.
From the above, it can be seen that silica minerals, chromite and siliceous ore are concentrated and separated in the coarse-grained part by classification of the ore slurry.

(Example 2)
As the step (B), hematite was concentrated and separated from the leaching residue by centrifugal classification.
Using the ore slurry shown in Table 1 above, sulfuric acid having a sulfuric acid concentration of 45 g / L was added to a slurry having a slurry concentration of 30% by mass, charged into an autoclave equipped with a stirrer, and leaching temperature of 245 ° C. Leaching was performed as a leaching time of 60 minutes after the temperature was raised to the leaching temperature. Then, after the leaching was completed, the leaching residue and the leachate were separated by filtration, and the obtained leaching residue (see Table 4 above) was classified using the same classification device as that used in Example 1.
The composition of the leachate was Ni: 7.1 g / L, Co: 0.6 g / L, and Fe: 5 g / L.
The results obtained are shown in Table 7.

From Table 7, by the centrifugal force classification, in the fine granule part obtained, it rose to 52.4% by mass with respect to the iron grade of 44.6% by mass. On the other hand, it is 2.2% by mass with respect to 2.52% by mass of chromium in the supply, 6.1% by mass with respect to 7.8% by mass of silicon in the supply, and 1.33% by mass of magnesium in the supply. % To 0.97% by mass.
From the above, it can be seen that hematite is concentrated and separated in the fine-grained part by classification of the leach residue.

(Example 3)
As the step (B), hematite was concentrated and separated from the final neutralized residue by centrifugal classification.
To the leaching residue (see Table 4 above), slaked lime slurry having a concentration of 25% by mass was added as a neutralizing agent, and neutralized at 60 ° C. to pH 8.5. Furthermore, the obtained final neutralization residue (see Table 5 above) was classified by the same classifier as that used in Example 1. Table 8 shows the obtained results.

  From Table 8, by the centrifugal force classification, in the fine granule part obtained, it rose to 40.2% by mass with respect to 35.7% by mass of iron grade in the mine. From the above, it can be seen that hematite is concentrated and separated in the fine-grained part by classification of the final neutralization residue slurry.

Example 4
As the step (B), hematite was concentrated and separated from the final neutralized residue by magnetic separation.
The final neutralized residue slurry (see Table 5 above) was magnetically selected using a high gradient magnetic separator (HGMS). The final neutralization conditions were the same as in Example 3. Table 9 shows the obtained results.

  From Table 9, the magnetic deposit obtained by magnetic separation increased to 48.5% by mass with respect to 35.7% by mass of iron grade in the supply, while on the other hand to 5.9% by mass of calcium in the supply. On the other hand, it decreased to 0.6% by mass. The slurry recovery rate at this time was 51%. From this, it can be seen that hematite is concentrated in the magnetic deposit and gypsum is reduced.

(Example 5)
As the step (B), hematite was concentrated and separated from the leaching residue by sieving classification.
Using the leaching residue shown in FIGS. 3 and 4 (iron quality: 47.6% by mass, chromium quality: 2.6% by mass, silicon quality: 7.1% by mass), a sieve having an opening of 20 μm and 75 μm, Each was subjected to wet sieving, and the quality and distribution of iron, chromium and silicon in the fine-grained part were determined. The results are shown in Table 10.

  From Table 10, by wet sieving with the classified particle size set in the range of 20 μm and 75 μm, a hematite concentrate (iron quality: 50.6, 53.2% by mass) with low chromium and silicon quality is obtained in the fine-grained part. You can see that

(Example 6)
As the step (B), hematite was concentrated and separated from the leaching residue by centrifugal classification.
Centrifugation was performed using the leach residue slurry obtained through Examples 1 to 3 above. However, in order to confirm the separation effect of chromium and silica by classification after the leaching residue of the present invention, separation of chromium and silica by classification before leaching in Example 1 was not performed.
For the centrifugation, a hydrocyclone (SP-50 model, manufactured by Japan Separation Co., Ltd.) having a rated classification point of 50 μm was used. Here, the underflow at the first stage of the cyclone supplied with the leaching residue slurry was supplied to the second stage of the cyclone to obtain coarse and coarse grains (underflow) and coarse and fine grains (overflow). Further, the first-stage overflow of the cyclone was supplied to the third-stage cyclone to obtain fine coarse grains (underflow) and fine grains (overflow). Thereafter, the distribution rate and composition of these products were determined. The results are shown in Table 11.

  From Table 11, it can be seen that fine particles having an iron quality of 61% by mass can be obtained with a mass distribution rate of 70%.

(Example 7)
As the step (A), chromite was concentrated and separated from the ore slurry by sieving classification.
Using the ore slurry shown in Table 2 above, when wet sieving is performed with sieves having openings of 37 μm, 75 μm, 100 μm, 850 μm, and 1000 μm, particle size range A: 100 to 850 μm, particle size range B: 75 to The grade and distribution rate of nickel, iron, chromium, silicon, and magnesium having a particle size range of 1000 μm, a particle size range C of 37 to 850 μm, a particle size range D of 37 to 1000 μm, and a particle size range F of 100 μm or less were determined.
From Table 3 above, it can be seen that in the particle size range C: 37 to 850 μm and the particle size range D: 37 to 1000 μm, a chromite concentrate having a chromium quality of 10% by mass or more can be obtained. In addition, in the particle size range G of 1000 μm or more, it can be seen that silicon is increased to 10.6% by mass and magnesium is increased to 9% by mass, and the silica mineral and the siliceous clay are concentrated and separated in the coarse part.
In particular, in the particle size range A: 100 to 850 μm and the particle size range B: 75 to 1000 μm, a concentrate having a chromium quality of about 20% by mass can be obtained. Moreover, the nickel quality in the concentrate is 0.5% by mass, the loss of nickel is minimized, and in the particle size range F of 100 μm or less, the chromium quality is reduced to 1.7% by mass, while iron And it can be seen that nickel is concentrated.

(Example 8, Reference Example 1)
In accordance with the smelting process diagram shown in FIG. 1, a hydrometallurgical method of nickel oxide ore including the processes of (A), (B), and (C) is performed to separate chromite, silica mineral, and siliceous ore and hematite. Was concentrated and separated.
First, as the process of (A), using the ore slurry shown in Table 2 above, wet sieving classification was performed with a sieve having an opening of 75 μm, and chromite, silica mineral and siliceous ore were separated as coarse particles. . Next, as a leaching step, sulfuric acid having a sulfuric acid concentration of 45 g / L is added to a slurry having a slurry concentration of 30% by mass using the obtained fine granule portion, and the slurry is charged into an autoclave equipped with a stirrer. After the temperature was raised to ° C., leaching was performed for 60 minutes to obtain a leaching residue slurry and a leaching solution. Subsequently, as a final neutralization step, a slaked lime slurry having a concentration of 25% by mass is added as a neutralizing agent to the obtained leaching residue slurry, and neutralized to a pH of 8.5 at 60 ° C., and finally, Using the obtained neutralization residue as the step (B), the fine-grained portion where hematite is concentrated by a hydrocyclone having a maximum centrifugal force of 24,000 G (manufactured by Nippon Chemical Machinery Co., Ltd., NHC-1 type). And the fine-grained portions of iron, calcium, sulfur, chromium, silicon, and magnesium were determined (Example 8). The results are shown in Table 12. In addition, as the step (C), the neutralized residue slurry obtained from the leachate neutralization step was subjected to a final neutralization treatment separately from the leach residue.
On the other hand, the leachate was neutralized to a pH of 2.5 by adding a 25% by mass slaked lime slurry as a neutralizing agent while maintaining the temperature at 60 ° C., and neutralized containing trivalent iron hydroxide. The quality of iron, calcium, sulfur, chromium, silicon, and magnesium in the fine-grained portion was determined in the same manner as in Example 8 except that a porridge slurry was obtained and mixed with the leaching residue (Reference Example 1). ). The results are shown in Table 12.

  From Table 12, in Example 8, the iron grade of the fine-grained portion is improved to 57% by mass, and at the same time, the calcium grade is reduced to 1.6% by mass, and a hematite concentrate having a quality that can be used as a steel material is obtained. I understand that. In contrast, in Reference Example 1, it can be seen that the separation of iron and calcium is insufficient.

  As apparent from the above, the method for hydrometallizing nickel oxide ore of the present invention is suitable as a method for smelting based on high pressure leaching utilized in the field of nickel oxide ore hydrometallurgy.

It is a smelting process figure showing an example of the embodiment by the hydrometallurgy method of the nickel oxide ore which concerns on this invention. It is a smelting process figure showing an example of the practical plant based on the hydrometallurgy method (patent document 2) of nickel oxide ore. It is a figure which shows the relationship between the particle size of a leaching residue, and the quality of iron, chromium, and silicon. It is a figure which shows the relationship between the particle size of a leaching residue, and the distribution rate of iron, chromium, and silicon.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ore processing process 2 Leaching process 3 Solid-liquid separation process 4 Neutralization process 5 Zinc removal process 6 Sulfurization process 7 Final neutralization process or final neutralization process (1)
8 Nickel oxide ore 9 Ore slurry 10 Leaching slurry 11 Leaching liquid 12 Leaching residue slurry 13 Neutralized residue slurry 14 Mother liquor (1)
15 Zinc sulfide deposit 16 Mother liquor (2)
17 Mixed sulfide 18 Poor liquid 19 Final neutralization residue or final neutralization residue (1)
20 Tailing Dam 21 (A) Step 22 Chromite etc. 23 (B) Step 24 Hematite Temple 25 Final Neutralization Step (2) (Step (C))
26 Final neutralization residue (2)

Claims (10)

In a hydrometallurgical method of recovering nickel and cobalt from nickel oxide ore by high-pressure acid leaching method including ore treatment process, leaching process, solid-liquid separation process, neutralization process, zinc removal process, sulfidation process and final neutralization process ,
A method for hydrometallurgy of nickel oxide ore comprising at least one step selected from the following steps (A) to (C).
(A) The particle | grains containing the at least 1 sort (s) chosen from the silica mineral in the ore slurry produced from the said ore processing process, a chromite, or a siliceous clay ore are separated and collect | recovered by a physical separation method.
(B) The hematite particles in the leach residue slurry produced from the solid-liquid separation step are separated and recovered by a physical separation method.
(C) The neutralized residue slurry produced from the neutralization step is subjected to final neutralization separately from the leaching residue produced from the solid-liquid separation step. When the step (C) is included, in the step (C), the zinc sulfide residue slurry produced from the zinc removal step is subjected to a final neutralization treatment simultaneously with the neutralized residue slurry. Item 2. A method for hydrometallizing nickel oxide ore according to Item 1.   The ore treatment step is a step of removing foreign matter from the mined raw material ore and adjusting the ore particle size to form an ore slurry, and the leaching step is performed by adding sulfuric acid to the ore slurry and stirring at high temperature and high pressure. A leaching slurry comprising a leaching residue and a leachate, and the solid-liquid separation step is a step of washing the leaching slurry in multiple stages to obtain a leachate containing nickel and cobalt and a leaching residue slurry, The neutralization step is a step of adding calcium carbonate to the leachate to form a neutralized precipitate slurry containing trivalent iron and a mother liquor for nickel recovery, and the zinc removal step includes hydrogen sulfide gas in the mother liquor. And forming a zinc sulfide slurry and a mother liquor for recovering nickel and cobalt, and the sulphurizing step comprises adding hydrogen sulfide to the mother liquor for recovering nickel and cobalt. Blowing is a step of producing a mixed sulfide containing nickel and cobalt and a poor solution, and the final neutralization step is to add an excess poor solution to the leaching residue slurry and adjust the pH to about 8 to 9, The method for hydrometallizing nickel oxide ore according to claim 1 or 2, wherein the method is a step of obtaining a final neutralization residue.   In the said ore processing process, ore particle size adjustment is attached | subjected to a sieving process by the particle size of 2 mm or less, The hydrometallurgy method of the nickel oxide ore of Claim 3 characterized by the above-mentioned. When the step (A) is included, in the step (A), the ore slurry is subjected to a physical separation method by sieving classification or centrifugal classification, and at that time, the classified coarse particle portion is subjected to silica mineral, chromite or It collect | recovers as a concentrate of a siliceous clay ore, The hydrometallurgy method of the nickel oxide ore in any one of Claims 1-4 characterized by the above-mentioned. The method for hydrometallurgy of nickel oxide ore according to claim 5, wherein the classification particle size is selected from the range of 20 to 850 µm when subjected to the physical separation method by sieving classification or centrifugal classification . When subjected to the physical separation method by sieving classification or centrifugal classification, the classification particle size is two particle sizes selected from the range of 850 μm or more and the range of 20 to 850 μm. First, the coarse particle classified by the particle size of the former range 6. Nickel according to claim 5, characterized in that the grain part is recovered as a concentrate of silica mineral or siliceous clay, and then the coarse part classified with a particle size in the latter range is recovered as a concentrate of chromite. A method for hydrometallizing oxide ore. In the case of including the step (B), in the step (B), the leaching residue slurry or the final neutralization residue slurry containing the slurry is subjected to a physical separation method by sieving classification or centrifugal classification. The method for hydrometallurgy of nickel oxide ore according to any one of claims 1 to 4, wherein the fine-grained portion is recovered as a hematite concentrate. The method for hydrometallurgy of nickel oxide ore according to claim 8, wherein the classification particle size is selected from a range of 20 to 100 µm when subjected to physical separation by sieving classification or centrifugal classification . In the case of including the step (B), in the step (B), the leaching residue slurry or the final neutralization residue slurry containing the slurry is subjected to a physical separation method by magnetic separation. The method for hydrometallurgy of nickel oxide ore according to claim 1, wherein the nickel oxide ore is recovered as follows.

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