Recovery of metals from metal or metal-containing materials

Abstract

A method of treating a metal or metal-containing material, comprising contacting the metal or metal-containing material with an agent selected from the group consisting of ferric chloride (FeCl3), hydrochloric acid (HCl), and combinations thereof, in an oxidizing or reducing digestion step, thereby producing a ferrous chloride (FeCl2) solution.

Description

Technical Field

[0001] This invention relates to the recovery of metals from solid metals or metal-containing materials. The invention provides a method for processing solid metals or metal-containing materials, recovering one or more metals from the metals or metal-containing materials using a chloride medium. In this sense, "metal" has a broad meaning, including both elemental metals and metal compounds. The invention extends to processes used to perform said method. Background Technology

[0002] Iron is a major contaminant in many concentrates and other metals or metal-containing materials. When these materials are beneficiated using hydrometallurgical processes, handling iron typically leads to high acid consumption and waste generation. This invention seeks to provide a more efficient and cost-effective method for beneficiating metals or metal-containing materials that is not limited to iron contamination.

[0003] Purpose of the invention The object of this invention is to treat metals or metal-containing materials containing metals other than iron, and to treat metals or metal-containing materials that optionally also contain iron, which is typically contained in a matrix containing other metals, to release these metals other than iron from these matrices. In this sense, "metal" has a broad meaning, including both elemental metals and metal compounds. Regarding metal compounds, it is conceivable that the compound form may be more readily selected compared to the original form in which these metals are expressed in the metal or metal-containing material. Summary of the Invention

[0004] In this specification, features provided in parentheses contribute to the substance of the specification and therefore also to the description of the features of the invention. In particular, where general chemical formulas and numerical values ​​of these general chemical formula symbols are provided in parentheses, they should be interpreted as substantially helpful to the description of the features of the invention.

[0005] According to a first aspect of the invention, a method is provided for processing a solid metal or metal-containing material, the metal or metal-containing material comprising one or more metals or metal compounds, to recover one or more metals from the metal or metal-containing material, the method comprising, in an oxidative or reductive digestion step, producing a ferrous chloride (FeCl2) solution by contacting the metal or metal-containing material with a digestion reagent selected from the group consisting of: Ferric chloride (FeCl3) is usually an aqueous solution. Gaseous hydrochloric acid (HCl). HCl aqueous solution, and Optionally, a combination of two or more of the above, and Any FeCl3 in the solution produced by contact between a metal or metal-containing material and the digestion reagent is reduced to FeCl2 in the solution.

[0006] Contact between metals or metal-containing materials and digestion reagents can be carried out in an aqueous medium. Therefore, FeCl2 solution can be an aqueous solution of FeCl2.

[0007] When the digestion reagent is HCl, contacting the metal or metal-containing material with HCl may include: Directly exposing metals or metal-containing materials to gaseous HCl (i.e., not in the form of an aqueous HCl solution); or The metal or metal-containing material is brought into contact with an aqueous HCl solution, preferably at a concentration of 30% v / v or higher, for example, between 30% and 36% v / v, such as 30% v / v.

[0008] When a metal or metal-containing material comes into contact with gaseous HCl, the metal or metal-containing material can be, in particular, a hydrous mineral material. This material can be a mineral material containing chemically bound water (as opposed to “free water,” i.e., non-chemically bound water), typically ranging from about 5% to about 70% by weight, for example, in the form of metal hydrates and / or metal hydroxides. Optionally, prior to digestion in the digestion step, this hydrous mineral material can be slightly moistened with free water (e.g., up to about 5% of the hydrous mineral mass).

[0009] The gaseous HCl can preferably be anhydrous gaseous HCl (e.g., produced according to the third aspect of the invention).

[0010] When a metal or metal-containing material comes into contact with an aqueous HCl solution, the method may include: An aqueous solution of HCl is prepared by washing gaseous HCl with water, and then the metal or metal-containing material is contacted with the prepared aqueous solution of HCl; or Prepare an aqueous suspension or slurry of metal or metal-containing material, and wash gaseous HCl with the suspension or slurry of metal or metal-containing material.

[0011] The gaseous HCl can be, in particular, gaseous HCl, and more specifically, anhydrous gaseous HCl produced according to the third aspect of the invention.

[0012] A reducing agent, such as metallic iron (Fe), can be used to contact the metal or metal-containing material with the digestion reagent to reduce FeCl3 to FeCl2. Depending on the composition of the metal or metal-containing material, contacting the metal or metal-containing material with the digestion reagent may produce a FeCl3 solution that does not contain FeCl2, or a solution that contains both FeCl2 and FeCl3. Therefore, a reducing agent is needed to reduce the FeCl3.

[0013] It is also possible to produce a solution that does not contain FeCl3, in which case reduction is not required.

[0014] Understandably, reduction is only necessary when FeCl3 is produced from the digestion of metals or metal-containing materials.

[0015] Therefore, the digestion reagent can be, for example: For example, gaseous HCl produced according to the third aspect of the present invention; For example, according to the third aspect of the present invention, an aqueous solution of HCl is produced by washing gaseous HCl with water; For example, according to the third aspect of the present invention, an aqueous HCl solution is generated by washing gaseous HCl with an aqueous suspension or slurry of metal or metal-containing material; For example, according to a third aspect of the invention, an aqueous solution of FeCl3 is produced by contacting solid hematite (Fe2O3) with an aqueous HCl solution, wherein the solid hematite (Fe2O3) is produced (for example) according to the third aspect of the invention, and the aqueous HCl solution is produced (for example) according to the third aspect of the invention by washing gaseous HCl with water; or For example, according to a third aspect of the invention, an aqueous solution of FeCl3 is produced by washing an aqueous suspension of solid hematite (Fe2O3) with gaseous HCl, wherein the aqueous suspension of solid hematite (Fe2O3) is produced, for example, according to the third aspect of the invention, and the gaseous HCl is produced, for example, according to the third aspect of the invention.

[0016] When the metal or metal-containing material includes iron in metallic or compound form, such iron is converted to ferrous chloride as described above and thus exists in the FeCl2 solution as ferrous chloride. When the metal or metal-containing material includes metals other than iron (M) in metallic or compound form, at least some of these metals (other than iron) are thus advantageously converted to soluble (e.g.,) their divalent chlorides (M). 2+ Cl2).

[0017] According to a second aspect of the invention, a method is provided for treating a solid metal or metal-containing material comprising one or more metals in metallic or compound form to recover one or more metals from the metal or metal-containing material in metallic or compound form. The method includes, in a displacement crystallization step, contacting a FeCl2 solution (typically an aqueous FeCl2 solution) generated from the oxidation / reduction digestion of the metal or metal-containing material with a displacement crystallization reagent (preferably HCl, most preferably gaseous HCl) to displace FeCl2 from the FeCl2 solution, thereby producing a solid ferrous chloride hydrate (FeCl2·xH2O, where x≥1, more preferably x>1), typically a solid ferrous chloride tetrahydrate (FeCl2·4H2O, x=4).

[0018] HCl can be in the gaseous form of anhydrous gaseous HCl.

[0019] The gaseous HCl that can be used to achieve displacement crystallization can be, in particular, gaseous HCl produced according to the third aspect of the invention, more preferably anhydrous gaseous HCl.

[0020] The production of ferrous chloride (FeCl2) solution by oxidation / reduction digestion of a metal or metal-containing material may include contacting the metal or metal-containing material with a digestion reagent selected from the following: FeCl3 is usually an aqueous solution. Gaseous HCl, HCl aqueous solution, and Optionally, a combination of two or more of the above, and Reduce any FeCl3 in the solution produced by contact between a metal or metal-containing material and the digestion reagent to FeCl2.

[0021] The FeCl2 solution may be, for example, the FeCl2 solution produced by the digestion step according to the first aspect of the invention.

[0022] As mentioned above, FeCl2·xH2O can be specifically FeCl2·4H2O, i.e., x = 4.

[0023] The substitution crystallization step may include, or more generally may be, following a dehydration (i.e., drying) step, which may include temperature treatment of FeCl2·xH2O to produce dehydrated solid ferrous chloride hydrate (FeCl2·yH2O, where x > y > 0). FeCl2·yH2O may specifically be FeCl2·H2O (ferrous chloride monohydrate), i.e., y = 1.

[0024] For the purposes of this specification, in the context of the dehydration step, the terms "dehydration" and "dehydrated" do not require complete dehydration to provide an anhydrous form, although the meaning of the words includes this possibility. Therefore, at least in terms of the change in hydration of ferrous chloride, the dehydration step can thus be more accurately described as a "partial" dehydration step.

[0025] The temperature treatment of FeCl2·xH2O in the dehydration step may include placing FeCl2·xH2O in a temperature range of 70 °C to 200 °C, more preferably in a range of 70 °C to below 200 °C, i.e., a temperature below 200 °C but not below 70 °C. For example, the temperature may be in the range of 70 °C to 150 °C.

[0026] The dehydration step can be carried out under non-oxidizing conditions, i.e., under conditions that avoid oxidation by FeCl2·xH2O. These non-oxidizing conditions may include avoiding or at least limiting the presence of exogenous oxygen. This may further include carrying out the dehydration step under positive pressure in a vapor environment, where the vapor may be vapor generated due to the dehydration of FeCl2·xH2O.

[0027] When substitution crystallization is used to achieve crystallization, the digestion reagent is usually not the gaseous HCl produced in the decomposition step, or is not generated using the gaseous HCl produced in the decomposition step, but rather an aqueous solution of HCl produced in the substitution crystallization step, or is generated using the aqueous solution of HCl produced in the substitution crystallization step.

[0028] When a metal or metal-containing material contains iron in metallic or compound form, this iron is converted to ferrous chloride in a digestion step, and then ferrous chloride hydrate is displaced from the FeCl2 solution in a displacement crystallization step.

[0029] When a metal or metal-containing material contains a metal other than iron (M) in metallic or compound form, at least some of such metals other than iron will therefore be advantageously converted into soluble (e.g.,) its divalent chloride (M) during the digestion step. 2+ Cl2), and thus it will also be advantageous in the substitution crystallization step as its divalent metal chloride (M 2+ Cl2·zH2O, where z>0) hydrates are displaced from the solution.

[0030] According to a third aspect of the invention, a method is provided for processing a solid metal or metal-containing material comprising one or more metals in metallic or compound form to recover one or more metals from the metal or metal-containing material in metallic or compound form. The method includes, in a thermal decomposition step, subjecting FeCl2·xH2O (where x ≥ 1, more preferably x > 1, and most preferably x 4, produced by crystallization of a FeCl2 solution generated from the oxidation / reduction digestion of the metal or metal-containing material) and / or FeCl2·yH2O (where x > y > 0, and y preferably 1, produced by dehydration of FeCl2·xH2O) at a certain temperature, thereby decomposing FeCl2·xH2O or FeCl2·yH2O to produce solid iron oxide (Fe2O3) and gaseous HCl.

[0031] Gaseous HCl can be, in particular, anhydrous gaseous HCl.

[0032] It should be noted that, in the context of the thermal decomposition step and the present invention, FeCl2·xH2O or FeCl2·yH2O is generally preferred over FeCl3 for thermal decomposition. This is because FeCl3, when thermally decomposed, does not decompose to produce gaseous HCl and Fe2O3, but rather sublimates.

[0033] Producing FeCl2 solution by oxidative / reductive digestion of a metal or metal-containing material may include contacting the metal or metal-containing material with a digestion reagent selected from the following: Ferric chloride (FeCl3) is usually an aqueous solution. Gaseous hydrochloric acid (HCl). HCl aqueous solution, and Optionally, their combination, and Reduce any FeCl3 in the solution produced by contact between a metal or metal-containing material and the digestion reagent to FeCl2.

[0034] The FeCl2 solution may be, for example, a FeCl2 solution produced by the method according to the first aspect of the present invention.

[0035] FeCl2·xH2O can be crystallized from FeCl2 solution using conventional methods, such as evaporation crystallization.

[0036] However, more preferably, according to a second aspect of the invention, FeCl2·xH2O can be crystallized from FeCl2 solution by displacement crystallization, which may involve contacting the FeCl2 solution produced by oxidation / reduction digestion of metal or metal-containing material with a displacement crystallization reagent (preferably hydrochloric acid (HCl), most preferably gaseous HCl) to displace FeCl2 from the solution, thereby producing FeCl2·xH2O.

[0037] Gaseous HCl, particularly anhydrous gaseous HCl, is preferably produced via the thermal decomposition step of the present invention.

[0038] Compared to evaporative crystallization, the present invention prefers the substitution crystallization method described above. This is because, in the case of evaporative crystallization, the pH changes due to the evaporation of water from the FeCl2 solution, making the FeCl2 in the solution significantly more easily oxidized to FeCl3, a situation that should be avoided in the context of the present invention. Therefore, as described above, FeCl3 sublimates at high temperatures (e.g., the high temperatures in the thermal decomposition step as described herein, utilized in the present invention).

[0039] When substitution crystallization is used to achieve crystallization, the digestion reagent is usually not the gaseous HCl produced in the decomposition step, or is usually not produced by using the gaseous HCl produced in the decomposition step, but by using an aqueous solution of HCl produced in the substitution crystallization step.

[0040] Furthermore, it is preferable to dehydrate FeCl2·xH2O to produce FeCl2·yH2O and then thermally decompose FeCl2·yH2O. As described with reference to the second aspect of the invention, this dehydration can be achieved by subjecting FeCl2·xH2O to a temperature range of 70°C to 200°C, more preferably within a temperature range of 70°C to below 200°C, i.e., at a temperature below 200°C but not below 70°C. For example, the temperature can be in the range of 70°C to 150°C.

[0041] Thermal decomposition of FeCl2·yH2O can creatively achieve and utilize the effect of producing anhydrous gaseous hydrochloric acid, which is considered to be a particularly inventive advantage of this invention.

[0042] Solid FeCl2·xH2O or FeCl2·yH2O can be, for example, FeCl2·xH2O or FeCl2·yH2O produced by the method according to the second aspect of the present invention. When the metal or metal-containing material includes iron in metallic or compound form, the iron will be converted into ferrous chloride, which will be displaced from the solution as ferrous chloride hydrate, dehydrated, and decomposed as described above.

[0043] When a metal or metal-containing material includes a metal other than iron (M) in metallic or compound form, at least some of such metals other than iron will also advantageously be converted into a soluble (e.g.) divalent chloride (M). 2+ Cl2), will act as its divalent chloride hydrate (M 2+ Cl2·zH2O, where z>0) is displaced from the solution, resulting in partial or complete dehydration (producing M). 2+ Cl2·aH2O, where z>a≥0), will decompose as described above (producing anhydrous M). 2+ Cl2).

[0044] When decomposition occurs, in contrast to the formation of ferrous chloride hydrate, other divalent metal chlorides or chloride hydrates of this type do not decompose. They remain unchanged, at most undergoing complete dehydration to their anhydrous divalent chloride forms. In this form, the metals are soluble and can therefore be readily separated from solid ferric oxide by solid-liquid separation.

[0045] According to a fourth aspect of the invention, a method is provided for processing a solid metal or metal-containing material comprising one or more metals in metallic or compound form to recover one or more metals from the metal or metal-containing material in metallic or compound form. The method includes... In the oxidative or reductive digestion step, a ferrous chloride (FeCl2) solution is produced by contacting the metal or metal-containing material with a digestion reagent selected from the following: Ferric chloride (FeCl3) aqueous solution, Gaseous hydrochloric acid (HCl). HCl aqueous solution, and Optionally, any combination of two or more of them, and Any FeCl3 in the solution produced by contact between a metal or metal-containing material and the digestion reagent is reduced to FeCl2 in the solution.

[0046] In the crystallization step, solid ferrous chloride hydrate (FeCl2·xH2O, where x≥1, preferably x>1, and most preferably 4) is crystallized from the FeCl2 solution. Optionally, in the dehydration step, FeCl2·xH2O is subjected to temperature treatment to produce dehydrated ferrous chloride hydrate (FeCl2·yH2O, where x > y > 0, preferably 1); and In the thermal decomposition step, FeCl2·xH2O and / or FeCl2·yH2O are subjected to temperature treatment to decompose FeCl2·xH2O and / or FeCl2·yH2O, producing solid iron oxide (Fe2O3) and gaseous HCl.

[0047] The oxidation or reduction digestion step can be the oxidation or reduction digestion step of the method of the first aspect of the present invention.

[0048] FeCl2·xH2O can be crystallized from FeCl2 solution using conventional methods, such as evaporation crystallization.

[0049] However, more preferably, FeCl2·xH2O can be crystallized from FeCl2 solution by displacement crystallization (i.e., the crystallization step can be a displacement crystallization step), which may include contacting FeCl2 solution with a displacement crystallization reagent (preferably HCl, more preferably gaseous HCl, most preferably anhydrous gaseous HCl, such as gaseous HCl recovered from a thermal decomposition step) and saturating the FeCl2 solution, thereby displacing FeCl2 from the solution and producing FeCl2·xH2O.

[0050] In the displacement crystallization step, the temperature of the FeCl2 solution can be from 10 ℃ to 60 ℃.

[0051] When the displacement crystallization reagent is HCl in gaseous form, displacement crystallization may include, for example, washing the gaseous HCl with FeCl2 solution.

[0052] In the displacement crystallization step, an aqueous HCl solution (i.e., dilute HCl) can be formed as a result.

[0053] When using displacement crystallization, the method may include: Solid FeCl2·xH2O and any other solid metal chloride hydrate (M) that crystallizes together with FeCl2·H2O during the crystallization step 2+ Cl2·zH2O, where z≥1 (as described below), is separated from the resulting aqueous HCl solution; and An aqueous solution of HCl is used as a digestion reagent in the digestion step, or an aqueous solution of HCl is used to produce a digestion reagent in the digestion step.

[0054] Therefore, this method may include a second separation step, performed after the displacement crystallization step and before the dehydration step, to recover solid FeCl2·xH2O, and any other possible solid metal chloride hydrates (M...) from the resulting HCl solution through solid-liquid separation. 2+ Cl2·zH2O, as described herein), thereby recovering FeCl2·xH2O and any solid M that may be present. 2+ Cl2·zH2O.

[0055] As described above, the method may further include recycling the HCl solution generated in the displacement crystallization step to the digestion step of the method, and / or using the HCl solution to generate a FeCl3 solution for the digestion step (by reacting the HCl in the HCl solution with Fe2O3, where Fe2O3 may be Fe2O3 generated in the thermal decomposition step of the present invention).

[0056] It is important to note that the recycling of the HCl solution produced during the displacement crystallization step may include the recycling of some metal chlorides that have not been converted into metal chloride hydrates, for example, due to excessively low concentrations. It is anticipated that once a sufficiently high concentration is reached, the accumulation of these metal chloride hydrates will eventually lead to this conversion.

[0057] The displacement crystallization step can be the displacement crystallization step of the method of the second aspect of the present invention.

[0058] The thermal decomposition step can be the thermal decomposition step of the method in the third aspect of the present invention.

[0059] The following statements apply to all aspects of the first to fourth aspects of the present invention: One or more metals composed of metals or metal-containing materials may include one or more of chromium (Cr), copper (Cu), vanadium (V), nickel (Ni), cobalt (Co), zinc (Zn), titanium (Ti), manganese (Mn), and iron (Fe) in metallic and / or compound forms.

[0060] Typically, the metal or metal-containing material includes at least iron in metallic or compound form, and preferably includes at least one metal (M) other than iron in metallic or compound form. For example, these other metals (M) can be one or more metals other than iron listed above.

[0061] If the metal or metal-containing material includes iron in metallic or compound form, the digestion reagent may include at least HCl.

[0062] In some embodiments of the present invention, the metal or metal-containing material may be, for example, one or more of the following: multioxide material (containing multiple metal oxides), polysulfide material (containing multiple metal sulfides), alloy material, metal slag material, metal powder material, and metal material.

[0063] Therefore, the metal in the metal or metal-containing material can be one or more of the following forms: metal oxide, metal sulfide, and metal.

[0064] In one specific embodiment of the invention, the metal-containing material can be an ore material. For example, the metal-containing material can be a titanomagnetite ore material, such as a vanadium-containing titanomagnetite ore material. Generally, it is envisioned that the invention can be applied to any ore material containing metal sulfides and / or metal oxides, especially those ore materials containing iron in metallic or compound form.

[0065] Therefore, depending on the composition of the metal-containing material, a FeCl2 solution may contain other metal chlorides besides FeCl2, and typically contains at least one other divalent metal chloride (M). 2+ Cl2), but not excluding monovalent metal chlorides, such as Cu2Cl2 or Cu2Cl2.

[0066] Therefore, the digestion step can at least convert metals, either in metallic or compound form, or certain metals contained in metal-containing materials, into metal chlorides (FeCl2 and M) in solution. 2+ Cl2 (or if other metals (M) are present) is contained in FeCl2 solution. This is desirable.

[0067] The digestion process can be carried out at temperatures ranging from 10 °C to 120 °C.

[0068] If FeCl3 is used as a digestion reagent in the digestion step, it can be a solution. Typically, it can be an aqueous solution with a concentration of 5 wt% to 70 wt%.

[0069] It should be noted that in order to generate FeCl3 in solution for use as a digestion reagent in the digestion step, solid Fe2O3 can be used in combination with HCl to generate FeCl3 solution in the digestion step, rather than producing it separately as a feed into the digestion step.

[0070] When used as a digestion reagent in the digestion step, HCl can be in solution and can be generated according to the first aspect of the invention. Typically, it can be an aqueous solution with a concentration of 5 wt% to 40 wt%, more preferably 30% to 36%, for example 33%.

[0071] Alternatively, when used as a digestion reagent in the digestion step, HCl can be gaseous HCl, as described in the first aspect of the invention.

[0072] Therefore, the digestion reagent can be, for example, Gaseous HCl, for example, produced during thermal decomposition; An aqueous solution of HCl, for example, is produced by washing with water to remove gaseous HCl generated during the thermal decomposition step; An aqueous solution of HCl, for example, is produced by washing gaseous HCl generated during a thermal decomposition step with an aqueous suspension or slurry of a solid metal or metal-containing material; An aqueous solution of FeCl3 is produced by contacting solid Fe2O3 generated during the thermal decomposition step with an aqueous solution of HCl, which is then produced by washing the gaseous HCl generated during the thermal decomposition step with water; or The FeCl3 aqueous solution is produced by washing the gaseous HCl generated in the thermal decomposition step with an aqueous suspension of solid Fe2O3 produced in the thermal decomposition step.

[0073] When using displacement crystallization, the digestion reagent is usually not the gaseous HCl produced in the decomposition step, or is not generated using the gaseous HCl produced in the decomposition step, but rather an aqueous solution of HCl produced in the displacement crystallization step or is generated using the aqueous solution of HCl produced in the displacement crystallization step.

[0074] Metallic iron can be used as a reducing agent.

[0075] When using metallic iron as a reducing agent, in addition to Fe 3+ Reduced to Fe 2+ In addition to reducing FeCl3 to FeCl2, it can also reduce other metals, possibly to solid metal forms, making these metals easier to recover through solid-liquid separation.

[0076] Reduction is only necessary when FeCl3, formed from the treatment of metals or metal-containing materials with digestion reagents, is present in the solution.

[0077] The method may include, in a first separation step following the digestion step, separating the solids from the FeCl2 solution by solid-liquid separation, thereby recovering the FeCl2 solution which is substantially free of solids (including other divalent metal chlorides in the solution).

[0078] When FeCl2 solution contains other metal chlorides (M 2+ When FeCl2 is crystallized, in addition to forming solid FeCl2·xH2O, other solid metal (M) chloride hydrates (M) can also be formed during the crystallization process. 2+ Cl2·zH2O, where z>0 and M (for example) can be selected from one or more of chromium (Cr), copper (Cu), vanadium (V), nickel (Ni), cobalt (Co), zinc (Zn), titanium (Ti) and manganese (Mn).

[0079] Referring to the crystallization step as described above, when the crystallization step includes displacement crystallization, the method may include a second separation step, performed after the crystallization step and before the dehydration step, to recover solid FeCl2·xH2O and any solid M that may be present. 2+ Cl2·zH2O.

[0080] A dehydration step is preferred.

[0081] According to a second aspect of the invention, the dehydration step can be performed by reacting FeCl2·xH2O with any M that may be present. 2+ This is achieved by temperature treatment using Cl2·zH2O, with the temperature range between 70 °C and 200 °C, more preferably between 70 °C and below 200 °C, i.e., below 200 °C but not below 70 °C. For example, the temperature can be between 70 °C and 150 °C.

[0082] Therefore, FeCl2·yH2O and M 2+ Cl2·zH2O (if present) can produce dehydrated solid divalent chloride hydrates or anhydrous solid divalent chlorides of other metals (M). 2+ Cl2·aH2O, where z>a≥0).

[0083] Then, the method may include taking FeCl2·yH2O produced in the dehydration step and any M 2+ Cl2·aH2O undergoes thermal decomposition.

[0084] The dehydration step can be carried out under non-oxidizing conditions. This may include avoiding or at least limiting the presence of exogenous oxygen during the drying step. It may also include carrying out the dehydration step under positive pressure in a steam environment, where the steam could be the steam generated after dehydration of FeCl2·xH2O.

[0085] As described above, when recovering solid M other than FeCl2·xH2O from the crystallization step 2+ When Cl2·zH2O is used, this solid M 2+ Cl2·zH2O will also undergo dehydration together with FeCl2·xH2O in the dehydration step. Thus, in addition to FeCl2·yH2O, the dehydration step will also produce dehydrated solid divalent chloride hydrates and / or anhydrous solid divalent chlorides of other metals (M... 2+ Cl2·aH2O, where z>a≥0, therefore including the anhydrous form when a=0).

[0086] The thermal decomposition step can be carried out at a temperature of 200 °C to 600 °C, more preferably at a temperature above 200 °C and at most 600 °C.

[0087] The thermal decomposition step can be carried out under oxidizing conditions, that is, in the presence of oxygen, which can be provided by, for example, air.

[0088] The gaseous HCl produced in the thermal decomposition step can be essentially dry, i.e., without moisture (anhydrous).

[0089] Therefore, the reactions that occur in the drying (dehydration) and thermal decomposition steps include (i) Drying (dehydration) is carried out at the above temperature and under non-oxidizing conditions. FeCl2·4H2O(s) → FeCl2·H2O(s) + 3H2O(g) (ii) at the above temperature and oxygen ( Thermal decomposition occurs under oxidizing conditions in the presence of O2 (provided by air). 2FeCl2·H2O(s) → Fe2O3(s) + 4HCl(g).

[0090] As described above, when M, excluding solid FeCl2·xH2O, is recovered from the crystallization step... 2+ When Cl2·zH2O is applied, a dehydration step is performed, during which solid M is produced in addition to solid FeCl2·yH2O. 2+ Cl2·aH2O, this solid M 2+ Cl2·zH2O and / or M 2+ Cl2·aH2O will also undergo temperature treatment together with FeCl2·xH2O / FeCl2·yH2O in the thermal decomposition step.

[0091] Excluding solid M 2+ Cl2·zH2O and / or M 2+ Cl2·aH2O and FeCl2·xH2O / FeCl2·yH2O will undergo thermal decomposition, but M2+ Cl2·zH2O and / or M 2+ As long as Cl2·aH2O is not completely dehydrated, it will be completely dehydrated in the thermal decomposition step, thus remaining as a completely dehydrated solid M after the thermal decomposition of FeCl2·xH2O / FeCl2·yH2O (preferably FeCl2·yH2O) into Fe2O3 and gaseous HCl. 2+ Cl2 (i.e., a=0). However, as can be seen from the preceding discussion, it is preferable to only treat FeCl2·yH2O and M. 2+ Cl2·aH2O undergoes thermal decomposition to produce iron oxide, anhydrous HCl gas, and solid M. 2+ Cl2.

[0092] Therefore, the thermal decomposition step typically produces solid Fe2O3 and solid M. 2+ A mixture of Cl2, which also produces gaseous HCl, is then used as described herein.

[0093] The method may then include, in the third separation step, M 2+ Cl2 dissolves in water and undergoes solid-liquid separation to obtain M. 2+ Insoluble Fe2O3 is recovered from Cl2 solution.

[0094] In the obtained M 2+ In a Cl2 solution, metals other than iron (M) that were originally contained in the metal or metal-containing material are released from the matrix of the metal or metal-containing material. This matrix may contain iron. These other metals can now be recovered from the resulting solution using conventional methods, such as hydrometallurgical methods.

[0095] Therefore, this method can also produce marketable Fe2O3 and products suitable for recycling to earlier process steps. For example, it is worth noting that FeCl2·xH2O / FeCl2·yH2O (preferably FeCl2·yH2O) undergoes thermal decomposition via temperature treatment to release gaseous HCl, especially when FeCl2·yH2O undergoes thermal decomposition, the desired anhydrous form of HCl is obtained.

[0096] This method may include recycling the HCl gas for use in a crystallization step for displacement crystallization. Alternatively, it may be recycled to a digestion step for use as a digestion reagent or for generating a digestion reagent.

[0097] In addition, as previously mentioned, Fe2O3 can react with the HCl solution from the displacement crystallization step (more specifically from the second separation step) to produce a FeCl3 solution for the digestion step.

[0098] A particular advantage and inventive feature of this invention is that the generation of FeCl2·xH2O and subsequent dehydration to FeCl2·yH2 enables the production of gaseous HCl, which, as understood, is concentrated and undiluted HCl, through the subsequent decomposition of the partially dehydrated FeCl2·yH2O. Furthermore, in the context of this invention, this gaseous HCl is substantially dry, i.e., free of moisture (anhydrous). This contrasts sharply with conventional methods of utilizing HCl in the digestion of solid metal-containing feedstocks, which inevitably result in diluted HCl solutions because the water balance is unfavorable for producing concentrated HCl, or even the desired concentration of diluted HCl. For example, although the maximum concentration of HCl at room temperature is approximately 33% v / v, existing methods using HCl rarely achieve the regeneration of HCl diluted above 18% v / v. This invention effectively solves this problem by using an iron precipitate as FeCl2·xH2O, which is partially dehydrated to produce FeCl2·yH2O, and then decomposed to produce undiluted gaseous HCl for use in earlier process steps.

[0099] As a fifth aspect of the invention, the invention extends to a process for carrying out the methods of the first to fourth aspects of the invention, the process comprising process stages and process operations corresponding to the respective method steps and for carrying out the respective method steps. Attached Figure Description

[0100] Figure 1 A method for processing solid metals or metal-containing materials according to the present invention is shown; Figure 2 The process flow of Example 1 is shown; Figure 3 The process flow of Example 2 is shown. Detailed Implementation

[0101] The invention will now be described in more detail with reference to the accompanying drawings, which illustrate the process according to the fifth aspect of the invention.

[0102] Reference Figure 1 Reference numeral 10 generally indicates a process for carrying out the methods of the first to fourth aspects of the present invention according to the fifth aspect of the present invention.

[0103] Process 10 includes the following process stages: - Oxidation / reduction digestion stage 12; - Reduction Phase 14; - First separation stage 16; - Replacement crystallization stage 18; - Second separation stage 20; - Drying stage 22; - Thermal decomposition stage 24; - Third separation stage 26; - Ferric chloride formation stage 28; and - Metal recycling stage 30.

[0104] In process 10, the following feed, transfer, recovery, and recirculation pipelines were defined: - Feed pipe 32; - Feed pipe 34; - Feed pipe 36; - Transfer piping 38; - Feed pipe 40; - Transfer piping 42; - Retract pipe 44; - Transfer piping 46; - Feed pipe 48; - Recirculation piping 50; - Transfer piping 52; - Recirculation piping 54; - Recirculation piping 56; - Transfer piping 58; - Transfer piping 60; - Transfer piping 62; - Transfer piping 64; - Transfer pipeline 66; - Recirculation piping 70; - Retract pipe 72; - Feed pipe 74; and - Recirculation line 76.

[0105] When carrying out the methods of the first to fourth aspects of the present invention using process 10, the metal or metal-containing material is fed into the digestion stage 12 along with one or a combination of FeCl3 solution and HCl solution via feed line 32 via feed line 34 and / or recirculation line 70, and via feed line 36 and / or recirculation line 54. With reference to recirculation lines 54, 70, and 76, alternative / additional methods for providing HCl solution and FeCl3 solution to the digestion stage 12 will be discussed below.

[0106] In digestion stage 12, the metal or metal-containing material is oxidized / reduced to produce a FeCl2 solution, which may contain residual FeCl3 and may contain chlorides of one or more other metals (M), such as chlorides of copper (Cu), vanadium (V), nickel (Ni), cobalt (Co), zinc (Zn), titanium (Ti), and manganese (Mn).

[0107] The FeCl2 solution is transferred from the digestion stage 12 to the reduction stage 14 along the transfer line 38, where it comes into contact with the reducing agent. The reducing agent is then fed into the reduction stage 14 along the feed line 40.

[0108] Then, the FeCl2 solution is transferred from the reduction stage 14 to the first separation stage 16 along the transfer line 42, where the solids contained in the FeCl2 solution are separated from the FeCl2 solution and recovered along the recovery line 44.

[0109] The recovered FeCl2 solution is then transferred along transfer line 46 through the first separation stage 16 to the displacement crystallization stage 18. Here, the FeCl2 solution is contacted with gaseous HCl, which is then fed into the displacement crystallization stage 18 along feed line 48 and / or recirculation line 50.

[0110] In the substitution crystallization stage 18, the FeCl2 solution is contacted with gaseous HCl, producing solid FeCl2·xH2O and solid M in the HCl solution (i.e., diluted hydrochloric acid). 2+ Cl2·zH2O (if other metal (M) chlorides are present in the FeCl2 solution) (x, z≥1).

[0111] Typically, the value of x is 4, therefore solid FeCl2·xH2O is FeCl2·4H2O (ferrous chloride tetrahydrate).

[0112] Solid FeCl2·xH2O and solid M 2+ Cl2·xH2O (if present) and an aqueous HCl solution are transferred along transfer line 52 to the second separation stage, where solid FeCl2·xH2O and solid M are separated. 2+ Cl2·xH2O (if present) is separated from the HCl aqueous solution and recovered along transfer line 58. The HCl aqueous solution is recirculated along recirculation line 54 to digestion stage 12, and / or along line 56 to FeCl3 formation stage 28. Solid FeCl2·xH2O and solid M 2+ Cl2·zH2O (if present) is transferred along transfer line 58 to dehydration stage 22.

[0113] It is important to note that the recycling of HCl aqueous solutions may include the recycling of some metal chlorides that have not been converted into metal chloride hydrates, for example, due to low concentrations. Once sufficiently high concentrations are reached, the accumulation of these metal chloride hydrates will eventually lead to this conversion.

[0114] In the dehydration stage 22, solid FeCl2·xH2O and solid M 2+Cl2·zH2O (if present) is dehydrated in a non-oxidizing environment. Temperature treatment is used at temperatures below 200 °C but not below 70 °C, more preferably in the temperature range of 70 °C to 150 °C, to produce solid FeCl2·yH2O and solid M. 2+ Cl2·aH2O (if present), (x>y≥0; z>a≥0).

[0115] More specifically, solid FeCl2·xH2O and solid M 2+ Cl2·zH2O (if present) is introduced and passed through an unventilated container, where it is subjected to temperature treatment, thereby creating a slight positive pressure relative to atmospheric pressure within the container. This positive pressure is determined by the temperature treatment and FeCl2·xH2O and M 2+ The vapor generated by the dehydration of Cl2·zH2O inside the container is used to replace any oxygen that may be present in the container (such as oxygen in the form of air), thereby preventing the oxidation of ferrous chloride.

[0116] Solid FeCl2·yH2O and solid M 2+ Cl2·aH2O is transferred along transfer pipe 60 to thermal decomposition stage 24, where solid FeCl2·yH2O and solid M are transferred. 2+ Temperature treatment with Cl2·aH2O decomposes solid FeCl2·yH2O to produce solid Fe2O3 and HCl gas, while solid M... 2+ Cl2·aH2O remains unchanged, therefore it will not be decomposed. But M 2+ Cl2·aH2O usually undergoes dehydration, therefore, in any case, M exists during the decomposition phase. 2+ When Cl2·aH2O (where a≥1), this M 2+ Cl2·aH2O will be converted into anhydrous M. 2+ Cl2 (i.e., a = 0). Temperature treatment favors the thermal decomposition of FeCl2·yH2O but is detrimental to M. 2+ This is achieved under the conditions of thermal decomposition of Cl2·aH2O. In fact, at any temperature at which FeCl2·yH2O decomposes, M 2+ Cl2·aH2O (z>a≥0) will not undergo thermal decomposition. The temperature treatment in thermal decomposition stage 24 is carried out under oxidizing conditions above 200 ℃ but not higher than 600 ℃ (i.e., in the presence of oxygen, for example, oxygen provided by air).

[0117] The HCl gas generated in the thermal decomposition stage 24 will be recovered and recycled to the displacement crystallization stage 18 along the recirculation pipeline 50.

[0118] To facilitate or achieve the oxidation conditions required for the thermal decomposition stage, a blower can be used to blow air into the thermal decomposition stage, thereby also expelling gaseous hydrochloric acid from the thermal decomposition stage for recovery and use as described herein.

[0119] It is understood that the gaseous HCl is concentrated, i.e., undiluted, and therefore essentially pure HCl. Furthermore, the HCl is essentially dry (i.e., free of moisture, and therefore anhydrous). Therefore, the process achieves a favorable water balance, thereby producing concentrated, essentially dry gaseous HCl for use in upstream processes. This contrasts with existing processes utilizing HCl in metal recovery operations, which produce diluted hydrochloric acid solutions with concentrations rarely exceeding 18% v / v.

[0120] Without dehydration of FeCl2·xH2O, the gaseous HCl produced in thermal decomposition stage 24 will be wet / diluted (i.e., containing water vapor), making it impossible to effectively displace the dissolved FeCl2 in the manner described in displacement crystallization stage 18. Therefore, the inventive method employed in this invention further avoids any need for evaporation operations to recover gaseous HCl for displacement crystallization stage 18.

[0121] Solid Fe2O3 and solid M 2+ Cl2 is transferred along transfer pipe 62 to the third separation stage 26. In this stage, solid M is... 2 + Cl2 dissolves in water to produce M. 2+ Cl2 solution was used for solid-liquid separation to recover M. 2+ Cl2 solution and solid Fe2O3.

[0122] M 2+ The Cl2 solution is transferred along transfer pipeline 64 to metal recovery stage 30 for the recovery of the metals contained therein.

[0123] Fe2O3 is recovered as a marketable product along recovery line 72 and / or transferred along transfer line 66 to FeCl3 generation stage 28, where Fe2O3 is contacted with HCl (HCl is fed into generation stage 28 along feed line 74 or recycled to generation stage 28 along recirculation line 56), and / or Fe2O3 is recycled along recirculation line 76 to digestion stage 12, where it is contacted with HCl to generate FeCl3 solution in situ.

[0124] The generated (regenerated) FeCl3 is then recycled from generation stage 28 to digestion stage 18.

[0125] Example Example 1 - Beneficiation of copper concentrate containing mixed oxides and sulfides The composition of the mineral concentrate in this embodiment is shown in Table 1 below. For the specific process flow, please refer to [link / reference needed]. Figure 2 .

[0126] 1. In a reflux glass beaker, 100 g of concentrate (ground to 75 μm) from the mine was digested at 105 °C for 4 hours with 250 g FeCl3 (43 wt%) solution, 55 g HCl (33 wt%) solution and 100 mL water (see Table 1).

[0127]

[0128] 2. After oxidative digestion of the above concentrate, the main soluble chlorides FeCl2, CuCl2, and Cu2Cl2 were produced in the solution. The water-soluble fraction was separated from the insoluble fraction by filtration. The insoluble fraction contained 51 g (30%, or 16 g of water), and after washing and drying at 110 °C, it was found to contain sulfur, silicates, and other insoluble substances (see Table 2). Based on the chemical composition of the insoluble fraction, 99.6% of the available copper could be extracted.

[0129]

[0130] 3. After filtration, approximately 400 mL of filtrate (470 g) was obtained. 19.8 g of iron powder was added to this filtrate with stirring. The reduction reaction was completed after 30 minutes.

[0131] 4. After washing, filtering, and drying, the copper binder produced by reduction yielded 27.4 g of Cu. It should be noted that this copper can be pressed and melted, or used to produce CuSO4·5H2O crystals.

[0132] 5. Use the remaining approximately 350 mL of filtrate (470 g) as a washing solution to wash 84 g of HCl gas (from decomposition step 8 below). During the washing of the HCl gas, maintain the temperature of the solution at 30–35 °C.

[0133] 6. In step 5, 228 g of FeCl2·4H2O crystals were formed. These crystals were filtered out from the remaining HCl solution (326 g).

[0134] 7. These crystals were dried at 150 °C to obtain approximately 166 g of FeCl2·H2O(s). This dried product was then ground in situ to -2 mm.

[0135] 8. The ground product is then heated in air at 400 °C. At this temperature, all FeCl2·H2O is oxidized to Fe2O3(s) and HCl(g).

[0136] 9. 91.5 g of Fe2O3 was recovered. Of this, 38.5 g could be sold, while 53 g was recycled using 326 g of HCl solution (step 6), 18 g of fresh HCl (33 wt%) solution (as a top reagent), and 108 g of water. Based on this, 100 g of feed can be added to restart the next digestion operation.

[0137] For more information, please also refer to Figure 2 .

[0138] Example 2 - Beneficiation of nickel sulfide concentrate The composition of the mineral concentrate in this embodiment is shown in Table 3 below. For the specific process flow, please refer to Table 3. Figure 3 .

[0139]

[0140] *Note: If the sulfur in the insoluble portion floats, then PGMs > 100 ppm.

[0141]

[0142] Note: These values ​​are semi-quantitative.

[0143] 1. Add 85 g of recycled Fe2O3 to 100 g of concentrate (-45 μm). Digest the feed by refluxing with 400 mL of HCl(c) (approximately 33%) at 105 °C for 4 hours.

[0144] 2. After digestion, while the solution is still warm, the slurry (including insoluble matter) is directly pumped into a tank containing excess scrap iron. This is used to neutralize excess HCl, reduce excess FeCl3 to FeCl2, and bind Cu. Approximately 6g of iron scrap was used in this step.

[0145] 3. The slurry was then filtered and washed, yielding 62 g of insoluble matter, 5 g of copper binder, and 370 mL of filtrate.

[0146] 4. Treat the insoluble matter and copper binder with diluted H2SO4 and HNO3 solutions to produce a CuSO4 solution. After filtration and washing, CuSO4 can crystallize into CuSO4·5H2O, while the insoluble matter contains upgraded PGMs.

[0147] 5. Wash approximately 100 g of HCl with 370 mL of filtrate. Maintain the temperature between 15 and 20 °C. Washing with HCl will displace the chlorides of ferrous, nickel, and cobalt from the solution, forming their solid hydrated crystals. The resulting solution contains approximately 30-36% HCl.

[0148] 6. After filtering the crystals, wash them with fresh filtrate to remove the HCl(c) background. Approximately 95% of the ferrous crystals and 70% of the Ni / Co crystals are obtained in this manner. The remaining portion is recycled back to the digestion step with HCl solution and accumulates in further operations, resulting in more crystals as the concentration increases.

[0149] 7. Dry the washed crystals at 150 °C, generating clean steam in the process.

[0150] 8. Then decompose the dried crystals at 400 °C to produce Fe2O3, anhydrous Ni(Co)Cl2 and HCl(g), and then recycle to step 5.

[0151] 9. Add cold water to Fe2O3 to dissolve Ni(Co)Cl2. After filtration and washing, excess Fe2O3 can be sold off, while Ni(Co)Cl2 is extracted from the solution.

[0152] For more information, please also refer to Figure 3 .

Claims

1. A method for processing a solid metal or metal-containing material, said metal or metal-containing material comprising one or more metals or metal compounds, to recover one or more metals from the metal or metal-containing material in metallic or compound form, said method comprising: In the oxidative or reductive digestion step, an aqueous solution of ferrous chloride (FeCl2) is produced by contacting the metal or metal-containing material with a digestion reagent selected from the following: Gaseous hydrochloric acid (HCl). HCl aqueous solution, and Ferric chloride (FeCl3) aqueous solution is produced by the reaction of ferric oxide (III) (Fe2O3) with HCl in an aqueous medium. And reduce any FeCl3 in the solution produced by contact between the metal or metal-containing material and the digestion reagent to FeCl2 in the solution; In the crystallization step, solid ferrous chloride hydrate FeCl2·xH2O is crystallized from FeCl2 solution, where x>1; In the dehydration step, FeCl2·xH2O is subjected to temperature treatment in a non-oxidizing environment of 70 °C to 150 °C to produce dehydrated solid ferrous chloride hydrate FeCl2·yH2O, where x > y > 0; and In the thermal decomposition step, FeCl2·yH2O is placed in an oxidizing environment with a temperature higher than 200 ℃ but not higher than 600 ℃ for temperature treatment, thereby decomposing FeCl2·yH2O to produce solid iron oxide (Fe2O3) and anhydrous gaseous HCl.

2. The method according to claim 1, wherein the digestion reagent is gaseous HCl, which is generated in the thermal decomposition step; An aqueous solution of HCl is produced by washing with water to remove gaseous HCl generated during the thermal decomposition process. An aqueous solution of HCl is produced by washing gaseous HCl generated during the thermal decomposition step with an aqueous suspension or slurry of a solid metal or metal-containing material. An aqueous solution of FeCl3 is produced by contacting solid Fe2O3 generated during the thermal decomposition step with an aqueous solution of HCl, wherein the aqueous solution of HCl is produced by washing with water to remove gaseous HCl generated during the thermal decomposition step; or The FeCl3 aqueous solution is produced by washing the gaseous HCl generated in the thermal decomposition step with an aqueous suspension of solid Fe2O3 produced in the thermal decomposition step.

3. The method according to claim 1, wherein the crystallization of FeCl2·xH2O from the FeCl2 solution is achieved by displacement crystallization, wherein the FeCl2 solution is contacted with gaseous HCl generated in the thermal decomposition step and the FeCl2 solution is saturated, thereby producing solid FeCl2·xH2O in the HCl aqueous solution.

4. The method of claim 3, further comprising: Separate solid FeCl2·xH2O and any other solid metal chloride hydrates that crystallize together with FeCl2·H2O during the crystallization step from the resulting aqueous HCl solution; and An aqueous solution of HCl is used as a digestion reagent in the digestion step, or an aqueous solution of HCl is used to produce a digestion reagent in the digestion step.

5. The method according to claim 1, wherein The metal or metal-containing material includes iron (Fe) and other metals (M) in metallic or compound form, wherein the other metals are selected from one or more of chromium (Cr), copper (Cu), vanadium (V), nickel (Ni), cobalt (Co), zinc (Zn), titanium (Ti), and manganese (Mn), and the metallic or compound form is selected from metal oxide form and metal sulfide form; Therefore, in addition to the FeCl2 in the solution, the FeCl2 solution also contains one or more additional metal chlorides (M). 2+ Cl2, wherein M is selected from chromium (Cr), copper (Cu), vanadium (V), nickel (Ni), cobalt (Co), zinc (Zn), titanium (Ti), and manganese (Mn)); and Therefore, in addition to forming FeCl2·xH2O, the crystallization step also forms one or more other solid metal chloride hydrates (M 2+ Cl2·zH2O, where M is selected from one or more of chromium (Cr), copper (Cu), vanadium (V), nickel (Ni), cobalt (Co), zinc (Zn), titanium (Ti), and manganese (Mn), and z > 0).

6. The method of claim 1, further comprising: In the first separation step following the digestion step, the solids are separated from the FeCl2 solution by solid-liquid separation, thereby recovering the FeCl2 solution which is essentially free of solids. as well as In a second separation step, which takes place after the crystallization step and before the dehydration and decomposition steps, solid FeCl2·xH2O and any solid M that crystallized together with FeCl2·xH2O during the crystallization step are recovered. 2+ Cl2·zH2O.

7. The method according to claim 6, wherein, In the dehydration step, the recovered solid M 2+ Cl2·zH2O is dehydrated together with the recovered FeCl2·xH2O, thereby producing not only FeCl2·yH2O, but also other dehydrated solid metal chloride hydrates or anhydrous metal chlorides M. 2+ Cl2·aH2O, where z>a≥0.

8. The method of claim 7, wherein Solid M recovered from the dehydration step 2+ Cl2·aH2O and FeCl2·yH2O are subjected to temperature treatment together in the thermal decomposition step; and FeCl2·yH2O undergoes thermal decomposition, eliminating solid M. 2+ Cl2·aH2O, in which the hydrate is completely dehydrated during the thermal decomposition step, thus producing solid Fe2O3 and other solid anhydrous metal chlorides (M 2+ A mixture of Cl2.

9. The method of claim 1, wherein the thermal decomposition step is carried out at a temperature above 200 °C but not above 600 °C.

10. The method of claim 1, wherein x = 4 and y = 1.

Images