Production of nickel tetracarbonyl from nickel-copper mattes

Abstract

The present disclosure relates to improvements in the working up of mattes comprising nickel, copper, cobalt, and iron.

Description

[0001] BASF SE B25.160P-WO

[0002] 67056 Ludwigshafen am Rhein 12.08.2024 / lg / np / jl

[0003] Production of nickel tetracarbonyl from nickel-copper mattes

[0004] Field of the invention

[0005] This invention relates to improvements in the working up of mattes comprising nickel, copper, cobalt, and iron.

[0006] Background

[0007] In traditional suspension smelting, finely divided sulfidic raw material containing metals such as copper, nickel and iron, the recirculated flue dust and fluxes, as well as the air and / or oxygen mixture to be used as the oxidizing gas, are conducted to the vertical reaction shaft of a suspension smelting furnace from top to bottom, so that the oxidizing reactions take place at a high temperature. Owing to the influence of reaction heat and possible additional fuel, the major part of the reaction products will melt. From the reaction shaft, the suspension falls into the horizontal part of the furnace, i.e. to the settler, which contains at least two but sometimes three molten layers. If the settler contains three molten layers, the lowermost layer is the raw metal layer. Most often there are only two layers in the furnace: lowermost the matte or metal layer, and the slag layer on top of it.

[0008] CA 2 098 521 A discloses a method for producing a high-grade nickel matte and a highly oxidized slag in a flash smelting furnace, and for reducing the slag from the flash smelting furnace and for sulfidizing the resulting matte in an electric furnace. The matte produced in the flash smelting furnace and in the electric furnace are both directly conducted to further hydrometallurgical treatment. The method consists of drying, flash smelting, slag cleaning, and sulfurizing in one or two electric furnace(s). This process produces two different types of matte: matte from smelting and matte from reduction. This means, that also two different leaching processes are required. Fractions rich in nickel and fractions rich in copper can be obtained from nickelcopper matte by comminuting the matte, preferably after having subjected it to an annealing treatment, and separating from the comminuted material by a mechanical separation process, such as sieving or flotation, a fraction consisting predominantly of nickel sulfide and a fraction consisting predominantly of copper sulfide This method only gives satisfactory yields of nickel sulfide poor in copper and copper sulfide poor in nickel, however, if the matte contains such an amount of sulfur that the amounts of nickel and copper contained therein are completely combined as sulfides In the technical production of nickel-copper matte, which, as is well known, is obtained by blowing the iron contained in the green furnace matte in a converter, it is, however, necessary for the most complete possible slagging of the iron to reduce the sulfur content below that necessary for binding the copper and nickel as sulfides.

[0009] Generally speaking, the sulfur content of the usual nickel-copper matte is about 20 wt% If such a matte having too low a sulfur content is subjected to an annealing treatment, comminution and mechanical separation, it is not possible to separate the nickel completely in the form of nickel sulfide and the copper completely in the form of copper sulfide but, as may be ascertained by microscopic sections, a third fraction remains which consists mainly of metallic crystallites, namely of nickel and copper.

[0010] A mechanical separation of the nickel from the copper in these crystallites is impossible because the copper and nickel metals therein are present as a copper-nickel alloy It has therefore already been proposed to convert the nickel and copper into sulfides by adding sulfur, for example by smelting with green furnace mattes and then to repeat the annealing treatment, the comminution, and the mechanical separation in order to recover nickel sulfide and copper sulfide separately. By this process, however, the high concentration of nickel and copper metal desired for the further processing is again considerably reduced and furthermore losses by slagging again occur in the repeated smelting process.

[0011] GB 0 702 011 A teaches to recover nickel carbonyl from nickel-copper mattes having insufficient sulfur to bind the nickel and copper as sulfides, e.g., 20 per cent sulfur or less, by comminuting the matte, preferably after annealing, separating the metallic copper and nickel fraction from the copper and nickel sulfide fraction, and treating the metallic fraction with carbon monoxide at pressures above 50 atmospheres and temperatures of 200 to 230°C to remove the nickel as carbonyl, which may then be reduced to metallic nickel. Cobalt or iron, if present in the matte, may be carbonylated simultaneously with the nickel and separated by distillation, or selective carbonylation of the nickel may be effected.

[0012] GB 429 274 A discloses a process for making nickel carbonyl by the action of carbon monoxide under pressure on nickel matte mechanically mixed without fusion with copper or iron in sufficient quantity for all the sulphur to be bound as cuprous or iron sulphide. The copper or iron may be added as metals, as oxides, in which case the mixture is reduced before the carbon monoxide treatment, as calcined, or calcined and reduced mattes, or as residues from the treatment. In the last case, the same copper or iron can be used repeatedly in cyclic manner until a sufficient quantity of precious metals has accumulated which is then recovered.

[0013] WO 20241041 978 A1 relates to a process for the preparation of NiO particles comprising the step of contacting a Ni(CO)4 gas stream having a temperature of less than 100 °C with an oxidizing gas stream to directly yield NiO particles in the product stream of a reactor

[0014] Summary of the invention

[0015] We have now found that recovery of nickel by carbonylation of sulfur-rich mattes, e.g., FSF mattes, can be improved by mixing the sulfur-rich matte with at least one matte having a low sulfur content, e.g., an EF matte and / or a converter matte. Additionally, less iron is removed from the mixture in comparison to carbonylation of pure EF mattes or converter mattes.

[0016] The mattes used in the process of the present disclosure, e.g. , FSF mattes, EF mattes, and converter mattes, all comprise nickel, copper, iron, cobalt, and sulfur. The mattes are derived from sulfidic ores in several beneficiation steps including a thermal treatment step at the end, and mainly consist of Ni, Cu, Fe, S and Co.

[0017] In the process of the present disclosure, a first matte having a sulfur content ci(S) which is higher than [0.25ci(Cu)+0.86ci(Fe)+0.54ci(Co)], ci(Cu) being the copper content of the first matte, ci(Fe) being the iron content of the first matte, and ci(Co) being the cobalt content of the first matte, is mixed with a second matte having a sulfur content C2(S) which is lower than [0.25C2(CU)+0.86 C2(Fe)+0.54c2(Co)], C2(Cu) being the copper content of the second matte, C2(Fe) being the iron content of the second matte, and C2(Co) being the cobalt content of the second matte, and / or a third matte having a sulfur content C3(S) which is lower than [0.25c3(Cu)+0.86c3(Fe)+0.54c3(Co)], cs(Cu) being the copper content of the third matte, cs(Fe) being the iron content of the third matte, and C3(Co) being the cobalt content of the third matte, at a mass ratio which produces a mixture having a sulfur content CM(S) in the range

[0018] [0.25cM(Cu)+0.86cM(Fe)+0.54cM(Co)] > cM(S) > [0.06cM(Cu)+0.08cM(Fe)+0.10cM(Co)], CM(CU) being the copper content of the mixture, CM(FO) being the iron content of the mixture, and CM(CO) being the cobalt content of the mixture.

[0019] All contents refer to the weight proportion of the respective element, relative to the total weight of the matte or mixture, respectively. For instance, CM(S) refers to the weight proportion (w / w) of sulfur in the mixture. Element contents are determined by ICP-OES. The mixture is reacted with carbon monoxide to obtain nickel tetracarbonyl and a residue depleted of nickel.

[0020] The process according to this invention offers the advantage of increasing the fraction of nickel in the sulfur-rich matte which is recovered as nickel carbonyl by adjusting the sulfur content of the mixture of sulfur-rich matte (e.g., FSF matte) and low-sulfur matte, for instance, EF matte and / or converter matte, to be within a defined range.

[0021] The process of the present disclosure is not only applicable to a nickel-copper matte which has been obtained in the usual way from ores by smelting and blowing green-nickel-copper furnace matte, but also to products containing nickel, copper, and sulfur which have been obtained in other ways, for example, from nickel-copper scrap by smelting with pyrites.

[0022] Brief description of the drawings

[0023] Fig. 1 shows an XRD diagram of a residue obtained after carbonylation of a 1 :1 mixture of a FSF matte and an EF matte,

[0024] Fig. 2 shows an XRD diagram of a FSF matte.

[0025] Fig. 3 shows an XRD diagram of an EF matte.

[0026] Fig. 4 shows an XRD diagram of a residue obtained after carbonylation of a FSF matte.

[0027] Detailed description

[0028] The present disclosure provides a process for the production of nickel tetracarbonyl, comprising the steps of a) mixing a first matte having a sulfur content ci(S) which is higher than [0.25ci(Cu)+0.86ci(Fe)+0.54ci(Co)], ci(Cu) being the copper content of the first matte, ci(Fe) being the iron content of the first matte, and ci(Co) being the cobalt content of the first matte, with a second matte having a sulfur content C2(S) which is lower than [0.25C2(CU)+0.86 C2(Fe)+0.54c2(Co)], C2(Cu) being the copper content of the second matte, C2(Fe) being the iron content of the second matte, and C2(Co) being the cobalt content of the second matte, and / or a third matte having a sulfur content C3(S) which is lower than [0.25C3(CU)+0.86 C3(Fe)+0.54c3(Co)], cs(Cu) being the copper content of the third matte, cs(Fe) being the iron content of the third matte, and C3(Co) being the cobalt content of the third matte, at a mass ratio which produces a mixture having a sulfur content CM(S) which is lower than [0.25cM(Cu)+0.86cM(Fe)+0.54cM(Co)], but higher than [0.06cM(Cu)+0.08cM(Fe)+0.10cM(Co)], CM(CU) being the copper content of the mixture, CM(FO) being the iron content of the mixture, and CM(CO) being the cobalt content of the mixture, and b) reacting the mixture with carbon monoxide to obtain nickel tetracarbonyl and a residue depleted of nickel.

[0029] In the context of the present disclosure, "matte" designates a material obtained by solidification of a molten metal sulfide phase formed during smelting of sulfidic ores comprising copper, nickel, and other base metals. Typically, a matte is the phase in which the principal metal being extracted is recovered prior to a final reduction process (usually converting). Molten mattes are insoluble in both slag and metal phases. This insolubility, combined with differences in specific gravities between mattes, slags, and metals, allows for separation of the molten phases.

[0030] In the context of the present disclosure, a FSF matte is a material obtained by solidification of a molten metal sulfide phase formed in a flash furnace. The matte from a flash furnace (FSF matte) is sulfur-rich and comprises from 15 to 55 wt% Ni, relative to the total weight of the FSF matte, and from 20 to 30 wt% S, relative to the total weight of the FSF matte. An exemplary FSF matte comprises 53 wt% nickel, 11 wt% copper, 8 wt% iron, 0.8 wt% cobalt, and 22 wt% sulfur. Another exemplary FSF matte comprises 32 wt% nickel, 13 wt% copper, 23 wt% iron, 1 wt% cobalt, and 27 wt% sulfur.

[0031] In the context of the present disclosure, an EF matte is a material obtained by solidification of a molten metal sulfide phase formed in an electric arc furnace. The matte from an electric arc furnace (EF matte) is iron-rich and comprises from 25 to 50 wt% Ni, relative to the total weight of the EF matte, from 20 to 40 wt% Fe, relative to the total weight of the EF matte, and from 2 to 20 wt% S, relative to the total weight of the EF matte. An exemplary EF matte comprises 46 wt% nickel, 9 wt% copper, 35 wt% iron, 3 wt% cobalt, and 4 wt% sulfur. Another exemplary EF matte comprises 26 wt% nickel, 12 wt% copper, 32 wt% iron, and 20 wt% sulfur.

[0032] In the context of the present disclosure, a converter matte is a material obtained by solidification of a molten metal sulfide phase formed in a converter. The converter matte is nickel-rich and comprises from 35 to 80 wt%, e.g. , from 50 to 75 wt%, Ni, relative to the total weight of the converter matte, from 1 to 5 wt% Fe, relative to the total weight of the converter matte, from 1 to 2 wt% Co, relative to the total weight of the converter matte, and from 4 to 20 wt%, e.g., from 5 to 18 wt%, S, relative to the total weight of the converter matte. An exemplary converter matte comprises 55 wt% nickel, 23 wt% copper, 3 wt% iron, 2 wt% Co, and 16 wt% sulfur.

[0033] Prior to mixing, the mattes are comminuted, e.g., by grinding or ball-milling, to form a powder. A typical range for particle size dso of the powder is from 1 to 200 pm, e.g., from 5 to 50 pm.

[0034] In step a) of the process of the present disclosure, a sulfur-rich matte (e.g., FSF matte) is mixed with a low-sulfur matte (EF matte and / or converter matte) to produce a mixture satisfying the formula

[0035] [0.06cM(Cu)+0.08cM(Fe)+0.10cM(Co)] < cM(S) < [0.25cM(Cu)+0.86cM(Fe)+0.54cM(Co)] (I) wherein CM(S) is the sulfur content of the mixture in wt%, relative to the total weight of the mixture,

[0036] CM(CU) is the copper content of the mixture in wt%, relative to the total weight of the mixture,

[0037] CM(FO) is the iron content of the mixture in wt%, relative to the total weight of the mixture, and

[0038] CM(CO) is the cobalt content of the mixture in wt%, relative to the total weight of the mixture.

[0039] It has been found that nearly quantitative carbonylation of Ni present in the mixture is possible within the composition range defined by formula (I).

[0040] In some embodiments of the process, the powder mixture is subsequently converted into a pieced form, for example by pressing, by making into a paste with a binding agent and drying, or by sintering together, so that the stream of carbon monoxide does not encounter too great a resistance during the carbonyl formation. By these measures, dust losses are also reduced by a minimum.

[0041] In step b) of the process, the mixture obtained in step a) is reacted with carbon monoxide to obtain nickel tetracarbonyl and a residue depleted of nickel. To recover nickel carbonyl from the reduced MHP, pressures in the range of from 1 bar to 250 bar, e.g., from 50 bar to 200 bar, or from 50 to 150 bar, may be used. At low pressures, formation of nickel tetracarbonyl proceeds slower. Temperatures in the range of from 20°C to 250°C, e.g., from 90°C to 230°C, or from 120°C to 200°C, or from 120 to 160°C, may be used to form nickel tetracarbonyl.

[0042] It has been found that the formation of nickel tetracarbonyl proceeds very slowly at temperatures below 80°C, so that it is preferred to use higher temperatures.

[0043] In some embodiments, the reaction time is in the range of from 1 hour to 24 hours, e.g., from 4 hours to 12 hours, for instance, from 4 to 8 hours. The mixture is reacted with a flow of gaseous carbon monoxide. The nickel tetracarbonyl formed is swept from the reactor by the flow of carbon monoxide and can be recovered from the gas stream, e.g., by condensation, or decomposed to obtain nickel metal.

[0044] In some embodiments, the nickel tetracarbonyl is oxidized to yield nanoparticulate NiO. The nanoparticulate NiO can be used as a precursor for the production of Cathode Active Materials (CAM) for lithium-ion batteries. It is particularly interesting for the subsequent production of single-crystal CAMs (sc- CAMs), which offer higher cycle stability than their polycrystalline counterparts.

[0045] Examples

[0046] The samples were prepared from two mattes derived from sulfidic ores in several beneficiation steps - including a thermal step at the end - and consisting mainly of Ni, Cu, Fe, S and Co: one iron-rich matte from an electric arc furnace (EF) with 46 wt% Ni and 35 wt% Fe, and 3.9 wt% S, and a second, sulfur-rich matte from a flash furnace (FSF) with 53 wt% Ni, 7.9 wt% Fe, and 22 wt% S (Table 1 ).

[0047] The carbonylation experiments were carried out in an autoclave. 7 g of the solid feedstock were filled into two small containers (3.5 g feedstock in each container) made of sintered steel with 60 pm pore size, which were mounted to the lid of the autoclave. The set-up allowed for the following parameter ranges: T = room temperature - 200 °C, p = 1 - 200 bar, and a flow rate between 5 and 20 NL / h. The default carbonylation duration was 8 h. In a typical experiment, the gas streams would be pre-heated before entering the autoclave via an inlet and leaving it via an outlet.

[0048] Feedstocks

[0049] Experiments were started with a set of three different primary feedstocks. The suitability of the set-up was tested and proven with elemental Ni in powder form. The other feedstocks comprised an iron-rich matte from an electric arc furnace (EF) with 46% Ni and 35% Fe, and a sulfur-rich matte from a flash furnace (FSF) with 53% Ni and 22% S (Table 1 ).

[0050] Sample Preparation

[0051] The three primary materials were comminuted prior to their use in carbonylation experiments. In case of both mattes, due to the considerable metal content of both feeds, usage of a ball mill (Retsch PM 100) was necessary to break down the lumps. Milling with 30 mm tungsten carbide (WC) balls yielded good comminution results.

[0052] Table 1 : Elemental composition, average particle size (d50) and identified phases according to XRD of FSF matte, EF matte, and a 1:1 mixture

[0053] Yield Determination

[0054] The carbonylation yields of the respective metals of interest (Ni / Co / Fe, depending on the feedstock) were calculated based on the amount of metal removed from the starting material during the experiment. To this end, ICP measurements were performed on the solid residue. Shortly after starting the project, XRF measurements were conducted in parallel which proved to be a valuable complementation. As XRF measurements could be carried out by RGU / BI directly they enabled a quick evaluation of the reaction outcome. Although of course less precise than ICP - if accuracies of ca. + / - 5% sufficed - ICP measurements could be saved. Carbonylation of Primary Feedstocks

[0055] The elemental Ni powder (BHP Group, dso = 162 pm) could be carbonylated quantitatively in several initial experiments targeted at the verification of the suitability of the set-up. Next, the qualitative carbonylation of the two mattes could be shown (reaction parameters in all cases relatively mild: p = 50 bar, T = 120°C, flow rate = 5 NL / h, t = 8 h) with Ni(CO)4 yields of around 40%, respectively (Table 2).

[0056] Table 2: Ni yields (Y(Ni)) during initial experiments with the primary feedstocks at p = 50 bar, T = 120 °C, flow rate = 5 NL / h, t = 8 h.

[0057] FSF matte

[0058] As the flash furnace is the more relevant production process, compared to the electric arc furnace, the initial focus was on the FSF matte. First, in order to rule out any inhibition by the sintered metal, the experiment listed in Table 2 was repeated with containers with a pore size of 0.5 pm rather than the usual 60 pm. Although a drop in yield was observed from 40% to 31 %, the difference is deemed small, compared to the change of pore size by more than one order of magnitude. It was thus concluded that diffusion through the pores 60 pm does not pose any hindrance to the reaction rate.

[0059] In subsequent experiments, the fundamental reaction parameters (flow rate, pressure, and temperature) were systematically varied to investigate their influence on the Ni(CO)4 yield (Table 3). Table 3: Reaction parameters and Ni yield of selected carbonylation experiments with FSF matte

[0060] The maximum yield could be increased from 40% to 60% by increasing pressure and temperature to 200 bar and 200°C, respectively. Nevertheless, a significant amount of Ni could not be carbonylated. Powder X-ray diffraction (XRD) analyses of the residue after carbonylation showed no Ni, but several sulfide phases containing Ni, such as NisS2, NiySe, and, most importantly, NiS (Figure 1 ).

[0061] EF Matte

[0062] Using the same reaction conditions (p = 200 bar, T = 200°C, flow rate = 8 NL / h, t = 8 h) that delivered 60% yield for the sulfur-rich FSF matte allowed for quantitative carbonylation (>99.5%) of the Ni content in the EF matte (Table 4). The high contents of Cu (8.1 %) and Fe (35%) do not prevent quantitative carbonylation of the EF matte. Quantitative carbonylation can also be obtained at 160°C and 120 bar, but not at 120°C and 80 bar (Ni yield « 70%).

[0063] Table 4: Reaction parameters and both Ni and Fe yield of carbonylation experiments with EF matte 1 :1 Mixture of FSF matte and EF matte

[0064] Using the same reaction conditions (p = 200 bar, T = 200°C, flow rate = 8 NL / h, t = 8 h), a mixture of FSF matte and EF matte in a mass ratio of 1 :1 was carbonylated. Results are shown in Table 5. About 96% of the nickel content of the mixture could be converted to nickel tetracarbonyl, as compared to 60% for the pure FSF matte. On the other hand, only about (27±1 )% of the iron content of the mixture was carbonylated, as compared to 91 % for the pure EF matte.

[0065] Table 5: Compositions and both Ni and Fe yield of carbonylation experiments with FSF matte, EF matte, and a 1:1 mixture.

[0066] Detailed description of the drawings

[0067] Figure 1 shows an XRD diagram (measured using Cu Ka radiation) of a residue obtained after carbonylation of a 1 :1 mixture of a FSF matte and an EF matte (A). Diffraction patterns for cubic CuFe2Ss (B) and pentlandite (Fe,Ni)gSs (C) are shown below the XRD diagram.

[0068] Figure 2 shows an XRD diagram (measured using Cu Ka radiation) of a FSF matte (A). Diffraction patterns for nickel (B), NisS2 (C), pentlandite (Fe,Ni)gSs (D), and bornite CusFeS4 (E) are shown below the XRD diagram. Figure 3 shows an XRD diagram (measured using Cu Ka radiation) of an EF matte (A). Diffraction patterns for nickel (B) and pentlandite (Fe,Ni)gSs (C) are shown below the XRD diagram. Figure 4 shows an XRD diagram (measured using Cu Ka radiation) of a residue obtained after carbonylation of a FSF matte. Diffraction patterns for pentlandite (Fe,Ni)gSs (B), chalcopyrite CuFeS2 (C), NiS (D), and bornite CusFeS4 (E) are shown below the XRD diagram.

Claims

BASF SE B25.160P-WO67056 Ludwigshafen am Rhein 12.08.2025 / lg / np / jlClaims1. A process for the production of nickel tetracarbonyl, comprising the steps of a) mixing a first matte having a sulfur content ci(S) in wt% which is higher than [0.25ci(Cu)+0.86ci(Fe)+0.54ci(Co)], ci(Cu) being the copper content of the first matte in wt%, ci(Fe) being the iron content of the first matte in wt%, and ci(Co) being the cobalt content of the first matte in wt%, with a second matte having a sulfur content C2(S) in wt% which is lower than [0.25C2(CU)+0.86 C2(Fe)+0.54c2(Co)], C2(Cu) being the copper content of the second matte in wt%, C2(Fe) being the iron content of the second matte in wt%, and C2(Co) being the cobalt content of the second matte in wt%, and / or a third matte having a sulfur content cs(S) in wt% which is lower than [0.25C3(CU)+0.86 C3(Fe)+0.54c3(Co)], cs(Cu) being the copper content of the third matte in wt%, cs(Fe) being the iron content of the third matte in wt%, and C3(Co) being the cobalt content of the third matte in wt%, at a mass ratio which produces a mixture having a sulfur content CM(S) in wt% which is lower than [0.25cM(Cu)+0.86cM(Fe)+0.54cM(Co)], but higher than [0.06cM(Cu)+0.08cM(Fe)+0.10cM(Co)], CM(CU) being the copper content of the mixture in wt%, CM(FO) being the iron content of the mixture in wt%, and CM(CO) being the cobalt content of the mixture in wt%, and b) reacting the mixture with carbon monoxide to obtain nickel tetracarbonyl and a residue depleted of nickel.

2. The process of claim 1 , wherein the first matte comprises from 30 to 55 wt% Ni, relative to the total weight of the first matte, and from 20 to 30 wt% S, relative to the total weight of the first matte.

3. The process of claim 1 or 2, wherein the second matte comprises from 25 to 50 wt% Ni, relative to the total weight of the second matte, from 20 to 40 wt% Fe, relative to the total weight of the second matte, and from 2 to 20 wt% S, relative to the total weight of the second matte.

4. The process of any one of claims 1 to 3, wherein the third matte comprises from 50 to 80 wt% Ni, relative to the total weight of the third matte, from 1 to 5 wt% Fe, relative to the total weight of the third matte, and from 5 to 18 wt% S, relative to the total weight of the third matte.

5. The process of any one of claims 1 to 4, wherein in step b) the mixture is reacted with carbon monoxide at pressures of from 50 bar to 200 bar.

6. The process of any one of claims 1 to 5, wherein in step b) the mixture is reacted with carbon monoxide at temperatures of from 90°C to 200°C.

7. The process of any one of claims 1 to 6, wherein in step b) the mixture is reacted with carbon monoxide for a time interval in the range of from 4 hours to 12 hours.

8. The process of any one of claims 1 to 7, additionally comprising a step c) of oxidizing the nickel tetracarbonyl obtained in step b) to yield nanoparticulate NiO.

9. The process of any one of claim 8, additionally comprising a step d) of using the nanoparticulate NiO as a precursor for the production of Cathode Active Materials (CAM) for lithium-ion batteries.

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