Method for separating molybdenum and ferrovanadium by regulating and controlling metal ion morphology

Abstract

The invention provides a method for separating molybdenum and ferrovanadium by regulating and controlling the form of metal ions, which comprises the following steps: (1) mixing a ferrovanadium-molybdenum solution with a reducing agent, and then mixing with inorganic acid to obtain a to-be-treated solution; (2) extracting a molybdenum element from the to-be-treated liquid obtained in the step (1) by adopting an extracting agent to obtain a molybdenum-containing organic phase and a vanadium-containing molten iron phase; and (3) mixing a stripping agent with the molybdenum-containing organic phase obtained in the step (2), and carrying out stripping to obtain a molybdenum-containing water phase and an extraction agent. According to the method, molybdenum, vanadium and iron are reduced, the form of metal ions is regulated and controlled by controlling the acidity of the solution, and the extraction agent is used for selectively extracting metal species in the form of anions, so that the molybdenum is combined with the extraction agent, the vanadium and the iron are left in the solution, and efficient separation of the molybdenum, the vanadium and the iron is achieved; and the extraction agent can be recycled, so that the method has relatively high environment-friendly and economic values, and has important significance on recycling of molybdenum and vanadium.

Description

Technical Field

[0001] The invention belongs to the field of separation technology and relates to a method for separating molybdenum and ferrovanadium, and in particular to a method for separating molybdenum and ferrovanadium by regulating the form of metal ions. Background Art

[0002] Molybdenum and vanadium occupy an important position in industrial production, petrochemical industry and new energy fields. Since molybdenum and vanadium occupy diagonal positions in the periodic table, their physical and chemical properties are similar, and they are often associated in coal, molybdenite, and vanadium-titanium magnetite. Molybdenum and vanadium in secondary resources include waste catalysts, smelting waste slag, petrochemical waste slag, etc. Regardless of the primary ore of molybdenum and vanadium or the secondary resources of molybdenum and vanadium, the separation of molybdenum and vanadium and iron elements has attracted much attention so far. Usually, acidic leaching with inorganic acids is the first step in the extraction and separation of molybdenum, vanadium and iron resources, but because inorganic acids are usually not selective, the molybdenum, vanadium, iron and other elements are extracted into the solution together. However, due to similar physical and chemical properties, elements such as molybdenum, vanadium and iron are difficult to separate in aqueous solution.

[0003] At present, the methods for separating molybdenum, vanadium and iron from the solution are mainly extraction separation, sulfide precipitation and ammonium salt precipitation separation. Since the sulfide precipitation and ammonium salt precipitation methods both have problems such as large acid and alkali consumption, large amount of wastewater and low product purity, the extraction separation method has become the preferred method for separating molybdenum, vanadium and iron. The traditional extraction separation method is to use an extractant to extract vanadium (V) and molybdenum (VI) into the organic phase through a cation exchange process, and then use sulfuric acid and ammonia water to step-by-step stripping of vanadium and molybdenum. However, vanadium and molybdenum are mixed in the stripping solution of molybdenum and vanadium, and qualified molybdenum and vanadium products cannot be prepared, and it is difficult to purify them again.

[0004] Therefore, achieving the selective extraction of a single metal from molybdenum-vanadium-iron metals is the key to avoiding impurity problems in metal products. Summary of the invention

[0005] In view of the problems in the prior art that the separation process of molybdenum and ferrovanadium is complicated and the product purity is low, the present invention provides a method for separating molybdenum and ferrovanadium by regulating the form of metal ions. The method has a simple separation process and high separation efficiency, and the separation medium can be recycled, thereby achieving efficient separation of molybdenum and ferrovanadium.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for separating molybdenum and ferrovanadium by regulating the form of metal ions, the method comprising the following steps:

[0008] (1) mixing a vanadium-molybdenum-iron solution and a reducing agent, and then mixing an inorganic acid to obtain a solution to be treated;

[0009] (2) extracting molybdenum from the liquid to be treated obtained in step (1) using an extractant to obtain an organic phase containing molybdenum and a phase containing vanadium and molten iron;

[0010] (3) mixing a stripping agent with the molybdenum-containing organic phase obtained in step (2), and obtaining a molybdenum-containing aqueous phase and an extractant after stripping.

[0011] The present invention reduces the molybdenum, vanadium and iron elements in the vanadium-molybdenum-iron solution by a reducing agent, and controls the acidity of the solution by an inorganic acid to regulate the metal ion form, and uses an anion extractant to selectively extract metal species in anionic form, so that molybdenum in anionic form is selectively combined with the extractant, while vanadium and iron in cationic form remain in the solution, thereby achieving efficient separation of molybdenum from vanadium and iron, avoiding the problem of low product purity caused by co-extraction of molybdenum with vanadium and iron; and the extractant can be recycled, with high economic and environmental value; the method described in the present invention has the characteristics of short process, mild conditions, high separation coefficient of molybdenum and vanadium-iron, and the like.

[0012] As a preferred technical solution of the present invention, the vanadium ion concentration in the vanadium-molybdenum-iron solution in step (1) is 0.1-50 g / L, for example, it can be 0.1 g / L, 1 g / L, 10 g / L, 20 g / L, 30 g / L, 40 g / L or 50 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0013] Preferably, the concentration of platinum ions in the vanadium-molybdenum-iron solution in step (1) is 0.1 to 50 g / L, for example, 0.1 g / L, 1 g / L, 10 g / L, 20 g / L, 30 g / L, 40 g / L or 50 g / L, but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0014] Preferably, the iron ion concentration in the vanadium-molybdenum-iron solution in step (1) is 0.1 to 20 g / L, for example, it can be 0.1 g / L, 1 g / L, 5 g / L, 8 g / L, 11 g / L, 14 g / L, 17 g / L or 20 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0015] As a preferred technical solution of the present invention, the reducing agent in step (1) includes any one of sodium sulfite, sodium pyrosulfite, ascorbic acid or sodium hypochlorite, or a combination of at least two of them. Typical but non-limiting combinations include: a combination of sodium sulfite and sodium pyrosulfite, a combination of sodium sulfite and ascorbic acid, a combination of sodium pyrosulfite and ascorbic acid, a combination of ascorbic acid and sodium hypochlorite, or a combination of sodium sulfite, sodium pyrosulfite, ascorbic acid and sodium hypochlorite.

[0016] Preferably, the amount of the reducing agent added in step (1) is 0.25 to 5 times the total molar amount of metal ions in the vanadium-molybdenum-iron solution, for example, it can be 0.25 times, 0.75 times, 1 times, 2 times, 3 times, 4 times or 5 times, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0017] In the present invention, the purpose of the reducing agent is to reduce the valence states of metal vanadium, molybdenum, iron and other elements in the vanadium-molybdenum-iron solution from +5, +6, +3 to +4, +5, +2 respectively; if the amount is too high, the sodium metal content or organic matter content in the solution will be too high, resulting in a reduction in the extraction ability of the extractant for molybdenum; if the amount is too low, the metal vanadium, molybdenum and iron cannot be completely reduced, so that the extractant extracts vanadium and molybdenum together, resulting in poor separation effect of vanadium and molybdenum.

[0018] As a preferred technical solution of the present invention, the inorganic acid in step (1) includes any one of hydrochloric acid, sulfuric acid or nitric acid, or a combination of at least two of them. Typical but non-limiting combinations include: a combination of hydrochloric acid and sulfuric acid, a combination of hydrochloric acid and nitric acid, a combination of sulfuric acid and nitric acid, or a combination of hydrochloric acid, sulfuric acid and nitric acid.

[0019] Preferably, the hydrogen ion concentration of the liquid to be treated in step (1) is 1.5 to 2.5 mol / L, for example, it can be 1.5 mol / L, 1.7 mol / L, 1.9 mol / L, 2.1 mol / L, 2.3 mol / L or 2.5 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0020] In the present invention, when the hydrogen ion concentration of the liquid to be treated is in the range of 1.5 to 2.5 mol / L, it is conducive to the conversion of molybdenum ion species into anionic forms, thereby selectively extracting with the N235 extractant, while the cationic forms of vanadium and iron ions continue to remain in the solution, thereby achieving effective separation of molybdenum from vanadium and iron; when the hydrogen ion concentration of the liquid to be treated is 1.5 mol / L, the ionic form of vanadium is partially converted into cations, thereby causing co-extraction of vanadium and molybdenum and deteriorating the separation effect; when the hydrogen ion concentration in the solution is higher than 2.5 mol / L, the extraction ability of the N235 extractant for molybdenum anionic species is reduced, thereby deteriorating the extraction and separation effect.

[0021] Preferably, the temperature of the mixed inorganic acid in step (1) is 20-60°C, for example, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C or 60°C, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 20-40°C.

[0022] Preferably, the time for mixing the inorganic acid in step (1) is 5 to 60 minutes, for example, 5 minutes, 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes or 60 minutes, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0023] In the present invention, the purpose of mixing the inorganic acid in step (1) is to control the form of molybdenum, vanadium and iron metal ions in the solution; if the mixing temperature is too high, it will easily lead to the co-precipitation of vanadium, molybdenum elements and iron ions in the solution to form precipitates such as iron vanadate and iron molybdate, thereby reducing the concentration of metal ions in the solution.

[0024] As a preferred technical solution of the present invention, the extractant in step (2) includes N235 extractant.

[0025] Preferably, the concentration of the N235 extractant is 5-40% (V / V), for example, it can be 5% (V / V), 10% (V / V), 20% (V / V), 30% (V / V) or 40% (V / V), but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] Preferably, the ratio of the extractant to the treated liquid in step (2) is 1 / 3 to 4 / 1, for example, it can be 1 / 3, 1 / 2, 1 / 1, 2 / 1, 3 / 1 or 4 / 1, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0027] Preferably, the molar ratio of the extractant in step (2) to the molybdenum ions in the vanadium-molybdenum-iron solution is 2 to 4:1, for example, it can be 2:1, 2.4:1, 2.8:1, 3.2:1, 3.6:1 or 4:1, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0028] In the present invention, the molar ratio of the extractant to the molybdenum ions in the vanadium-molybdenum-iron solution is 2 to 4:1. If the amount of the extractant is too low, the extraction rate of molybdenum will be low, making the separation effect of molybdenum and vanadium-iron worse. On the contrary, if the amount of the extractant is too high, the content of molybdenum in the oil phase will be relatively low, which is not conducive to the stripping operation, and at the same time increases the consumption of the extractant, which increases the cost.

[0029] As a preferred technical solution of the present invention, the extraction temperature in step (2) is 20-40°C, for example, it can be 20°C, 24°C, 28°C, 32°C, 36°C or 40°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0030] Preferably, the contact time for the extraction in step (2) is 4 to 20 min, for example, 4 min, 7 min, 10 min, 13 min, 16 min or 20 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0031] As a preferred technical solution of the present invention, the stripping agent in step (3) includes aqueous ammonia.

[0032] Preferably, the concentration of the ammonia water is 5 to 20 wt%, for example, 5 wt%, 8 wt%, 11 wt%, 14 wt%, 17 wt% or 20 wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0033] As a preferred technical solution of the present invention, the ratio of the molybdenum-containing organic phase in step (3) to the stripping agent is 1 / 2 to 4 / 1, for example, it can be 1 / 2, 1 / 1, 2 / 1, 3 / 1 or 4 / 1, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0034] As a preferred technical solution of the present invention, the extractant obtained in step (3) can be reused in step (2).

[0035] As a preferred technical solution of the present invention, the method for regulating the metal ion form to separate molybdenum and ferrovanadium provided by the present invention comprises the following steps:

[0036] (1) mixing a vanadium-molybdenum-iron solution and a reducing agent, and then mixing an inorganic acid at 20 to 60° C. to obtain a solution to be treated having a hydrogen ion concentration of 1.5 to 2.5 mol / L;

[0037] Wherein, the vanadium ion concentration in the vanadium-molybdenum-iron solution is 0.1-50 g / L, the molybdenum ion concentration is 0.1-50 g / L, and the iron ion concentration is 0.1-20 g / L;

[0038] The amount of the reducing agent added is 0.25 to 5 times the total molar amount of metal ions in the vanadium-molybdenum-iron solution;

[0039] (2) extracting molybdenum from the liquid to be treated obtained in step (1) using an N235 extractant having a concentration of 5 to 40% (V / V) to obtain an organic phase containing molybdenum and a phase containing vanadium and molten iron;

[0040] The ratio of the extractant to the mixed solution to be treated is 1 / 3 to 4 / 1; the molar ratio of the extractant to the molybdenum ions in the vanadium-molybdenum-iron solution is 2 to 4:1; the extraction temperature is 20 to 40°C, and the contact time is 4 to 20 minutes;

[0041] (3) mixing ammonia water having a concentration of 5 to 20 wt % with the molybdenum-containing organic phase obtained in step (2), and obtaining a molybdenum-containing aqueous phase and an extractant that can be reused in step (2) after stripping;

[0042] Wherein, the ratio of the molybdenum-containing organic phase to the stripping agent is 1 / 4 to 1 / 1.

[0043] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] (1) The method provided by the present invention reduces metal ions and controls the acidity of the solution to regulate the metal ion form, and uses N235 extractant to selectively extract metal species in anionic form, so that molybdenum in anionic form is selectively combined with N235 extractant, while vanadium and iron in cationic form remain in the solution, thereby achieving efficient separation of molybdenum from vanadium and iron, and avoiding the problem of low product purity caused by co-extraction of molybdenum with vanadium and iron;

[0046] (2) The extractant provided by the method of the present invention can be recycled and has high economic and environmental value;

[0047] (3) The method provided by the present invention has the characteristics of short process, mild conditions, high separation coefficient of molybdenum and ferrovanadium, and high product purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a process flow chart of the method for separating molybdenum and ferrovanadium by regulating the metal ion form provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0049] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0050] Example 1

[0051] This embodiment provides a method for regulating the metal ion form to separate molybdenum and vanadium iron, such as Figure 1 As shown, the method comprises the following steps:

[0052] (1) mixing the vanadium-molybdenum-iron solution with sodium sulfite, and then mixing with sulfuric acid at 40° C. to obtain a solution to be treated having a hydrogen ion concentration of 2.0 mol / L;

[0053] Wherein, the vanadium ion concentration in the vanadium-molybdenum-iron solution is 30 g / L, the molybdenum ion concentration is 30 g / L, and the iron ion concentration is 10 g / L;

[0054] The amount of the reducing agent added is 1.5 times the total molar amount of metal ions in the vanadium-molybdenum-iron solution;

[0055] (2) extracting molybdenum from the liquid to be treated obtained in step (1) using an N235 extractant having a concentration of 35% (V / V) to obtain an organic phase containing molybdenum and a phase containing vanadium and molten iron;

[0056] The ratio of the extractant to the mixed solution to be treated is 1 / 1; the molar ratio of the extractant to the molybdenum ions in the vanadium-molybdenum-iron solution is 2.5:1; the extraction temperature is 25°C and the contact time is 10 minutes;

[0057] (3) mixing 20 wt% ammonia water with the molybdenum-containing organic phase obtained in step (2), and obtaining an ammonium molybdate solution and an extractant that can be reused in step (2) after stripping;

[0058] Wherein, the ratio of the molybdenum-containing organic phase to the stripping agent is 1 / 2; and the stripping time is 10 minutes.

[0059] Example 2

[0060] This embodiment provides a method for regulating the form of metal ions to separate molybdenum and ferrovanadium, the method comprising the following steps:

[0061] (1) mixing the vanadium-molybdenum-iron solution and sodium pyrosulfite, and then mixing with hydrochloric acid at 20° C. to obtain a solution to be treated having a hydrogen ion concentration of 1.5 mol / L;

[0062] Wherein, the vanadium ion concentration in the vanadium-molybdenum-iron solution is 5 g / L, the molybdenum ion concentration is 5 g / L, and the iron ion concentration is 5 g / L;

[0063] The amount of the reducing agent added is 1 times the total molar amount of metal ions in the vanadium-molybdenum-iron solution;

[0064] (2) extracting molybdenum from the liquid to be treated obtained in step (1) using an N235 extractant having a concentration of 5% (V / V) to obtain an organic phase containing molybdenum and a phase containing vanadium and molten iron;

[0065] The ratio of the extractant to the mixed solution to be treated is 2 / 1; the molar ratio of the extractant to the molybdenum ions in the vanadium-molybdenum-iron solution is 4:1; the extraction temperature is 20°C and the contact time is 20 minutes;

[0066] (3) mixing 20 wt% ammonia water with the molybdenum-containing organic phase obtained in step (2), and obtaining an ammonium molybdate solution and an extractant that can be reused in step (2) after stripping;

[0067] The ratio of the molybdenum-containing organic phase to the stripping agent is 2 / 1, and the stripping time is 10 min.

[0068] Example 3

[0069] This embodiment provides a method for regulating the form of metal ions to separate molybdenum and ferrovanadium, the method comprising the following steps:

[0070] (1) mixing the vanadium-molybdenum-iron solution with ascorbic acid, and then mixing with nitric acid at 60° C. to obtain a solution to be treated having a hydrogen ion concentration of 2.5 mol / L;

[0071] Wherein, the vanadium ion concentration in the vanadium-molybdenum-iron solution is 40 g / L, the molybdenum ion concentration is 42.5 g / L, and the iron ion concentration is 15 g / L;

[0072] The amount of the reducing agent added is 4 times the total molar amount of metal ions in the vanadium-molybdenum-iron solution;

[0073] (2) extracting molybdenum from the liquid to be treated obtained in step (1) using an N235 extractant having a concentration of 10% (V / V) to obtain an organic phase containing molybdenum and a phase containing vanadium and molten iron;

[0074] The ratio of the extractant to the liquid to be treated is 4 / 1; the molar ratio of the extractant to the molybdenum ions in the vanadium-molybdenum-iron solution is 2:1; the extraction temperature is 40°C and the contact time is 4 minutes;

[0075] (3) mixing 5 wt% ammonia water with the molybdenum-containing organic phase obtained in step (2), and obtaining an ammonium molybdate solution and an extractant that can be reused in step (2) after stripping;

[0076] The ratio of the molybdenum-containing organic phase to the stripping agent is 1 / 1, and the stripping time is 10 minutes.

[0077] Example 4

[0078] This embodiment provides a method for separating molybdenum and ferrovanadium by regulating the form of metal ions. The method is different from that of Embodiment 1 only in that:

[0079] In this embodiment, the hydrogen ion concentration in the liquid to be treated in step (1) is adjusted to 1.0 mol / L.

[0080] Example 5

[0081] This embodiment provides a method for separating molybdenum and ferrovanadium by regulating the form of metal ions. The method is different from that of Embodiment 1 only in that:

[0082] In this embodiment, the hydrogen ion concentration in the liquid to be treated in step (1) is adjusted to 4.0 mol / L.

[0083] Example 6

[0084] This embodiment provides a method for separating molybdenum and ferrovanadium by regulating the form of metal ions. The method is different from that of Embodiment 1 only in that:

[0085] In this embodiment, the temperature of the mixed inorganic acid in step (1) is adjusted to 65°C.

[0086] Example 7

[0087] This embodiment provides a method for separating molybdenum and ferrovanadium by regulating the form of metal ions. The method is different from that of Embodiment 1 only in that:

[0088] In this embodiment, the amount of reducing agent added in step (1) is adjusted to 0.1 times the total molar amount of metal ions in the vanadium-molybdenum-iron solution.

[0089] Example 8

[0090] This embodiment provides a method for separating molybdenum and ferrovanadium by regulating the form of metal ions. The method is different from that of Embodiment 1 only in that:

[0091] In this embodiment, the amount of reducing agent added in step (1) is adjusted to 6 times the total molar amount of metal ions in the vanadium-molybdenum-iron solution.

[0092] Example 9

[0093] This embodiment provides a method for separating molybdenum and ferrovanadium by regulating the form of metal ions. The method is different from that of Embodiment 1 only in that:

[0094] In this embodiment, the extraction temperature in step (2) is adjusted to 50°C.

[0095] Example 10

[0096] This embodiment provides a method for separating molybdenum and ferrovanadium by regulating the form of metal ions. The method is different from that of Embodiment 1 only in that:

[0097] In this embodiment, the molar ratio of the extractant in step (2) to the molybdenum ions in the vanadium-molybdenum-iron solution is adjusted to 1:1.

[0098] Embodiment 11

[0099] This embodiment provides a method for separating molybdenum and ferrovanadium by regulating the form of metal ions. The method is different from that of Embodiment 1 only in that:

[0100] In this embodiment, the molar ratio of the extractant in step (2) to the molybdenum ions in the vanadium-molybdenum-iron solution is adjusted to 4.5:1.

[0101] Comparative Example 1

[0102] This comparative example provides a method for separating molybdenum and ferrovanadium by regulating the form of metal ions. The method is different from Example 1 only in that:

[0103] In this comparative example, the mixing process of the reducing agent in step (1) was omitted.

[0104] Comparative Example 2

[0105] This comparative example provides a method for separating molybdenum and ferrovanadium by regulating the form of metal ions. The method is different from Example 1 only in that:

[0106] In this comparative example, step (1) is adjusted as follows: the inorganic acid is mixed first, and then the reducing agent is mixed.

[0107] Performance Testing

[0108] According to the methods provided in the above embodiments and comparative examples, the molybdenum extraction efficiency (%), vanadium loss rate (%) and iron loss rate (%) were tested, and the results are shown in Table 1. The specific test method is as follows:

[0109] The molybdenum extraction rate and the vanadium and iron loss rates are calculated by the following formula:

[0110]

[0111] Wherein, C1 and V1 are the concentration and volume of the metal element in the aqueous phase after extraction, and C0 and V0 are the concentration and volume of the metal element in the liquid to be treated.

[0112] Table 1

[0113]

[0114]

[0115] According to Table 1, we can know the following points:

[0116] (1) Comprehensive analysis of Examples 1-3 shows that the method provided by the present invention can achieve a molybdenum extraction rate of more than 94.5% in the vanadium-molybdenum-iron solution, and the loss rate of vanadium and iron is as low as 0%, thereby achieving efficient separation of molybdenum and vanadium-iron in the acidic solution based on ion regulation;

[0117] (2) Comprehensive analysis of Example 1 and Examples 4-5 shows that the hydrogen ion concentration in the liquid to be treated in step (1) affects the morphology of metal ions in the solution. When the hydrogen ion concentration in the liquid to be treated is low (such as Example 4), the ion form of vanadium is partially converted into cations, thereby increasing the loss rate of vanadium and iron; when the hydrogen ion concentration in the liquid to be treated is high (such as Example 5), the extraction ability of the N235 extractant for molybdenum anion species is reduced, which greatly reduces the extraction efficiency of molybdenum ions;

[0118] (3) Comprehensive analysis of Example 1 and Example 6 shows that the temperature at which the mixed inorganic acid is used to regulate the metal ion form will affect the ion concentration in the solution; when the regulation temperature is too high, it will cause the co-precipitation of vanadium and molybdenum elements in the solution with iron ions, forming precipitates such as iron vanadate and iron molybdate floating in the solution, which will cause serious inclusions in the extraction process, thereby deteriorating the separation effect;

[0119] (4) Comprehensive analysis of Example 1, Examples 7-8 and Comparative Example 1 shows that the amount of reducing agent added will affect the reduction effect of ions in the solution;

[0120] When the amount of reducing agent added is too high, the sodium metal content or organic matter content in the solution will be too high, which will reduce the extraction ability of the extractant for molybdenum; when the amount of reducing agent added is too low, it will lead to the inability to completely reduce the metal vanadium, molybdenum and iron, so that the extractant will extract vanadium and molybdenum at the same time, thereby making the separation effect of vanadium and molybdenum worse;

[0121] (5) Comprehensive analysis of Example 1 and Examples 9-11 shows that the process parameters in the process of extracting molybdenum will affect the extraction capacity of the extractant; when the extraction temperature is too high, the extraction capacity of the extractant will decrease, and the extractant is easy to volatilize at high temperature; when the molar ratio of the extractant to the molybdenum ions in the vanadium-molybdenum-iron solution is too low, the amount of the extractant is too low, resulting in a low extraction rate of molybdenum, making the separation effect of molybdenum and vanadium-iron worse; if the molar ratio is too high, the content of molybdenum in the oil phase will be relatively low, which is not conducive to the stripping operation. At the same time, on the basis of increasing the molybdenum extraction rate by a limited amount, the consumption of the extractant is increased, further increasing the processing cost;

[0122] (6) Comprehensive analysis of Example 1 and Comparative Example 2 shows that the mixing order of the reducing agent and the inorganic acid in step (1) affects the reduction efficiency of the reducing agent, and ultimately affects the result of morphological regulation. Furthermore, mixing the inorganic acid first and then the reducing agent will result in excessive acidity, which will deteriorate the reduction effect of the unit reducing agent, and the reduction and regulation results of vanadium will not be thorough, resulting in partial co-extraction of vanadium, thereby affecting the separation effect.

[0123] In summary, the present invention reduces molybdenum, vanadium and iron, and controls the form of metal ions by controlling the acidity of the solution, and uses the N235 extractant to selectively extract metal species in the form of anions, so that molybdenum is combined with the extractant, while vanadium and iron remain in the solution, thereby achieving efficient separation of molybdenum from vanadium and iron; and the N235 extractant can be recycled, has high environmental and economic value, and is of great significance to the resource utilization of molybdenum and vanadium.

[0124] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for separating molybdenum and ferrovanadium by regulating the form of metal ions, characterized in that: The method comprises the following steps: (1) mixing a vanadium-molybdenum-iron solution and a reducing agent, and then mixing an inorganic acid to obtain a solution to be treated; (2) extracting molybdenum from the liquid to be treated obtained in step (1) using an extractant to obtain an organic phase containing molybdenum and a phase containing vanadium and molten iron; (3) mixing a stripping agent with the molybdenum-containing organic phase obtained in step (2), and obtaining a molybdenum-containing aqueous phase and an extractant after stripping.

2. The method according to claim 1, characterized in that: The vanadium ion concentration in the vanadium-molybdenum-iron solution of step (1) is 0.1-50 g / L; Preferably, the concentration of molybdenum ions in the vanadium-molybdenum-iron solution in step (1) is 0.1 to 50 g / L; Preferably, the iron ion concentration in the vanadium-molybdenum-iron solution in step (1) is 0.1 to 20 g / L.

3. The method according to claim 1 or 2, characterized in that: The reducing agent in step (1) comprises any one of sodium sulfite, sodium pyrosulfite, ascorbic acid or sodium hypochlorite, or a combination of at least two thereof; Preferably, the amount of the reducing agent added in step (1) is 0.25 to 5 times the total molar amount of metal ions in the vanadium-molybdenum-iron solution.

4. The method according to any one of claims 1 to 3, characterized in that: The inorganic acid in step (1) includes any one of hydrochloric acid, sulfuric acid or nitric acid, or a combination of at least two thereof; Preferably, the hydrogen ion concentration of the liquid to be treated in step (1) is 1.5 to 2.5 mol / L; Preferably, the temperature of the mixed inorganic acid in step (1) is 20-60°C.

5. The method according to any one of claims 1 to 4, characterized in that: The extractant in step (2) comprises N235 extractant; Preferably, the concentration of the N235 extractant is 5 to 40% (V / V); Preferably, the ratio of the extractant to the liquid to be treated in step (2) is 1 / 3 to 4 / 1; Preferably, the molar ratio of the extractant in step (2) to the molybdenum ions in the vanadium-molybdenum-iron solution is 2 to 4:

1.

6. The method according to any one of claims 1 to 5, characterized in that: The extraction temperature in step (2) is 20-40° C. Preferably, the contact time of the extraction in step (2) is 4 to 20 minutes.

7. The method according to any one of claims 1 to 6, characterized in that: The stripping agent in step (3) comprises aqueous ammonia; Preferably, the concentration of the ammonia water is 5-20 wt %.

8. The method according to any one of claims 1 to 7, characterized in that: The ratio of the molybdenum-containing organic phase to the stripping agent in step (3) is 1 / 2 to 4 / 1.

9. The method according to any one of claims 1 to 8, characterized in that: The extractant obtained in step (3) can be reused in step (2).

10. The method according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: (1) mixing a vanadium-molybdenum-iron solution and a reducing agent, and then mixing an inorganic acid at 20 to 60° C. to obtain a solution to be treated having a hydrogen ion concentration of 1.5 to 2.5 mol / L; Wherein, the vanadium ion concentration in the vanadium-molybdenum-iron solution is 0.1-50 g / L, the molybdenum ion concentration is 0.1-50 g / L, and the iron ion concentration is 0.1-20 g / L; The amount of the reducing agent added is 0.25 to 5 times the total molar amount of metal ions in the vanadium-molybdenum-iron solution; (2) extracting molybdenum from the liquid to be treated obtained in step (1) using an N235 extractant having a concentration of 5 to 40% (V / V) to obtain an organic phase containing molybdenum and a phase containing vanadium and molten iron; The ratio of the extractant to the mixed solution to be treated is 1 / 3 to 4 / 1; the molar ratio of the extractant to the molybdenum ions in the vanadium-molybdenum-iron solution is 2 to 4:1; the extraction temperature is 20 to 40°C, and the contact time is 4 to 20 minutes; (3) mixing ammonia water having a concentration of 5 to 20 wt % with the molybdenum-containing organic phase obtained in step (2), and obtaining a molybdenum-containing aqueous phase and an extractant that can be reused in step (2) after stripping; Wherein, the ratio of the molybdenum-containing organic phase to the stripping agent is 1 / 2 to 4 / 1.

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