Desulfurization method for calcium-process vanadium extraction tailings

Abstract

The invention relates to the technical field of chemical engineering, and provides a calcium-process vanadium extraction tailing desulfurization method which comprises the following steps: mixing calcium-process vanadium extraction tailings with water, and blending into ore pulp; the ore pulp is input into reselection equipment for reselection separation, the stage number of reselection separation is controlled to be larger than or equal to one, and light-phase slurry and heavy-phase slurry are obtained; and respectively filtering the light-phase slurry and the heavy-phase slurry to obtain a corresponding sulfur-containing gypsum material and iron-rich ore, and recovering filtrate. According to the scheme, separation of sulfur, iron and vanadium is achieved to the maximum extent, the desulfurization integrity of the calcium-process vanadium extraction tailings is improved, meanwhile, the whole desulfurization process is simple, the extra production cost is reduced, and the desulfurization cost is effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of chemical industry, and in particular to a method for desulfurizing tailings from vanadium extraction using a calcium process. Background Art

[0002] There are two ways to extract vanadium from vanadium slag: sodium method and calcium method. The sodium method will produce HCl, Cl 2 、SO 2 、SO 3 Compared with the sodium method, the calcium method has the advantages of low cost and less pollution. The calcium vanadium tailings refer to the solid waste residue obtained by the calcium method, which contains about 30% iron and 1-2% vanadium. Therefore, the calcium vanadium tailings have a certain utilization value, but the sulfur content in the calcium vanadium tailings is high, which is not conducive to returning to the factory for use. At the same time, the content of heavy metals such as vanadium and chromium also exceeds the standard, so its discharge needs to be treated in a special way, which not only increases the cost, but also causes waste of resources.

[0003] In the existing method of desulfurization of calcium-based vanadium tailings, adding calcium-based vanadium tailings into the sintering ingredients can achieve large-scale recycling, but the strength of the sintered ore will be weakened, and the sulfur content of the sintering flue gas will increase significantly, resulting in increased desulfurization costs.

[0004] Based on this, the existing technology is in urgent need of improvement. Summary of the invention

[0005] In view of this, in view of the problem that in the prior art, when calcium vanadium extraction tailings are added to the sintering ingredients, the strength of the sintered ore will be weakened, the sulfur content of the sintering flue gas will be greatly increased, and the desulfurization cost will be increased, the present disclosure provides a method for desulfurization of calcium vanadium extraction tailings.

[0006] According to a first aspect of the present invention, a method for desulfurization of tailings from vanadium extraction by calcium process is provided, comprising: Step a, mixing the calcium process vanadium extraction tailings with water to form a slurry; Step b, inputting the ore pulp into a gravity separation device for gravity separation, controlling the gravity separation stage to be greater than or equal to 1, and obtaining a light phase slurry and a heavy phase slurry; Step c: filtering the light phase slurry and the heavy phase slurry respectively to obtain the corresponding sulfur-containing gypsum material and rich iron ore, and recovering the filtrate.

[0007] In some embodiments, step a comprises: The calcium-based vanadium extraction tailings are mixed with water, and the solid-liquid ratio is controlled to be in the range of 1:3~1:20 (kg / L) during the mixing process to prepare a slurry.

[0008] In some embodiments, the gravity separation device is a gravity separation device using water as a medium.

[0009] In some embodiments, the gravity separation equipment is any one of a hydrocyclone, a shaking table, a jig, and a spiral chute.

[0010] In some embodiments, the gravity separation equipment is the hydrocyclone, the diameter of the hydrocyclone is 70-200 mm, the feed pressure is 0.1-0.3 MPa, and the diameter of the sand settling nozzle is 12-40 mm.

[0011] In some embodiments, step b comprises: Step b1, inputting the ore pulp into a gravity separation device using water as a medium for gravity separation, and obtaining a primary light phase slurry and a primary heavy phase slurry by primary separation; Step b2, monitoring the particle size composition of the primary light phase slurry and the primary heavy phase slurry, and determining whether to perform multi-stage separation to obtain light phase slurry and heavy phase slurry according to the complexity of the particle size composition.

[0012] In some embodiments, step c comprises: Step c1, filtering the light phase slurry and the heavy phase slurry respectively to obtain corresponding sulfur-containing gypsum material and iron-rich ore, and filtrate; Step c2, monitoring the vanadium concentration in the filtrate, and comparing the vanadium concentration with the vanadium recovery concentration to determine whether to recover the vanadium in the filtrate and then return the remaining filtrate to step a for preparing the ore pulp.

[0013] In some embodiments, step c2 comprises: The vanadium concentration in the filtrate is monitored to compare whether the vanadium concentration reaches the vanadium recovery concentration. If the vanadium concentration reaches the vanadium recovery concentration, the vanadium in the filtrate is recovered and then the remaining filtrate is returned to step a for preparing the ore pulp.

[0014] In some embodiments, the vanadium recovery concentration is 0.5-2 g / L.

[0015] In some embodiments, the calcium process vanadium extraction tailings contain S, CaO, MgO, MnO, TFe, SiO 2 、TiO 2 , V, Al 2 O 3 and remaining impurities.

[0016] The above-mentioned method for desulfurization of calcium-based vanadium tailings is to mix the calcium-based vanadium tailings with water and prepare them into slurry, and then input the slurry into a gravity separation device for gravity separation. At the same time, at least one level of gravity separation is controlled to obtain a light phase slurry and a heavy phase slurry, and the two are filtered separately to obtain corresponding sulfur-containing gypsum material and rich iron ore, and the filtrate is recovered. The sulfur element is accumulated in the gypsum ore in large quantities, which greatly reduces the content of sulfur element in the iron-rich ore. At the same time, vanadium is mainly concentrated in the filtrate, and the separation of sulfur from iron and vanadium is achieved to the greatest extent, thereby improving the integrity of the desulfurization of the calcium-based vanadium tailings. At the same time, the entire desulfurization process is simple, which reduces additional production costs and effectively reduces the desulfurization costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A flow chart of a method for desulfurization of tailings from vanadium extraction using calcium process is provided as an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The following is a further detailed description of the embodiments of the present disclosure in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate the principles of the present disclosure, but cannot be used to limit the scope of the present disclosure. The present disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

[0020] The present disclosure provides these embodiments to make the present disclosure thorough and complete, and to fully express the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the parts and steps, the composition of the materials, the numerical expressions and the numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary, and not as limiting.

[0021] It should be noted that, in the description of the present disclosure, unless otherwise specified, the meaning of "multiple" is greater than or equal to two; the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating the orientation or positional relationship, are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present disclosure. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0022] In addition, the words "first", "second" and similar words used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. The words "include" or "comprise" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements.

[0023] It should also be noted that in the description of the present disclosure, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to the specific circumstances. When a specific device is described as being located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device.

[0024] All terms used in the present disclosure have the same meanings as those understood by those of ordinary skill in the art to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, for example, should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined as such herein.

[0025] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0026] It should be understood that the embodiments of the present invention shown in the exemplary embodiments are only illustrative. Although only a few embodiments are described in detail in the present invention, it is easy for those skilled in the art to appreciate that multiple modifications are feasible without actually departing from the teaching of the subject matter of the present invention. Accordingly, all such modifications should be included within the scope of the present invention. Without departing from the gist of the present invention, other replacements, modifications, changes and deletions may be made to the design, operating conditions and parameters of the following exemplary embodiments.

[0027] Please refer to Figure 1 , Figure 1 The flowchart of the method for desulfurization of tailings from calcium vanadium extraction is provided in one embodiment of the present invention. A method 100 for desulfurization of tailings from calcium vanadium extraction comprises: Step a, mixing the calcium process vanadium extraction tailings with water to form a slurry; Step b, inputting the ore pulp into a gravity separation device for gravity separation, controlling the number of gravity separation stages to be greater than or equal to 1, and obtaining a light phase slurry and a heavy phase slurry; Step c: filtering the light phase slurry and the heavy phase slurry respectively to obtain the corresponding sulfur-containing gypsum material and rich iron ore, and recovering the filtrate.

[0028] The above-mentioned method for desulfurization of calcium-based vanadium tailings is to mix the calcium-based vanadium tailings with water and prepare them into slurry, and then input the slurry into a gravity separation device for gravity separation. At the same time, at least one level of gravity separation is controlled to obtain a light phase slurry and a heavy phase slurry, and the two are filtered separately to obtain corresponding sulfur-containing gypsum material and rich iron ore, and the filtrate is recovered. The sulfur element is accumulated in the gypsum ore in large quantities, which greatly reduces the content of sulfur element in the iron-rich ore. At the same time, vanadium is mainly concentrated in the filtrate, and the separation of sulfur from iron and vanadium is achieved to the greatest extent, thereby improving the integrity of the desulfurization of the calcium-based vanadium tailings. At the same time, the entire desulfurization process is simple, which reduces additional production costs and effectively reduces the desulfurization costs.

[0029] According to several embodiments of the present invention, step a includes: mixing calcium-based vanadium extraction tailings with water, controlling the solid-liquid ratio in the mixing process to be in the range of 1:3 to 1:20 (kg / L) to prepare a slurry. By controlling the solid-liquid ratio, the tailings can form a slurry of suitable concentration in water, providing good conditions for subsequent separation, extraction and other processing steps. Under a specific solid-liquid ratio, it is beneficial to further recover valuable elements such as iron and vanadium in the tailings by gravity separation, thereby improving the comprehensive utilization rate of resources.

[0030] According to some embodiments of the present invention, the gravity separation equipment is a gravity separation equipment using water as a medium. The gravity separation equipment uses the difference in specific gravity of different mineral particles for separation. In the tailings desulfurization process, the specific gravity of sulfur-containing minerals is usually different from that of other minerals. The sulfur-containing minerals can be effectively separated by gravity separation, thereby improving the pertinence and efficiency of desulfurization. At the same time, the use of gravity separation equipment using water as a medium is conducive to reducing the cost of desulfurization.

[0031] According to several embodiments of the present invention, the gravity separation equipment is any one of a hydrocyclone, a shaking table, a jig, and a spiral chute.

[0032] According to some embodiments of the present invention, the gravity separation equipment is a hydrocyclone, the diameter of the hydrocyclone is 70-200 mm, the feed pressure is 0.1-0.3 MPa, and the diameter of the sand trap is 12-40 mm. By reasonably controlling the size of the hydrocyclone, sulfur can be better separated from iron and vanadium, and the efficiency of desulfurization of calcium vanadium tailings can be further improved.

[0033] According to several embodiments of the present invention, step b includes: step b1, inputting the ore pulp into a gravity separation device using water as a medium for gravity separation, and obtaining a first-stage light phase slurry and a first-stage heavy phase slurry by a first-stage separation; step b2, monitoring the particle size composition of the first-stage light phase slurry and the first-stage heavy phase slurry, and determining whether to perform multi-stage separation to obtain the light phase slurry and the heavy phase slurry according to the complexity of the particle size composition. After obtaining the first-stage light phase slurry and the first-stage heavy phase slurry by the first-stage separation, their particle size composition is monitored. If the particle size composition is relatively complex, it indicates that a single separation may not achieve the ideal separation effect. Performing multi-stage separation can perform more refined separation operations on particles in different particle size ranges, gradually improve the separation accuracy, and make the final light phase slurry and heavy phase slurry have higher purity.

[0034] According to some embodiments of the present invention, step c includes: step c1, filtering the light phase slurry and the heavy phase slurry respectively to obtain the corresponding sulfur-containing gypsum material and the rich iron ore, and the filtrate; step c2, monitoring the vanadium concentration in the filtrate, and comparing the vanadium concentration with the vanadium recovery concentration to determine whether to recover the vanadium in the filtrate and then return the remaining filtrate to step a for preparing the ore slurry. By monitoring the vanadium concentration in the filtrate, the vanadium content in the filtrate can be timely understood.

[0035] According to some embodiments of the present invention, step c2 includes: monitoring the vanadium concentration in the filtrate, comparing whether the vanadium concentration reaches the vanadium recovery concentration, and if the vanadium concentration reaches the vanadium recovery concentration, recovering the vanadium in the filtrate and then returning the remaining filtrate to step a for preparing the ore pulp. When the vanadium concentration reaches or exceeds the vanadium recovery concentration, the vanadium in the filtrate is recovered and processed, which can maximize the extraction and utilization of vanadium resources, avoid the loss of vanadium, and thus improve the vanadium resource recovery rate in the entire production process.

[0036] According to some embodiments of the present invention, the vanadium recovery concentration is 0.5-2 g / L.

[0037] According to some embodiments of the present invention, the components of the calcium process vanadium extraction tailings include S, CaO, MgO, MnO, TFe, SiO 2 、TiO 2 , V, Al 2 O 3 and remaining impurities.

[0038] In order to further understand the desulfurization method of calcium vanadium tailings provided by the present invention, it is further described in detail in the following specific examples. The components of the calcium vanadium tailings selected in the following examples include S, CaO, MgO, MnO, TFe, SiO 2 、TiO 2 , V, Al 2 O 3And the remaining impurities, including S, CaO, MgO, MnO, TFe, SiO 2 、TiO 2 , V, Al 2 O 3 The corresponding contents are shown in Table 1 below: Table 1 Element S CaO MgO MnO TFe <![CDATA[SiO 2 ]]> <![CDATA[TiO 2 ]]> V <![CDATA[Al 2 THE 3 ]]> content / % 4.9 10.0 2.2 4.7 24.6 11.4 10.1 2.2 2.0 Example 1 The contents of the main components in the calcium vanadium tailings are shown in Table 1. The calcium vanadium tailings are mixed with water, and the solid-liquid ratio of the calcium vanadium tailings to water is controlled to be 1:3 (kg / L) to prepare the slurry. The slurry is transported to the FX150 hydrocyclone by a slurry pump for primary separation. The feed pressure of the slurry transportation is 0.1~0.3MPa, and the diameter of the sand settling nozzle of the cyclone is 12mm. The light phase slurry L and the heavy phase slurry H are obtained by primary separation. The particle size composition of the light phase slurry L and the heavy phase slurry H is monitored to reach the light phase slurry and the heavy phase slurry, and there is no need for multi-stage separation. After that, the light phase slurry L and the heavy phase slurry H are directly filtered to obtain sulfur-containing gypsum and iron-rich material, as well as the filtrate, and the sulfur content in the sulfur-containing gypsum, the iron content in the iron-rich material, and the vanadium content in the filtrate are detected respectively. The sulfur content in the sulfur-containing gypsum material was detected to be 16.5%, and the purity of the dihydrate gypsum calculated based on the sulfur content in the sulfur-containing gypsum material was 88.69%; the iron content in the iron-rich material was 33.8%, the vanadium content was increased to 2.83%, and the sulfur content was reduced to 0.09%, and the sulfur removal rate in the iron-rich material was calculated to be 98.8%; the vanadium content in the filtrate was detected to be 0.08 g / L, wherein the vanadium concentration in the filtrate was monitored to compare whether the vanadium concentration reached the vanadium recovery concentration (0.5~2 g / L). Obviously, the vanadium concentration in the filtrate obtained in this embodiment is much less than 0.5 g / L, and therefore, it does not reach the benchmark for recovering the vanadium element in the filtrate.

[0039] The filtrate is recovered and used to make slurry from calcium vanadium tailings. The solid-liquid ratio of calcium vanadium tailings and water is kept at 1:3 (kg / L) during mixing, and new filtrate is obtained by circulation. After multiple cycles, the vanadium content in the filtrate corresponding to different cycle times is shown in Table 2: Table 2 Cycle times 1 3 5 7 10 12 15 Vanadium concentration 0.08 0.25 0.42 0.55 0.76 0.90 1.16 It can be seen from Table 2 that as the number of cycles increases, the vanadium concentration in the obtained filtrate increases continuously. When the vanadium concentration reaches the vanadium recovery concentration (0.5~2g / L), vanadium is recovered from the filtrate.

[0040] The above-mentioned calcium-based vanadium tailings desulfurization method has a simple process, few procedures, and good separation effect between sulfur, iron and vanadium. According to the test, the sulfur content in the iron-rich material can be reduced to below 0.1%, and the iron grade is increased by about 8 percentage points; the purity of the gypsum material is above 85%, and it can be further used as a raw material for gypsum building materials. The filtrate in the desulfurization process can be recycled, and the soluble vanadium can be recycled after enrichment in the filtrate, which is conducive to improving the comprehensive utilization of calcium-based vanadium tailings desulfurization.

[0041] Example 2 The contents of the main components in the calcium-based vanadium extraction tailings are shown in Table 1. The calcium-based vanadium extraction tailings are mixed with water, and the solid-liquid ratio of the calcium-based vanadium extraction tailings to water is controlled to be 1:20 (kg / L) to prepare a slurry. The slurry is conveyed to the FX100 hydrocyclone by a slurry pump for primary separation. The feed pressure of the slurry conveying is 0.1~0.12MPa, and the diameter of the sand settling nozzle of the cyclone is 40mm. The light phase slurry L1 and the heavy phase slurry H1 are obtained by primary separation. If the heavy phase slurry H1 has not yet reached the heavy phase slurry that meets the particle size composition requirements, the heavy phase slurry H1 is mixed with water at a solid-liquid ratio of 1:15 (kg / L) to form a slurry, which is conveyed to the FX175 hydrocyclone by a slurry pump for secondary cyclone classification. The feed pressure of the slurry conveying is 0.15~0.18MPa, and the diameter of the sand settling nozzle of the cyclone is 32mm. The light phase slurry L2 and the heavy phase slurry H2 are obtained. After testing, it is monitored that the particle size composition of the light phase slurry L2 and the heavy phase slurry H2 reaches the light phase slurry and the heavy phase slurry, and no separation is required. Afterwards, the light phase slurry L1, the light phase slurry L2 and the heavy phase slurry H2 were filtered respectively to obtain sulfur-containing gypsum material 1, sulfur-containing gypsum material 2 and iron-rich material respectively. The sulfur contents in sulfur-containing gypsum material 1 and sulfur-containing gypsum material 2 were 17.4% and 13.5% respectively. After mixing the two, the sulfur content was 16.8%. The purity of dihydrate gypsum was calculated to be 90.3% based on the sulfur content in the sulfur-containing gypsum material; the iron content in the iron-rich material was 34.1%, the vanadium content was increased to 2.89%, and the sulfur content was reduced to 0.07%. The sulfur removal rate in the iron-rich material was calculated to be 99%; the vanadium content in the filtrate was detected to be 0.07 g / L. Obviously, the vanadium concentration in the filtrate obtained in this embodiment is much less than 0.5 g / L, so it does not meet the benchmark for recovering vanadium elements in the filtrate.

[0042] The above-mentioned method for desulfurization of calcium-based vanadium tailings is to mix the calcium-based vanadium tailings with water and prepare them into slurry, and then input the slurry into a gravity separation device for gravity separation. At the same time, at least one level of gravity separation is controlled to obtain a light phase slurry and a heavy phase slurry, and the two are filtered separately to obtain corresponding sulfur-containing gypsum material and rich iron ore, and the filtrate is recovered. The sulfur element is accumulated in the gypsum ore in large quantities, which greatly reduces the content of sulfur element in the iron-rich ore. At the same time, vanadium is mainly concentrated in the filtrate, and the separation of sulfur from iron and vanadium is achieved to the greatest extent, thereby improving the integrity of the desulfurization of the calcium-based vanadium tailings. At the same time, the entire desulfurization process is simple, which reduces additional production costs and effectively reduces the desulfurization costs.

[0043] So far, various embodiments of the present disclosure have been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.

[0044] Although some specific embodiments of the present disclosure have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present disclosure. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict.

Claims

1. A method for desulfurization of tailings from vanadium extraction by calcium process, characterized in that: include: Step a, mixing the calcium process vanadium extraction tailings with water to form a slurry; Step b, inputting the ore pulp into a gravity separation device for gravity separation, controlling the gravity separation stage to be greater than or equal to 1, and obtaining a light phase slurry and a heavy phase slurry; Step c: filtering the light phase slurry and the heavy phase slurry respectively to obtain the corresponding sulfur-containing gypsum material and rich iron ore, and recovering the filtrate.

2. The method for desulfurization of tailings from vanadium extraction by calcium process according to claim 1, characterized in that: The step a comprises: The calcium-based vanadium extraction tailings are mixed with water, and the solid-liquid ratio is controlled to be in the range of 1:3~1:20 (kg / L) during the mixing process to prepare a slurry.

3. The method for desulfurization of tailings from vanadium extraction by calcium process according to claim 1, characterized in that: The gravity separation equipment is a gravity separation equipment using water as a medium.

4. The method for desulfurization of tailings from vanadium extraction by calcium process according to claim 3, characterized in that: The gravity separation equipment is any one of a hydrocyclone, a shaking table, a jig, and a spiral chute.

5. The method for desulfurization of tailings from vanadium extraction by calcium process according to claim 4, characterized in that: The gravity separation equipment is the hydrocyclone, the diameter of the hydrocyclone is 70-200 mm, the feed pressure is 0.1-0.3 MPa, and the diameter of the sand settling nozzle is 12-40 mm.

6. The method for desulfurization of tailings from vanadium extraction by calcium process according to claim 1, characterized in that: The step b comprises: Step b1, inputting the ore pulp into a gravity separation device using water as a medium for gravity separation, and obtaining a primary light phase slurry and a primary heavy phase slurry by primary separation; Step b2, monitoring the particle size composition of the primary light phase slurry and the primary heavy phase slurry, and determining whether to perform multi-stage separation to obtain light phase slurry and heavy phase slurry according to the complexity of the particle size composition.

7. The method for desulfurization of tailings from calcium vanadium extraction according to claim 1, characterized in that: The step c comprises: Step c1, filtering the light phase slurry and the heavy phase slurry respectively to obtain corresponding sulfur-containing gypsum material and iron-rich ore, and filtrate; Step c2, monitoring the vanadium concentration in the filtrate, and comparing the vanadium concentration with the vanadium recovery concentration to determine whether to recover the vanadium in the filtrate and then return the remaining filtrate to step a for preparing the ore pulp.

8. The method for desulfurization of tailings from vanadium extraction by calcium process according to claim 7, characterized in that: The step c2 comprises: The vanadium concentration in the filtrate is monitored to compare whether the vanadium concentration reaches the vanadium recovery concentration. If the vanadium concentration reaches the vanadium recovery concentration, the vanadium in the filtrate is recovered and then the remaining filtrate is returned to step a for preparing the ore pulp.

9. The method for desulfurization of tailings from vanadium extraction by calcium process according to claim 8, characterized in that: The vanadium recovery concentration is 0.5-2 g / L.

10. The method for desulfurization of tailings from vanadium extraction by calcium process according to claim 1, characterized in that: The components of the calcium-process vanadium extraction tailings include S, CaO, MgO, MnO, TFe, SiO2, TiO2, V, Al2O3 and remaining impurities.

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