Feso 4 electrolyte, and preparation method therefor and use thereof

Abstract

Disclosed in the present invention are a FeSO4 electrolyte, and a preparation method therefor and a use thereof. The method for using iron ore to prepare a FeSO4 electrolyte comprises the following steps: crushing iron ore and grinding same to obtain ore powder; carrying out oxidation roasting on the ore powder at 550°C-750°C for 30 min-120 min to obtain roasted ore powder; carrying out acid leaching on the roasted ore powder and then carrying out filtration to obtain a first filtrate; adding iron powder to the filtrate to implement a reduction reaction, so as to reduce Fe3+ to Fe2+, and when the pH reaches 3-7, using a magnet to attract the iron powder to obtain a second filtrate; adding a heavy metal precipitant Na2S to the second filtrate to convert heavy metals into metal sulfide precipitates, and after the heavy metal precipitation reaction, adding a flocculant to carry out flocculation and precipitation, and then carrying out filtration to obtain a FeSO4 electrolyte.

Description

A FeSO4 electrolyte, its preparation method and application Technical Field

[0001] This invention relates to the fields of materials and metallurgical technology, and more specifically, to an FeSO4 electrolyte, its preparation method, and its application. Background Technology

[0002] High-purity iron can be prepared by electrolysis. The FeSO4 electrolyte required for electrolysis is generally prepared by dissolving iron powder or ferrous sulfate. Ferrous sulfate is generally a by-product of industrial titanium dioxide production. It contains many harmful impurities and has a high content, making purification difficult. Iron powder is also obtained from iron ore through traditional smelting methods, which leads to a high cost of electrolyte preparation.

[0003] Currently, directly using iron ore, which has low content of harmful impurities, low cost, and wide availability of raw materials, to prepare FeSO4 electrolyte is a good option. However, the main components of iron ore are Fe2O3 and Fe3O4. Under normal conditions, iron ore is difficult to dissolve in sulfuric acid and hydrochloric acid. Only by adding hydrofluoric acid can dissolution be accelerated. However, hydrofluoric acid will cause environmental pollution, affect electrolysis, and has a high cost, which makes it impossible to promote the application of direct acid hydrolysis of iron ore to prepare electrolyte. At present, there is no method to efficiently prepare FeSO4 electrolyte from iron ore.

[0004] Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned defects in the existing technology and provide a FeSO4 electrolyte and its preparation method and application. Under the condition of not adding strong corrosive reagents such as hydrofluoric acid, the activity of iron ore is improved by controlling the atmosphere, temperature and time during the roasting process, making it more soluble in acid, and the acid electrolyte is purified to remove harmful impurities. This realizes the efficient preparation of FeSO4 electrolyte from iron ore, which is of great significance to promoting the preparation of pure iron by electrolysis.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A method for preparing FeSO4 electrolyte from iron ore includes the following steps:

[0008] (1) The iron ore is crushed and then ground to obtain ore powder;

[0009] (2) The ore powder is oxidized and roasted at 550℃~750℃ for 30min~120min to obtain roasted ore powder;

[0010] (3) The roasted ore powder is acid-leached and then filtered to obtain the first filtrate;

[0011] (4) Add iron powder to the first filtrate to carry out a reduction reaction, so as to remove Fe 3+Reduced to Fe 2+ When the pH reaches 3-7, iron powder is adsorbed by a magnet to obtain the second filtrate.

[0012] (5) Add Na2S, a heavy metal precipitant, to the second filtrate to convert the heavy metals into metal sulfide precipitates. After the heavy metal precipitation reaction, add a flocculant for flocculation and precipitation, and then filter to obtain the FeSO4 electrolyte.

[0013] The present invention also discloses an FeSO4 electrolyte prepared by the preparation method described above.

[0014] The present invention also discloses a FeSO4 electrolyte prepared by the preparation method described above, or the application of the FeSO4 electrolyte described above in the preparation of high-purity iron.

[0015] Implementing the embodiments of the present invention will have the following beneficial effects:

[0016] This invention addresses the problems of natural iron ore being poorly soluble in sulfuric acid and the difficulty in purifying FeSO4 solution, leading to high costs and severe pollution in the preparation of FeSO4 electrolyte. By controlling the roasting atmosphere, roasting temperature, and roasting time, the crystal structure of the iron ore is modulated and made more porous, increasing its surface area and enhancing its activity. This makes it easier to dissolve in acid, releasing iron ions and facilitating subsequent acid leaching processes. Furthermore, the pH value is adjusted to allow Al... 3+ The FeSO4 electrolyte is prepared by removing harmful impurities through precipitation, and then by adding heavy metal precipitants and flocculants to precipitate harmful impurities. This achieves low-cost, high-efficiency and environmentally friendly preparation of FeSO4 electrolyte.

[0017] This invention enables the transfer of iron elements from iron ore into a solution through acid dissolution, thereby improving the leaching rate and leaching efficiency, effectively removing harmful impurities from the solution, providing a stable sulfate electrolyte for subsequent electrolysis, and ensuring the supply of raw materials for the electrolytic production of pure or high-purity iron from iron ore. This is of great significance for achieving completely zero carbon emissions in the ironmaking process. Detailed Implementation

[0018] The present invention will be further described below with reference to specific embodiments, but this does not limit the present invention in any way.

[0019] This invention discloses a method for preparing FeSO4 electrolyte from iron ore, comprising the following steps:

[0020] (1) The iron ore is crushed and then ground to obtain ore powder.

[0021] In one specific embodiment, step (1) specifically includes: crushing the iron ore and grinding it with a ceramic ball mill to obtain ore powder with a particle size of 0μm to 100μm, and drying the obtained ore powder until the moisture content is ≤5%.

[0022] In one specific embodiment, the minerals in the iron ore include one or more of magnetite, siderite, and hematite.

[0023] Specifically, in this embodiment of the invention, ore powder with a particle size of 0μm to 100μm is obtained through crushing and grinding, which ensures sufficient mineral liberation, increases the specific surface area of ​​the mineral, and is beneficial to subsequent oxidative roasting and iron ion leaching reactions. Furthermore, a ceramic ball mill is used for grinding to avoid the introduction of other harmful impurities.

[0024] (2) The ore powder is oxidized and roasted at 550℃~750℃ for 30min~120min to obtain roasted ore powder.

[0025] In one specific embodiment, the oxidizing atmosphere for oxidative roasting includes either air or oxygen; the gas flow rate of the oxidizing atmosphere is 1.0 L / min to 2.0 L / min.

[0026] In one specific embodiment, the roasting is carried out using one of a muffle furnace, a horizontal tube furnace, or a vertical tube furnace.

[0027] Specifically, compared to the disadvantages of reduction roasting, such as high cost, expensive reactors, and low reduction rate, the embodiments of the present invention utilize the advantages of easy and low-cost oxidizing atmospheres. Oxidative roasting is selected, and the iron ore crystal structure is controlled and made more porous by adjusting the roasting temperature and roasting time. This increases the surface area, enhances the activity of the iron ore, makes it easier to dissolve in acid, and releases iron ions.

[0028] (3) After acid leaching, the roasted ore powder is filtered to obtain the first filtrate.

[0029] In one specific embodiment, the acid leaching uses sulfuric acid with a concentration of 0.5 mol / L to 3 mol / L and citric acid with a concentration of 0.5 mol / L to 1 mol / L.

[0030] In one specific embodiment, the acid leaching temperature is 100℃~200℃; the acid leaching time is 1h~2h; and the liquid-solid ratio of acid solution to roasted ore powder during acid leaching is (5~10):1.

[0031] (4) Add iron powder to the first filtrate to carry out a reduction reaction, so as to remove Fe 3+ Reduced to Fe 2+ When the reaction reaches a pH of 3-7, iron powder is adsorbed by a magnet to obtain the second filtrate.

[0032] In one specific embodiment, the purity of the iron powder is ≥99.9%; the amount of iron powder added is equal to the Fe content in the filtrate. 3+ 0.5 to 1 times the molar amount.

[0033] In one specific embodiment, the temperature of the reduction reaction is 60°C to 100°C.

[0034] Specifically, the reducing agent required in step (4) must have both reducing and pH-regulating properties, and because Fe 3+ Ions readily precipitate, therefore the pH cannot be adjusted by adding alkaline substances; instead, it can only be achieved by consuming H+. + To adjust the pH value, and to avoid introducing other impurities, this invention preferably adds iron powder at room temperature to reduce Fe. 3+ Reduced to Fe 2+ and consume excessive H + Adjust the pH to 3-7 to allow Al 3+ Removed by precipitation.

[0035] (5) Add heavy metal precipitant Na2S to the second filtrate to convert the heavy metals into metal sulfide precipitates. After the heavy metal precipitation reaction, add flocculant for flocculation and precipitation, and then filter to obtain FeSO4 electrolyte.

[0036] In one specific embodiment, step (5) specifically includes: adding 2 to 3 times the molar amount of manganese ions of Na2S to the second filtrate; after the heavy metal precipitation reaction, adding one or two of nonionic polyacrylamide and sodium polyacrylate with a concentration of 0.5‰ to 2‰ and stirring for 10 min to 30 min; allowing to stand and filter to obtain FeSO4 electrolyte, effectively removing harmful impurities in the solution.

[0037] The present invention also discloses a FeSO4 electrolyte prepared by the preparation method of any embodiment of the present invention.

[0038] The present invention also discloses a FeSO4 electrolyte prepared by the preparation method of any embodiment of the present invention, or the application of the FeSO4 electrolyte of any embodiment of the present invention in the preparation of high-purity iron.

[0039] The following are specific embodiments.

[0040] Example 1

[0041] The results of multi-element chemical analysis of the ore and the results of iron phase chemical analysis of the ore in this embodiment are shown in Tables 1 and 2, respectively.

[0042] Table 1. Results of multi-element chemical analysis of the ore (%)

[0043] Table 2. Results of iron phase chemical analysis of ore (%)

[0044] (1) The properties of the ore used are shown in the table above. The content of TFe is 27.19%, the content of magnetic iron (mFe) is 20.40% with a distribution rate of 75.03%, the content of iron carbonate (cFe) is 0.9% with a distribution rate of 3.31%, and the content of iron oxide (oFe) is 3.89% with a distribution rate of 14.30%. Therefore, the ore is mainly magnetite, with a small amount of hematite / limonite and siderite. The iron ore is first crushed and then ground in a ceramic ball mill to a particle size of -38μm with a content of 90%. The ore is then dried to a moisture content of 1%.

[0045] (2) The mineral powder obtained in step (1) is roasted in a muffle furnace. The roasting temperature is set to 680℃, the roasting time is 60min, and air is introduced at a rate of 1.4L / min during the roasting process.

[0046] (3) After cooling the roasted mineral powder obtained in step (2) to room temperature, mix it with a mixed acid prepared by 1 mol / L sulfuric acid and 0.5 mol / L citric acid for leaching. The liquid-solid ratio is 5:1, the leaching temperature is 200℃, and the leaching time is 2h. The leaching process should be continuously stirred. After the leaching is completed, filter it to obtain the first filtrate.

[0047] (4) Add Fe from the solution to the first filtrate obtained in step (3) at room temperature. 3+ The total amount of iron powder is 0.8 times that with a purity of 99.9%. The solution temperature is then heated to 80°C, the pH value is adjusted to 4, and the excess iron powder is removed with a magnet to obtain the second filtrate.

[0048] (5) Add twice the amount of Na2S to the second filtrate obtained in step (4) and stir.

[0049] (6) Add nonionic polyacrylamide with a concentration of 1.5‰ as a flocculant to the filtrate obtained in step (5), stir for 30 min, let stand, and then filter to obtain FeSO4 electrolyte free of harmful impurities. The leaching rate of iron from the iron ore was found to be 65%, and the concentrations of the main ions in the solution are shown in Table 3 below.

[0050] Table 3. Concentrations of major ions in the solution (g / L)

[0051] Example 2

[0052] The results of multi-element chemical analysis of the ore and the results of iron phase chemical analysis of the ore in this embodiment are shown in Tables 4-5.

[0053] Table 4. Results of multi-element chemical analysis of the ore (%)

[0054] Table 5. Results of iron phase chemical analysis of ore (%)

[0055] (1) The properties of the ore used are shown in the table above. The content of TFe is 29.01%, the content of magnetic iron (mFe) is 22.60% with a distribution rate of 77.90%, the content of iron carbonate (cFe) is 0.24% with a distribution rate of 0.83%, and the content of iron oxide (oFe) is 4.86% with a distribution rate of 16.75%. Therefore, the ore is mainly magnetite with a small amount of hematite / limonite. The iron ore is first crushed and then ground in a ceramic ball mill to a particle size of -38μm with a content of 92%. The ore is then dried to a moisture content of 1%.

[0056] (2) The mineral powder obtained in step (1) is roasted in a muffle furnace. The roasting temperature is set to 700℃, the roasting time is 55min, and air is introduced at a rate of 1.3L / min during the roasting process.

[0057] (3) After cooling the roasted mineral powder obtained in step (2) to room temperature, mix it with a mixed acid prepared by 1 mol / L sulfuric acid and 0.5 mol / L citric acid for leaching. The liquid-solid ratio is 5:1, the leaching temperature is 200℃, and the leaching time is 2h. The leaching process should be continuously stirred. After the leaching is completed, filter it to obtain the first filtrate.

[0058] (4) Add Fe from the solution to the first filtrate obtained in step (3) at room temperature. 3+ The total amount of iron powder with a purity of 99.9% was 1, and the solution temperature was heated to 80°C. The pH value was adjusted to 4, and the excess iron powder was removed with a magnet to obtain the second filtrate.

[0059] (5) Add twice the amount of Na2S to the second filtrate obtained in step (4) and stir.

[0060] (6) Add nonionic polyacrylamide with a concentration of 1.4‰ as a flocculant to the filtrate obtained in step (5), stir for 30 min, let stand, and then filter to obtain FeSO4 electrolyte free of harmful impurities. The leaching rate of iron from the iron ore was found to be 63.8%, and the concentrations of the main ions in the solution are shown in Table 6 below.

[0061] Table 6. Concentrations of major ions in the solution (g / L)

[0062] Example 3

[0063] The results of multi-element chemical analysis of the ore and the results of iron phase chemical analysis of the ore in this embodiment are shown in Tables 7 and 8, respectively.

[0064] Table 7. Multi-element chemical analysis results of the ore (%)

[0065] Table 8. Results of iron phase chemical analysis of ore (%)

[0066] (1) The properties of the ore used are shown in the table above. The content of TFe is 48.49%, the content of magnetic iron (mFe) is 32.72% with a distribution rate of 67.48%, the content of iron carbonate (cFe) is 0.65% with a distribution rate of 1.38%, and the content of iron oxide (oFe) is 11.22% with a distribution rate of 23.82%. Therefore, the ore is mainly magnetite with a small amount of hematite / limonite. The iron ore is first crushed and then ground in a ceramic ball mill to a particle size of -38μm with a content of 90%. The ore is then dried to a moisture content of 1%.

[0067] (2) The mineral powder obtained in step (1) is roasted in a muffle furnace. The roasting temperature is set to 680℃, the roasting time is 60min, and air is introduced at a rate of 1.4L / min during the roasting process.

[0068] (3) After cooling the roasted mineral powder obtained in step (2) to room temperature, mix it with a mixed acid prepared by 1 mol / L sulfuric acid and 0.5 mol / L citric acid for leaching. The liquid-solid ratio is 6:1, the leaching temperature is 200℃, and the leaching time is 2h. The leaching process should be continuously stirred. After the leaching is completed, filter to obtain the first filtrate.

[0069] (4) Add Fe from the solution to the first filtrate obtained in step (3) at room temperature. 3+ The total amount of iron powder is 0.8 times that with a purity of 99.9%. The solution temperature is then heated to 90°C, the pH is adjusted to 4, and excess iron powder is removed with a magnet to obtain the second filtrate.

[0070] (5) Add twice the amount of Na2S to the second filtrate obtained in step (4) and stir.

[0071] (6) Add nonionic polyacrylamide at a concentration of 1‰ as a flocculant to the filtrate obtained in step (5), stir for 30 minutes, let stand, and then filter to obtain FeSO4 electrolyte free of harmful impurities. The leaching rate of iron from the iron ore was found to be 67.3%, and the concentrations of the main ions in the solution are shown in Table 9 below.

[0072] Table 9. Concentrations of major ions in the solution (g / L)

[0073] Example 4

[0074] The results of multi-element chemical analysis of the ore and the results of iron phase chemical analysis of the ore in this embodiment are shown in Tables 10 and 11, respectively.

[0075] Table 10. Results of Multi-Element Chemical Analysis of Ore (%)

[0076] Table 11. Results of iron phase chemical analysis of ore (%)

[0077] (1) The properties of the ore used are shown in the table above. The content of TFe is 65.70%, the content of magnetic iron (mFe) is 64.56% with a distribution rate of 98.26%, the content of iron carbonate (cFe) is 0.09% with a distribution rate of 0.14%, and the content of iron oxide (oFe) is 0.76% with a distribution rate of 1.16%. Therefore, the ore is mainly magnetite. First, the iron ore is crushed and then ground with a ceramic ball mill to a particle size of -38μm with a content of 95%. The ore is then dried to a moisture content of 1%.

[0078] (2) The mineral powder obtained in step (1) is roasted in a muffle furnace. The roasting temperature is set to 650℃, the roasting time is 60min, and air is introduced at a rate of 1.5L / min during the roasting process.

[0079] (3) After cooling the roasted mineral powder obtained in step (2) to room temperature, mix it with a mixed acid prepared by 1.5 mol / L sulfuric acid and 0.7 mol / L citric acid for leaching. The liquid-solid ratio is 7:1, the leaching temperature is 200℃, and the leaching time is 2h. The leaching process should be continuously stirred. After the leaching is completed, filter it to obtain the first filtrate.

[0080] (4) Add Fe from the solution to the first filtrate obtained in step (3) at room temperature. 3+ The total amount of iron powder is 0.8 times that with a purity of 99.9%. The solution temperature is then heated to 90°C, the pH is adjusted to 4, and excess iron powder is removed with a magnet to obtain the second filtrate.

[0081] (5) Add twice the amount of Na2S to the filtrate obtained in step (4) and stir.

[0082] (6) Add nonionic polyacrylamide at a concentration of 1.2‰ as a flocculant to the filtrate obtained in step (5), stir for 30 min, let stand, and then filter to obtain FeSO4 electrolyte free of harmful impurities. The leaching rate of iron from the iron ore was found to be 70.5%, and the concentrations of the main ions in the solution are shown in Table 12 below.

[0083] Table 12 Concentrations of major ions in the solution (g / L)

[0084] Example 5

[0085] The results of multi-element chemical analysis of the ore and the results of iron phase chemical analysis of the ore in this embodiment are shown in Tables 13 and 14, respectively.

[0086] Table 13. Multi-element chemical analysis results of the ore (%)

[0087] Table 14. Results of iron phase chemical analysis of ore (%)

[0088] (1) The properties of the ore used are shown in the table above. The content of TFe is 66.33%, the content of magnetic iron (mFe) is 32.12% with a distribution rate of 48.42%, the content of iron carbonate (cFe) is 2.15% with a distribution rate of 3.24%, and the content of iron oxide (oFe) is 31.48% with a distribution rate of 47.46%. Therefore, the ore is mainly composed of magnetite and hematite / limonite, with a small amount of siderite. The iron ore is first crushed and then ground using a ceramic ball mill to grind the particle size to -38μm with a content of 90%. The ore is then dried to a moisture content of 1%.

[0089] (2) The mineral powder obtained in step (1) is roasted in a muffle furnace. The roasting temperature is set to 680℃, the roasting time is 60min, and air is introduced at a rate of 1.4L / min during the roasting process.

[0090] (3) After cooling the roasted mineral powder obtained in step (2) to room temperature, mix it with a mixed acid prepared by 1.5 mol / L sulfuric acid and 0.7 mol / L citric acid for leaching. The liquid-solid ratio is 7:1, the leaching temperature is 200℃, and the leaching time is 2h. The leaching process should be continuously stirred. After the leaching is completed, filter it to obtain the first filtrate.

[0091] (4) Add Fe from the solution to the first filtrate obtained in step (3) at room temperature. 3+ The total amount of iron powder is 0.8 times that with a purity of 99.9%. The solution temperature is then heated to 80°C, the pH value is adjusted to 4, and the excess iron powder is removed with a magnet to obtain the second filtrate.

[0092] (5) Add twice the amount of Na2S to the second filtrate obtained in step (4) and stir.

[0093] (6) Add nonionic polyacrylamide with a concentration of 1.4‰ as a flocculant to the filtrate obtained in step (5), stir for 30 min, let stand, and then filter to obtain FeSO4 electrolyte free of harmful impurities. The leaching rate of iron from the iron ore was found to be 62.5%, and the concentrations of the main ions in the solution are shown in Table 15 below.

[0094] Table 15. Concentrations of major ions in the solution (g / L)

[0095] In summary, this invention improves the activity of iron ore by controlling the atmosphere, temperature, and time during roasting without adding highly corrosive reagents such as hydrofluoric acid, making it more soluble in acid. Furthermore, it purifies the acid electrolyte to remove harmful impurities, thus achieving efficient preparation of FeSO4 electrolyte from iron ore. This invention is of great significance for promoting the electrolytic preparation of pure iron.

[0096] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for preparing FeSO4 electrolyte from iron ore, characterized in that, Includes the following steps: (1) The iron ore is crushed and then ground to obtain ore powder; (2) The ore powder is oxidized and roasted at 550℃~750℃ for 30min~120min to obtain roasted ore powder; (3) The roasted ore powder is acid-leached and then filtered to obtain the first filtrate; (4) Add iron powder to the first filtrate to carry out a reduction reaction, so as to remove Fe 3+ Reduced to Fe 2+ When the pH reaches 3-7, iron powder is adsorbed by a magnet to obtain the second filtrate. (5) Add Na2S, a heavy metal precipitant, to the second filtrate to convert the heavy metals into metal sulfide precipitates. After the heavy metal precipitation reaction, add a flocculant for flocculation and precipitation, and then filter to obtain the FeSO4 electrolyte.

2. The method for preparing FeSO4 electrolyte from iron ore according to claim 1, characterized in that, In step (1), the minerals in the iron ore include one or more of magnetite, siderite, and hematite; The grinding process employs a ceramic ball mill. The particle size of the ore powder is 0μm to 100μm.

3. The method for preparing FeSO4 electrolyte from iron ore according to claim 1, characterized in that, Step (1) also includes drying the crushed and ground ore powder until the moisture content is ≤5%.

4. The method for preparing FeSO4 electrolyte from iron ore according to claim 1, characterized in that, In step (2), the oxidizing atmosphere of the oxidative roasting includes either air or oxygen; The gas flow rate of the oxidizing atmosphere is 1.0 L / min to 2.0 L / min.

5. The method for preparing FeSO4 electrolyte from iron ore according to claim 1, characterized in that, Step (3) involves acid leaching using sulfuric acid with a concentration of 0.5 mol / L to 3 mol / L and citric acid with a concentration of 0.5 mol / L to 1 mol / L. The acid leaching temperature is 100℃~200℃; the acid leaching time is 1h~2h; The liquid-to-solid ratio of the acid solution and the roasted ore powder during acid leaching is (5-10):

1.

6. The method for preparing FeSO4 electrolyte from iron ore according to claim 1, characterized in that, In step (4), the purity of the iron powder is ≥99.9%; The amount of iron powder added is equal to the Fe content in the filtrate. 3+ 0.5 to 1 times the molar amount; The reduction reaction is carried out at a temperature of 60℃ to 100℃.

7. The method for preparing FeSO4 electrolyte from iron ore according to claim 1, characterized in that, In step (5), the amount of Na2S added is 2 to 3 times the molar amount of manganese ions in the second filtrate; The flocculant includes one or both of nonionic polyacrylamide and sodium polyacrylate. The concentration of the flocculant is 0.5‰ to 2‰.

8. A FeSO4 electrolyte prepared by the preparation method according to any one of claims 1-7.

9. An FeSO4 electrolyte prepared by any one of claims 1-7, or the application of the FeSO4 electrolyte as described in claim 8 in the preparation of high-purity iron.

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