FeSO4 ELECTROLYTE, 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

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of materials and metallurgical technology, in particular to an FeSO4 electrolyte, a method therefor, and an application thereof. BACKGROUND ART

[0002] High-purity iron can be prepared through electrolysis, and the FeSO4 electrolyte required for the electrolysis is generally prepared by dissolving iron powder or ferrous sulfate. Ferrous sulfate is generally a by-product of industrial titanium dioxide production, which contains a high amount of harmful impurities that are difficult to purify, and iron powder is obtained from iron ore through traditional smelting methods, which lead to high costs in electrolyte preparation.

[0003] At present, it is a preferable option to prepare FeSO4 electrolyte by means of directly using iron ore with fewer harmful impurities, low cost and wide availability of raw materials. However, iron ore has the main components of Fe2O3 and Fe3O4, which are difficult to dissolve in sulfuric acid and hydrochloric acid under conventional conditions, and only the addition of hydrofluoric acid can accelerate the dissolution. However, hydrofluoric acid will cause environment pollution, affect electrolysis and increase costs, resulting in direct acid hydrolysis of iron ore to prepare electrolyte cannot be popularized and applied. Currently, there is no method available to efficiently prepare FeSO4 electrolyte by using iron ore. SUMMARY

[0004] An objective of the present disclosure is to overcome the above-mentioned defects in the prior art by providing an FeSO4 electrolyte, its preparation method and applications. Without the addition of highly corrosive reagents such as hydrofluoric acid, the present disclosure improves the activity of iron ore only by controlling the atmosphere, temperature and time during the calcination process, making iron ore easy to dissolve in acid; additionally, the present disclosure removes harmful impurities from the acidolysis solution for purification. The present disclosure realizes the efficient preparation of FeSO4 electrolyte from iron ore, which is of great significance for promoting the preparation of pure iron by electrolysis method.

[0005] To realize the above objective, technical solutions of the present disclosure are as follows:

[0006] A method for preparing FeSO4 electrolyte from iron ore, comprising the following steps of:

[0007] (1) Crushing the iron ore, followed by grinding to obtain ore powder;

[0008] (2) Subjecting the ore powder to oxidative calcination at 550 °C to 750 °C for 30 min to 120 min to obtain calcined ore powder;

[0009] (3) Acid leaching the calcined ore powder and filtering it to obtain a first filtrate;

[0010] (4) Adding iron powder into the first filtrate for a reduction reaction to reduce Fe3+ to Fe2+, and adsorbing iron powder through a magnet when the pH of the reaction is 3-7 to obtain a second filtrate; and

[0011] (5) Adding a heavy metal precipitant Na2S into the second filtrate to convert heavy metals into metal sulfide precipitates, followed by adding a flocculant for flocculation and filtering to obtain the FeSO4 electrolyte.

[0012] The present disclosure further discloses an FeSO4 electrolyte prepared by the above preparation method.

[0013] The present disclosure further discloses an FeSO4 electrolyte prepared by the above preparation method, or a use of the FeSO4 electrolyte prepared by the above preparation method for preparing high purity iron.

[0014] Implementations of the present disclosure have the following beneficial effects:

[0015] In view of the problems of natural iron ore being difficult to dissolve in sulfuric acid and high difficulty in purifying FeSO4 solutions, which result in high costs and severe pollution during the preparation of FeSO4 electrolyte including, the present disclosure controls the calcination atmosphere, calcination temperature and calcination time to regulate the crystal structure of iron ore to make iron ore porous and increase its surface area, which improves the activity of iron ore to make iron ore easily dissolve with acid and release iron ions, facilitating the subsequent acid leaching process. Further according to the present disclosure, Al3+ is removed in the form of precipitates through adjusting pH, and then harmful impurities are precipitated through adding heavy metal precipitant and the flocculants to prepare an FeSO4 electrolyte without harmful impurities. The present disclosure realizes the preparation of FeSO4 electrolyte with low costs, high efficiency and environmental protection.

[0016] The present disclosure realizes the transfer of iron element from iron ore to the solution through acid dissolution, improves the leaching rate and leaching speed of iron element, and effectively removes harmful impurities in the solution, which provides a stable sulfate electrolyte for subsequent electrolysis, ensures a reliable raw material supply for the electrolytic production of pure iron or high purity iron from iron ore, having great significance for realizing zero carbon emission in iron-making processes. DESCRIPTION OF EMBODIMENTS

[0017] The present disclosure is further described below with reference to embodiments, but the present disclosure is not limited in any way.

[0018] The present disclosure discloses a method for preparing FeSO4 electrolyte from iron ore, including the following steps of:

[0019] (1) Crushing the iron ore and then grinding it to obtain ore powder.

[0020] In an embodiment, step (1) includes: crushing the iron ore and then grinding it using a ceramic ball mill to obtain ore powder with a particle size of 0 pm to 100 pm, and drying the obtained ore powder until its moisture is less than or equal to 5%.

[0021] In an embodiment, the iron ore includes minerals selected from at least one of magnetite, siderite and hematite.

[0022] Further, in the embodiment of the present disclosure, ore powder with a particle size of 0 pm to 100 pm obtained by crushing and grinding ensures sufficient dissociation of the minerals, increases the specific surface area of the mineral, and facilitates subsequent oxidative calcination and iron ion leaching reactions. In addition, the ceramic ball mill is used for grinding to avoid the introduction of other harmful impurities.

[0023] (2) Subjecting the ore powder to oxidative calcination at 550 °C to 750 °C for 30 minutes to 120 minutes to obtain calcined ore powder.

[0024] In an embodiment, an oxidizing atmosphere of the oxidative calcination includes one of air and oxygen, and a gas flow rate of the oxidizing atmosphere is 1.0 L / min to 2.0 L / min.

[0025] In an embodiment, one of muffle furnace, horizontal tubular furnace and vertical tubular furnace is used for calcination.

[0026] Further, compared with the disadvantages of high costs, expensive reactor and low reduction rate of reductive calcination, the embodiment of the present disclosure selects oxidative calcination due to the advantages of easy to realize and low in cost of oxidizing atmosphere. By means of controlling the calcination temperature and calcination time, the present disclosure regulates the iron ore crystal structure to make it become looser, increase the surface area and improve the activity of the iron ore, making the iron ore easy to dissolve in acid and release iron ions.

[0027] (3) Acid leaching the calcined ore powder and filtering it to obtain a first filtrate.

[0028] In an embodiment, a sulfuric acid with a concentration of 0.5 mol / L-3 mol / L and citric acid with a concentration of 0.5 mol / L-1 mol / L are used for acid leaching.

[0029] In an embodiment, an acid leaching temperature is 100 °C-200 °C, an acid leaching time is 1 hour to 2 hours, and a liquid-to-solid ratio of an acid solution to the calcined ore powder for the acid leaching is (5-10) : 1.

[0030] (4) Adding iron powder into the first filtrate for a reduction reaction to reduce Fe3+ to Fe2+, and adsorbing iron powder through a magnet when the pH of the reaction is 3-7 to obtain a second filtrate.

[0031] In an embodiment, a purity of the iron powder is more than or equal to 99.9%, and an addition amount of the iron powder is 0.5-1 times a molar amount of Fe3+ in the first filtrate.

[0032] In an embodiment, a reduction reaction temperature is 60 °C-100 °C.

[0033] Further, the reducing agent required in step (4) needs to have both reducing effect and pH-adjusting effect. In addition, since Fe3+ ions are prone to precipitation, pH cannot be raised by adding alkaline substances and can only be raised by consuming H+. Meanwhile, in order to avoid introducing other impurities, the present disclosure preferably adds iron powder at normal temperature to reduce Fe3+ to Fe2+ and consume excessive H+ to adjust pH to 3-7 to remove Al3+ in the form of precipitation.

[0034] (5) Adding heavy metal precipitant Na2S into the second filtrate to convert heavy metals into metal sulfide precipitates, after the heavy metal precipitation reaction, adding a flocculant for flocculation and filtering to obtain the FeSO4 electrolyte.

[0035] In an embodiment, step (5) includes: Na2S that 2-3 times the molar amount of manganese ions is added to the second filtrate for heavy metal precipitation reaction, and then at least one of nonionic polyacrylamide and sodium polyacrylate with a concentration of 0.5 %o -2%o is added to the reaction product and stirred for 10min-30min, followed by settling and filtration to obtain the FeSO4 electrolyte that harmful impurities therein are effectively removed.

[0036] The present disclosure further discloses an FeSO4 electrolyte prepared by the preparation method according to any embodiment in the present disclosure.

[0037] The present disclosure also discloses an FeSO4 electrolyte prepared by the preparation method according to any embodiment in the present disclosure, or a use of the FeSO4 electrolyte according to any embodiment in the present disclosure for preparing high purity iron.

[0038] Some embodiments are as follows: Example 1

[0039] The results of multi-element chemical analysis and iron phase chemical analysis of the ore in this example are shown in Table 1 and Table 2, respectively. Table 1 Results of multi-element chemical analysis of ore (%) Element TFe FeO SiO2 AhOs CaO MgO Mn S P Ig Content 27.19 10.12 43.49 3.25 3.20 3.22 0.150 0.145 0.068 1.02 Table 2 Results of iron phase chemical analysis of ore (%) Iron phase TFe mFe siFe sFe cFe oFe Content 27.19 20.40 1.69 0.31 0.90 3.89 Distribution rate 100.00 75.03 6.22 1.14 3.31 14.30

[0040] (1) The properties of the ore used in the example are shown in the tables above. The TFe content is 27.19%, the magnetic iron (mFe) content is 20.40% with a distribution rate of 75.03%, the iron carbonate (cFe) content is 0.9% with a distribution rate of 3.31%, and the iron oxide (oFe) content is 3.89% with a distribution rate of 14.30%. Therefore, the ore used is mainly composed of magnetite, with small amount of hematite / limonite and siderite. Firstly, the iron ore was crushed and then ground with a ceramic ball mill until 90% of an obtained ore powder had a particle size of less than 38 pm, and then the ore powder was dried until its moisture was 1%.

[0041] (2) The dried ore powder obtained in step (1) was calcined with a muffle furnace at a calcination temperature of 680 °C for 60 minutes, and air was introduced at a flow rate of 1.4 L / min during the calcination process.

[0042] (3) The calcined ore powder obtained in step (2) was cooled to room temperature, and then was mixed with a mixed acid prepared from 1 mol / L sulfuric acid and 0.5 mol / L citric acid for leaching with a liquid-solid ratio of 5:1, the leaching temperature was 200 °C and the leaching time was 2 hours. The leaching process was accompanied by continuous stirring, and the leaching mixture was filtered after completion of the leaching to obtain a first filtrate.

[0043] (4) Iron powder with a purity of 99.9% was added into the first filtrate in an amount of 0.8 times the total amount of Fe3+ in the first filtrate obtained in step (3) and at normal temperature followed by heating to 80 °C to adjust the pH of the solution to 4, and then excess iron powder was removed using a magnet to obtain a second filtrate.

[0044] (5) Na2S was added into the second filtrate obtained in step (4) in an amount of 2 times the molar amount of manganese ions and stirred, followed by filtering to obtain a filtrate.

[0045] (6) Nonionic polyacrylamide with a concentration of 1.5%o was added into the filtrate obtained in step (5) as a flocculant and was stirred for 30 minutes, followed by settling and filtration to obtain the FeSO4 electrolyte without harmful impurities. By detection, the iron leaching rate from the iron ore was 65%, and the concentrations of main ions in the FeSO4 electrolyte are shown in Table 3 below. Table 3 Concentrations of main ions in the FeSO4 electrolyte (g / L) Ion Fe2+ Al3+ Na+ Ca2+ Mg2+ Mn2+ Concentration 41 0.07 0.78 0.0001 0.61 0.08 Example 2

[0046] The results of multi-element chemical analysis and iron phase chemical analysis of the ore in this example are shown in Table 4 and Table 5, respectively. Table 4 Results of multi-element chemical analysis of ore (%) Element TFe FeO SiO2 AhOs CaO MgO Mn S P Ig Content 29.01 9.39 52.50 1.25 0.93 0.98 0.130 0.123 0.071 1.21 Table 5 Results of iron phase chemical analysis of ore (%) Iron phase TFe mFe siFe sFe cFe oFe Content 29.01 22.60 1.00 0.31 0.24 4.86 Distribution rate 100.00 77.90 3.45 1.07 0.83 16.75

[0047] (1) The properties of the ore used in the example are shown in the tables above. The TFe content is 29.01%, the magnetic iron (mFe) content is 22.60% with a distribution rate of 77.90%, the iron carbonate (cFe) content is 0.24% with a distribution rate of 0.83%, and the iron oxide (oFe) content is 4.86% with a distribution rate of 16.75%. Therefore, the ore used is mainly composed of magnetite, with small amount of hematite / limonite. Firstly, the iron ore was crushed and then ground with a ceramic ball mill until 92% of an obtained ore powder had a particle size of less than 38 pm, and then the ore powder was dried until its moisture was 1%.

[0048] (2) The dried ore powder obtained in step (1) was calcined with a muffle furnace at a calcination temperature of 700 °C for 55 minutes, and air was introduced at a flow rate of 1.3 L / min during the calcination process.

[0049] (3) The calcined ore powder obtained in step (2) was cooled to room temperature, and then was mixed with a mixed acid prepared from 1 mol / L sulfuric acid and 0.5 mol / L citric acid for leaching with a liquid-solid ratio of 5:1, the leaching temperature was 200 °C and the leaching time was 2 hours. The leaching process was accompanied by continuous stirring, and the leaching mixture was filtered after completion of the leaching to obtain a first filtrate.

[0050] (4) Iron powder with a purity of 99.9% was added into the first filtrate in an amount of 1 time the total amount of Fe3+ in the first filtrate obtained in step (3) and at normal temperature followed by heating to 80 °C to adjust the pH of the solution to 4, and then excess iron powder was removed using a magnet to obtain a second filtrate.

[0051] (5) Na2S was added into the second filtrate obtained in step (4) in an amount of 2 times the molar amount of manganese ions and stirred, followed by filtering to obtain a filtrate.

[0052] (6) Nonionic polyacrylamide with a concentration of 1.4^ was added into the filtrate obtained in step (5) as a flocculant and was stirred for 30 minutes, followed by settling and filtration to obtain the FeSO4 electrolyte without harmful impurities. By detection, the iron leaching rate from the iron ore was 63.8%, and the concentrations of main ions in the FeSO4 electrolyte are shown in Table 6 below. Table 6 Concentrations of main ions in the FeSO4 electrolyte (g / L) Ion Fe2+ Al3+ Na+ Ca2+ Mg2+ Mn2+ Concentration 42.5 0.03 0.68 0.0001 0.22 0.07 Example 3

[0053] The results of multi-element chemical analysis and iron phase chemical analysis of the ore in this example are shown in Table 7 and Table 8, respectively. Table 7 Results of multi-element chemical analysis of ore (%) Element TFe FeO SiO2 AhOs CaO MgO Mn S P Ig Content 48.49 13.42 27.91 0.35 0.58 0.57 0.165 0.085 0.018 1.02 Table 8 Results of iron phase chemical analysis of ore (%) Iron phase TFe mFe siFe sFe cFe oFe Content 48.49 32.72 3.65 0.25 0.65 11.22 Distribution rate 100.00 67.48 7.75 0.53 1.38 23.82

[0054] (1) The properties of the ore used in the example are shown in the tables above. The TFe content is 48.49%, the magnetic iron (mFe) content is 32.72% with a distribution rate of 67.48%, the iron carbonate (cFe) content is 0.65% with a distribution rate of 1.38%, and the iron oxide (oFe) content is 11.22% with a distribution rate of 23.82%. Therefore, the ore used is mainly composed of magnetite, with small amount of hematite / limonite. Firstly, the iron ore was crushed and then ground with a ceramic ball mill until 90% of an obtained ore powder had a particle size of less than 38 pm, and then the ore powder was dried until its moisture was 1%.

[0055] (2) The dried ore powder obtained in step (1) was calcined with a muffle furnace at a calcination temperature of 680 °C for 60 minutes, and air was introduced at a flow rate of 1.4 L / min during the calcination process.

[0056] (3) The calcined ore powder obtained in step (2) was cooled to room temperature, and then was mixed with a mixed acid prepared from 1 mol / L sulfuric acid and 0.5 mol / L citric acid for leaching with a liquid-solid ratio of 6:1, the leaching temperature was 200 °C and the leaching time was 2 hours. The leaching process was accompanied by continuous stirring, and the leaching mixture was filtered after completion of the leaching to obtain a first filtrate.

[0057] (4) Iron powder with a purity of 99.9% was added into the first filtrate in an amount of 0.8 times the total amount of Fe3+ in the first filtrate obtained in step (3) and at normal temperature followed by heating to 90 °C to adjust the pH of the solution to 4, and then excess iron powder was removed using a magnet to obtain a second filtrate.

[0058] (5) Na2S was added into the second filtrate obtained in step (4) in an amount of 2 times the molar amount of manganese ions and stirred, followed by filtering to obtain a filtrate.

[0059] (6) Nonionic polyacrylamide with a concentration of 1.4^ was added into the filtrate obtained in step (5) as a flocculant and was stirred for 30 minutes, followed by settling and filtration to obtain the FeSO4 electrolyte without harmful impurities. By detection, the iron leaching rate from the iron ore was 67.3%, and the concentrations of main ions in the FeSO4 electrolyte are shown in Table 9 below. Table 9 Concentrations of main ions in the FeSO4 electrolyte (%) Ion Fe2+ Al3+ Na+ Ca2+ Mg2+ Mn2+ Concentration 42.5 0.03 0.68 0.0001 0.22 0.07 Example 4

[0060] The results of multi-element chemical analysis and iron phase chemical analysis of the ore in this example are shown in Table 10 and Table 11, respectively. Table 10 Results of multi-element chemical analysis of ore (%) Element TFe FeO SiO2 Al2O3 CaO MgO Mn S P Ig Content 65.70 27.26 8.26 0.20 0.18 0.17 0.120 0.025 0.006 0.27 Table 11 Results of iron phase chemical analysis of ore iron phase (%) Iron phase TFe mFe siFe sFe cFe oFe Content 65.70 64.56 0.23 0.06 0.09 0.76 Distribution rate 100.00 98.26 0.35 0.09 0.14 1.16

[0061] (1) The properties of the ore used in the example are shown in the tables above. The TFe content is 65.70%, the magnetic iron (mFe) content is 64.56% with a distribution rate of 98.26%, the iron carbonate (cFe) content is 0.09% with a distribution rate of 0.14%, and the iron oxide (oFe) content is 0.76% with a distribution rate of 1.16%. Therefore, the ore used is mainly composed of magnetite. Firstly, the iron ore was crushed and then ground with a ceramic ball mill until 95% of an obtained ore powder had a particle size of less than 38 pm, and then the ore powder was dried until its moisture was 1%.

[0062] (2) The dried ore powder obtained in step (1) was calcined with a muffle furnace at a calcination temperature of 650 °C for 60 minutes, and air was introduced at a flow rate of 1.5 L / min during the calcination process.

[0063] (3) The calcined ore powder obtained in step (2) was cooled to room temperature, and then was mixed with a mixed acid prepared from 1.5 mol / L sulfuric acid and 0.7 mol / L citric acid for leaching with a liquid-solid ratio of 7:1, the leaching temperature was 200 °C and the leaching time was 2 hours. The leaching process was accompanied by continuous stirring, and the leaching mixture was filtered after completion of the leaching to obtain a first filtrate.

[0064] (4) Iron powder with a purity of 99.9% was added into the first filtrate in an amount of 0.8 times the total amount of Fe3+ in the first filtrate obtained in step (3) and at normal temperature followed by heating to 90 °C to adjust the pH of the solution to 4, and then excess iron powder was removed using a magnet to obtain a second filtrate.

[0065] (5) Na2S was added into the second filtrate obtained in step (4) in an amount of 2 times the molar amount of manganese ions and stirred, followed by filtering to obtain a filtrate.

[0066] (6) Nonionic polyacrylamide with a concentration of 1.2^ was added into the filtrate obtained in step (5) as a flocculant and was stirred for 30 minutes, followed by settling and filtration to obtain the FeSO4 electrolyte without harmful impurities. By detection, the iron leaching rate from the iron ore was 70.5%, and the concentrations of main ions in the FeSO4 electrolyte are shown in Table 12 below. Table 12 Concentrations of main ions in the FeSO4 electrolyte (g / L) Ion Fe2+ Al3+ Na+ Ca2+ Mg2+ Mn2+ Concentration 67.5 0.02 0.63 0.0001 0.08 0.07 Example 5

[0067] The results of multi-element chemical analysis and iron phase chemical analysis of the ore in this example are shown in Table 13 and Table 14, respectively. Table 13 Results of multi-element chemical analysis of ore (%) Element TFe FeO SiO2 Al2O3 CaO MgO Mn S P Ig Content 66.33 16.80 5.06 0.37 0.17 0.22 0.090 0.037 0.010 0.72 Table 14 Results of iron phase chemical analysis of ore (%) Iron phase TFe mFe siFe sFe cFe oFe Content 66.33 32.12 0.50 0.08 2.15 31.48 Distribution rate 100.00 48.42 0.75 0.12 3.24 47.46

[0068] (1) The properties of the ore used in the example are shown in the tables above. The TFe content is 66.33%, the magnetic iron (mFe) content is 32.12% with a distribution rate of 48.42%, the iron carbonate (cFe) content is 2.15% with a distribution rate of 3.24%, and the iron oxide (oFe) content is 31.48% with a distribution rate of 47.46%. Therefore, the ore used is mainly composed of magnetite and hematite / limonite, with small amount of siderite. Firstly, the iron ore was crushed and then ground with a ceramic ball mill until 90% of an obtained ore powder had a particle size of less than 38 pm, and then the ore powder was dried until its moisture was 1%.

[0069] (2) The dried ore powder obtained in step (1) was calcined with a muffle furnace at a calcination temperature of 680 °C for 60 minutes, and air was introduced at a flow rate of 1.4 L / min during the calcination process.

[0070] (3) The calcined ore powder obtained in step (2) was cooled to room temperature, and then was mixed with a mixed acid prepared from 1.5 mol / L sulfuric acid and 0.7 mol / L citric acid for leaching with a liquid-solid ratio of 7:1, the leaching temperature was 200 °C and the leaching time was 2 hours. The leaching process was accompanied by continuous stirring, and the leaching mixture was filtered after completion of the leaching to obtain a first filtrate.

[0071] (4) Iron powder with a purity of 99.9% was added into the first filtrate in an amount of 0.8 times the total amount of Fe3+ in the first filtrate obtained in step (3) and at normal temperature followed by heating to 80 °C to adjust the pH of the solution to 4, and then excess iron powder was removed using a magnet to obtain a second filtrate.

[0072] (5) Na2S was added into the second filtrate obtained in step (4) in an amount of 2 times the molar amount of manganese ions and stirred, followed by filtering to obtain a filtrate.

[0073] (6) Nonionic polyacrylamide with a concentration of 1.5% was added into the filtrate obtained in step (5) as a flocculant and was stirred for 30 minutes, followed by settling and filtration to obtain the FeSO4 electrolyte without harmful impurities. By detection, the iron leaching rate from the iron ore was 62.5%, and the concentrations of main ions in the FeSO4 electrolyte are shown in Table 15 below. Table 15 Concentrations of main ions in the FeSO4 electrolyte (g / L) Ion Fe2+ Al3+ Na+ Ca2+ Mg2+ Mn2+ Concentration 62.3 0.02 0.46 0.0001 0.09 0.06

[0074] In conclusion, the present disclosure improves the activity of iron ore by controlling the atmosphere, temperature and time during the calcination process without the addition of highly corrosive reagents such as hydrofluoric acid, making the iron ore easy to dissolve in acid, and the present disclosure removes harmful impurities from acidolysis solution for purification. The present disclosure realizes efficient preparation of FeSO4 electrolyte from iron ore, which is of great significance for promoting the preparation of pure iron by electrolysis method.

[0075] The embodiments described above only several implementations of the present disclosure, and the description is relatively specific and detailed, but it should not be construed as limitations on the scope of the present disclosure. It should be noted that those skilled in the art may make various modifications and improvements without departing from the inventive concept of the present disclosure, and such modifications and improvements fall within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the appended claims.

Claims

1. A method for preparing FeSO4 electrolyte from iron ore, comprising the following steps of:(1) crushing the iron ore, followed by grinding to obtain ore powder;(2) subjecting the ore powder to oxidative calcination at 550 °C to 750 °C for 30 min to 120 min to obtain calcined ore powder;(3) acid leaching the calcined ore powder and filtering it to obtain a first filtrate;(4) adding iron powder into the first filtrate for a reduction reaction to reduce Fe3+ to Fe2+, and adsorbing iron powder through a magnet when the pH of the reaction is 3-7 to obtain a second filtrate; and(5) adding a heavy metal precipitant Na2S into the second filtrate to convert heavy metals into metal sulfide precipitates, followed by adding a flocculant for flocculation and filtering to obtain the FeSO4 electrolyte.

2. The method for preparing FeSO4 electrolyte from iron ore according to claim 1, wherein in step (1), the iron ore comprises minerals selected from at least one of magnetite, siderite and hematite;the grinding is performed with a ceramic ball mill; anda particle size of the ore powder is 0 pm to 100 pm.

3. The method for preparing FeSO4 electrolyte from iron ore according to claim 1, wherein step further comprises drying the ore powder after crushing and grinding to reduce a moisture content of the ore powder to less than or equal to 5%.

4. The method for preparing FeSO4 electrolyte from iron ore according to claim 1, wherein in step (2), an oxidizing atmosphere of the oxidative calcination comprises one of air and oxygen; anda 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, wherein in step (3), sulfuric acid with a concentration of 0.5 mol / L-3 mol / L and citric acid with a concentration of 0.5 mol / L-1 mol / L are used for acid leaching;an acid leaching temperature is 100 °C to 200 °C; an acid leaching time is 1 hour to 2 hours; anda liquid-to-solid ratio of an acid solution to the calcined ore powder for acid leaching is (5-10) : 1.

6. The method for preparing FeSO4 electrolyte from iron ore according to claim 1,wherein in step (4), a purity of the iron powder is more than or equal to 99.9%;an addition amount of the iron powder is 0.5-1 times a molar amount of Fe3+ in the first filtrate; anda reduction reaction temperature is 60 °C-100 °C.

7. The method for preparing FeSO4 electrolyte from iron ore according to claim 1, wherein in step (5), an addition amount of Na2S is 2-3 times a molar amount of manganese ions in the second filtrate;the flocculant comprises at least one of nonionic polyacrylamide and sodium polyacrylate; anda concentration of the flocculant is 0.5%o-2%o.

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

9. An FeSO4 electrolyte prepared by the preparation method according to any one of the claims 1 to 7, or a use of the FeSO4 electrolyte according to claim 8 for preparing high purity iron.