Method for removing iron from hematite of iron-containing sulfate solution

Abstract

The invention relates to a hematite iron removal method for an iron-containing sulfate solution, which comprises the following steps: providing an iron removal device which comprises N vertical reaction kettles and a horizontal reaction kettle, and connecting the discharge ports of the N vertical reaction kettles to the feed port of the horizontal reaction kettle in parallel; n is an integer greater than or equal to 2; inputting the iron-containing sulfate solution into part of the vertical reaction kettle, inputting steam and oxygen into the vertical reaction kettle, and carrying out first iron removal treatment in the vertical reaction kettle to obtain first iron-removed slurry; the iron removal efficiency in the first iron removal treatment period is 16-24 kg.m <-3 >. H <-1 >; inputting the first iron-removed slurry into a horizontal reaction kettle, inputting steam and oxygen into the horizontal reaction kettle, and carrying out second iron removal treatment in the horizontal reaction kettle to obtain second iron-removed slurry; wherein the time in the second iron removal treatment period is 5-7 kg.m <-3 >. H <-1 >. According to the invention, continuous feeding and continuous discharging type continuous treatment of the iron-containing sulfate solution can be realized, the iron removal efficiency is effectively improved, and a good iron removal effect is ensured.

Description

Technical Field

[0001] The invention relates to a method for removing iron from hematite using an iron-containing sulfate solution, and belongs to the field of hydrometallurgy. Background Art

[0002] In 1971, Japan's Iijima Zinc Plant was the first to use the hematite iron removal method. It has a production capacity of 200,000 t / a. The plant has been in production for more than 50 years. Currently, the plant is operating normally. Due to the strong confidentiality of the plant, the actual production situation is little known to the outside world. According to reports, the plant uses SO 2 Flue gas reduction leaching slag, part of SO 2 The conversion to sulfuric acid causes an increase in sulfuric acid in the system. In order to maintain the acid balance of the system, lime must be added for neutralization to remove excess sulfate, which produces a large amount of gypsum slag that cannot be sold. The high zinc content in the gypsum slag requires separate treatment, resulting in high production costs. The second factory in the world to use the hematite iron removal method was the Ruhr Zinc Plant in Germany, which was built in 1979 with a production scale of 130,000 tons / a of electrolytic zinc. The plant discontinued the hematite iron removal process in 1993. It is understood that the main reasons are: first, the high production cost, and second, there are many system engineering problems, such as scaling in the reactor. The basic principle of hematite iron removal is: react under high temperature and high pressure conditions to remove Fe 2+ Oxidation forms hematite slag to remove iron. The chemical reaction formula is as follows:

[0003] 4FeSO 4 +O 2 +4H 2 O→2Fe 2 O 3 ↓+4H 2 SO 4 .

[0004] There are two main problems in the hematite iron removal method: one is Fe 2+ The first is the reduction method, how to maintain the acid balance of the system and not produce gypsum slag; the second is how to deal with the iron slag deposition and scaling problem in the reactor.

[0005] Chinese invention patent specification CN104004913B discloses a method for removing iron from an iron-containing zinc sulfate solution. The method comprises: supplying the iron-containing zinc sulfate solution to a vertical reactor, and introducing steam and oxygen into the vertical reactor, so as to perform a first iron removal treatment in the vertical reactor, and obtain a first iron removal slurry; and supplying the first iron removal slurry to a horizontal reactor, and introducing steam and oxygen into the horizontal reactor, so as to perform a second iron removal treatment in the horizontal reactor, and obtain a second iron removal slurry. During the reaction process, the vertical reactor and the horizontal reactor are combined, and the reaction temperature, oxygen partial pressure and other conditions of the two are consistent. It is inevitable that the iron precipitation in the vertical reactor and the horizontal reactor is similar, so the iron slag may be deposited in both the vertical reactor and the horizontal reactor. Therefore, after running for a period of time, it is necessary to stop at least one of the vertical reactor and the horizontal reactor for cleaning, so it is actually difficult to achieve continuous feeding and continuous discharging type continuous processing. Summary of the invention

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide a method for removing iron from hematite in an iron-containing sulfate solution, so as to achieve continuous feeding and discharging of the iron-containing sulfate solution.

[0007] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0008] A method for removing iron from hematite using an iron sulfate solution comprises the following steps:

[0009] S1. Provide iron removal device;

[0010] Wherein, the iron removal device comprises N vertical reactors and 1 horizontal reactor, and the discharge ports of the N vertical reactors are connected to the feed port of the horizontal reactor; N is an integer ≥ 2;

[0011] S2,

[0012] S2-1, inputting an iron-containing sulfate solution into M vertical reactors, and inputting steam and oxygen into the M vertical reactors to perform a first iron removal treatment in the M vertical reactors to obtain a first iron-removed slurry;

[0013] S2-2, after the M vertical reactors have been running for a target time, stop inputting the iron-containing sulfate solution into the M vertical reactors, input the iron-containing sulfate solution into H vertical reactors among the other vertical reactors, and input steam and oxygen into the H vertical reactors to perform a first iron removal treatment in the H vertical reactors to obtain a first iron-removed slurry; during the operation of the H vertical reactors, clean the M vertical reactors;

[0014] S2-3, after the H vertical reactors have been running for a target time, stop inputting the iron-containing sulfate solution into the H vertical reactors, input the iron-containing sulfate solution into M vertical reactors among the other vertical reactors, and input steam and oxygen into the M vertical reactors to perform a first iron removal treatment in the M vertical reactors to obtain a first iron-removed slurry; during the operation of the M vertical reactors, clean the H vertical reactors;

[0015] S2-4, repeat S2-2 to S2-3;

[0016] During the first iron removal treatment, the temperature T1 in the vertical reactor in operation is controlled to be 185-199°C, the pressure is 1.6-1.9 MPa, and the residence time is 0.4-0.9 h, so that the iron removal efficiency is 16-24 kg·m -3 ·h -1 ;

[0017] M is an integer ≥1 and <N; H is an integer ≥1 and ≤(NM);

[0018] S3, inputting the first iron-removed slurry into a horizontal reactor, and inputting steam and oxygen into the horizontal reactor to perform a second iron-removal treatment in the horizontal reactor to obtain a second iron-removed slurry;

[0019] During the second iron removal treatment, the temperature T2 in the horizontal reactor is controlled to be 165-180°C, the pressure is 1.6-1.9 MPa, and the residence time is 1.8-3.5 h, so that the iron removal efficiency is 5-7 kg·m -3 ·h -1 ;T1>T2.

[0020] In the present invention, iron removal efficiency refers to the amount of iron removed per cubic meter of reaction volume per hour (iron removal kg·reactor volume m -3 ·Residence time -1 );Wherein, the amount of iron removal is measured by the mass of Fe ions removed from the solution.

[0021] Furthermore, the iron removal device also includes a flash tank and a solid-liquid separation mechanism, and the horizontal reactor, the flash tank and the solid-liquid separation mechanism are connected in sequence; after S3, the second iron-removed slurry is input into the flash tank, and after cooling and reducing the pressure, it is input into the solid-liquid separation mechanism for solid-liquid separation to obtain hematite slag and iron-removed liquid; preferably, the solid-liquid separation mechanism includes a thickener.

[0022] Preferably, the vertical reactor has a manhole.

[0023] Further, N is 2-4.

[0024] Furthermore, the volume of the horizontal reactor is greater than the total volume of the vertical reactors in operation in S2. Preferably, the volume of the horizontal reactor is 2-6 times, more preferably 3-5 times, the total volume of the vertical reactors in operation in S2.

[0025] Furthermore, the target time is 20-80 days, preferably 30-60 days.

[0026] Furthermore, the iron content in the iron-containing sulfate solution is ≥20 g / L, preferably 21-40 g / L; the iron content in the liquid phase of the slurry after the first iron removal is <20 g / L, preferably 13-19 g / L. Thus, when the iron content in the iron-containing sulfate solution is above 20 g / L and the temperature is 185-199°C, the iron removal efficiency is 16-24 kg·m -3 ·h -1 , so that about 40% of the iron in the iron sulfate solution is converted into iron slag in the vertical reactor and partially deposited. When the liquid phase iron content of the slurry after the first iron removal is less than 20g / L and the medium temperature is 165-180℃, the iron removal efficiency is 5-7kg·m -3 ·h -1 , so that about 60% of the iron in the remaining solution enters the horizontal reactor and is converted into iron slag. The iron slag rarely deposits in the horizontal reactor, so that the entire iron removal process can be carried out continuously for a long time.

[0027] Furthermore, in S2, the total volume of the iron-containing sulfate solution input into the operating vertical reactor per hour is 1-2.5 times, preferably 1.25-2.25 times, and more preferably 1.5-2 times, the total volume of the operating vertical reactor.

[0028] Furthermore, the difference between T1 and T2 is 5-25°C, preferably 10-20°C.

[0029] Furthermore, during the first iron removal treatment, the temperature T1 in the vertical reactor in operation is controlled to be 188-196°C, the pressure is 1.7-1.9 MPa, and the residence time is 0.5-0.8 h, so that the iron removal efficiency is 16.2-23.8 kg·m -3 ·h -1 .

[0030] Furthermore, during the second iron removal treatment, the temperature T2 in the horizontal reactor is controlled to be 168-176°C, the pressure is 1.7-1.9 MPa, and the residence time is 2-3.3 h, so that the iron removal efficiency is 5.2-6.8 kg·m -3 ·h -1 .

[0031] Optionally, the iron-containing sulfate solution is one of an iron-containing zinc sulfate solution, an iron-containing nickel sulfate solution, and an iron-containing copper sulfate solution.

[0032] Optionally, the valence state of iron in the iron-containing sulfate solution is +2.

[0033] See also Figure 1 In the zinc smelting process, in order to produce low-acid leaching solution, the returned acid-containing leaching solution and the roasted sand produced by boiling roasting of zinc concentrate are usually subjected to neutral leaching. After neutral leaching, the intermediate leaching solution can be sent for purification and electrolytic treatment. At the same time, the intermediate leaching residue needs to be subjected to hot acid reduction leaching. The basic principle of hot acid reduction leaching is as follows: the zinc ferrite in the intermediate leaching residue reacts to form zinc sulfate and ferric sulfate under high temperature and high acid conditions. The ferric sulfate is reduced to ferrous sulfate under the action of the reducing agent zinc concentrate, thereby achieving the purpose of zinc ferrite leaching and iron reduction. The chemical reaction formula is as follows:

[0034] ZnO·Fe 2 O 3 +4H 2 SO 4 =ZnSO 4 +Fe 2 (SO 4 ) 3 +4H 2 O;

[0035] ZnS+Fe 2 (SO 4 ) 3 =ZnSO 4 +2FeSO 4 +S 0 ;

[0036] As can be seen from the above formula, using zinc concentrate as a reducing agent, sulfur is converted into elemental sulfur, which will not affect the acid balance of the system, but the iron content in the leachate is bound to be still high, and it is an iron-containing zinc sulfate solution. Further, the above leachate is subjected to iron removal treatment by the iron removal method of the present invention, which can effectively reduce the iron content in the solution system, and prepare for returning the solution to the neutral leaching step and obtaining a low-iron leaching solution (subsequently sent to the purification and electrolysis process). Therefore, the iron removal method of the present invention plays an important role at least in the field of zinc smelting.

[0037] Generally, both vertical and horizontal reactors are equipped with stirring devices. Therefore, in the process of iron removal by the hematite method, the strong and uniform stirring of the stirrer can prevent the deposition of iron slag and make the leaching solution react evenly to a certain extent. However, hematite slag is a viscous solid, so the effect of stirring to prevent the deposition of iron slag is limited. To prevent the deposition and scaling of hematite slag in reactors such as reactors, the iron slag formed by the reaction must be discharged from the reactor in time. If the residence time is too long, the iron slag formed by the reaction cannot be discharged in time and is easy to deposit and scale; if the residence time is too short, the iron removal process is incomplete and it is difficult to meet production requirements. Therefore, the traditional idea is generally to control the appropriate parameters such as the residence time, and to maximize the iron removal effect while minimizing the amount of deposited scaling. However, to obtain an improved iron removal effect, it is often difficult to avoid iron slag deposition and scaling in this way.

[0038] The present invention connects N vertical reactors and horizontal reactors in parallel, so that each vertical reactor can serve as a backup for each other. At the same time, some vertical reactors are in operation while others are stopped or undergoing cleaning and maintenance. The invention breaks through the traditional thinking and controls the iron removal efficiency of the first iron removal process in the vertical reactor to be as high as 16-24 kg·m -3 ·h -1 , actively speeding up the conversion of iron into hematite in this process, so that the iron slag formed by the reaction is scaled in the corresponding vertical reactor, so that the concentration of iron slag in the slurry after the first iron removal is low, which can effectively reduce the possibility of iron slag scaling in the subsequent second iron removal process. Furthermore, the solution entering the second iron removal process of the present invention has a low initial iron concentration, and through the control of reaction conditions, the iron removal efficiency of the second iron removal process in the horizontal reactor is reduced to 5-7 kg·m -3 ·h -1 , so that the iron removal reaction at this stage is quite gentle, so the possibility or amount of iron slag deposition in the horizontal reactor is very low, and after two stages of iron removal, the iron removal effect can be well guaranteed. And each vertical reactor can be operated and cleaned in turn (can be cleaned regularly through the manhole), so that the first iron removal process and the second iron removal process can be carried out continuously, thereby ensuring the continuous operation of the entire iron removal process and ensuring a good iron removal effect. Therefore, the iron removal method of the present invention can effectively solve the problem that the process cannot be carried out continuously due to the deposition and scaling of iron slag in the reactor during the iron removal process of iron-containing sulfate, and can ensure a good iron removal effect.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The iron removal method of the present invention can realize continuous feeding and discharging of the iron-containing sulfate solution, effectively improve the iron removal efficiency, and ensure a good iron removal effect.

[0041] In the iron removal process of the present invention, part of the iron is deposited and scaled in the vertical reactor, which can effectively reduce the possibility of deposition and scaling in the downstream horizontal reactor. The continuous iron removal process is effectively guaranteed by the rotation operation and cleaning of each vertical reactor.

[0042] The present invention can use zinc concentrate as a reducing agent, does not require an additional reducing agent, saves production costs, does not increase sulfuric acid, maintains system acid balance, and does not generate gypsum slag. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of the smelting process of zinc concentrate.

[0044] Figure 2 It is a structural diagram of an iron removal device of the present invention.

[0045] Figure 3 This is the XRD spectrum of the hematite slag obtained during the first iron removal treatment in Example 2 of the present invention. DETAILED DESCRIPTION

[0046] The present invention will be described in detail below in conjunction with the embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict. For the convenience of description, if the words "upper", "lower", "left" and "right" appear in the following, they only indicate that they are consistent with the upper, lower, left and right directions of the drawings themselves, and do not limit the structure. Unless otherwise specified, the relevant percentages refer to mass percentages. Example 1

[0047] This embodiment relates to a method for processing zinc concentrate, comprising the following steps:

[0048] The zinc concentrate is roasted into roasted sand after boiling, and the flue gas produced is sent to the acid plant.

[0049] The roasted sand is subjected to neutral leaching, waste electrolyte is added, the temperature is controlled at 60-70°C, 1-2h, the end point pH is 5.0-5.2, intermediate leaching residue is produced, and the intermediate leaching liquid is sent for purification, electrolysis, and casting to produce electric zinc.

[0050] The intermediate leaching residue is subjected to hot acid reduction leaching, waste electrolytic solution and zinc concentrate are added, the temperature is controlled at 90-95°C, the time is 3-4h, the final acid is 50-70g / L, the leaching solution is produced, and the leaching residue is sent to the pyrolysis slag treatment.

[0051] The leaching solution is pre-neutralized, roasted sand is added, the temperature is controlled at 60-65°C, the time is 0.5-1.5h, the end point pH is 1.0-2.0, and the pre-neutralized slag is returned to the neutral leaching to produce the pre-neutralized liquid, i.e. the pre-iron removal liquid (the iron concentration in the iron-containing zinc sulfate solution is 20-40g / L). Example 2

[0052] The method for removing iron from hematite in the iron-containing zinc sulfate solution of this embodiment comprises the following steps:

[0053] S1. Provide iron removal device;

[0054] The iron removal device comprises a pump 1, two vertical reactors 2 and a horizontal reactor 3, a flash tank 4 and a solid-liquid separation mechanism 5, a steam delivery pipeline 15 and an oxygen delivery pipeline 16. The horizontal reactor, the flash tank and the solid-liquid separation mechanism are connected in sequence, and the discharge ports of the two vertical reactors are connected to the feed port of the horizontal reactor; the solid-liquid separation mechanism comprises a thickener; a first valve 8 is provided at the feed port of the vertical reactor 2, a second valve 9 is provided at the discharge port of the vertical reactor 2, a first air inlet is provided at the bottom of the vertical reactor 2, and a third valve 10 is provided at the air inlet; a fourth valve 11 is provided at the feed port of the horizontal reactor 3, and a fourth valve 12 is provided at the discharge port of the vertical reactor 2. A fifth valve 13 is provided at the discharge port of the horizontal reactor 3, and a plurality of second air inlets are provided at the bottom of the horizontal reactor 3; the outlet of the pump 1 is connected to the inlets of the two first valves 8, and the outlets of the two second valves 9 are connected to the inlet of the fourth valve 11; the outlet of the fifth valve 13 is connected to the flash tank 4, and a sixth valve 14 is also provided on the pipeline between the fifth valve 13 and the flash tank 4; a seventh valve 12 is provided at the second air inlet; an eighth valve 6 is provided on the steam delivery pipeline 15, and a ninth valve 7 is provided on the oxygen delivery pipeline 16, and the outlet of the eighth valve 6 is respectively connected to the third valve 10 and the seventh valve 12, and the ninth valve 7 is respectively connected to the third valve 10 and the seventh valve 12. A stirring mechanism is provided in both the vertical reactor and the horizontal reactor. The vertical reactor has a manhole.

[0055] S2,

[0056] S2-1, inputting the iron-containing zinc sulfate solution into a vertical reactor (referred to as a "first vertical reactor"), and inputting steam and oxygen into the vertical reactor to perform a first iron removal treatment in the vertical reactor to obtain a first iron-removed slurry;

[0057] S2-2, after the first vertical reactor has been running for a target time, stop inputting the iron-containing zinc sulfate solution into the first vertical reactor, input the iron-containing zinc sulfate solution into another vertical reactor (referred to as the "second vertical reactor"), and input steam and oxygen into the second vertical reactor to perform a first iron removal treatment in the second vertical reactor to obtain a first iron-removed slurry; during the operation of the second vertical reactor, clean the first vertical reactor through a manhole to remove deposited iron slag;

[0058] S2-3, after the second vertical reactor has been running for a target time, stop inputting the iron-containing zinc sulfate solution into the second vertical reactor, input the iron-containing zinc sulfate solution into the first vertical reactor, and input steam and oxygen into the first vertical reactor to perform a first iron removal treatment in the first vertical reactor to obtain a first iron-removed slurry; during the operation of the first vertical reactor, clean the second vertical reactor through a manhole to remove deposited iron slag;

[0059] S2-4, repeat S2-2 to S2-3;

[0060] During the first iron removal process, the temperature T1 in the vertical reactor in operation was controlled to be 195°C, the pressure to be 1.75 MPa, and the residence time to be 0.8 h, so that the iron removal efficiency was 23.75 kg·m -3 ·h -1 ; The target time is 30d; the volume of the vertical reactor is 1m 3 ; The iron content in the iron-containing zinc sulfate solution is 38g / L; The iron content in the liquid phase of the slurry after the first iron removal is 19g / L; During this period, 32.76kg of hematite slag (containing 58% Fe, its XRD pattern see Figure 3 ); the input rate of the iron-containing zinc sulfate solution is 1.25m 3 / h;

[0061] S3, the first iron-removed slurry is heated to 1.25m 3 / h into a horizontal reactor, and steam and oxygen are input into the horizontal reactor to perform a second iron removal treatment in the horizontal reactor to obtain a second iron-removed slurry;

[0062] During the second iron removal treatment, the temperature T2 in the horizontal reactor was controlled to be 180°C, the pressure was 1.75 MPa, and the residence time was 3.2 h, so that the iron removal efficiency was 5.31 kg·m -3 ·h -1 ; The volume of the horizontal reactor is 4m 3 During this period, 118.20 kg of hematite slag (containing 57.5% iron) was produced;

[0063] S4. The second deironing slurry is input into a flash tank, and after cooling and reducing the pressure, it is input into a solid-liquid separation mechanism for solid-liquid separation to obtain hematite slag and deironing liquid (containing 2 g / L iron).

[0064] The results show that the cleaning cycle of the vertical reactor is 30 days; after the horizontal reactor has been running continuously for 150 days, there is no obvious scaling in the reactor. Example 3

[0065] The method for removing iron from hematite in the iron-containing zinc sulfate solution of this embodiment comprises the following steps:

[0066] S1. Provide the iron removal device described in Example 2;

[0067] S2,

[0068] S2-1, inputting the iron-containing zinc sulfate solution into a vertical reactor (referred to as a "first vertical reactor"), and inputting steam and oxygen into the vertical reactor to perform a first iron removal treatment in the vertical reactor to obtain a first iron-removed slurry;

[0069] S2-2, after the first vertical reactor has been running for a target time, stop inputting the iron-containing zinc sulfate solution into the first vertical reactor, input the iron-containing zinc sulfate solution into another vertical reactor (referred to as the "second vertical reactor"), and input steam and oxygen into the second vertical reactor to perform a first iron removal treatment in the second vertical reactor to obtain a first iron-removed slurry; during the operation of the second vertical reactor, clean the first vertical reactor through a manhole to remove deposited iron slag;

[0070] S2-3, after the second vertical reactor has been running for a target time, stop inputting the iron-containing zinc sulfate solution into the second vertical reactor, input the iron-containing zinc sulfate solution into the first vertical reactor, and input steam and oxygen into the first vertical reactor to perform a first iron removal treatment in the first vertical reactor to obtain a first iron-removed slurry; during the operation of the first vertical reactor, clean the second vertical reactor through a manhole to remove deposited iron slag;

[0071] S2-4, repeat S2-2 to S2-3;

[0072] During the first iron removal process, the temperature T1 in the vertical reactor in operation was controlled to be 190°C, the pressure to be 1.70 MPa, and the residence time to be 0.65 h, so that the iron removal efficiency was 18.48 kg·m -3 ·h -1 ; The target time is 40d; the volume of the vertical reactor is 1m 3 ; The iron content in the iron-containing zinc sulfate solution is 30g / L; The iron content in the liquid phase of the slurry after the first iron removal is 18g / L; During this period, 21.45kg of hematite slag (containing 56% Fe) was produced; The input rate of the iron-containing zinc sulfate solution is 1.54m 3 / h;

[0073] S3, the first iron-removed slurry is heated to 1.54m 3 / h into a horizontal reactor, and steam and oxygen are input into the horizontal reactor to perform a second iron removal treatment in the horizontal reactor to obtain a second iron-removed slurry;

[0074] During the second iron removal treatment, the temperature T2 in the horizontal reactor was controlled to be 175°C, the pressure was 1.70 MPa, and the residence time was 2.6 h, so that the iron removal efficiency was 6.23 kg·m -3 ·h -1 ; The volume of the horizontal reactor is 4m 3 During this period, 116.1 kg of hematite slag (containing 55.8% iron) was produced;

[0075] S4. The second deironing slurry is input into a flash tank, and after cooling and reducing the pressure, it is input into a solid-liquid separation mechanism for solid-liquid separation to obtain hematite slag and deironing liquid (containing 1.8 g / L iron).

[0076] The results show that the cleaning cycle of the vertical reactor is 40 days; after the horizontal reactor has been running continuously for 160 days, there is no obvious scaling in the reactor. Example 4

[0077] The method for removing iron from hematite in the iron-containing zinc sulfate solution of this embodiment comprises the following steps:

[0078] S1. Provide the iron removal device described in Example 2;

[0079] S2,

[0080] S2-1, inputting the iron-containing zinc sulfate solution into a vertical reactor (referred to as a "first vertical reactor"), and inputting steam and oxygen into the vertical reactor to perform a first iron removal treatment in the vertical reactor to obtain a first iron-removed slurry;

[0081] S2-2, after the first vertical reactor has been running for a target time, stop inputting the iron-containing zinc sulfate solution into the first vertical reactor, input the iron-containing zinc sulfate solution into another vertical reactor (referred to as the "second vertical reactor"), and input steam and oxygen into the second vertical reactor to perform a first iron removal treatment in the second vertical reactor to obtain a first iron-removed slurry; during the operation of the second vertical reactor, clean the first vertical reactor through a manhole to remove deposited iron slag;

[0082] S2-3, after the second vertical reactor has been running for a target time, stop inputting the iron-containing zinc sulfate solution into the second vertical reactor, input the iron-containing zinc sulfate solution into the first vertical reactor, and input steam and oxygen into the first vertical reactor to perform a first iron removal treatment in the first vertical reactor to obtain a first iron-removed slurry; during the operation of the first vertical reactor, clean the second vertical reactor through a manhole to remove deposited iron slag;

[0083] S2-4, repeat S2-2 to S2-3;

[0084] During the first iron removal process, the temperature T1 in the vertical reactor in operation was controlled to be 185°C, the pressure to be 1.60 MPa, and the residence time to be 0.55 h, so that the iron removal efficiency was 18.2 kg·m -3 ·h -1 ; The target time is 50d; the volume of the vertical reactor is 1m 3 ; The iron content of the iron-containing zinc sulfate solution is 25g / L; The iron content of the liquid phase of the slurry after the first iron removal is 15g / L; During this period, 18.2kg of hematite slag (containing 55% Fe) was produced; The input rate of the iron-containing zinc sulfate solution is 1.82m 3 / h;

[0085] S3, the first iron-removed slurry is heated to 1.82 m 3 / h into a horizontal reactor, and steam and oxygen are input into the horizontal reactor to perform a second iron removal treatment in the horizontal reactor to obtain a second iron-removed slurry;

[0086] During the second iron removal treatment, the temperature T2 in the horizontal reactor was controlled to be 170°C, the pressure was 1.60 MPa, and the residence time was 2.2 h, so that the iron removal efficiency was 6.05 kg·m -3 ·h -1 ; The volume of the horizontal reactor is 4m 3 During this period, 96.8 kg of hematite slag (containing 55% iron) was produced;

[0087] S4. The second deironing slurry is input into a flash tank, and after cooling and reducing the pressure, it is input into a solid-liquid separation mechanism for solid-liquid separation to obtain hematite slag and deironing liquid (containing 1.7 g / L iron).

[0088] The results show that the cleaning cycle of the vertical reactor is 50 days; after the horizontal reactor has been running continuously for 175 days, there is no obvious scaling in the reactor. Example 5

[0089] The method for removing iron from hematite in the iron-containing zinc sulfate solution of this embodiment comprises the following steps:

[0090] S1. Provide the iron removal device described in Example 2;

[0091] S2,

[0092] S2-1, inputting the iron-containing zinc sulfate solution into a vertical reactor (referred to as a "first vertical reactor"), and inputting steam and oxygen into the vertical reactor to perform a first iron removal treatment in the vertical reactor to obtain a first iron-removed slurry;

[0093] S2-2, after the first vertical reactor has been running for a target time, stop inputting the iron-containing zinc sulfate solution into the first vertical reactor, input the iron-containing zinc sulfate solution into another vertical reactor (referred to as the "second vertical reactor"), and input steam and oxygen into the second vertical reactor to perform a first iron removal treatment in the second vertical reactor to obtain a first iron-removed slurry; during the operation of the second vertical reactor, clean the first vertical reactor through a manhole to remove deposited iron slag;

[0094] S2-3, after the second vertical reactor has been running for a target time, stop inputting the iron-containing zinc sulfate solution into the second vertical reactor, input the iron-containing zinc sulfate solution into the first vertical reactor, and input steam and oxygen into the first vertical reactor to perform a first iron removal treatment in the first vertical reactor to obtain a first iron-removed slurry; during the operation of the first vertical reactor, clean the second vertical reactor through a manhole to remove deposited iron slag;

[0095] S2-4, repeat S2-2 to S2-3;

[0096] During the first iron removal process, the temperature T1 in the vertical reactor in operation was controlled to be 185°C, the pressure to be 1.60 MPa, and the residence time to be 0.5 h, so that the iron removal efficiency was 16.0 kg·m -3 ·h -1 ; The target time is 60d; the volume of the vertical reactor is 1m 3 ; The iron content in the iron-containing zinc sulfate solution is 21g / L; The iron content in the liquid phase of the slurry after the first iron removal is 13g / L; During this period, 14.55kg of hematite slag (containing 55% Fe) was produced; The input rate of the iron-containing zinc sulfate solution is 2m 3 / h;

[0097] S3, the first iron removal slurry at 2m 3 / h into a horizontal reactor, and steam and oxygen are input into the horizontal reactor to perform a second iron removal treatment in the horizontal reactor to obtain a second iron-removed slurry;

[0098] During the second iron removal treatment, the temperature T2 in the horizontal reactor was controlled to be 165°C, the pressure was 1.60 MPa, and the residence time was 2 h, so that the iron removal efficiency was 5.6 kg·m -3 ·h -1 ; The volume of the horizontal reactor is 4m 3 During this period, 80.72 kg of hematite slag (containing 55.5% iron) was produced;

[0099] S4. The second deironing slurry is input into a flash tank, and after cooling and reducing the pressure, it is input into a solid-liquid separation mechanism for solid-liquid separation to obtain hematite slag and deironing liquid (containing 1.8 g / L iron).

[0100] The results show that the cleaning cycle of the vertical reactor is 60 days; after the horizontal reactor has been running continuously for 200 days, there is no obvious scaling in the reactor.

[0101] Comparative Example 1

[0102] Example 5 was repeated, except that during the first iron removal treatment, the temperature T1 in the vertical reactor in operation was controlled to be 180°C, the pressure was 1.60 MPa, and the residence time was 0.5 h, so that the iron removal efficiency was 15.5 kg·m -3 ·h -1 .

[0103] The results show that the cleaning cycle of the vertical reactor is 65 days; after the horizontal reactor has been running continuously for 160 days, iron slag scaling occurs in the reactor. Example 6

[0104] Example 5 was repeated, except that during the first iron removal treatment, the temperature T1 in the vertical reactor in operation was controlled to be 198°C, the pressure was 1.60 MPa, and the residence time was 0.5 h, so that the iron removal efficiency was 24 kg·m -3 ·h -1 .

[0105] The results show that the cleaning cycle of the vertical reactor is 30 days; after the horizontal reactor has been running continuously for 200 days, there is no obvious scaling in the reactor.

[0106] Comparative Example 2

[0107] Example 5 was repeated, except that during the first iron removal treatment, the temperature T1 in the vertical reactor in operation was controlled to be 205°C, the pressure was 1.90 MPa, and the residence time was 0.5 h, so that the iron removal efficiency was 24.5 kg·m -3 ·h -1 .

[0108] The results show that the cleaning cycle of the vertical reactor is 20 days; after the horizontal reactor has been running continuously for 200 days, there is no obvious scaling in the reactor. At this time, the cleaning cycle of the vertical reactor is too short, which may increase the cleaning workload.

[0109] Comparative Example 3

[0110] Example 5 was repeated, except that during the first iron removal treatment, the input rate of the iron-containing zinc sulfate solution was 2.86 m 3 / h, the residence time is 0.35h; during the second iron removal treatment, the residence time is 1.40h.

[0111] The results show that the iron content in the liquid phase of the first iron removal slurry is 15.4g / L, and the second iron removal liquid contains 8.68g / L. At this time, the iron content of the liquid after iron removal is high, which affects the subsequent processes.

[0112] The contents explained in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the present invention, and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

Claims

1. A method for removing iron from hematite using an iron sulfate solution, characterized in that: The steps include: S1. Provide an iron removal device; wherein the iron removal device comprises N vertical reactors and 1 horizontal reactor, and the discharge ports of the N vertical reactors are connected to the feed port of the horizontal reactor; N is an integer ≥ 2; S2, S2-1, inputting the iron-containing sulfate solution into M vertical reactors, and inputting steam and oxygen into the M vertical reactors to perform a first iron removal treatment in the M vertical reactors to obtain a first iron-removed slurry; S2-2, after the M vertical reactors have been running for a target time, stop inputting the iron-containing sulfate solution into the M vertical reactors, input the iron-containing sulfate solution into H vertical reactors among the other vertical reactors, and input steam and oxygen into the H vertical reactors to perform a first iron removal treatment in the H vertical reactors to obtain a first iron-removed slurry; during the operation of the H vertical reactors, clean the M vertical reactors; S2-3, after the H vertical reactors have been running for a target time, stop inputting the iron-containing sulfate solution into the H vertical reactors, input the iron-containing sulfate solution into M vertical reactors among the other vertical reactors, and input steam and oxygen into the M vertical reactors to perform a first iron removal treatment in the M vertical reactors to obtain a first iron-removed slurry; during the operation of the M vertical reactors, clean the H vertical reactors; S2-4, repeat S2-2 to S2-3; wherein, during the first iron removal treatment, the temperature T1 in the vertical reactor in operation is controlled to be 185-199°C, the pressure is 1.6-1.9 MPa, and the residence time is 0.4-0.9 h, so that the iron removal efficiency is 16-24 kg·m -3 ·h -1 ; M is an integer ≥1 and <N; H is an integer ≥1 and ≤(NM); S3, inputting the first iron-removed slurry into a horizontal reactor, and inputting steam and oxygen into the horizontal reactor to perform a second iron-removal treatment in the horizontal reactor to obtain a second iron-removal slurry; wherein, during the second iron-removal treatment, the temperature T2 in the horizontal reactor is controlled to be 165-180°C, the pressure is 1.6-1.9MPa, and the residence time is 1.8-3.5h, so that the iron removal efficiency is 5-7kg·m -3 ·h -1 ;T1>T2.

2. The hematite iron removal method according to claim 1, characterized in that: The iron removal device also includes a flash tank and a solid-liquid separation mechanism, and the horizontal reactor, the flash tank and the solid-liquid separation mechanism are connected in sequence; after S3, the second iron-removed slurry is input into the flash tank, and after cooling and reducing the pressure, it is input into the solid-liquid separation mechanism for solid-liquid separation to obtain hematite slag and iron-removed liquid.

3. The iron removal method according to claim 2, characterized in that: The solid-liquid separation mechanism comprises a thickener; preferably, the vertical reactor has a manhole.

4. The method for removing iron from hematite according to claim 1, wherein: N is 2-4.

5. The method for removing iron from hematite according to claim 1, wherein: The volume of the horizontal reactor is greater than the total volume of the vertical reactors in operation in S2. Preferably, the volume of the horizontal reactor is 2-6 times, more preferably 3-5 times, the total volume of the vertical reactors in operation in S2.

6. The method for removing iron from hematite according to claim 1, wherein: The target time is 20-80 days, preferably 30-60 days.

7. The method for removing iron from hematite according to claim 1, characterized in that: The iron content in the iron-containing sulfate solution is ≥20 g / L, preferably 21-40 g / L; the iron content in the liquid phase of the slurry after the first iron removal is <20 g / L, preferably 13-19 g / L.

8. The method for removing iron from hematite according to claim 1, characterized in that: The difference between T1 and T2 is 5-25°C, preferably 10-20°C.

9. The method for removing iron from hematite according to any one of claims 1 to 8, characterized in that: During the first iron removal treatment, the temperature T1 in the vertical reactor in operation is controlled to be 188-196°C, the pressure is 1.7-1.9 MPa, and the residence time is 0.5-0.8 h, so that the iron removal efficiency is 16.2-23.8 kg·m -3 ·h -1 .

10. The method for removing iron from hematite according to any one of claims 1 to 8, characterized in that: During the second iron removal treatment, the temperature T2 in the horizontal reactor is controlled to be 168-176°C, the pressure is 1.7-1.9 MPa, and the residence time is 2-3.3 h, so that the iron removal efficiency is 5.2-6.8 kg·m -3 ·h -1 .

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