A method for metallurgical iron removal using a Venturi reactor

Abstract

The present invention provides a method for metallurgical iron removal using a Venturi reactor, which belongs to the field of hydrometallurgical technology. The method for metallurgical iron removal using a Venturi reactor provided by the present invention can improve Fe 2+ Fe 3+ The speed of conversion, as well as the energy required for the formation and growth of goethite nuclei, enhance the washing effect of non-ferrous ions in goethite slag. Therefore, the method provided by the present invention is not only conducive to improving the purity of goethite, but also can reduce the loss of rare earth due to inclusion. No new impurities are introduced in the goethite method iron removal process adopted by the present invention, which reduces the difficulty and cost of subsequent impurity removal and improves the comprehensive recovery efficiency. At the same time, the goethite method proposed by the present invention requires a simple reaction device and mild reaction conditions, which is easy to realize industrial application.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to a method for metallurgical iron removal using a Venturi reactor. Background Art

[0002] Common iron removal methods used in hydrometallurgy include neutralization and hydrolysis, jarosite, goethite, and hematite. In the current rare earth metallurgy field, the efficient separation of rare earth elements from iron in rare earth feed solutions is a pressing challenge facing industrial production and a current research hotspot.

[0003] The common industrial method for separating rare earths from iron is neutralization hydrolysis (magnesium oxide is commonly used as a precipitant in sulfuric acid systems, and ammonium bicarbonate is commonly used as a precipitant in hydrochloric acid systems) to remove iron impurities from rare earth solutions. Common iron removal methods used in wet smelting include the jarosite method, the goethite method, and the hematite method. The jarosite method removes trivalent iron ions in the sulfuric acid system in the form of MeFe3(SO4)2(OH)6, where Me represents a monovalent ion, such as K + 、Na + NH 4+ The goethite method removes ferric iron from the reaction solution in the form of FeOOH, while the hematite method removes ferric iron from the reaction solution in the form of Fe2O3. As can be seen from the chemical formula, the jarosite method is applicable to sulfate systems, while the goethite and hematite methods are not limited to solution systems. However, the hematite method requires a high temperature and high pressure environment to dehydrate the Fe(OH)3 generated in the reaction system to produce Fe2O3. Therefore, the hematite method not only has strict requirements on the reaction equipment, but also requires high temperature and high pressure, making it a high-safety and high-cost iron removal method. Summary of the Invention

[0004] The object of the present invention is to provide a method for metallurgical iron removal using a Venturi reactor, which is not only beneficial to improving the purity of goethite, but also can reduce the loss of rare earth caused by inclusions.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for metallurgical iron removal using a Venturi reactor, comprising the following steps:

[0007] The metal chloride liquid to be treated is mixed with an oxidant and passed through a Venturi reactor to undergo an oxidation reaction to obtain an oxidized liquid;

[0008] The oxidized liquid is mixed with a precipitant, passed through a Venturi reactor for precipitation reaction, and filtered after the reaction to obtain goethite slag 1 and a deironed liquid;

[0009] The goethite slag 1 is mixed with a hydrochloric acid solution and washed to obtain goethite slag 2 and a filtrate.

[0010] Preferably, the oxidation reaction completely oxidizes the divalent iron ions in the metal chloride liquid to be treated into trivalent iron ions.

[0011] Preferably, the oxidant is selected from one or more of oxygen, ozone or hydrogen peroxide.

[0012] Preferably, the precipitant is selected from one or more of hydroxide precipitants, sulfide precipitants, iron alum double salt precipitants, ammonia water, urea, ammonium bicarbonate or activated magnesium oxide.

[0013] Preferably, the hydroxide precipitant includes a buffered hydroxide and a rare earth hydroxide, wherein the buffered hydroxide includes aluminum hydroxide, magnesium hydroxide, zinc hydroxide or calcium hydroxide; the rare earth hydroxide includes cerium hydroxide, lanthanum hydroxide, praseodymium hydroxide, neodymium hydroxide, samarium hydroxide, lanthanum-cerium hydroxide, cerium-praseodymium hydroxide or cerium-neodymium hydroxide;

[0014] The sulfide precipitant includes sodium sulfide, hydrogen sulfide or sodium hydrosulfide;

[0015] The ferrosite double salt precipitant includes yellow jarosite, yellow sodium jarosite or yellow ammonium jarosite.

[0016] Preferably, the molar ratio of the oxidant to the divalent iron ions in the metal chloride liquid to be treated is 2.5-4:1.

[0017] Preferably, the molar ratio of the precipitant to the trivalent iron ions in the oxidized feed solution is 3 to 3.6:1.

[0018] Preferably, the precipitation reaction temperature is 70-90° C., and the time is 0.5-1.5 h.

[0019] Preferably, the pH of the hydrochloric acid solution is 3.5-4.5;

[0020] And / or, the liquid-to-solid ratio of the goethite slag 1 mixed with the hydrochloric acid solution is 1-3:1;

[0021] And / or, the washing temperature is 40-80°C;

[0022] And / or, the washing time is 0.5~2h.

[0023] Preferably, the metal chloride liquid to be treated is a rare earth chloride liquid to be de-ironized.

[0024] Beneficial effects of the present invention:

[0025] The method for metallurgical iron removal using a Venturi reactor provided by the present invention can utilize the changes in fluid velocity and pressure as well as the turbulent kinetic energy and cavitation generated during the oxidation, precipitation and washing processes to improve Fe 2+ Fe 3+ The speed of conversion, as well as the energy required for the formation and growth of goethite nuclei, enhance the washing effect of non-ferrous ions in goethite slag. Therefore, the method provided by the present invention is not only conducive to improving the purity of goethite, but also can reduce the loss of rare earth due to inclusion. No new impurities are introduced in the goethite method iron removal process adopted by the present invention, which reduces the difficulty and cost of subsequent impurity removal and improves the comprehensive recovery efficiency. At the same time, the goethite method proposed by the present invention requires a simple reaction device and mild reaction conditions, which is easy to realize industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a process flow chart;

[0027] Figure 2 Schematic diagram of the reaction device;

[0028] Figure 3 This is a scanning electron microscope image of goethite;

[0029] Figure 4 This is the XRD (X-ray diffraction) pattern of goethite. DETAILED DESCRIPTION

[0030] The present invention provides a method for metallurgical iron removal using a Venturi reactor, comprising the following steps:

[0031] The metal chloride liquid to be treated is mixed with an oxidant and passed through a Venturi reactor to undergo an oxidation reaction to obtain an oxidized liquid;

[0032] The oxidized liquid is mixed with a precipitant, passed through a Venturi reactor for precipitation reaction, and filtered after the reaction to obtain goethite slag 1 and a deironed liquid;

[0033] The goethite slag 1 is mixed with a hydrochloric acid solution and washed to obtain goethite slag 2 and a filtrate.

[0034] In the present invention, preferably, the oxidation reaction completely oxidizes the divalent iron ions in the metal chloride liquid to be treated to ferric iron ions. Preferably, the oxidant is selected from one or more of oxygen, ozone, or hydrogen peroxide. Preferably, the molar ratio of the oxidant to the divalent iron ions in the metal chloride liquid to be treated is 2.5 to 4:4.

[0035] In the present invention, the ferrous ion oxidation reaction equation is as follows:

[0036] (1)

[0037] (2)

[0038] (3)

[0039] The amount of the oxidant used is 2.5 to 4 times the theoretical equivalent of the reaction equation. For example, as shown in reaction equation (1), taking the oxidant oxygen as an example, 4 mol of divalent iron ions requires a theoretical equivalent of 1 mol of oxygen, which requires 2.5 to 4 times the theoretical equivalent, that is, 2.5 mol to 4 mol of oxygen.

[0040] In the present invention, preferably, the precipitant is selected from one or more of a hydroxide precipitant, a sulfide precipitant, a ferrosite complex salt precipitant, ammonia, urea, ammonium bicarbonate, or activated magnesium oxide. Preferably, the hydroxide precipitant includes a buffered hydroxide and a rare earth hydroxide, wherein the buffered hydroxide includes aluminum hydroxide, magnesium hydroxide, zinc hydroxide, or calcium hydroxide; the rare earth hydroxide includes cerium hydroxide, lanthanum hydroxide, praseodymium hydroxide, neodymium hydroxide, samarium hydroxide, lanthanum-cerium hydroxide, cerium-praseodymium hydroxide, or cerium-neodymium hydroxide; the sulfide precipitant includes sodium sulfide, hydrogen sulfide, or sodium hydrosulfide; and the ferrosite complex salt precipitant includes jarosite, sodium ferrosite, or ammonium ferrosite. Preferably, the molar ratio of the precipitant to the trivalent iron ion in the oxidized feed solution is 3 to 3.6:1. Preferably, the precipitation reaction temperature is 70 to 90°C, and the reaction time is 0.5 to 1.5 hours.

[0041] The reaction chemical formula of the precipitant and the trivalent iron ions in the rare earth chloride solution is as follows:

[0042] (4)

[0043] (5)

[0044] (6)

[0045] The amount of precipitant used is 1.0 to 1.2 times the theoretical equivalent of the chemical reaction formula. As shown in chemical reaction equations (4) to (6), taking the precipitant ammonia water as an example, 1 mol of ammonium bicarbonate decomposes into 1 mol of ammonia water, and 1 mol of trivalent iron ions requires 3 mol of ammonia water. Therefore, the amount of ammonia water required for 1 mol of trivalent iron ions is 1.0 to 1.2 times the theoretical equivalent, that is, 3 mol to 3.6 mol of ammonia water.

[0046] In the present invention, preferably, the pH of the hydrochloric acid solution is 3.5-4.5; and / or the liquid-to-solid ratio of the goethite slag 1 to the hydrochloric acid solution is 1-3:1; and / or the washing temperature is 40-80°C; and / or the washing time is 0.5-2 hours. Preferably, the metal chloride liquid to be treated is a rare earth chloride liquid to be de-ironized.

[0047] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0048] Example 1

[0049] The raw materials used in this example contain 40 g / L TFe (Fe 2+ 28 g / L), REO 300 g / L, and oxygen as the oxidant at 2.5-4.0 times the theoretical amount (0.15 mol). Ammonia water was used as the precipitant at 1.0-1.2 times the theoretical amount (0.64 mol NH₄OH). First, the oxidized rare earth chloride solution and oxygen were passed through a Venturi reactor in parallel. The reaction conditions were 40°C for 2 hours, and the acidity of the oxidized rare earth chloride solution was pH 2. After the oxidation reaction, the oxidized rare earth chloride solution and ammonia water were passed through a Venturi reactor in parallel. The precipitation reaction conditions were 85°C for 1 hour. After the precipitation reaction, solid-liquid separation was performed. The filter residue obtained from the solid-liquid separation was mixed with hydrochloric acid solution at pH 4 and passed through a Venturi reactor. The washing conditions were 60°C for 1 hour, and a liquid-to-solid ratio of 1:1. After washing, solid-liquid separation was performed to obtain goethite slag and washing liquid, which was then concentrated and returned to the rare earth chloride feed solution to be deironed. The deironing results are shown in Table 1.

[0050] Example 2

[0051] The raw materials used in this example contain 50 g / L TFe (Fe 2+ 28 g / L), REO was 200 g / L, ozone was used as the oxidant at 2.5-4.0 times the theoretical amount (0.1 mol of ozone), and the washing solution was a hydrochloric acid solution with a pH of 4.5. The precipitant was ammonium bicarbonate at 1.0-1.2 times the theoretical amount (0.96 mol of NH₄HCO₃). The oxidation reaction temperature was 50°C, the oxidation time was 3.5 hours, the acidity of the oxidized rare earth chloride solution was pH 1.5, the precipitation reaction temperature was 90°C, the reaction time was 0.5 hours, the washing temperature was 70°C, the washing time was 1 hour, and the liquid-to-solid ratio was 1:1. The entire oxidation, precipitation, and washing process was identical to that of Example 1. After washing, solid-liquid separation was performed to obtain goethite slag and washing solution. The washing solution was concentrated and returned to the rare earth chloride solution to be de-ironified. The de-ironification results are shown in Table 1.

[0052] Example 3

[0053] The raw materials used in this example contain 70 g / L TFe (Fe 2+ 28 g / L), REO 250 g / L, hydrogen peroxide oxidant at 2.5–4.0 times the theoretical amount (0.3 mol H₂O₂), and a hydrochloric acid solution with a pH of 3.5 as the washing solution. Ammonia water precipitant at 1.0–1.2 times the theoretical amount (1.35 mol NH₄OH) was used as the precipitant. The oxidation reaction temperature was 35°C, the oxidation time was 5 hours, the acidity of the oxidized rare earth chloride solution was pH 2.0, the precipitation reaction temperature was 80°C, the reaction time was 1.5 hours, the washing temperature was 55°C, the washing time was 1.5 hours, and the liquid-to-solid ratio was 2:1. After washing, solid-liquid separation was performed to obtain goethite slag and washing solution, which was then concentrated and returned to the rare earth chloride solution to be de-ironed. The de-ironing results are shown in Table 1.

[0054] Table 1 Example parameter settings and results

[0055]

[0056] As can be seen from Table 1, the iron removal method of the present invention can achieve an iron removal rate of more than 97%, while the rare earth loss rate is less than 1.6%. Therefore, the present invention has the characteristics of high iron removal rate and low rare earth loss rate.

[0057] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for metallurgical iron removal using a Venturi reactor, characterized in that: The following steps are involved: The metal chloride liquid to be treated is mixed with an oxidant and passed through a Venturi reactor to undergo an oxidation reaction to obtain an oxidized liquid; The oxidized liquid is mixed with a precipitant, passed through a Venturi reactor for precipitation reaction, and filtered after the reaction to obtain goethite slag 1 and a deironed liquid; washing the mixed flow of goethite slag 1 and hydrochloric acid solution through a venturi reactor to obtain goethite slag 2 and a filtrate; The precipitation reaction temperature is 70-90° C., and the time is 0.5-1.5 h.

2. The method for metallurgical iron removal using a Venturi reactor according to claim 1, wherein: The oxidation reaction completely oxidizes the divalent iron ions in the metal chloride liquid to be treated into trivalent iron ions.

3. The method for metallurgical iron removal using a Venturi reactor according to claim 2, wherein: The oxidant is selected from one or more of oxygen, ozone or hydrogen peroxide.

4. The method for metallurgical iron removal using a Venturi reactor according to claim 1, wherein: The precipitant is selected from one or more of hydroxide precipitants, iron alum double salt precipitants, ammonia water, urea, ammonium bicarbonate or active magnesium oxide.

5. The method for metallurgical iron removal using a Venturi reactor according to claim 4, wherein: The hydroxide precipitant includes a buffered hydroxide and a rare earth hydroxide, wherein the buffered hydroxide includes aluminum hydroxide, magnesium hydroxide, zinc hydroxide or calcium hydroxide; the rare earth hydroxide includes cerium hydroxide, lanthanum hydroxide, praseodymium hydroxide, neodymium hydroxide, samarium hydroxide, lanthanum cerium hydroxide, cerium praseodymium hydroxide or cerium neodymium hydroxide; The ferrosite double salt precipitant includes yellow jarosite, yellow sodium jarosite or yellow ammonium jarosite.

6. The method for metallurgical iron removal using a Venturi reactor according to claim 3, wherein: The molar ratio of the oxidant to the divalent iron ions in the metal chloride liquid to be treated is 2.5-4:

1.

7. The method for metallurgical iron removal using a Venturi reactor according to claim 4, wherein: The molar ratio of the precipitant to the trivalent iron ions in the oxidized feed solution is 3 to 3.6:

1.

8. The method for metallurgical iron removal using a Venturi reactor according to claim 1, wherein: The pH of the hydrochloric acid solution is 3.5-4.5; The liquid-to-solid ratio of the goethite slag 1 mixed with the hydrochloric acid solution is 1-3:1; The washing temperature is 40-80°C; The washing time is 0.5 to 2 hours.

9. The method for metallurgical iron removal using a Venturi reactor according to any one of claims 1 to 8, wherein: The metal chloride material liquid to be treated is a rare earth chloride material liquid to be de-ironized.

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