Method for removing nickel from hydrochloric acid leaching solution containing magnesium minerals under high magnesium concentration
By adding neutralizing agents and iron inducing agents to the hydrochloric acid leaching liquid with magnesium-containing minerals under high magnesium concentration conditions, the co-precipitation removal of nickel impurities is achieved, and the problems of low nickel slag grade and high magnesium loss are solved, and the economic value of nickel slag is improved.
Patent Information
- Application Number
- CN202411580549.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-07
- Publication Date
- 2025-03-18
AI Technical Summary
Under high magnesium concentration conditions, it is difficult to effectively remove nickel impurities from the hydrochloric acid leaching solution of magnesium-containing minerals, resulting in low grade of nickel slag, high magnesium loss, and high nickel impurities in magnesium chloride salt solution.
By using the co-precipitation method, the iron ions and nickel ions are added to the leachate solution to co-precipitation reaction, thereby removing nickel impurities.
It effectively reduces the Ni ion concentration in the magnesium chloride salt solution, improves the grade and economic value of nickel slag, and reduces the loss of magnesium.
Smart Images
Figure CN119640052A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for removing impurities from a hydrochloric acid leaching solution containing a magnesium mineral, and in particular to a method for removing nickel from a hydrochloric acid leaching solution containing a magnesium mineral at a high magnesium concentration. Background Art
[0002] China is a country with abundant magnesium resources. It is one of the countries with large reserves of major magnesium-containing minerals such as magnesite, dolomite, serpentine, and talc. Magnesium-containing minerals are mainly divided into two categories: solid minerals and liquid minerals. Common solid minerals include magnesite, dolomite, serpentine, etc. Liquid minerals exist in seawater, underground brine, and salt lake brine. The main component of brine is MgC12, and hydrochlorobenzene is a crystalline mineral of brine. These minerals can be used to process various magnesium products, including magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium chloride, magnesium sulfate, metallic magnesium, etc. They are widely used in metallurgy, building materials, chemicals, automobiles, electronics, aerospace and other fields.
[0003] In recent years, with the development of magnesium products, its demand has grown rapidly. The common method for the resource utilization of magnesium ore is to add organic acid or inorganic acid to the raw material for direct acid leaching to prepare magnesium-containing compound products. The magnesium salt solution of magnesium-containing minerals such as magnesia, pyroxene, amphibole, serpentine, etc. after leaching in the acid system usually contains impurities such as nickel. The magnesium sulfate solution obtained by the sulfuric acid leaching process has a relatively mature technology for removing impurities such as nickel. If it is a hydrochloric acid leaching system, this part of nickel is generally removed by adjusting the pH value during precipitation, but there will be a different phenomenon from the removal of nickel impurities with conventional magnesium sulfate solution.
[0004] In the chloride system, there is a clear correspondence between the magnesium ion concentration and the final pH threshold. When the magnesium ion concentration is at a certain level, there will be an adjustment limit pH threshold, that is, even if a neutralizer is added, the pH value is difficult to effectively increase. At the same time, Mg will precipitate into the slag in the form of basic magnesium chloride, Mg(OH)2·MgCl2, Mg(OH)Cl magnesium hydroxide, etc., affecting the grade and value of nickel slag. The degree of nickel precipitation is related to the pH value. This means that if the magnesium ion concentration in the magnesium chloride salt solution is high, when it is adjusted to the corresponding pH threshold range, the Ni removal degree will not meet the requirements of the magnesium chloride salt solution.
[0005] The present invention has verified the above theory through a series of experiments. Taking the solution after hydrochloric acid leaching of a certain ore as an example, the pH value is 1, and the solution composition is shown in Table 1.
[0006] Table 1 Metal components in hydrochloric acid leaching solution of a certain ore
[0007] Metal Type Ni Co Mg Ion concentration (mg / L) 300 35 60，000
[0008] The solution was concentrated or diluted with water to obtain solutions with different Mg ion concentrations, and the theoretical compositions are shown in Table 2.
[0009] Table 2 Solution composition with different Mg ion concentrations
[0010] Mg(g / L) Ni(mg / L) Co(mg / L) Mg(mg / L) 70 350 40.83 70，000 65 325 37.92 65，000 55 275 32.08 55，000 50 250 29.17 50，000 45 225 26.25 45，000 40 200 23.33 40，000 35 175 20.42 35，000 30 150 17.50 30，000
[0011] MgO dry powder was used for nickel precipitation, and the experimental conditions are shown in Table 3.
[0012] Table 3 Nickel deposition conditions
[0013] project Numeric unit temperature 60 ℃ Air flow 1 L / min time 5 h
[0014] The ion concentrations after precipitation are shown in Table 4.
[0015] Table 4 Ion concentration after precipitation at different Mg ion concentrations
[0016]
[0017]
[0018] As can be seen from Table 4, the higher the initial Mg ion concentration, the higher the Ni ion concentration in the magnesium chloride salt solution after impurity removal, and even if magnesium oxide powder is added at this time, the pH is difficult to increase significantly, and the pH value that reduces the Ni ion concentration to below 2 mg / L cannot be reached. On the contrary, after continuing to add magnesium oxide, a large amount of magnesium will enter the slag, and Mg will precipitate into the slag in the form of basic magnesium chloride, Mg(OH)2·MgCl2, Mg(OH)Cl, magnesium hydroxide, magnesium oxide, etc., which wastes magnesium on the one hand and leads to a lower nickel grade in the nickel slag on the other hand, as shown in Table 5. When the initial Mg ion concentration is above 50 g / L, if the traditional method is used to remove it, the Ni grade in the nickel slag is below 1%, and the magnesium content is high, and the economic value is low.
[0019] Table 5 Nickel grade in nickel slag
[0020]
[0021] Under the same conditions, the relationship between nickel ion concentration and pH value in the leaching solution is as follows: Figure 1 As shown in the figure, to reduce the Ni ion concentration to below 5 mg / L, 2 mg / L, and 1 mg / L, the corresponding pH values are 7.0, 7.3, and 7.5. When the magnesium ion concentration in the initial solution is high, the pH value threshold (approximate value) of the final slurry after precipitation usually does not reach the pH value that allows the nickel ions in the liquid to be precipitated and removed to the expected value.
[0022] At present, there is no effective method for removing nickel from magnesium chloride salt solution when the magnesium content is high after magnesium-containing minerals are leached in the hydrochloric acid system. If the magnesium chloride salt solution higher than 50% is diluted to a relatively dilute concentration, it is necessary to replenish water. The higher the initial magnesium chloride concentration, the more water replenishment, and the larger the volume of subsequent impurity removal equipment, which will increase equipment investment. At the same time, if the magnesium chloride after impurity removal needs to be evaporated and crystallized to obtain magnesium chloride hexahydrate, and finally dehydrated and electrolyzed to produce metallic magnesium, the larger the amount of water, the higher the energy consumption required for evaporation. Therefore, the present invention provides a method for removing nickel impurities by coprecipitation when the magnesium concentration is high (greater than 50g / L), which has good nickel removal effect, high nickel slag grade, less magnesium loss, and low nickel impurities in magnesium chloride salt solution. Summary of the invention
[0023] The technical problem to be solved by the present invention is to provide a method for removing nickel from a hydrochloric acid leaching solution containing magnesium minerals at a high magnesium concentration.
[0024] The present invention is achieved in that:
[0025] A method for removing nickel from a hydrochloric acid leachate containing magnesium minerals at a high magnesium concentration, wherein the high magnesium concentration is a magnesium concentration greater than 50 g / L. The method is a coprecipitation method, wherein a neutralizer and an iron inducer are respectively added to the leachate to cause a coprecipitation reaction between iron ions and nickel ions.
[0026] Furthermore, the neutralizing agent is an oxide or hydroxide of sodium, magnesium or calcium.
[0027] Preferably, the neutralizing agent is magnesium oxide or hydroxide.
[0028] Furthermore, the iron inducer includes one or more of ferric chloride and ferric hydroxide.
[0029] Furthermore, the iron inducer is added at a certain pH value, and the pH value is controlled to be above 3.8.
[0030] Furthermore, the molar concentration of iron in the iron inducer is 1-10 times that of nickel ions.
[0031] Preferably, the molar concentration of iron in the iron inducer is 3-5 times that of nickel ions.
[0032] Further, the magnesium-containing mineral includes magnesite, pyroxene, amphibole or serpentine.
[0033] The present invention has the following advantages:
[0034] (1) Adding iron inducer can effectively remove impurities such as nickel when the magnesium ion concentration is high. No additional water dilution is required, and the current production scale is not affected.
[0035] (2) The nickel slag obtained after impurity removal has high nickel content and high economic value.
[0036] (3) Iron inducers are cheap. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.
[0038] Figure 1 is the relationship between nickel ion concentration and pH value in hydrochloric acid leaching solution.
[0039] Figure 2 It is a process flow chart of the present invention.
[0040] Figure 3 This is the relationship between the nickel ion concentration and pH value in the solution when the molar concentration of iron is 1, 3, 5, and 10 times that of nickel ions, respectively.
[0041] Figure 4 The nickel ion concentration corresponding to different pH values in the solution after adding inducer at different pH values. DETAILED DESCRIPTION
[0042] The technical scheme of the present invention will be described clearly and completely below in conjunction with the accompanying drawings and specific embodiments. If specific conditions are not specified in the examples, they are carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.
[0043] In order to effectively reduce the Ni ion concentration in the magnesium chloride salt solution, the present invention provides a method for removing nickel from a hydrochloric acid leachate containing magnesium minerals at a high magnesium concentration. When the magnesium concentration is high (greater than 50 g / L), an inducer is added to remove nickel impurities by coprecipitation. The process flow is as follows: Figure 2 shown.
[0044] Take the hydrochloric acid leaching solution of a certain ore as an example, the pH value is 1, the Mg ion concentration of the solution is 60g / L, and the Ni ion concentration is 300mg / L. When an iron inducer is added to the solution, and the molar concentration of iron in the inducer is 1, 3, 5, and 10 times that of nickel ions, the corresponding relationship between the nickel ion concentration and the pH value in the solution is as follows: Figure 3 shown.
[0045] The iron inducer includes one or more of iron-containing materials such as ferric chloride and ferric hydroxide.
[0046] After adding the inducer, at the same pH value, the Ni precipitation effect is significantly better than that without adding the inducer, and the nickel ion concentration in the liquid is significantly lower.
[0047] When the molar concentration of iron in the inducer is 1, 3, 5, and 10 times that of nickel ions, the contents of iron, magnesium, and nickel in the nickel-iron slag obtained when the nickel ion concentration is reduced to 5 mg / L, 2 mg / L, and 1 mg / L, respectively, are shown in Table 6.
[0048] Table 6 Iron, magnesium and nickel contents in nickel-iron slag at different multiples of iron molar concentration
[0049]
[0050] It can be seen that the addition of appropriate iron inducer can precipitate nickel at a relatively low pH value, so the nickel grade in the slag is higher, the magnesium grade is lower, and the economic value is higher. Generally speaking, adding 3 to 5 times of iron inducer is the best.
[0051] The mechanism of removing nickel ions by adding iron inducer is mainly that in the chloride system, iron ions and nickel ions will undergo coprecipitation reaction to produce Fe(OH)3, Ni(OH)2, FeOCl, Fe(OH)Cl, iron-nickel oxide coprecipitation, etc. In addition, because the iron precipitate has a certain adsorption capacity, it will also adsorb nickel ions in the solution.
[0052] When the molar amount of iron in the iron inducer is three times the molar amount of nickel in the solution, after adding the inducer at different pH values of 3.8, 4.5, 5.3, 5.6 and 6, the nickel ion concentrations corresponding to different pH values in the solution are as follows: Figure 4 shown.
[0053] It can be seen that due to the co-precipitation of iron ions and nickel ions and the adsorption characteristics of iron ions, the effects of adding inducers at different pH values are different. Usually, the end point pH value should be between 6.8 and 7, and the nickel ion concentration should be controlled below 2 mg / L. In order to achieve a good nickel precipitation effect, the pH value of adding iron inducers should be controlled above 3.8. The main mechanism is that iron ions need to co-precipitate with nickel ions. If iron ions are added at a lower pH value, the iron ions will precipitate faster and be converted into iron slag, and the co-precipitation reaction effect with nickel ions will be weakened.
[0054] Example 1 Nickel removal from hydrochloric acid leaching solution of a certain magnesite
[0055] The Mg ion concentration of the hydrochloric acid leachate of a certain magnesite is 60g / L, the impurity nickel ion concentration is 692mg / L, the iron ion concentration is 510mg / L, the solution pH is 2.1, magnesium oxide is used as a neutralizer, the neutralization temperature is 50℃, the iron inducer is ferric hydroxide, the inducer is added at a pH of 3.8, the molar amount of iron added to the iron inducer is 3 times the molar amount of nickel in the solution, the pH after neutralization is 6.7, the neutralization time is 2h, the nickel ion concentration of the magnesium chloride salt solution is reduced to 4.6mg / L, and the nickel grade of the obtained nickel slag is 9.2%.
[0056] Example 2 Nickel Removal from a Serpentine Hydrochloric Acid Leachate
[0057] The Mg ion concentration of a serpentine hydrochloric acid leachate is 69g / L, the impurity nickel ion concentration is 317mg / L, the iron ion concentration is 792mg / L, the solution pH is 1.6, magnesium oxide is used as a neutralizer, the neutralization temperature is 70℃, the iron inducer is ferric hydroxide, the inducer is added at a pH of 5, the molar amount of iron added to the iron inducer is 3 times the molar amount of nickel in the solution, the pH after neutralization is 6.6, the neutralization time is 4h, the nickel ion concentration in the magnesium chloride salt solution is reduced to 4.9mg / L, and the nickel grade of the obtained nickel slag is 10.11%.
[0058] Example 3 Removal of Nickel from a Certain Magnesite Hydrochloric Acid Leachate
[0059] The Mg ion concentration of the hydrochloric acid leachate of a certain magnesite is 52g / L, the impurity nickel ion concentration is 389mg / L, the iron ion concentration is 941mg / L, the solution pH is 2, magnesium oxide is used as a neutralizer, the neutralization temperature is 50℃, the iron inducer is ferric chloride, the inducer is added at a pH of 7, the molar amount of iron added to the iron inducer is 5 times the molar amount of nickel in the solution, the pH after neutralization is 7.1, the neutralization time is 4h, the nickel ion concentration of the magnesium chloride salt solution is reduced to 0.7mg / L, and the nickel grade of the obtained nickel slag is 4.97%.
[0060] Example 4 Nickel Removal from a Serpentine Hydrochloric Acid Leachate
[0061] The Mg ion concentration of a serpentine hydrochloric acid leachate is 59g / L, the impurity nickel ion concentration is 527mg / L, and the iron ion concentration is 2041mg / L. Magnesium oxide is used as a neutralizer, the solution pH is 1, the neutralization temperature is 80℃, and the iron inducer is ferric chloride. The inducer is added at a pH of 5.3, and the molar amount of iron added to the iron inducer is 5 times the molar amount of nickel in the solution. The pH value after neutralization is 7.1, the neutralization time is 4h, and the nickel ion concentration of the magnesium chloride salt solution is reduced to 0.62mg / L, and the nickel grade of the obtained nickel slag is 4.75%.
[0062] Example 5 Nickel removal from hydrochloric acid leaching solution of a certain magnesite
[0063] The Mg ion concentration of the hydrochloric acid leachate of a certain magnesite is 51g / L, the impurity nickel ion concentration is 217mg / L, the solution pH is 0.9, the iron ion concentration is 1741mg / L, magnesium oxide is used as a neutralizer, the neutralization temperature is 60℃, the iron inducer is ferric chloride, the inducer is added at a pH of 4, the molar amount of iron added to the iron inducer is 10 times the molar amount of nickel in the solution, the pH after neutralization is 6.5, the neutralization time is 4h, the nickel ion concentration of the magnesium chloride salt solution is reduced to 0.92mg / L, and the nickel grade of the obtained nickel slag is 3.52%.
[0064] In summary, the technical points of the present invention are as follows:
[0065] (1) When the main component of the initial reaction system is a chloride solution system of magnesium chloride, the impurities are mainly nickel ions. When the magnesium ion concentration is greater than 50g / L and the nickel ion concentration is 10-1000mg / L, it is difficult for conventional precipitation methods to effectively remove nickel ions to 2mg / L and obtain nickel slag with higher economic value. To remove nickel ions from the system, when the iron ion concentration in the system is zero or low, it is necessary to add an iron inducer to precipitate and remove nickel. The temperature range is 40-99°C, the preferred range is 50-80°C, and the reaction time is 30min-10h, preferably 2-5h.
[0066] (2) The molar concentration of iron added by the inducer is 1 to 10 times the amount of nickel ions, preferably 3 to 5 times. The type of inducer is a trivalent iron compound soluble in hydrochloric acid or water, such as ferric hydroxide and ferric chloride. If it is a divalent iron compound, oxygen or air needs to be introduced when removing nickel. The inducer can be one or more of them. When the inducer is added, the pH value of the solution is 1 to 7.5, and the preferred value is 3.8 to 6.5.
[0067] (4) The neutralizing agent used for neutralizing the magnesium chloride salt solution is an oxide or hydroxide of sodium, magnesium or calcium, preferably an oxide or hydroxide of magnesium.
[0068] Although the specific implementation modes of the present invention are described above, those skilled in the art should understand that the specific implementation modes described are only illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included in the scope of protection of the claims of the present invention.
Claims
1. A method for removing nickel from a hydrochloric acid leachate containing magnesium minerals at a high magnesium concentration, characterized in that: The high magnesium concentration means that the magnesium concentration is greater than 50 g / L. The method is a co-precipitation method, in which a neutralizer and an iron inducer are respectively added to the leaching solution to cause a co-precipitation reaction between iron ions and nickel ions.
2. The method for removing nickel from the hydrochloric acid leachate of magnesium-containing minerals at high magnesium concentration according to claim 1, characterized in that: The neutralizing agent is an oxide or hydroxide of sodium, magnesium or calcium.
3. The method for removing nickel from the hydrochloric acid leachate of magnesium-containing minerals at high magnesium concentration according to claim 2, characterized in that: The neutralizing agent is magnesium oxide or hydroxide.
4. The method for removing nickel from a hydrochloric acid leachate containing magnesium minerals at a high magnesium concentration according to claim 1, characterized in that: The iron inducer includes one or more of ferric chloride and ferric hydroxide.
5. The method for removing nickel from a hydrochloric acid leachate containing magnesium minerals at a high magnesium concentration according to claim 1, characterized in that: The iron inducer is added at a certain pH value, and the pH value is controlled to be above 3.
8.
6. The method for removing nickel from a hydrochloric acid leachate containing magnesium minerals at a high magnesium concentration according to claim 1, characterized in that: The molar concentration of iron in the iron inducer is 1-10 times that of nickel ions.
7. The method for removing nickel from a hydrochloric acid leachate containing magnesium minerals at a high magnesium concentration according to claim 6, characterized in that: The molar concentration of iron in the iron inducer is 3-5 times that of nickel ions.
8. The method for removing nickel from a hydrochloric acid leachate containing magnesium minerals at a high magnesium concentration according to claim 1, characterized in that: Magnesium-containing minerals include magnesite, pyroxene, amphibole or serpentine.