A magnesium-based cobalt precipitation agent and its preparation method and application

Abstract

The invention discloses a magnesium-based cobalt precipitation agent and a preparation method and application thereof, and relates to the technical field of composite materials. The method comprises: subjecting a first magnesium ore to calcination dissociation, enhanced leaching, carbonization separation, efficient pyrolysis, solid-liquid separation, and dry calcination to obtain active magnesium oxide; subjecting a second magnesium ore to calcination dissociation, hydration and impurity removal, solid-liquid separation, and low-temperature calcination to obtain high-purity magnesium oxide; mixing and modifying active magnesium oxide and high-purity magnesium oxide to obtain a magnesium-based cobalt precipitation agent; the mass ratio of active magnesium oxide to high-purity magnesium oxide is 1:2-10, the modifier is a quaternary ammonium salt organic powder, and the amount of the modifier added is 0.02-1% of the total mass of magnesium oxide. The magnesium-based cobalt precipitation agent prepared by the method has high activity, and has the advantages of high efficiency, low price, low unit consumption, and environmental friendliness in the wet smelting of nickel and cobalt in copper-cobalt ore and laterite nickel ore, and can greatly reduce the material cost in the production process of nickel and cobalt hydroxide.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, and in particular to a magnesium-based cobalt precipitation agent and a preparation method and application thereof. Background Art

[0002] Cobalt is an indispensable component of battery materials in the current electric vehicle industry. The rapid development of electric vehicles in recent years has led to a surge in demand for cobalt in the field of power batteries. At present, cobalt resources are mostly associated with copper-cobalt and nickel-cobalt deposits. Cobalt resources are usually extracted using a wet process of "acid leaching - copper extraction - iron removal - cobalt precipitation - drying - crude cobalt". The principle of cobalt precipitation in the wet process is to rely on the ionization of OH by an alkaline precipitant. - With Co 2+ Reaction, so that the solution of Co 2+ It precipitates as Co(OH)2.

[0003] Currently, the commonly used alkaline precipitants include sodium hydroxide, sodium carbonate, calcium oxide, magnesium oxide, etc. Magnesium oxide is widely used in wet cobalt precipitation process because of its significant advantages such as less impurities, high cobalt product grade, strong sustained release ability, not easy to overdo and partially over-alkali, and the generated magnesium sulfate liquid is not easy to crystallize and easy to handle.

[0004] In the related technology, raw materials such as dolomite, hydromagnesite, brine, microcrystalline magnesite, etc. are mostly used to prepare basic salt precursors by carbonization, direct calcination, carbon ammonium method, calcination hydration method, etc., and then further obtain magnesium oxide powder for cobalt precipitation by thermal decomposition. However, the above preparation methods usually have at least one of the following problems: (1) The hydration degree and magnesium oxide content of the obtained magnesium oxide are low, resulting in high cobalt precipitation unit consumption; (2) The activity and bulk density of the obtained magnesium oxide are inversely proportional. When the activity of magnesium oxide is high, the bulk density is low, resulting in high transportation costs; when the bulk density of magnesium oxide is large, its activity is low, resulting in high cobalt precipitation unit consumption; (3) The product production cost is too high and the price is expensive. Therefore, it is urgent to improve the preparation method of magnesium oxide cobalt precipitation agent. Summary of the invention

[0005] The invention discloses a magnesium-based cobalt precipitation agent, a preparation method and application thereof, and aims to provide a preparation method of a magnesium-based cobalt precipitation agent with high activity, high hydration degree, low particle size and high dispersibility.

[0006] In order to solve the above problems, the present invention adopts the following technical solutions:

[0007] The first aspect of the present invention provides a method for preparing a magnesium-based cobalt precipitation agent.

[0008] The preparation method of the magnesium-based cobalt precipitation agent of the present invention comprises the following steps:

[0009] S100: The first magnesium ore is subjected to calcination dissociation, enhanced leaching, carbonization separation, efficient pyrolysis, solid-liquid separation, and drying and calcining to obtain active magnesium oxide;

[0010] S200: calcining and dissociating the second magnesium ore, hydrating and removing impurities, solid-liquid separation, and low-temperature calcining to obtain high-purity magnesium oxide;

[0011] S300: adding active magnesium oxide and high-purity magnesium oxide to a mixed modified agitator, adding a modifier to the agitator and vigorously mechanically stirring to obtain a magnesium-based cobalt precipitation agent; wherein the mass ratio of active magnesium oxide to high-purity magnesium oxide is 1:2-10, the modifier is a quaternary ammonium salt organic powder, and the addition amount of the modifier is 0.02-1% of the total mass of magnesium oxide.

[0012] According to an optional embodiment, in step S300, the mechanical stirring time is 5 to 240 minutes, and the stirring speed is 2000 to 5000 rpm.

[0013] According to an optional embodiment, in step S100, obtaining active magnesium oxide comprises the following steps:

[0014] S110, calcining the first magnesium ore in a high temperature furnace to dissociate it into calcined white;

[0015] S120, leaching the calcined white and the digestion water intensified, and then filtering the residues to obtain the digestion solution;

[0016] S130, pumping the digestion liquid into an enhanced gas-liquid reactor and adding an activator, and introducing carbon dioxide to carbonize the digestion liquid;

[0017] S140, the carbonized liquid is subjected to solid-liquid separation to obtain calcium carbonate and active low-calcium and magnesium-rich liquid;

[0018] S150, pumping active low-calcium magnesium-rich liquid into a pyrolysis tank, heating it to obtain a solid-liquid mixture, and then performing solid-liquid separation to obtain basic magnesium carbonate wet slag and pyrolysis liquid;

[0019] S160, the wet slag of basic magnesium carbonate is transported to a flash dryer, broken up, dried into powder, and then calcined at low temperature to obtain active magnesium oxide.

[0020] According to an optional embodiment, in step S130, the activator is one or more of oxalic acid, sodium phosphate, and magnesium polycarboxylate, and the mass ratio of oxalic acid, sodium phosphate, and magnesium polycarboxylate is: 1-15:0-8:0-1;

[0021] The dosage of the activator is 0.05% to 5.0% of the mass of magnesium oxide in the digestive solution, and the activator is prepared as a solution with a mass concentration of 10% and added to the digestive solution.

[0022] According to an optional embodiment, the activator is oxalic acid, sodium phosphate and magnesium polycarboxylate, the mass ratio of oxalic acid, sodium phosphate and magnesium polycarboxylate is 6~12:5:1, and the addition amount of the activator is 0.5%~2.0% of the mass of magnesium oxide in the digestive juice.

[0023] According to an optional embodiment, in step S200, obtaining high-purity magnesium oxide includes the following steps:

[0024] S210, calcining and dissociating the second magnesium ore in a high temperature furnace to obtain a calcined material;

[0025] S220, adding additives to the calcined material for hydration activation and impurity removal, and solid-liquid separation to obtain magnesium hydroxide wet slag;

[0026] S230, calcining the wet magnesium hydroxide slag at low temperature to obtain high-purity magnesium oxide.

[0027] According to an optional embodiment, in step S210, the second magnesium ore is one or more of magnesite, hydromagnesite, brucite, magnesium carbonate, and magnesium hydroxide, and the particle size of the second magnesium ore is 200-325 mesh.

[0028] According to an optional embodiment, in step S220, the additive is an aqueous solution of sodium hexametaphosphate and ammonium fluoride, the mass ratio of sodium hexametaphosphate to ammonium fluoride is 5-15:1, the solid-liquid ratio of the additive aqueous solution is 1 g:15 ml; and the dosage of the additive is 0.2-1.0 kg / t calcined material.

[0029] The second aspect of the present invention provides a magnesium-based cobalt precipitation agent.

[0030] The magnesium-based cobalt precipitation agent prepared by the preparation method of the magnesium-based cobalt precipitation agent according to any technical solution of the present invention comprises the following components: 1 part by weight of active magnesium oxide, 2 to 10 parts by weight of high-purity magnesium oxide and a modifier, wherein the modifier is a quaternary ammonium salt organic powder, and the addition amount of the modifier is 0.02 to 1% of the total mass of the active magnesium oxide and the high-purity magnesium oxide;

[0031] The bulk density of the magnesium-based cobalt precipitation agent is greater than 0.5 g / cm 3 , hydration degree is higher than 80%, citric acid value is lower than 16s, and average particle size D50 is 6~15μm.

[0032] The third aspect of the present invention also provides an application of a magnesium-based cobalt precipitation agent.

[0033] According to the application of the magnesium-based cobalt precipitating agent described in any technical solution of the present invention, the magnesium-based cobalt precipitating agent is used to extract cobalt from cobalt-containing ore, and the addition amount of the magnesium-based cobalt precipitating agent is the theoretically required mass of the cobalt precipitating agent, and the calculation formula for the theoretically required mass of the cobalt precipitating agent is:

[0034] ,

[0035] Wherein, M is the mass of the theoretically required cobalt precipitation agent; C is the cobalt ion content in the cobalt precipitation pre-solution, in g / L; V is the volume of the cobalt precipitation pre-solution, in L.

[0036] The technical solution adopted by the present invention can achieve the following beneficial effects:

[0037] The preparation method of the magnesium-based cobalt precipitation agent of the present invention comprises mixing active magnesium oxide and high-purity magnesium oxide in proportion, adding a modifier and providing a strong mechanical force to promote the coupling modification of the two powders, so as to improve the hydration performance and cobalt precipitation performance of the magnesium-based cobalt precipitation composite material. During the modification process, a quaternary ammonium salt modifier with a positive charge is adsorbed on the surface of the powder to form an ordered mixture, and is fixed and film-formed in multiple layers on the surface of the powder to become a carrier linking the two magnesium oxide materials; and under the action of strong mechanical stirring, the modifier penetrates into the magnesium oxide crystal layer and modifies it by the exchange between positive and negative ions. Since the modifier has uneven charge distribution and strong polarity, the modified magnesium-based cobalt precipitation agent has extremely strong hydrophilicity.

[0038] The magnesium-based cobalt precipitation agent prepared by the method of the present invention has high activity. The magnesium-based cobalt precipitation agent is used for wet smelting of copper-cobalt ore and laterite nickel ore to precipitate nickel and cobalt, which has the advantages of high efficiency, low price, low unit consumption, and environmental friendliness, and can greatly reduce the production cost of nickel cobalt hydroxide.

[0039] In addition, the preferred technical solution of the present invention also has the following beneficial effects:

[0040] The preparation method of the magnesium-based cobalt precipitation agent of the present invention can accelerate the hydration process of magnesium oxide by adding an activator during the preparation of active magnesium oxide, so that the crystals of the hydration product become thinner, thereby improving the hydration efficiency and increasing the reaction activity, and at the same time improving the dispersibility of the active magnesium oxide precursor product, reducing the product size, and significantly increasing the surface roughness of the product; utilizing the steric hindrance effect and electrostatic repulsion of the activator, the mutual agglomeration between ultrafine particles can also be slowed down, and the high dispersibility and high site activity of the product can be maintained; in addition, during the calcination process, the combination product of oxalic acid and sodium phosphate with magnesium is decomposed into magnesium oxide, carbon dioxide and water, which can also increase the active sites on the surface of the powder without affecting the quality of the product, and further improve the reaction activity of the active magnesium oxide product.

[0041] The preparation method of the magnesium-based cobalt precipitation agent of the present invention comprises the following steps: in the process of preparing high-purity magnesium oxide, a magnesium ore calcined material with less impurities is used, and further hydrated and activated to generate magnesium hydroxide with small particle size, good crystallization performance and rough surface; and under the action of additives, impurities such as calcium and silicon are separated by being converted into soluble complexes or gaseous substances, and high-purity magnesium oxide with moderate density is obtained by low-temperature calcination. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 This is a process flow chart of preparing a magnesium-based cobalt precipitation agent in an embodiment of the present application;

[0044] Figure 2 This is a SEM image of the magnesium-based cobalt precipitation agent of Example 1 of the present application. DETAILED DESCRIPTION

[0045] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0046] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0047] Figure 1 The process flow chart of the present application for preparing a magnesium-based cobalt precipitation agent is shown. Figure 1 As shown, the preparation method of the magnesium-based cobalt precipitation agent comprises the following steps:

[0048] S100: The first magnesium ore is subjected to calcination dissociation, enhanced leaching, carbonization separation, efficient pyrolysis, solid-liquid separation, and drying and calcining to obtain active magnesium oxide.

[0049] Specifically, obtaining active magnesium oxide comprises the following steps:

[0050] S110, calcining the first magnesium ore in a high temperature furnace to dissociate it into calcined white.

[0051] S120, the calcined white and the digestion water are subjected to enhanced leaching and then micro-filtered to remove the residue to obtain the digestion solution.

[0052] S130, pumping the digestion liquid into the enhanced gas-liquid reactor and adding an activator, and introducing carbon dioxide to carbonize to obtain a carbonized liquid.

[0053] S140, the carbonized liquid is subjected to solid-liquid separation to obtain calcium carbonate and active low-calcium and magnesium-rich liquid.

[0054] S150, pumping active low-calcium magnesium-rich liquid into a pyrolysis tank, heating it to obtain a solid-liquid mixture, and then separating the solid from the liquid to obtain basic magnesium carbonate wet slag and pyrolysis liquid.

[0055] S160, the wet slag of basic magnesium carbonate is transported to a flash dryer, broken up, dried into powder, and then calcined at low temperature to obtain active magnesium oxide.

[0056] S200: The second magnesium ore is subjected to calcination dissociation, hydration and impurity removal, solid-liquid separation and low-temperature calcination to obtain high-purity magnesium oxide.

[0057] Specifically, obtaining high-purity magnesium oxide includes the following steps:

[0058] S210, calcining and dissociating the second magnesium ore in a high temperature furnace to obtain a calcined material;

[0059] S220, adding additives to the calcined material for hydration activation and impurity removal, and solid-liquid separation to obtain magnesium hydroxide wet slag;

[0060] S230, calcining the wet magnesium hydroxide slag at low temperature to obtain high-purity magnesium oxide.

[0061] S300: Add active magnesium oxide and high-purity magnesium oxide to a mixed modified agitator, add a modifier to the agitator and stir vigorously mechanically to obtain a magnesium-based cobalt precipitation agent. Preferably, the mass ratio of active magnesium oxide to high-purity magnesium oxide is 1:2-10. The modifier is a quaternary ammonium salt organic powder. The amount of the modifier added is 0.02-1% of the total mass of magnesium oxide.

[0062] Exemplarily, the quaternary ammonium salt organic powder is dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, and the like.

[0063] In steps S110 and S210, the first magnesium ore and the second magnesium ore are calcined and dissociated in a high-temperature furnace. The high-temperature furnace may be a roller kiln, a suspension kiln, a rotary kiln, a boiling kiln or a ring kiln. Exemplarily, the high-temperature furnace is indirectly heated by gas calcination. Exemplarily, the carbon dioxide flue gas generated by the oxidation of the gas and the decomposition of the material in step S110 is compressed and purified and reused in the carbonization process of S130, and the waste heat generated by the heat exchange of the carbon dioxide flue gas is supplied to the pyrolysis system of step S150; the waste heat generated by the plate heat exchange of the carbon dioxide flue gas generated by the oxidation of the gas and the decomposition of the material in step S210 is supplied to the flash drying system of step S160, thereby achieving full utilization of heat.

[0064] In step S110, the first magnesium ore is one of dolomite, magnesite, and by-product magnesium salt. By-product magnesium salt is an inorganic salt solid such as magnesium carbonate and magnesium hydroxide produced by an industrial production enterprise, and other impurities are mainly calcium carbonate. Exemplarily, the size of the first magnesium ore is less than 50 mm, the calcination dissociation temperature is 800-1200° C., and the calcination time is 0.1-240 min.

[0065] The first magnesium ore calcination dissociation reaction formula is: MgCO3+CaCO3=MgO+CaO+2CO2↑.

[0066] In step S120, the enhanced leaching solid-liquid ratio is 1g:15-50ml, the temperature is 30-90°C, and the time is 30-90min.

[0067] The reaction formula of calcined enhanced leaching is: MgO+CaO+2H2O=Mg(OH)2+Ca(OH)2.

[0068] In step S130, the carbonization process is a primary carbonization process or a multi-stage carbonization process.

[0069] Exemplarily, the endpoint pH is 7.5-10.0 and the temperature is 15-40°C.

[0070] Exemplarily, the activator is one or more of oxalic acid, sodium phosphate, and magnesium polycarboxylate. The mass ratio of oxalic acid, sodium phosphate, and magnesium polycarboxylate is: 1~15:0~8:0~1. The dosage of the activator is 0.05%~5.0% of the mass of magnesium oxide in the digestive solution. The activator is prepared as a solution with a mass concentration of 10% and added to the digestive solution. Preferably, the activator is oxalic acid, sodium phosphate, and magnesium polycarboxylate, and the mass ratio of oxalic acid, sodium phosphate, and magnesium polycarboxylate is: 6~12:5:1, and the dosage of the activator is 0.5%~2.0% of the mass of magnesium oxide in the digestive solution.

[0071] The reaction formula for carbonization separation of digestive fluid is:

[0072] Mg(OH)2+Ca(OH)2+3CO2=Mg(HCO3)2+CaCO3↓+H2O.

[0073] In step S140, the solid-liquid separation method is preferably centrifugal dehydration or plate and frame filter press dehydration. The active low-calcium magnesium-rich solution is a magnesium bicarbonate solution, wherein the calcium ion concentration is less than 1 mmol / L and the magnesium ion concentration is higher than 0.15 mol / L.

[0074] In step S150, during the heating process, the stirring rate is 30-200 rpm, the pressure is -40--10 kPa, the heating temperature is 50-90°C, and the pyrolysis time is 30-180 min.

[0075] Furthermore, the pyrolysis liquid can be returned to the digestion tank through a water pump for reuse as digestion water.

[0076] The pyrolysis reaction formula of active low calcium and magnesium-rich liquid is as follows:

[0077] 5Mg(HCO3)2=4MgCO3·Mg(OH)2·4H2O+6CO2↑.

[0078] In step S160, the flash drying temperature is 120-250° C. The low-temperature calcination equipment is a rotary kiln, a suspension kiln or a boiling kiln, the calcination temperature is 500-800° C., and the calcination time is 0.1-120 min.

[0079] The calcination reaction formula of basic magnesium carbonate is as follows:

[0080] 4MgCO3·Mg(OH)2·4H2O=5MgO+5H2O+4CO2↑.

[0081] In step S210, the second magnesium ore is one or more of magnesite, hydromagnesite, brucite, magnesium carbonate, and magnesium hydroxide, and the particle size of the second magnesium ore is 200-325 meshes. The calcination and dissociation temperature of the second magnesium ore is 650-1000° C., and the calcination time is 0.5-120 min.

[0082] The second magnesium ore calcination dissociation reaction formula is: MgCO3=MgO+CO2↑;

[0083] Or Mg(OH)2=MgO+H2O;

[0084] Or 4MgCO3·Mg(OH)2·4H2O=5MgO+5H2O+4CO2↑.

[0085] In step S220, the additives are sodium hexametaphosphate and ammonium fluoride aqueous solution, the mass ratio of sodium hexametaphosphate to ammonium fluoride is 5-15:1, the solid-liquid ratio of the additive aqueous solution is 1g:15ml, and the dosage (solid amount) of the additive is 0.2-1.0kg / t calcined material.

[0086] In step S230, the low-temperature calcination equipment is a rotary kiln, a suspension kiln or a boiling kiln, the calcination temperature is 600-800°C, and the calcination time is 0.5-60 minutes.

[0087] In step S300, the mechanical stirring time is 5 to 240 minutes and the stirring speed is 2000 to 5000 rpm.

[0088] The magnesium-based cobalt precipitation agent prepared according to the above method has a loose bulk density greater than 0.5 g / cm 3 , hydration degree is higher than 80%, citric acid value is lower than 16s, and average particle size D50 is 6~15μm.

[0089] For the sake of clarity, the magnesium-based cobalt precipitation agent provided in the present application and its preparation method and application are described in detail through specific examples below.

[0090] Example 1

[0091] The preparation method of the magnesium-based cobalt precipitation agent in this embodiment comprises the following steps:

[0092] S100: Preparation of highly active magnesium oxide.

[0093] S110: Dolomite with a particle size of 10-30 mm and a magnesium content (calculated as magnesium oxide) of 21.68% is used as raw material and calcined in a muffled roller kiln at 1100°C for 2.5 hours to obtain calcined white.

[0094] S120: The calcined molten metal is conveyed to the digestion tank by a belt. Digestion water is added at a solid-liquid ratio of 1g:40ml at 50°C. After leaching for 60 minutes, a mixed solution is obtained. The mixed solution is filtered through a drum microfilter to remove large particles of impurities that cannot be digested, and then a digestion solution is obtained.

[0095] S130: cooling the digestion liquid through a water-cooling jacket and then pumping it into an enhanced gas-liquid reactor, introducing carbon dioxide to carry out a carbonization reaction until the end point pH is 7.6, and using a diaphragm filter press to separate the carbonized liquid into solid and liquid to obtain calcium carbonate and active low-calcium magnesium-rich liquid;

[0096] The active low-calcium and magnesium-rich liquid is pumped into the next-stage enhanced gas-liquid reactor, an activator is added, and carbon dioxide is introduced to carbonize to a pH of 8.2 to obtain a carbonized liquid.

[0097] S140: A membrane filter press is used to separate the carbonized liquid into solid and liquid to obtain magnesium-rich slag and active low-calcium magnesium-rich liquid. The magnesium-rich slag returns to the digestion section, and the active low-calcium magnesium-rich liquid enters the buffer stirring tank.

[0098] In this embodiment, the mass of the activator added to the enhanced gas-liquid reactor is 0.05% of the total mass of magnesium oxide in the digestive liquid. The activator is a 10% solution prepared by mixing oxalic acid, sodium phosphate and magnesium polycarboxylate in a mass ratio of 12:5:1.

[0099] S150: The active low-calcium magnesium-rich liquid is pumped into the pyrolysis tank, and pyrolyzed for 60 minutes at a stirring rate of 120 rpm, a pressure of -40 kPa, and a heating temperature of 60°C. The mixed liquid after pyrolysis is transported to a centrifugal dehydrator through a hot water pump for solid-liquid separation to obtain wet slag of basic magnesium carbonate with a moisture content of 65% and a pyrolysis liquid.

[0100] S160: The wet slag of basic magnesium carbonate is conveyed to a flash dryer at a temperature of 180°C through a screw feeder. After drying, basic magnesium carbonate dry powder with a moisture content of 1.3% is obtained. The basic magnesium carbonate dry powder is conveyed to a rotary kiln by negative pressure. After calcination, cooling and spiral discharging, high-purity and high-activity magnesium oxide with a hydration activity of 92.4% and a purity of 97.6% is obtained.

[0101] S200: Preparation of high purity magnesium oxide.

[0102] S210: Using 200-325 mesh magnesite powder as raw material, calcining at high temperature for 25 minutes in a boiling kiln at 950°C to obtain magnesium oxide calcined material.

[0103] S220: The mass ratio of sodium hexametaphosphate to ammonium fluoride is 9:1. Sodium hexametaphosphate and ammonium fluoride are added into water to prepare an aqueous solution of sodium hexametaphosphate and ammonium fluoride with a solid-liquid ratio of 1g:8ml. The total dosage of solid additives is 0.5kg / t calcined material. After stirring for 60 minutes, a membrane filter press is used for solid-liquid separation to obtain magnesium hydroxide wet slag.

[0104] S230: The wet magnesium hydroxide slag is calcined in a rotary kiln at 700°C for 45 minutes to obtain high-purity magnesium oxide with a hydration activity of 78.4% and a purity of 96.3%.

[0105] S300: Active magnesium oxide and high-purity magnesium oxide are added to a mixed modified agitator at a mass ratio of 1:4, and a modifier, dodecyl trimethyl ammonium chloride, is added at 0.5% of the total mass of magnesium oxide. The mechanical stirring time is 180 minutes. The stirring speed is 3000 rpm, and a magnesium-based cobalt precipitation agent is obtained after physical and chemical modification.

[0106] The loose bulk density of the magnesium-based cobalt precipitation agent obtained in this embodiment is greater than 0.56 g / cm 3, hydration degree is 85.2%, citric acid value is 12.4s, average particle size D50 is 7.8μm (such as Figure 2 as shown).

[0107] Example 2

[0108] The preparation method of the magnesium-based cobalt precipitation agent in this embodiment is different from that in Embodiment 1 in that the mass ratio of active magnesium oxide to high-purity magnesium oxide is 1:2.

[0109] Example 3

[0110] The preparation method of the magnesium-based cobalt precipitation agent in this embodiment is different from that in Embodiment 1 in that the mass ratio of active magnesium oxide to high-purity magnesium oxide is 1:10.

[0111] Example 4

[0112] The preparation method of the magnesium-based cobalt precipitation agent in this embodiment is different from that in Embodiment 1 in that the amount of the modifier added is 0.02% of the total mass of magnesium oxide.

[0113] Example 5

[0114] The preparation method of the magnesium-based cobalt precipitation agent in this embodiment is different from that in Embodiment 1 in that the amount of the modifier added is 1% of the total mass of magnesium oxide.

[0115] Example 6

[0116] The preparation method of the magnesium-based cobalt precipitation agent in this embodiment is different from that in Embodiment 1 in that the mass of the activator added to the enhanced gas-liquid reactor is 0.5% of the total mass of magnesium oxide in the digestion liquid.

[0117] Example 7

[0118] The preparation method of the magnesium-based cobalt precipitation agent in this embodiment is different from that in Embodiment 1 in that the mass of the activator added to the enhanced gas-liquid reactor is 2.0% of the total mass of magnesium oxide in the digestion liquid.

[0119] Example 8

[0120] The preparation method of the magnesium-based cobalt precipitation agent in this embodiment is different from that in Embodiment 1 in that the mass of the activator added to the enhanced gas-liquid reactor is 5.0% of the total mass of magnesium oxide in the digestion liquid.

[0121] Comparative Example 1

[0122] The preparation method of the magnesium-based cobalt precipitation agent in this embodiment is different from that in Embodiment 1 in that no modifier is added.

[0123] Comparative Example 2

[0124] The preparation method of the magnesium-based cobalt precipitation agent in this embodiment is different from that in Embodiment 1 in that no activator is added.

[0125] The magnesium-based cobalt precipitation agents prepared in Examples 1 to 8, Comparative Example 1 and Comparative Example 2 were tested, and the test results are shown in Tables 1 and 2 below.

[0126] The bulk density is determined according to GB / T 23771-2009 Determination of bulk density in inorganic chemical products.

[0127] The citric acid value adopts the determination method of HG / T 3928-2012 Industrial Active Light Magnesium Oxide.

[0128] The hydration degree is determined by the determination method of chemical activity of light-burned magnesium oxide in YB / T 4019-2006.

[0129] The average particle size adopts HG / T 3821-2006 industrial magnesium hydroxide.

[0130] Table 1 Test results of magnesium-based cobalt precipitation agents obtained in Examples 1 to 5 and Comparative Example 1

[0131] .

[0132] Table 2 Test results of magnesium-based cobalt precipitation agents obtained in Examples 1, 6-8 and Comparative Example 2

[0133] .

[0134] It can be seen from Table 1 and Table 2 above that the bulk density of the magnesium-based cobalt precipitation agent obtained in Examples 1 to 8 is greater than 0.5 g / cm 3 , hydration degree is higher than 80%, citric acid value is lower than 16s, and average particle size D50 is 6~9μm. It can also be seen from Tables 1 and 2 that the appropriate amount of modifier and / or the ratio of active magnesium oxide to high-purity magnesium oxide can help to increase the bulk density and hydration degree of the magnesium-based cobalt precipitation agent and reduce the citric acid value and average particle size D50 of the magnesium-based cobalt precipitation agent.

[0135] Example 9

[0136] The Co content of a certain enterprise's copper-cobalt ore after iron removal is 12.5g / L, the Mn content is 1.75g / L, the Cu content is 0.15g / L, the Fe content is 0.05g / L, the Mg content is 2.10g / L, and the pH is 4.00.

[0137] The magnesium-based cobalt precipitation agent obtained in Example 1 is used to extract cobalt from the above iron-removed liquid, comprising the following steps:

[0138] (1) Turn on the constant temperature water bath and set the temperature to 40°C.

[0139] (2) Pour 800 mL of the deironed liquid into a beaker, place it in a constant temperature water bath, connect a digital electric stirrer, and set the speed to 600 rpm.

[0140] (3) The magnesium-based cobalt precipitating agent is prepared into a 10% slurry and stirred for 30 minutes. The theoretical amount of magnesium oxide is drawn with a syringe and slowly added to the iron-removed liquid in step (2). After completion, the timing is started and the reaction lasts for a total of 6 hours. The theoretical amount of magnesium-based cobalt precipitating agent is 6.8g.

[0141] (4) After the reaction is completed, the reaction solution is filtered, the solution volume is recorded, and then a sample of the solution after cobalt precipitation is taken.

[0142] (5) Transfer the cobalt hydroxide slag to a reaction beaker and add clean water to rinse. After rinsing, send it to a forced air drying oven to dry to constant weight, and place the cobalt hydroxide in a sample bag and test the Co element content with the cobalt precipitation liquid.

[0143] (6) After the experiment, calculate the cobalt precipitation rate and magnesium oxide consumption: consumption = magnesium oxide amount / cobalt hydroxide Co metal amount; cobalt precipitation rate = 1-Co metal amount in the liquid after cobalt precipitation / Co metal amount in the liquid before cobalt precipitation.

[0144] In this embodiment, the volume of the liquid after cobalt precipitation is 826 ml, the cobalt concentration is 267 mg / L, the dry mass of the cobalt hydroxide slag is 21.4 g, and the cobalt grade is 44.8%. The cobalt precipitation efficiency of the magnesium-based cobalt precipitation agent is 97.8%, and the unit consumption is 710 kg / t Co.

[0145] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0146] In addition, it should be noted that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in a reverse order according to the functions involved. For example, the described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. In addition, features described with reference to certain examples may be combined in other examples.

[0147] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a magnesium-based cobalt precipitation agent, characterized in that: The steps include: S100: calcining and dissociating the first magnesium ore, strengthening leaching, carbonizing and separating, efficiently pyrolyzing, solid-liquid separation, and drying and calcining to obtain active magnesium oxide, wherein an activator is added during the carbonizing and separating process, and the activator is one or more of oxalic acid, sodium phosphate, and magnesium polycarboxylate; S200: calcining and dissociating the second magnesium ore, hydrating and removing impurities, solid-liquid separation, and low-temperature calcining to obtain high-purity magnesium oxide; S300: adding active magnesium oxide and high-purity magnesium oxide to a mixed modified agitator, adding a modifier to the agitator and vigorously mechanically stirring to obtain a magnesium-based cobalt precipitation agent; wherein the mass ratio of active magnesium oxide to high-purity magnesium oxide is 1:2-10, the modifier is a quaternary ammonium salt organic powder, and the addition amount of the modifier is 0.02-1% of the total mass of magnesium oxide.

2. The method for preparing the magnesium-based cobalt precipitation agent according to claim 1, characterized in that: In step S300, the mechanical stirring time is 5 to 240 minutes, and the stirring speed is 2000 to 5000 rpm.

3. The method for preparing the magnesium-based cobalt precipitation agent according to claim 1 or 2, characterized in that: In step S100, obtaining active magnesium oxide includes the following steps: S110, calcining the first magnesium ore in a high temperature furnace to dissociate it into calcined white; S120, leaching the calcined white and the digestion water intensified, and then filtering the residues to obtain the digestion solution; S130, pumping the digestion liquid into an enhanced gas-liquid reactor and adding an activator, and introducing carbon dioxide to carbonize the digestion liquid; S140, the carbonized liquid is subjected to solid-liquid separation to obtain calcium carbonate and active low-calcium and magnesium-rich liquid; S150, pumping active low-calcium magnesium-rich liquid into a pyrolysis tank, heating it to obtain a solid-liquid mixture, and then performing solid-liquid separation to obtain basic magnesium carbonate wet slag and pyrolysis liquid; S160, the wet slag of basic magnesium carbonate is transported to a flash dryer, broken up, dried into powder, and then calcined at low temperature to obtain active magnesium oxide.

4. The method for preparing the magnesium-based cobalt precipitation agent according to claim 3, characterized in that: In step S130, the mass ratio of oxalic acid, sodium phosphate, and magnesium polycarboxylate is 1-15:0-8:0-1; The dosage of the activator is 0.05% to 5.0% of the mass of magnesium oxide in the digestive solution, and the activator is prepared as a solution with a mass concentration of 10% and added to the digestive solution.

5. The method for preparing the magnesium-based cobalt precipitation agent according to claim 4, characterized in that: The activator is oxalic acid, sodium phosphate and magnesium polycarboxylate, the mass ratio of oxalic acid, sodium phosphate and magnesium polycarboxylate is 6-12:5:1, and the dosage of the activator is 0.5%-2.0% of the mass of magnesium oxide in the digestive fluid.

6. The method for preparing the magnesium-based cobalt precipitation agent according to claim 1 or 2, characterized in that: In step S200, obtaining high-purity magnesium oxide includes the following steps: S210, calcining and dissociating the second magnesium ore in a high temperature furnace to obtain a calcined material; S220, adding additives to the calcined material for hydration activation and impurity removal, and solid-liquid separation to obtain magnesium hydroxide wet slag; S230, calcining the wet magnesium hydroxide slag at low temperature to obtain high-purity magnesium oxide.

7. The method for preparing the magnesium-based cobalt precipitation agent according to claim 6, characterized in that: In step S210, the second magnesium ore is one or more of magnesite, hydromagnesite, brucite, magnesium carbonate, and magnesium hydroxide, and the particle size of the second magnesium ore is 200-325 meshes.

8. The method for preparing the magnesium-based cobalt precipitation agent according to claim 6, characterized in that: In step S220, the additive is an aqueous solution of sodium hexametaphosphate and ammonium fluoride, the mass ratio of sodium hexametaphosphate to ammonium fluoride is 5-15:1, and the solid-liquid ratio of the aqueous solution of the additive is 1g:15ml; and The dosage of additives is 0.2~1.0kg / t calcined material.

9. A magnesium-based cobalt-precipitating agent obtained by the method for preparing a magnesium-based cobalt-precipitating agent according to any one of claims 1 to 8, characterized in that: The magnesium-based cobalt precipitation agent comprises the following components: 1 part by weight of active magnesium oxide, 2 to 10 parts by weight of high-purity magnesium oxide and a modifier, wherein the modifier is a quaternary ammonium salt organic powder, and the addition amount of the modifier is 0.02 to 1% of the total mass of the active magnesium oxide and the high-purity magnesium oxide; The bulk density of the magnesium-based cobalt precipitation agent is greater than 0.5 g / cm 3 , hydration degree is higher than 80%, citric acid value is lower than 16s, and average particle size D50 is 6~15μm.

10. An application of the magnesium-based cobalt precipitation agent according to claim 9, characterized in that: The magnesium-based cobalt precipitating agent is used to extract cobalt from cobalt-containing ores. The amount of the magnesium-based cobalt precipitating agent added is the theoretically required mass of the cobalt precipitating agent, and the calculation formula for the theoretically required mass of the cobalt precipitating agent is: ， Wherein, M is the mass of the theoretically required cobalt precipitation agent; C is the cobalt ion content in the cobalt precipitation pre-solution, in g / L; V is the volume of the cobalt precipitation pre-solution, in L.

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