A nickel alloy smelting method

Abstract

The invention discloses a nickel alloy smelting method, belongs to the field of nickel alloy smelting technology, comprises the following steps: S2, the nickel ore sample after milling is placed in XFD-63 flotation cell for froth flotation step, before flotation, 1-hydroxyethyl diphosphonic acid is first added in XFD-63 flotation cell, and then collector and frother are added; after flotation is completed, pentlandite concentrate and serpentine concentrate are obtained; S3, serpentine concentrate is activated pre-treated, then acid leaching is carried out, and the leachate enriched with magnesium is obtained; S4, the leachate enriched with magnesium is decontaminated, and nickel slag and magnesium sulfate solution are obtained after filtering and separation; nickel slag and pentlandite concentrate are mixed together, smelted in refining furnace, and nickel alloy is obtained after smelting through subsequent conventional processes. The method of the present invention can improve the content of nickel alloy after ore smelting, and the method is feasible, and the MgO grade in flotation concentrate is low, and the smelting of flotation concentrate will not bring operational problems.

Description

Technical Field

[0001] The invention relates to the technical field of refined slag steelmaking, and in particular to a nickel alloy smelting method. Background Art

[0002] Low-grade nickel ores containing large amounts of serpentine minerals have historically been difficult to process effectively. About 96% of the nickel in the ore is in the form of pentlandite, which can be recovered by true flotation, however the remaining 4% is distributed in non-sulfidic minerals and can only be recovered by entrainment mechanisms or in combination with pentlandite. The MgO content in the ore is 37% w / w, determined by X-ray diffraction, and is mainly distributed in serpentine (46% w / w) and olivine (19% w / w). Serpentine [(Mg8(Si4O 10 )(OH)8)] is a common magnesium silicate mineral, often coexisting with sulfide minerals such as pentlandite, chalcopyrite and pyrite. Serpentine, as a layered clay mineral, generally exposes the tetrahedral layer of [SiO4] (also known as the T layer, "talc-like" layer) and the octahedral layer of [MgO8] (also known as the O layer, hydrophilic layer) during the cracking process. During the grinding process, serpentine can easily cross the ground and turn into mud. In the xanthate flotation system, serpentine mucus firmly covers the surface of sulfide minerals, seriously weakening their floatability. In the process of bubbles rising from the bottom of the flotation tank to the foam zone, the bubbles carried will reduce the grade of sulfide minerals in the flotation concentrate.

[0003] The lower grade of sulfide minerals in the flotation concentrate leads to an increase in the grade of MgO in the feed of the nickel smelter, which will cause operational problems in the smelting of the flotation concentrate in the smelter, because during the smelting process, MgO will increase the temperature and viscosity of the slag liquid, resulting in poor slag-sand separation, and a large amount of metal loss in the slag liquid due to the entrainment of slag. MgO has a high melting point and requires furnace operation at a higher temperature, which shortens the life of the furnace refractory materials. Therefore, the MgO content in the flotation concentrate must be controlled below 7-10% to prevent operational problems in the nickel alloy smelting process. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, one of the objects of the present invention is to provide a nickel alloy smelting method, which can increase the content of nickel alloy after ore smelting, the method is feasible, the MgO grade in the flotation concentrate is low, and will not cause operational problems in the smelting of the flotation concentrate in the smelter.

[0005] A second object of the present invention is to provide a nickel alloy.

[0006] One of the purposes of the present invention is achieved by the following technical solution:

[0007] A nickel alloy smelting method comprises the following steps:

[0008] S1. Nickel ore samples were crushed to 2 mm. In each flotation experiment, the samples were ground in a mild steel rod mill. The ore was ground to a particle size of 74 μm. During the grinding process, pH regulator sodium carbonate was added to adjust the pH to 9.

[0009] S2, placing the ground nickel ore sample into an XFD-63 flotation cell for froth flotation. Before flotation, 1-hydroxyethyl diphosphonic acid is first added to the XFD-63 flotation cell, followed by a collector and a frother. When flotation begins, air is injected into the XFD-63 flotation cell to start flotation, and the air flow rate is maintained at 0.1 Nm 3 / h, monitored by flow meter; after flotation, pentlandite concentrate and serpentine concentrate are obtained;

[0010] S3, subjecting the serpentine concentrate to activation pretreatment, followed by acid leaching to obtain a leachate enriched with magnesium, wherein the activation pretreatment comprises at least one of supercritical fluid treatment, subcritical fluid treatment, ultrasonic treatment, and microwave treatment;

[0011] S4, removing impurities from the magnesium-enriched leachate, filtering and separating to obtain nickel slag and magnesium sulfate solution; mixing the nickel slag and pyrite concentrate together, smelting them in a refining furnace, and performing subsequent conventional processes after smelting to obtain the nickel alloy.

[0012] Serpentine is actually a hydrated magnesium-rich silicate mineral. The ideal compound formula of serpentine should be Mg8(Si4O 10 )(OH)8, its main chemical components are MgO and SiO2, and it may also contain a small amount of other components. The crystal structure of serpentine is mainly composed of multiple layers of metal ions in the crystal. The ideal structure of its crystal is a trioctahedron, which is composed of a combination of a silicon oxygen tetrahedron layer and a magnesium hydroxide octahedron layer, and it has a relatively weak van der Waals force with adjacent serpentine flakes. Because serpentine has a stable silicate structure, it is difficult for the magnesium in it to break free from the constraints and enter the solution. On the other hand, many scholars have learned through in-depth research on the crystal structure and chemical composition of serpentine that serpentine has many active groups. It is precisely because of the existence of these active groups that serpentine has a very high chemical activity. These active groups are easily oxidized by oxygen in the air and lose their activity, making the activated serpentine powder more difficult to leach, so the activated serpentine powder should be vacuum sealed. The melting point of serpentine itself is low, but if the magnesium oxide content is too high, the melting point of serpentine will become very high and it will be more difficult to leach.

[0013] Furthermore, in the froth flotation step, the flotation volume is 1.5 L, the stirring speed is 1800 rpm, and the solid density in the flotation cell is 35% by weight.

[0014] Furthermore, in S3, the fluid component in the supercritical fluid treatment and the subcritical fluid treatment is at least one of water and carbon dioxide.

[0015] Furthermore, in S3, the ultrasonic power is 300-800W.

[0016] Furthermore, in S3, the power of the microwave treatment process is 300-800W.

[0017] Furthermore, in S3, the activation pretreatment time is 5 to 60 minutes.

[0018] Furthermore, in S3, the acid solution used in the acid leaching process is an aqueous solution of an inorganic strong acid; the inorganic strong acid is at least one of sulfuric acid, nitric acid and hydrochloric acid.

[0019] A second object of the present invention is to provide a nickel alloy, which is achieved by using any of the above technical solutions.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The present invention provides a nickel alloy smelting method. In S2, 1-hydroxyethyl diphosphonic acid (HEDP) is first added to the XFD-63 flotation cell. 1-Hydroxyethyl diphosphonic acid is a negatively charged reagent and has a strong affinity for the active Mg sites exposed on the octahedral layer of serpentine [MgO8], so that the surface potential of serpentine is reversed from a positive potential to a negative potential. Pentlandite also has a negative potential. Due to the effect of electrostatic repulsion, the aggregation of serpentine to sulfide minerals should be weakened, thereby dispersing the fine serpentine particles on the surface of pentlandite, improving the nickel recovery rate, eliminating the interference of hydrophilic serpentine mucus on the flotation performance of pentlandite, increasing the adsorption density of xanthine on pentlandite, improving the flotation performance of pentlandite, and realizing the flotation separation of pentlandite and serpentine after flotation.

[0022] (2) The present invention provides a nickel alloy smelting method. After the flotation separation of pentlandite and serpentine, the nickel grade of the pentlandite is improved, which will not cause operational problems for the smelting of the flotation concentrate in the smelter, and S3, the serpentine concentrate is subjected to activation pretreatment, followed by acid leaching to obtain a leachate enriched with magnesium, S4, impurities are removed from the leachate enriched with magnesium, and nickel slag and magnesium sulfate solution are obtained after filtration and separation; the nickel slag and the pentlandite concentrate are mixed together and smelted in a refining furnace, thereby further improving the nickel grade of the pentlandite, and finally the smelted nickel alloy has a high nickel metal content. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with specific embodiments. It should be noted that, under the premise of no conflict, the embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0024] The collectors used in the examples are three xanthates, namely potassium butyl xanthate (PBX), potassium octyl xanthate (POX), and methyl isobutyl carbinol (MIBC).

[0025] Example 1

[0026] This embodiment provides a nickel alloy smelting method, comprising the following steps:

[0027] S1. Nickel ore samples were crushed to 2 mm. In each flotation experiment, the samples were ground in a mild steel rod mill. The ore was ground to a particle size of 74 μm. During the grinding process, pH regulator sodium carbonate was added to adjust the pH to 9.

[0028] S2, placing the ground nickel ore sample into an XFD-63 flotation cell for froth flotation. Before flotation, 1-hydroxyethyl diphosphonic acid, collector potassium butyl xanthate (PBX) (150 g / t) and frother (30 g / t) are added to the XFD-63 flotation cell. At the beginning of flotation, air is injected into the XFD-63 flotation cell to start flotation, and the air flow rate is maintained at 0.1 Nm 3 / h, monitored by flow meter; after flotation, pentlandite concentrate and serpentine concentrate are obtained;

[0029] In the froth flotation step, the volume of the flotation cell was 1.5 L, the stirring speed was 1800 rpm, and the solid density in the flotation cell was 35% by weight.

[0030] S3, subjecting the serpentine concentrate to activation pretreatment for 5 minutes, followed by sulfuric acid leaching to obtain a leachate enriched with magnesium, wherein the activation pretreatment is microwave treatment, and the power of the microwave treatment process is 300 to 800 W;

[0031] S4, removing impurities from the magnesium-enriched leachate, filtering and separating to obtain nickel slag and magnesium sulfate solution; mixing the nickel slag and pyrite concentrate together, smelting them in a refining furnace, and performing subsequent conventional processes after smelting to obtain the nickel alloy.

[0032] Example 2

[0033] This embodiment provides a nickel alloy smelting method, comprising the following steps:

[0034] S1. Nickel ore samples were crushed to 2 mm. In each flotation experiment, the samples were ground in a mild steel rod mill. The ore was ground to a particle size of 74 μm. During the grinding process, pH regulator sodium carbonate was added to adjust the pH to 9.

[0035] S2, placing the ground nickel ore sample into an XFD-63 flotation cell for froth flotation. Before flotation, 1-hydroxyethyl diphosphonic acid, a collector potassium octyl xanthate (POX) (150 g / t) and a frother (30 g / t) are first added to the XFD-63 flotation cell. At the beginning of flotation, air is injected into the XFD-63 flotation cell to start flotation, and the air flow rate is maintained at 0.1 Nm 3 / h, monitored by flow meter; after flotation, pentlandite concentrate and serpentine concentrate are obtained;

[0036] In the froth flotation step, the volume of the flotation cell was 1.5 L, the stirring speed was 1800 rpm, and the solid density in the flotation cell was 35% by weight.

[0037] S3, subjecting the serpentine concentrate to activation pretreatment for 20 min, followed by nitric acid leaching to obtain a leachate enriched with magnesium, wherein the activation pretreatment is supercritical fluid treatment, and the fluid component is water;

[0038] S4, removing impurities from the magnesium-enriched leachate, filtering and separating to obtain nickel slag and magnesium sulfate solution; mixing the nickel slag and pyrite concentrate together, smelting them in a refining furnace, and performing subsequent conventional processes after smelting to obtain the nickel alloy.

[0039] Example 3

[0040] This embodiment provides a nickel alloy smelting method, comprising the following steps:

[0041] S1. Nickel ore samples were crushed to 2 mm. In each flotation experiment, the samples were ground in a mild steel rod mill. The ore was ground to a particle size of 74 μm. During the grinding process, pH regulator sodium carbonate was added to adjust the pH to 9.

[0042] S2, placing the ground nickel ore sample into an XFD-63 flotation cell for froth flotation. Before flotation, 1-hydroxyethyl diphosphonic acid, methyl isobutyl carbinol (MIBC) (150 g / t) and frother (30 g / t) are added to the XFD-63 flotation cell. When flotation starts, air is injected into the XFD-63 flotation cell to start flotation, and the air flow rate is maintained at 0.1 Nm 3 / h, monitored by flow meter; after flotation, pentlandite concentrate and serpentine concentrate are obtained;

[0043] In the froth flotation step, the volume of the flotation cell was 1.5 L, the stirring speed was 1800 rpm, and the solid density in the flotation cell was 35% by weight.

[0044] S3, subjecting the serpentine concentrate to activation pretreatment for 60 min, followed by hydrochloric acid leaching to obtain a leachate enriched with magnesium, wherein the activation pretreatment is ultrasonic treatment with an ultrasonic power of 300 to 800 W;

[0045] S4, removing impurities from the magnesium-enriched leachate, filtering and separating to obtain nickel slag and magnesium sulfate solution; mixing the nickel slag and pyrite concentrate together, smelting them in a refining furnace, and performing subsequent conventional processes after smelting to obtain the nickel alloy.

[0046] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A nickel alloy smelting method, characterized in that: The following steps are involved: S1. Nickel ore samples were crushed to 2 mm. In each flotation experiment, the samples were ground in a mild steel rod mill. The ore was ground to a particle size of 74 μm. During the grinding process, pH regulator sodium carbonate was added to adjust the pH to 9. S2, placing the ground nickel ore sample into an XFD-63 flotation cell for froth flotation. Before flotation, 1-hydroxyethyl diphosphonic acid is first added to the XFD-63 flotation cell, followed by a collector and a frother. When flotation begins, air is injected into the XFD-63 flotation cell to start flotation, and the air flow rate is maintained at 0.1 Nm 3 / h, monitored by flow meter; after flotation, pentlandite concentrate and serpentine concentrate are obtained; S3, subjecting the serpentine concentrate to activation pretreatment, followed by acid leaching to obtain a leachate enriched with magnesium, wherein the activation pretreatment comprises at least one of supercritical fluid treatment, subcritical fluid treatment, ultrasonic treatment, and microwave treatment, wherein the fluid component in the supercritical fluid treatment and subcritical fluid treatment is at least one of water and carbon dioxide; the ultrasonic power is 300 to 800 W; and the power of the microwave treatment process is 300 to 800 W; S4, removing impurities from the magnesium-enriched leachate, filtering and separating to obtain nickel slag and magnesium sulfate solution; mixing the nickel slag and pyrite concentrate together, smelting them in a refining furnace, and performing subsequent conventional processes after smelting to obtain the nickel alloy.

2. A nickel alloy smelting method according to claim 1, characterized in that: In the froth flotation step, the flotation volume is 1.5 L, the stirring speed is 1800 rpm, and the solid density in the flotation cell is 35% by weight.

3. A nickel alloy smelting method according to claim 1, characterized in that: In S3, the activation pretreatment time is 5 to 60 minutes.

4. A nickel alloy smelting method according to claim 1, characterized in that: In S3, the acid solution used in the acid leaching process is an aqueous solution of a strong inorganic acid; the strong inorganic acid is at least one of sulfuric acid, nitric acid and hydrochloric acid.