Comprehensive utilization method of laterite nickel ore

Abstract

The application belongs to the field of mineral processing, and particularly relates to a comprehensive utilization method of laterite nickel ore. A mixture containing laterite nickel ore and sodium-aluminum-silicon adjusting agent is subjected to first-stage reduction roasting, and then first-stage magnetic separation to obtain first-stage magnetic separation material containing nickel, cobalt and iron and first-stage magnetic separation tailings. The first-stage magnetic separation tailings are subjected to second-stage roasting in a functional atmosphere containing carbon dioxide, and then second-stage magnetic separation to obtain second-stage magnetic separation material containing iron and nepheline tailing product. In the mixture, the molar ratio of sodium to silicon is 0.8-1.25, and the molar ratio of aluminum to silicon is 0.65-1.0. The temperature of the first-stage reduction roasting is 950-1150 DEG C. The temperature of the second-stage roasting is 750-1050 DEG C. The content of carbon dioxide in the functional atmosphere is 40 vol.%. The application realizes full-component utilization of resources by step-by-step recovery of components of laterite nickel ore, provides a feasible way for efficient comprehensive utilization of low-grade laterite nickel ore, and has extremely high popularization and application value.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of metallurgy, in particular to the field of recovery of laterite nickel ore. BACKGROUND

[0002] Laterite nickel ore is rich in reserves and widely distributed, and is an important nickel-cobalt resource. However, it has low nickel-cobalt grade and uneven distribution of nickel and cobalt (nickel mainly exists in the form of isomorphism in iron minerals, and cobalt is mainly present in manganese minerals), combined with a large amount of aluminum, magnesium, and silicon gangue minerals, which makes it difficult to selectively extract nickel and cobalt, and traditional processes have poor economic benefits and heavy pollution. Therefore, how to realize the multi-element comprehensive utilization of nickel, cobalt, iron, aluminum, silicon, and other components in laterite nickel ore, improve resource value, and reduce environmental impact is a research hotspot and difficulty in the current field of metallurgy.

[0003] The industrial processing of laterite nickel ore mainly uses pyrometallurgy and hydrometallurgy. In pyrometallurgy, the rotary kiln-electric furnace method (RKEF) is the most widely used, but it has prominent problems of high energy consumption (requiring a large amount of reducing agent and electric energy) and environmental pollution (producing sulfur dioxide, dust, and slag), and cobalt is not utilized. Although hydrometallurgy has high nickel and cobalt recovery rates and can be selectively leached, it has limitations such as high acid consumption (due to the presence of a large amount of magnesium and aluminum in the ore), difficulty in purifying the leaching solution (high impurity content requiring multiple purification steps), severe equipment corrosion (high-pressure acid leaching requires high corrosion resistance of equipment), and high risk of environmental pollution (large amount of leaching residue). In summary, although traditional metallurgical processes can process laterite nickel ore to some extent, they have problems such as high energy consumption, severe environmental pollution, and low nickel recovery rate, making it difficult to meet the requirements of sustainable development.

[0004] The carbon thermal reduction-magnetic separation process has great development potential due to its short process, low smelting temperature and energy consumption, and small investment. In view of the urgent demand for nickel-cobalt resources in the new energy battery industry, existing technologies also disclose a method for preparing phosphorus iron and nickel-cobalt-manganese hydroxide battery precursor materials using nickel-cobalt-iron alloy prepared by carbon thermal reduction-magnetic separation as raw material (CN101413053A, CN113060712A). The precursor prepared by this method can be used to produce high-performance lithium iron phosphate and lithium nickel-cobalt-manganese oxide battery materials, efficiently utilizing the nickel-cobalt resources in laterite nickel ore and meeting the demand for battery materials in energy transformation. However, this process retains most of the iron, magnesium, aluminum, and silicon components in the magnetic separation tailings, which poses a secondary pollution risk.

[0005] Therefore, although the carbon thermal reduction process is simple and easy to implement, it is still difficult to efficiently recover valuable components such as iron, aluminum, and silicon. SUMMARY

[0006] In view of the problems of low comprehensive recovery rate of elements, and more valuable elements such as iron remaining in tailings in the existing laterite nickel ore recovery process, the application aims to provide a comprehensive utilization method of laterite nickel ore, which aims to efficiently recover valuable metal elements in laterite nickel ore and co-produce low-iron and high-quality nepheline tailings products.

[0007] The element composition of laterite nickel ore is complex, and the content of most valuable elements is relatively low, which is difficult to efficiently recover, for example, there are more valuable elements remaining in the tailings, and the element loss is large. In addition, the prior art does not have the technical idea and method of efficiently recovering valuable elements and co-producing nepheline tailings products meeting industry standards. In view of the current situation of the industry, the application provides the following improved scheme after in-depth research:

[0008] A comprehensive utilization method of laterite nickel ore, the mixture containing laterite nickel ore, sodium aluminum silicon adjusting agent is subjected to first stage reduction roasting, and then first stage magnetic separation is carried out to obtain nickel cobalt iron first stage magnetic separation material and first stage magnetic separation tailings; the first stage magnetic separation tailings are subjected to second stage roasting in a functional atmosphere containing carbon dioxide, and then second stage magnetic separation is carried out to obtain iron-containing second stage magnetic separation material and nepheline tailings products;

[0009] In the mixture, the molar ratio of sodium to silicon is 0.8-1.25, and the molar ratio of aluminum to silicon is 0.65-1.0;

[0010] The temperature of the first stage reduction roasting is 950-1150℃; the temperature of the second stage roasting is 750-1050℃;

[0011] The content of carbon dioxide in the functional atmosphere is 40vol.% or more.

[0012] There is still a lack of technology for efficient recovery of elements in laterite nickel ore and co-production of high-quality nepheline in the industry, and the main difficulty lies in the complex composition of laterite nickel ore, which is difficult to selectively control the phase of valuable elements such as iron, for example, it is difficult to effectively control the synthesis of nepheline, and it is difficult to selectively realize the phase selectivity of valuable elements during the synthesis of nepheline. In view of the problems faced by the technical idea of the application, the application innovatively controls the molar amount of sodium and silicon, the molar amount of aluminum and silicon, the atmosphere and temperature of the second stage roasting, etc. in the first stage roasting process based on the combination of the special two-stage roasting process, which can realize synergy, effectively recover valuable components in laterite nickel ore, and also facilitate the synthesis of nepheline, reduce the generation of iron olivine phase, and facilitate the obtainment of low-iron and high-quality nepheline products.

[0013] In the present application, the laterite nickel ore can be a conventional laterite nickel ore with any composition, and the content of the main components is not particularly required, for example, the content of iron element is greater than or equal to 35 wt.%, the content of MgO is less than or equal to 10 wt.%, and the content of SiO2 is less than or equal to 10 wt.%. Considering the economy of the recovery process, the content of iron element can be 40-50 wt.%, the content of MgO can be 2-5 wt.%, and the content of SiO2 can be 1-10 wt.%.

[0014] In addition, the laterite nickel ore also contains the conventional Ni, Co, Cr2O3, MnO and Al2O3 elements and components. Further, the content of Ni element can be 0.5-2 wt.%, the content of Co element can be 0.05-0.5 wt.%, the content of Cr2O3 can be 0.5-5 wt.%, the content of MnO can be 0.5-5 wt.%, and the content of Al2O3 can be 0.5-5 wt.%. Further, the content of Ni element can be 1-1.5 wt.%, the content of Co element can be 0.1-0.3 wt.%, the content of Cr2O3 can be 2-4 wt.%, the content of MnO can be 2.5-4.5 wt.%, and the content of Al2O3 can be 2-4 wt.%.

[0015] In the present application, the sodium-aluminum-silicon regulator can be any component that can regulate the molar ratio of sodium, aluminum and silicon in the mixture, for example, at least one of sodium sulfate, sodium sulfite, sodium thiosulfate, sodium aluminate or sodium silicate.

[0016] In the present application, the sodium-aluminum-silicon regulator is used to regulate the molar ratio of sodium and silicon and the molar ratio of aluminum and silicon in the mixture, which is beneficial to the combination of the roasting temperature and the two-stage roasting process under the special functional atmosphere, and can further optimize the phase selectivity of valuable components such as iron, for example, can control the fayalite phase, can improve the recovery of valuable metals, and in addition, can also co-produce nepheline products with low iron content.

[0017] Preferably, in the mixture, the molar ratio of sodium to silicon is 1-1.2, and the molar ratio of aluminum to silicon is 0.7-1.0.

[0018] In the present application, the reducing agent in the first-stage reduction roasting can be at least one of a gaseous reducing agent and a solid reducing agent; wherein the gaseous reducing agent includes at least one of hydrogen, CO and CH4; and the solid reducing agent includes a carbonaceous reducing agent.

[0019] The amount of the reducing agent used can be reasonably adjusted according to requirements, for example, can be 0.20-0.50 times the theoretical molar amount of iron in the laterite nickel ore reduced to elemental iron, and further can be 0.25-0.35 times. For example, when the reducing agent is a solid reducing agent, the amount thereof can be 2-10 wt.% of the weight of the laterite nickel ore, and further can be 3-7 wt.%.

[0020] In the present application, the temperature of the first-stage reduction roasting can be 1000-1100 DEG C; and further can be 1050-1100 DEG C. Research shows that at the preferred temperature, it is helpful to further and process combined synergy, and is helpful to further strengthen the recovery of valuable metals in the laterite nickel ore, and to obtain low-iron high-quality nepheline as a byproduct.

[0021] In the present application, the time of the first-stage reduction roasting is 0.5-3 h, preferably 0.5-2.5 h, and considering the process efficiency, can be further 1-2 h.

[0022] In the present application, the strength of the first-stage magnetic separation is 600-1200 Gs, preferably 800-1200 Gs; and further can be 950-1050 Gs.

[0023] In the present application, the second-stage roasting treatment at the temperature is carried out under the functional atmosphere, which can optimize the phase of iron, reduce the selectivity of fayalite, and can obtain higher valuable metal recovery rate and low-iron high-quality nepheline.

[0024] Preferably, in the functional atmosphere, the content of carbon dioxide is 45-85 vol.%; and further can be 60-80 vol.%.

[0025] Preferably, in the functional atmosphere, oxygen is further contained. Research shows that the second-stage roasting treatment under the preferred mixed atmosphere containing carbon dioxide and oxygen can optimize the phase of iron, reduce the selectivity of fayalite, and can obtain higher valuable metal recovery rate and low-iron high-quality nepheline.

[0026] Preferably, in the functional atmosphere, the content of oxygen is 1-5 vol.%; and preferably 2-3 vol.%.

[0027] In the present application, the functional atmosphere further contains a dilution gas, which contains at least one of nitrogen and a rare gas.

[0028] In the present application, the temperature of the second-stage roasting can be 850-950 DEG C. At the temperature in the present application, the process can be combined, the valuable components in the laterite nickel ore can be further effectively recovered, it is also beneficial to synthesize nepheline, reduce the selectivity of phases such as fayalite, and is beneficial to obtain low-iron high-quality nepheline products.

[0029] In the present application, the second stage roasting time is 0.2-4h, preferably 0.5-3h, and can be further 1-2h in consideration of process efficiency.

[0030] The present application research shows that, by selecting the microwave heating method for the second stage roasting, the separation effect of each component can be further improved, for example, the fayalite is effectively inhibited, and the phase selectivity of nepheline is improved, the recovery rate of valuable elements can be improved, and high-quality nepheline with low iron content can be obtained.

[0031] Preferably, the microwave heating power is 800-1100W, and further 950-1100W.

[0032] In the present application, the second stage magnetic separation is a staged magnetic separation, which includes a magnetic separation A process with a magnetic separation strength of 500-1000Gs, and a magnetic separation B process with a magnetic separation strength of 12000-16000Gs. Further, the magnetic separation strength in the magnetic separation A process can be 700-900Gs, and the magnetic separation strength in the magnetic separation B process can be 13000-15500Gs.

[0033] In the present application, the iron-containing second stage magnetic separation material includes a multi-metal doped ferrite material and a ferrochrome concentrate; wherein the multi-metal doped ferrite material is enriched in the magnetic separation A process, and the ferrochrome concentrate is enriched in the magnetic separation B process.

[0034] Beneficial effects

[0035] The comprehensive utilization method of laterite nickel ore provided by the present application enriches nickel and cobalt through the first stage reduction roasting, and recovers elements such as iron, magnesium, chromium, aluminum, silicon and sodium through the second stage roasting and staged magnetic separation technology, realizing efficient utilization of laterite nickel ore resources. The method has the advantages of high resource utilization rate and environmental friendliness, and is expected to become a highly competitive laterite nickel ore processing method with wide application prospects.

[0036] The present application research also shows that, by using a mixed functional atmosphere containing carbon dioxide-oxygen for the second stage roasting, and / or by using microwave-assisted second stage roasting, the reaction selectivity of fayalite and nepheline can be further optimized, which is helpful to obtain high iron recovery rate, and in addition, high-quality nepheline with low iron content can be obtained. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The process flowchart of the present application.

[0038] Figure 2 The XRD pattern of the multi-metal doped ferrite in Example 1.

[0039] Figure 3 The magnetic analysis chart of the multi-metal doped ferrite in Example 1.

[0040] Figure 4 XRD pattern of the chromium iron concentrate in Example 1.

[0041] Figure 5 XRD pattern of the nepheline product in Example 1. DETAILED DESCRIPTION

[0042] The application will be further described in detail below in combination with specific examples.

[0043] The application does not have special requirements for the type of laterite nickel ore, for example, as an optional solution, in the following case, the used laterite nickel ore is one of the easily accessible low-nickel laterite ores, wherein the Ni content is 1.37 wt.%, the Fe content is 45.03 wt.%, the Co content is 0.15 wt.%, the Cr2O3 content is 3.09 wt.%, the MnO content is 1.13 wt.%, the MgO content is 3.78 wt.%, the Al2O3 content is 2.98 wt.%, and the SiO2 content is 8.49 wt.%.

[0044] DETAILED DESCRIPTION Figure 1 The steps shown are as follows:

[0045] Step 1: After mixing the crushed laterite nickel ore, sodium aluminum silicon adjusting agent and reducing agent to form a briquette, drying and first-stage reduction roasting, the roasted briquette is ground and separated by first-stage magnetic separation to obtain a nickel-cobalt-iron alloy powder product (first-stage magnetic separation material) and a first-stage magnetic separation tailing;

[0046] Step 2: After the first-stage magnetic separation tailing is subjected to second-stage roasting in a functional atmosphere containing carbon dioxide and oxygen, grinding and separation by staged magnetic separation, a multi-metal doped ferrite material, iron-chromium concentrate and nepheline product are obtained. In the following case, unless otherwise specified, the first-stage and second-stage roasting processes are both electric heating.

[0047] Example 1

[0048] Step 1:

[0049] After mixing the crushed laterite nickel ore, sodium aluminum silicon adjusting agent and reducing agent to form a briquette, drying and first-stage reduction roasting, the roasted briquette is ground and separated by first-stage magnetic separation to obtain a nickel-cobalt-iron alloy powder product (first-stage magnetic separation material) and a first-stage magnetic separation tailing;

[0050] In the first-stage reduction roasting process, the added reducing agent is anthracite, and the amount is 0.30±0.05 times the theoretical molar amount of iron in the laterite nickel ore reduced to elemental iron, and the sodium aluminum silicon adjusting agent includes sodium sulfate and aluminum hydroxide, wherein the sodium silicon molar ratio in the mixture after adding the sodium aluminum silicon adjusting agent is 1.19, and the aluminum silicon molar ratio is 0.73;

[0051] The first-stage reduction roasting temperature is 1050°C (marked as T1), and the time is 1.5 h; the first-stage reduction roasting product is ground to a size of -0.074 mm, and the proportion is more than 95%; and the magnetic field strength in the magnetic separation process is 1000 Gs. The nickel-cobalt-iron alloy is recovered by the first-stage magnetic separation, and the recovery rates of nickel, cobalt and iron are 94.74%, 92.56% and 17.76% respectively.

[0052] Step 2:

[0053] After the second-stage roasting, grinding and multi-stage magnetic separation of the tailings of the first-stage magnetic separation in a functional atmosphere containing carbon dioxide and oxygen, a multi-metal doped ferrite material (XRD is shown in Figure 2 , the magnetic analysis results are shown in Figure 3 ), an iron-chromium concentrate (XRD is shown in Figure 4 ) and nepheline (the tailings of the second-stage magnetic separation, XRD is shown in Figure 5 ) are obtained.

[0054] The atmosphere of the second-stage roasting is a mixture of carbon dioxide, oxygen and nitrogen, wherein the content of carbon dioxide is 80 vol.% and the content of oxygen is 3 vol.%; the temperature of the second-stage roasting is 900°C (marked as T2), and the time is 1 h;

[0055] The second-stage roasting product is ground to a size of -0.048 mm, and the proportion is more than 95% for multi-stage magnetic separation; the magnetic field strength in the multi-stage magnetic separation process is 800 Gs (magnetic separation A process strength) and 15000 Gs (magnetic separation B process strength) respectively. The iron recovery rate in the process of recovering the multi-metal doped ferrite material is 94.95% when the magnetic field strength is 800 Gs, the chromium content in the chromium-iron concentrate is 35.11% when the magnetic field strength is 15000 Gs, and the iron content in the nepheline product is 0.29%. At the same time, the Na2O content in the obtained nepheline is 24.94%, the SiO2 content is 22.53%, and the SiO2 content is 47.09%, which meets the JC-T 2395-2017 nepheline raw material standard.

[0056] Example 2

[0057] Compared with Example 1, the difference is only that T1 in Step 1 is changed, and other conditions are shown in Example 1 respectively; the experimental groups are as follows:

[0058] Group A: T1 is 1000°C; the nickel-cobalt-iron alloy is recovered by the first-stage reduction roasting-magnetic separation, and the recovery rates of nickel, cobalt and iron are 91.44%, 87.36% and 15.35% respectively. The iron recovery rate in the process of recovering the multi-metal doped ferrite material after the second-stage roasting-grinding is 94.21%, the chromium content in the chromium-iron concentrate is 33.91%, and the iron content in the nepheline product is 2.51%.

[0059] Group B: T1 is 1100℃; after the first stage of reduction roasting-magnetic separation to recover nickel-cobalt-iron alloy, the recovery rate of nickel, cobalt and iron is 96.29%, 94.14% and 19.83% respectively. After the second stage of roasting-milling separation to recover multi-metal doped ferrite material process, the recovery rate of iron is 94.99%, the chromium content in chromium-iron concentrate is 35.61%, and the iron content in nepheline product is 0.27%.

[0060] Comparative group A: T1 is 850℃; after the first stage of reduction roasting-magnetic separation to recover nickel-cobalt-iron alloy, the recovery rate of nickel, cobalt and iron is 65.43%, 55.20% and 55.10% respectively. After the second stage of roasting-milling separation to recover multi-metal doped ferrite material process, the recovery rate of iron is 75.51%, the chromium content in chromium-iron concentrate is 29.61%, and the iron content in nepheline product is 13.27%.

[0061] From each group of example 1 and 2, it can be seen that the first stage of reduction roasting at the temperature described in the application can effectively improve the recovery rate of nickel and cobalt in the first stage of magnetic separation, and the selection of appropriate T1 has an important influence on the subsequent separation and recovery process of the tailings of the first stage of magnetic separation.

[0062] Example 3

[0063] Compared with example 1, the only difference is that the type and amount of sodium-aluminum-silicon adjusting agent in the first stage of reduction roasting process of step 1 is changed, and other conditions are respectively seen in example 1; the experimental groups are respectively:

[0064] Group A: the sodium-aluminum-silicon adjusting agent is sodium thiosulfate and sodium aluminate, the molar ratio of sodium to silicon in the mixture is 1.03, and the molar ratio of aluminum to silicon is 0.97; after the first stage of reduction roasting-magnetic separation to recover nickel-cobalt-iron alloy, the recovery rate of nickel, cobalt and iron is 94.19%, 92.21% and 17.91% respectively. After the second stage of roasting-milling separation to recover multi-metal doped ferrite material process, the recovery rate of iron is 94.97%, the chromium content in chromium-iron concentrate is 35.26%, and the iron content in nepheline product is 0.28%.

[0065] Group B: the sodium-aluminum-silicon adjusting agent is sodium aluminate and sodium sulfite, the molar ratio of sodium to silicon in the mixture is 1.15, and the molar ratio of aluminum to silicon is 0.78; after the first stage of reduction roasting-magnetic separation to recover nickel-cobalt-iron alloy, the recovery rate of nickel, cobalt and iron is 94.07%, 92.91% and 17.80% respectively. After the second stage of roasting-milling separation to recover multi-metal doped ferrite material process, the recovery rate of iron is 94.92%, the chromium content in chromium-iron concentrate is 35.35%, and the iron content in nepheline product is 0.27%.

[0066] Comparative group A: no sodium-aluminum-silicon regulator was added, the molar ratio of sodium to silicon in the mixture was 0.03, and the molar ratio of aluminum to silicon was 0.41; after the first-stage reduction roasting-magnetic separation, the nickel-cobalt-iron alloy was recovered, and the recovery rates of nickel, cobalt and iron were 59.62%, 54.58% and 23.80%, respectively; after the second-stage roasting-milling separation, the recovery rate of iron in the process of recovering the multi-metal doped ferrite material was 76.83%, the chromium content in the chromium-iron concentrate was 26.11%, and the iron content in the nepheline product was 23.29%.

[0067] Comparative group B: the sodium-aluminum-silicon regulator was sodium sulfate, the molar ratio of sodium to silicon in the mixture was 0.99, and the molar ratio of aluminum to silicon was 0.41; after the first-stage reduction roasting-magnetic separation, the nickel-cobalt-iron alloy was recovered, and the recovery rates of nickel, cobalt and iron were 86.05%, 86.47% and 19.55%, respectively; after the second-stage roasting-milling separation, the recovery rate of iron in the process of recovering the multi-metal doped ferrite material was 91.16%, the chromium content in the chromium-iron concentrate was 35.47%, and the iron content in the nepheline product was 11.39%.

[0068] It can be seen from each group of examples 1 and 3 that, by using the sodium-silicon ratio and the aluminum-silicon ratio in the range of the present application for the first-stage reduction roasting, not only the recovery of nickel and cobalt in the first-stage roasting-magnetic separation process is significantly improved, but also the recovery rate of nickel and cobalt can reach more than 90%, and the recovery rate of iron is less than 20%, which can improve the enrichment efficiency of nickel and cobalt, and at the same time, the control of the sodium-silicon ratio and the aluminum-silicon ratio can produce beneficial effects on the roasting-segmented magnetic separation process of the tailings of the first-stage magnetic separation, the recovery rate of iron in the multi-metal doped ferrite is significantly improved, the iron content in the obtained nepheline product is greatly reduced, and better separation indexes are exhibited.

[0069] The lower recovery rate of iron in the process of extracting nickel and cobalt means that less iron enters the first-stage magnetic separation material in the magnetic separation process, which helps to improve the content of nickel and cobalt in the magnetic product and improve the enrichment efficiency thereof, so that the subsequent process of purifying nickel and cobalt (such as leaching or solvent extraction) is more efficient, and the separation cost is reduced.

[0070] Example 4

[0071] Compared with example 1, the only difference is that the atmosphere of the second-stage roasting process in step 2 is changed, and other conditions are shown in example 1, respectively. The experiment only affects the results of step 2, and the experimental groups are as follows:

[0072] Group A: the atmosphere is a mixture of carbon dioxide-oxygen-nitrogen, wherein the content of carbon dioxide is 60 vol.%, and the content of oxygen is 2%; after the second-stage roasting-milling separation, the recovery rate of iron in the process of recovering the multi-metal doped ferrite material was 94.50%, the chromium content in the chromium-iron concentrate was 34.41%, and the iron content in the nepheline product was 0.91%.

[0073] Group B: the atmosphere is a mixture of carbon dioxide-oxygen-nitrogen, the content of carbon dioxide is 50 vol.%, the content of oxygen is 3%; the iron recovery rate of the process of recovering the multi-metal doped ferrite material after the second stage of roasting-grinding and separation is 92.66%, the content of chromium in the chromium iron concentrate is 31.69%, and the content of iron in the nepheline product is 3.74%.

[0074] Group C: the functional gas in the atmosphere is single carbon dioxide, and the content of the functional gas in the atmosphere is the same as that in example 1, that is, the atmosphere is a mixture of 83 vol.% carbon dioxide and nitrogen; the iron recovery rate of the process of recovering the multi-metal doped ferrite material after the second stage of roasting-grinding and separation is 94.11%, the content of chromium in the chromium iron concentrate is 34.27%, and the content of iron in the nepheline product is 1.16%.

[0075] Comparative group A: the atmosphere is a mixture of carbon dioxide-oxygen-nitrogen, the content of carbon dioxide is 10 vol.%, the content of oxygen is 3%; the iron recovery rate of the process of recovering the multi-metal doped ferrite material after the second stage of roasting-grinding and separation is 63.40%, the content of chromium in the chromium iron concentrate is 17.12%, and the content of iron in the nepheline product is 13.84%.

[0076] Comparative group B: the atmosphere is a mixture of carbon dioxide-oxygen-nitrogen, the content of carbon dioxide is 80 vol.%, the content of oxygen is 10%; the iron recovery rate of the process of recovering the multi-metal doped ferrite material after the second stage of roasting-grinding and separation is 62.68%, the content of chromium in the chromium iron concentrate is 15.39%, and the content of iron in the nepheline product is 15.61%.

[0077] Comparative group C: the functional gas in the atmosphere is single oxygen, and the content of the functional gas in the atmosphere is the same as that in example 1, that is, the atmosphere is a mixture of 83 vol.% oxygen and nitrogen; the iron recovery rate of the process of recovering the multi-metal doped ferrite material after the second stage of roasting-grinding and separation is 59.87%, the content of chromium in the chromium iron concentrate is 14.16%, and the content of iron in the nepheline product is 15.73%.

[0078] It can be known from each group of example 1 and 4 that, compared with low carbon dioxide and high oxygen content, the second stage of roasting in the atmosphere described in the application can unexpectedly improve the selectivity of the oxidation process, so that the difference in the magnetic properties of each phase in the tailings of the first stage of magnetic separation can be enlarged, and the separation effect of the multi-stage magnetic separation can be improved.

[0079] Example 5

[0080] Compared with example 1, the difference is only that T2 of step 2 is changed, and other conditions are shown in example 1, respectively, and the experiment only affects the results of step 2, and the experimental groups are as follows:

[0081] Group A: T2 is 850℃; iron recovery rate of the process of recovering multi-metallic doped ferrite material after second stage roasting-milling and separation is 92.43%, chromium content in chromium iron concentrate is 31.98%, and iron content in nepheline product is 1.22%.

[0082] Group B: T2 is 950℃; iron recovery rate of the process of recovering multi-metallic doped ferrite material after second stage roasting-milling and separation is 94.71%, chromium content in chromium iron concentrate is 34.95%, and iron content in nepheline product is 0.26%.

[0083] Group C: T2 is 1050℃; iron recovery rate of the process of recovering multi-metallic doped ferrite material after second stage roasting-milling and separation is 91.67%, chromium content in chromium iron concentrate is 30.80%, and iron content in nepheline product is 0.49%.

[0084] Comparative group A: T2 is 650℃; iron recovery rate of the process of recovering multi-metallic doped ferrite material after second stage roasting-milling and separation is 69.40%, chromium content in chromium iron concentrate is 22.76%, and iron content in nepheline product is 9.91%.

[0085] Comparative group B: T2 is 1200℃; iron recovery rate of the process of recovering multi-metallic doped ferrite material after second stage roasting-milling and separation is 89.63%, chromium content in chromium iron concentrate is 28.84%, and iron content in nepheline product is 1.67%.

[0086] It can be seen from each group of example 1 and 5 that, by using the atmosphere and further adding the temperature control, the selectivity of the oxidation process can be unexpectedly facilitated, and the separation effect of the multi-stage magnetic separation can be improved.

[0087] Example 6

[0088] Compared with example 5, the difference is only that the heating mode and temperature of the second stage roasting process of step 2 are changed, and other conditions are shown in example 5, respectively. The experiment only affects the results of step 2, and the experimental groups are as follows:

[0089] Group A: the second stage roasting is microwave heating, the microwave heating power is 1000W, and T2 is 850℃; iron recovery rate of the process of recovering multi-metallic doped ferrite material after second stage roasting-milling and separation is 95.37%, chromium content in chromium iron concentrate is 38.19%, and iron content in nepheline product is 0.23%.

[0090] Group B: the second stage roasting is microwave heating, the microwave heating power is 950W, and T2 is 950℃; iron recovery rate of the process of recovering multi-metallic doped ferrite material after second stage roasting-milling and separation is 96.17%, chromium content in chromium iron concentrate is 40.95%, and iron content in nepheline product is 0.19%.

[0091] From each group of Examples 5 and 6, it can be seen that, in the present application, the second roasting process selects the mode of microwave heating, which can further improve the separation effect and can obtain ideal separation effect at a lower roasting temperature. Specifically: when microwave heating is selected at 850℃, compared with conventional heating, the iron recovery rate is increased from 92.43% to 95.37%, the chromium content in the chromium-iron concentrate is increased from 31.98% to 38.19%, and the iron content in the nepheline is reduced from 1.22% to 0.23%.

Claims

1. A method for the comprehensive utilization of laterite nickel ore, characterized in that, The mixture containing laterite nickel ore and sodium aluminum silicon regulator is subjected to a first-stage reduction roasting, followed by a first-stage magnetic separation to obtain nickel-cobalt-iron first-stage magnetic separation feed and first-stage magnetic separation tailings; the first-stage magnetic separation tailings are subjected to a second-stage roasting in a functional atmosphere containing carbon dioxide, followed by a second-stage magnetic separation to obtain iron-containing second-stage magnetic separation feed and nepheline tailings products. In the mixture, the molar ratio of sodium to silicon is 0.8~1.25, and the molar ratio of aluminum to silicon is 0.65~1.0; the temperature of the first stage of reduction roasting is 950~1150℃; the temperature of the second stage of roasting is 750~1050℃. The functional atmosphere is a mixture of carbon dioxide and dilution gas, wherein the carbon dioxide content is 45-85 vol.%. Alternatively, the functional atmosphere is a mixture of carbon dioxide, oxygen, and diluent gas; wherein the carbon dioxide content is 40 vol.% or more, and the oxygen content is 1-5 vol.%. The dilution gas contains at least one of nitrogen and rare gases.

2. The comprehensive utilization method of laterite nickel ore as described in claim 1, characterized in that, The laterite nickel ore contains ≥35 wt.% iron, ≤10 wt.% MgO, and ≤10 wt.% SiO2. Lateritic nickel ore also contains elements or components such as Ni, Co, Cr2O3, MnO, and Al2O3.

3. The comprehensive utilization method of laterite nickel ore as described in claim 1, characterized in that, The sodium aluminum silicate modifier is at least one of sodium sulfate, sodium sulfite, sodium thiosulfate, sodium aluminate, or sodium silicate.

4. The comprehensive utilization method of laterite nickel ore as described in claim 1, characterized in that, The reducing agent in the first stage of reduction roasting is at least one of a gaseous reducing agent and a solid reducing agent; wherein, the gaseous reducing agent includes at least one of hydrogen, CO, and CH4; Solid reducing agents include carbonaceous reducing agents; The amount of reducing agent used is 0.20 to 0.50 times the theoretical molar amount of iron in laterite nickel ore to be reduced to elemental form.

5. The comprehensive utilization method of laterite nickel ore as described in claim 1, characterized in that, The first stage of reduction roasting takes 0.5 to 3 hours.

6. The comprehensive utilization method of laterite nickel ore as described in claim 1, characterized in that, The intensity of the first stage of magnetic separation is 600~1200 Gs.

7. The comprehensive utilization method of laterite nickel ore as described in claim 1, characterized in that, In the functional atmosphere, the oxygen content is 2-3 vol.%.

8. The comprehensive utilization method of laterite nickel ore as described in claim 1, characterized in that, The second roasting time is 0.2~4 hours.

9. The comprehensive utilization method of laterite nickel ore as described in any one of claims 1 to 8, characterized in that, Microwave heating is used in the roasting process, with a power of 800~1100W.

10. The comprehensive utilization method of laterite nickel ore as described in claim 1, characterized in that, The second stage of magnetic separation is graded magnetic separation, which includes magnetic separation process A with a magnetic separation intensity of 500~1000Gs and magnetic separation process B with a magnetic separation intensity of 12000~16000Gs. The iron-containing two-stage magnetic separation material includes multi-metal doped ferrite material and iron-chromium concentrate; wherein, magnetic separation A process enriches the multi-metal doped ferrite material, and magnetic separation B process enriches the iron-chromium concentrate.

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