Method for comprehensively recovering valuable metals in high-iron bonded copper oxide ore

Abstract

The invention discloses a method for comprehensively recovering valuable metals in high-iron bonded copper oxide ore, and belongs to the technical field of resource recovery. According to the method, the high-iron bonded copper oxide ore is subjected to precise ore phase conversion, so that limonite in the high-iron bonded copper oxide ore is converted into magnetite. In the ore phase conversion process, pores and cracks are generated on the surface of the high-iron bonded copper oxide mineral, and grain boundary dislocation occurs between iron minerals and copper minerals, so that release of the bonded copper minerals is promoted; the ore phase conversion product is subjected to mechanical activation, selective enhanced leaching and solid-liquid separation, and iron-rich leaching residues and copper-rich leaching liquid are prepared; and the iron-rich leaching residues are further subjected to low-intensity magnetic separation, and efficient recovery of iron ore concentrate is easily achieved. According to the method, the iron ore concentrate and the copper-rich leachate are finally obtained, and efficient comprehensive recovery of iron and copper valuable metals in the high-iron combined copper oxide ore is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of resource recovery, and particularly relates to a method for comprehensively recovering valuable metals in high-iron combined copper oxide ore. Background Art

[0002] As important strategic metals, copper and iron play an irreplaceable role in many cutting-edge technical fields such as the national economy and national defense industry. However, China's external dependence on copper and iron is as high as over 70% and 80% respectively, which are metals with significant security supply risks. Therefore, the development and utilization of complex and refractory copper and iron ore resources are of great significance for ensuring the safe supply of China's copper and iron ore resources. At present, the reserves of high-iron combined copper oxide ore in the II and V ore bodies of the Yulong Copper Mine in the "Three Rivers" region of Tibet are approximately 20 million tons, with an average Cu grade of 1.79% and an average TFe grade of 33.78%, accounting for 77.46% of the total reserved copper oxide ore resources. The iron minerals in this copper-iron ore resources mainly exist in the form of weakly magnetic and refractory hematite and limonite, while most of the copper ore resources are hosted in the iron minerals in a combined state, resulting in extremely difficult separation. For a long time, it has been difficult to effectively recover and a large amount has been stockpiled, which not only causes a waste of a large amount of scarce resources, but also greatly restricts the development of nearly 1 billion tons of deep high-quality copper resources. Therefore, strengthening the efficient resource utilization of refractory iron-copper ores is of great significance.

[0003] Patent CN106944244A discloses a method for the recovery and utilization of encapsulated complex copper oxide ore. This method uses sulfidation, and combines xanthate, fatty acid salt and hydroxamic acid to flotation free copper oxide, and recovers the iron and biotite minerals encapsulating copper minerals in the ore by magnetic separation, obtaining a large amount of low-grade copper-containing tailings; further, the copper ore resources in the encapsulated copper concentrate are intensively leached by high-temperature and high-pressure, and the waste heat of the high-temperature leaching pulp is utilized and the copper minerals in the low-grade copper-containing tailings are leached with acid; however, this method also does not consider the recovery of iron ore resources, and requires high-temperature and high-pressure leaching equipment. In addition, a large amount of impurity ions are easily contained in the copper leaching solution during the high-temperature and high-pressure acid leaching process, which is not conducive to the extraction of subsequent processes. Patent CN108787155A discloses a method for flotation treatment of high-sulfur iron-copper ore. This invention uses a process of one roughing, four cleanings, four scavengings and one magnetic separation to treat the complex iron-copper ore with high sulfur iron, and solves the problem that pyrrhotite and pyrite in the high-sulfur iron-copper ore viciously cycle in the flotation process and affect the separation efficiency by carrying out branch and parallel treatment of the middlings. However, this method finally puts the iron minerals into the tailings pond and only recovers the copper minerals, resulting in a waste of a large amount of iron ore resources and the problem of a long process flow.

[0004] For high-iron combined copper oxide ore resources, it is difficult to effectively separate and recover copper and iron resources by a single beneficiation method, and it is difficult to achieve efficient leaching of copper minerals by a single metallurgical method. Patent CN107971123 A proposes a beneficiation and metallurgy method for iron-coated mixed copper ore, which improves the recovery rate of iron-coated copper ore by flotation + magnetic separation + sulfuric acid leaching. This patent first obtains flotation copper concentrate through three-stage sulfide flotation, further performs high-gradient magnetic separation on the flotation copper tailings to obtain copper-containing magnetic concentrate, and finally performs sulfuric acid leaching on the copper-containing magnetic concentrate to obtain copper-containing leaching solution. However, this method only recovers copper minerals and cannot achieve the comprehensive recovery of copper and iron minerals. Moreover, the leaching effect of iron minerals is not considered during the acid leaching process, which easily results in a large amount of iron impurities in the leaching solution.

[0005] Patent CN 119351770 A proposes a method for obtaining copper and ferrous sulfate from low-grade sulfur-oxygen mixed iron copper ore. This patent combines roasting, leaching, and extraction processes to provide a new idea for the comprehensive recovery of copper and iron in iron copper ore. This patent first performs ammonium salt roasting on iron copper ore, further leaches copper and iron in iron copper ore synchronously with sulfuric acid, and finally separates copper and iron in the leaching solution by extraction process. However, this method has the problem of a long roasting time (100 - 120 min), and the leaching solution needs to be further extracted and separated, increasing the process flow. Summary of the Invention

[0006] Aiming at the problems of low comprehensive recovery efficiency, high energy consumption, and poor selective leaching effect in the treatment of high-iron combined copper oxide ore in the prior art, the present invention provides a method for comprehensively recovering valuable metals in high-iron combined copper oxide ore, aiming to achieve the efficient comprehensive recovery of iron and copper in high-iron combined copper oxide ore.

[0007] A method for comprehensively recovering valuable metals in high-iron combined copper oxide ore specifically includes the following steps:

[0008] (1) The high-iron combined copper oxide ore is subjected to particle fine crushing, particle classification, and material dehumidification using a jaw crusher, a pair-roll crusher, and a disc crusher to obtain ore powder with a particle size < 0.45 mm;

[0009] (2) The ore powder obtained in step (1) is added to a fluidized bed roasting device and subjected to dehydroxylation roasting in an air atmosphere to obtain dehydroxylated minerals; subsequently, the dehydroxylated minerals are placed in a fluidized bed roasting device and subjected to directional mineral phase transformation in a reducing atmosphere to obtain mineral phase transformation products;

[0010] (3) The mineral phase transformation products are cooled to below 120 °C, and the mineral phase transformation products are further mechanically activated;

[0011] (4) The leaching reagent ammonia water, the complexing reagent ammonium salt, and water are formulated into a chemical extraction solution, which is added to the mechanically activated product for stirring leaching;

[0012] (5) Filter the product obtained in step (4) by suction filtration, and wash the filter cake with deionized water 2 to 3 times to obtain a copper-rich alkali leaching solution and an iron-rich leaching residue.

[0013] (6) Put the iron-rich leaching residue into a mill, grind it with water and then dry it.

[0014] (7) The dried iron-rich leaching residue in step (6) is subjected to magnetic separation in a magnetic separation device. After suction filtration and drying of the product obtained by magnetic separation, iron concentrate and magnetic separation tailings are obtained.

[0015] Wherein:

[0016] In the said step (2), during the dehydroxylation roasting process, the temperature in the fluidized roasting device is 350 °C to 500 °C, air atmosphere is continuously introduced at the bottom at 400 mL / min to 600 mL / min, and the roasting time is 3 min to 5 min.

[0017] In the said step (2), during the directional mineral phase transformation process, the temperature in the fluidized roasting device is 450 °C to 550 °C, and the mineral phase transformation time is 10 min to 25 min.

[0018] In the said step (2), the reducing atmosphere is one or more of CO and H2, the gas flow rate introduced is 80 mL / min to 200 mL / min, and at the same time, N2 with a gas flow rate of 300 mL / min to 500 mL / min is introduced as a protective gas.

[0019] In the said step (3), the cooling method is one of nitrogen cooling or water quenching cooling, and the particle size of the product after mechanical activation < 0.074 mm accounts for more than 70% of the total weight.

[0020] In the said step (4), the ammonia water concentration is 0.75 mol / L to 1.5 mol / L, the ammonium salt is selected from ammonium chloride, ammonium carbonate, ammonium sulfate, and the ammonium ion concentration in the chemical extraction solution is 0.75 mol / L to 1.5 mol / L.

[0021] In the said step (4), the liquid-solid ratio of the chemical extraction solution to the mechanically activated product is (8 - 12):1, the solution temperature is kept at room temperature during the leaching process, and the leaching time is 20 min to 50 min.

[0022] In the said step (6), the mill is one of a conical ball mill and a rod mill, and the grinding time is 3 min to 5 min.

[0023] In the said step (7), the magnetic field intensity for magnetic separation is set at 0.1 T to 0.2 T, and the magnetic separation time is set at 3 min to 5 min.

[0024] The total copper recovery rate ≥ 78%, the iron loss rate is less than 1%, the recovery rate of iron concentrate ≥ 95%, and the grade of iron concentrate ≥ 63%.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] (1) Compared with single beneficiation and metallurgy processes, the present invention adopts a beneficiation and metallurgy technology of precise mineral phase transformation - selective enhanced leaching - magnetic separation recovery, which can realize the selective comprehensive recovery of iron and copper in high-iron combined copper oxide ore.

[0027] (2) Compared with the ammonium salt roasting - leaching - extraction process, the mineral phase transformation - ammonia leaching technology adopted by the present invention has technical advantages such as short roasting time, high leaching selectivity, and simple process.

[0028] (3) Compared with the flotation enrichment - leaching technology, the limonite in the present invention generates a loose and porous structure during the process of removing crystal water and crystal structure transformation, creating favorable conditions for the efficient leaching of copper minerals tightly combined with limonite.

[0029] (4) Compared with acid leaching treatment, the present invention uses ammonia leaching to treat the mineral phase transformation minerals, which can greatly reduce the loss of iron minerals and improve the grade of iron minerals. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Process flow diagram of a method for comprehensive recovery of valuable metals in high-iron combined copper oxide ore of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] Example 1

[0032] A method for comprehensive recovery of valuable metals in high-iron combined copper oxide ore, the process flow diagram of which is as Figure 1 shown, and specifically includes the following steps:

[0033] In this example, the high-iron combined copper oxide ore from Yulong, Tibet is used as the raw material. By mass fraction, the content of TFe in the raw ore is 48.67%, and the content of Cu is 1.62%.

[0034] (1) The high-iron combined copper oxide ore is subjected to particle fine crushing, particle classification, and material dehumidification using a jaw crusher, a pair-roll crusher, and a disc crusher to obtain ore powder with a particle size < 0.45 mm.

[0035] (2) The ore powder obtained in step (1) is added to a fluidized bed roasting device at a temperature of 500 °C for dehydroxylation roasting. During the roasting process, air atmosphere is continuously introduced at the bottom of the device at a rate of 500 mL / min. After roasting for 3 min, dehydroxylated minerals are obtained;

[0036] Subsequently, the dehydroxylated mineral was placed in a fluidized roasting device at a temperature of 500 °C, and directional mineral phase transformation was carried out under a reducing atmosphere. The reducing gas introduced was H2 at 150 mL / min, and at the same time, 500 mL / min of N2 was introduced as a protective gas. After 15 min, a mineral phase transformation product was obtained.

[0037] (3) Continuously introduce N2 atmosphere in the fluidized roasting device to cool the mineral phase transformation product to below 120 °C, and further mechanically activate the cooled product with a ball mill for 4 min. The particle size of the obtained product <0.074 mm accounts for more than 70% of the total weight.

[0038] (4) Prepare a chemical extraction solution by mixing the leaching reagent ammonia water, the complexing reagent ammonium chloride and water. The concentration of ammonia water is 0.75 mol / L, and the concentration of ammonium ions in the chemical extraction solution is 0.75 mol / L. Add the mechanically activated product according to a liquid-solid ratio of 12:1, and carry out stirring leaching. During the leaching process, the solution temperature is kept at room temperature, the stirring speed is 400 r / min, and the leaching time is 50 min.

[0039] (5) Filter the product obtained in step (4) by suction, and wash the filter cake with deionized water 3 times to obtain a copper-rich alkaline leaching solution and an iron-rich leaching residue.

[0040] (6) Put the iron-rich leaching residue into a conical ball mill, and carry out wet grinding with a liquid-solid ratio of 1:1 for 4 min. Dry the ground product in an oven.

[0041] (7) Carry out magnetic separation on the iron-rich leaching residue dried in step (6) in a magnetic separation device. The magnetic field intensity is set at 0.12 T, and the magnetic separation time is set at 5 min. After suction filtration and drying of the product obtained by magnetic separation, iron concentrate and magnetic separation tailings are obtained.

[0042] In this example, the total copper recovery rate obtained is 79.51%, the iron loss rate is less than 1%, the recovery rate of iron concentrate is 97.17%, and the grade of iron concentrate is 63.11%.

[0043] Example 2

[0044] A method for comprehensive recovery of valuable metals from a high-iron combined copper oxide ore specifically includes the following steps:

[0045] In this example, the Tibet Yulong high-iron combined copper oxide ore was used as the raw material. By mass fraction, the content of TFe in the raw ore is 48.49%, and the content of Cu is 1.60%.

[0046] (1) The high-iron combined copper oxide ore was subjected to particle fine crushing, particle grading, and material dehumidification using a jaw crusher, a pair-roll crusher, and a disc crusher to obtain ore powder with a particle size <0.45 mm.

[0047] (2) Add the ore powder obtained in step (1) to a fluidized roasting device at a temperature of 450 °C for dehydroxylation roasting. During the roasting process, air atmosphere is continuously introduced at the bottom of the device at a rate of 600 mL / min. After roasting for 5 min, dehydroxylated minerals are obtained.

[0048] Subsequently, place the dehydroxylated minerals in a fluidized roasting device at a temperature of 520 °C and carry out directional mineral phase transformation under a reducing atmosphere. The reducing gas introduced is H2 at a rate of 120 mL / min, and at the same time, N2 at a rate of 500 mL / min is introduced as a protective gas. After 15 min, mineral phase transformation products are obtained.

[0049] (3) Cool the mineral phase transformation products in cold water to room temperature, and further mechanically activate the cooled products in a ball mill for 5 min. The particle size of the obtained product is less than 0.074 mm, accounting for more than 75% of the total weight.

[0050] (4) Prepare a chemical extraction solution by mixing the leaching reagent ammonia water, the complexing reagent ammonium chloride and water. The concentration of ammonia water is 1 mol / L, and the concentration of ammonium ions in the chemical extraction solution is 1 mol / L. Add the mechanically activated product according to a liquid-solid ratio of 10:1, and carry out stirring leaching. During the leaching process, the solution temperature is kept at room temperature, the stirring speed is 400 r / min, and the leaching time is 30 min.

[0051] (5) Filter the product obtained in step (4) by suction, and wash the filter cake 3 times with deionized water to obtain a copper-rich alkaline leaching solution and an iron-rich leaching residue.

[0052] (6) Put the iron-rich leaching residue into a rod mill, and carry out wet grinding with a liquid-solid ratio of 1:1 for 5 min. Dry the ground product in an oven.

[0053] (7) Carry out magnetic separation on the iron-rich leaching residue dried in step (6) in a magnetic separation device. The magnetic field intensity is set at 0.14 T, and the magnetic separation time is set at 4 min. After suction filtration and drying of the products obtained by magnetic separation, iron concentrate and magnetic separation tailings are obtained.

[0054] In this example, the total copper recovery rate obtained is 78.56%, the iron loss rate is less than 1%, the recovery rate of iron concentrate is 96.65%, and the grade of iron concentrate is 63.85%.

[0055] Example 3

[0056] A method for comprehensive recovery of valuable metals from high-iron combined copper oxide ore specifically includes the following steps:

[0057] In this example, the high-iron combined copper oxide ore from Yulong, Tibet is used as the raw material. By mass fraction, the content of TFe in the original ore is 48.99%, and the content of Cu is 1.61%.

[0058] (1) The high-iron combined copper oxide ore is subjected to particle fine crushing, particle classification, and material dehumidification using a jaw crusher, a pair-roll crusher, and a disc crusher to obtain ore powder with a particle size of -0.45 mm accounting for 90%.

[0059] (2) The ore powder obtained in step (1) is added to a fluidized roasting device at a temperature of 400 °C for dehydroxylation roasting. During the roasting process, air atmosphere is continuously introduced at the bottom of the device at a rate of 400 mL / min. After roasting for 5 min, dehydroxylated minerals are obtained;

[0060] Subsequently, the dehydroxylated minerals are placed in a fluidized roasting device at a temperature of 550 °C for directional mineral phase transformation under a reducing atmosphere. The reducing gas introduced is 100 mL / min of H2 and 50 mL / min of CO, and at the same time 400 mL / min of N2 is introduced as a protective gas. After 10 min, mineral phase transformation products are obtained.

[0061] (3) N2 atmosphere is continuously introduced in the fluidized roasting device to cool the mineral phase transformation products to below 120 °C. Further, the cooled products are mechanically activated by a ball mill for 5 min, and the particle size of the obtained product is <0.074 mm accounting for more than 75% of the total weight.

[0062] (4) The leaching reagent ammonia water, the complexing reagent ammonium chloride, and water are formulated into a chemical extraction solution. The concentration of ammonia water is 1.5 mol / L, and the concentration of ammonium ions in the chemical extraction solution is 1.5 mol / L. According to a liquid-solid ratio of 8:1, the mechanically activated product is added for stirring leaching. During the leaching process, the solution temperature is kept at room temperature, the stirring speed is 500 r / min, and the leaching time is 30 min.

[0063] (5) The product obtained in step (4) is subjected to suction filtration, and the filter cake is washed 3 times with deionized water to obtain a copper-rich alkali leaching solution and an iron-rich leaching residue.

[0064] (6) The iron-rich leaching residue is put into a conical ball mill and ground with water at a liquid-solid ratio of 1:1 for 3 min. The ground product is dried in an oven.

[0065] (7) The iron-rich leaching residue dried in step (6) is subjected to magnetic separation in a magnetic separation device. The magnetic field intensity is set at 0.2 T, and the magnetic separation time is set at 3 min. The products obtained by magnetic separation are suction filtered and dried to obtain iron concentrate and magnetic separation tailings.

[0066] In this example, the total copper recovery rate obtained is 78.39%, the iron loss rate is less than 1%, the recovery rate of iron concentrate is 95.87%, and the grade of iron concentrate is 64.36%.

[0067] Example 4

[0068] A method for comprehensive recovery of valuable metals in high-iron combined copper oxide ore, specifically including the following steps:

[0069] In this embodiment, the high-iron combined copper oxide ore from Yulong, Tibet is used as the raw material. By mass fraction, the content of TFe in the raw ore is 48.49%, and the content of Cu is 1.62%.

[0070] (1) The high-iron combined copper oxide ore is subjected to particle fine crushing, particle classification, and material dehumidification using a jaw crusher, a pair-roll crusher, and a disc crusher to obtain ore powder with a particle size < 0.45 mm.

[0071] (2) The ore powder obtained in step (1) is added to a fluidized-bed roasting device at a temperature of 350 °C for dehydroxylation roasting. During the roasting process, air atmosphere is continuously introduced at the bottom of the device at a rate of 500 mL / min. After roasting for 5 min, dehydroxylated minerals are obtained;

[0072] Subsequently, the dehydroxylated minerals are placed in a fluidized-bed roasting device at a temperature of 520 °C for directional mineral phase transformation under a reducing atmosphere. The reducing gas introduced is H2 at a rate of 80 mL / min, and at the same time, 300 mL / min of N2 is introduced as a protective gas. After 25 min, mineral phase transformation products are obtained.

[0073] (3) N2 atmosphere is continuously introduced in the fluidized-bed roasting device to cool the mineral phase transformation products to below 120 °C. Further, the cooled products are mechanically activated by a ball mill for 5.5 min, and the particle size of the obtained product with < 0.074 mm accounts for more than 80% of the total weight.

[0074] (4) The leaching reagent ammonia water, the complexing reagent ammonium chloride, and water are formulated into a chemical extraction solution. The concentration of ammonia water is 1.2 mol / L, and the concentration of ammonium ions in the chemical extraction solution is 1.2 mol / L. According to the liquid-solid ratio of 12:1, the mechanically activated product is added for stirring leaching. During the leaching process, the solution temperature is kept at room temperature, the stirring speed is 500 r / min, and the leaching time is 20 min.

[0075] (5) The product obtained in step (4) is subjected to suction filtration, and the filter cake is washed 3 times with deionized water to obtain a copper-rich alkali leaching solution and an iron-rich leaching residue.

[0076] (6) The iron-rich leaching residue is put into a rod mill and ground with water at a liquid-solid ratio of 1:1 for 5 min, and the grinding product is dried in an oven.

[0077] (7) The iron-rich leaching residue dried in step (6) is subjected to magnetic separation in a magnetic separation device. The magnetic field intensity is set at 0.1 T, and the magnetic separation time is set at 5 min. After suction filtration and drying of the products obtained by magnetic separation, iron concentrate and magnetic separation tailings are obtained.

[0078] In this example, the total copper recovery rate was 79.61%, the iron loss rate was less than 1%, the recovery rate of iron concentrate was 96.14%, and the grade of iron concentrate was 63.74%.

[0079] Example 5

[0080] A method for comprehensive recovery of valuable metals from high-iron combined copper oxide ore specifically includes the following steps:

[0081] In this example, the high-iron combined copper oxide ore from Yulong, Tibet was used as the raw material. By mass fraction, the content of TFe in the raw ore was 48.99%, and the content of Cu was 1.61%.

[0082] (1) The high-iron combined copper oxide ore was subjected to particle fine crushing, particle classification, and material dehumidification using a jaw crusher, a pair-roll crusher, and a disk crusher to obtain ore powder with a particle size < 0.45 mm.

[0083] (2) The ore powder obtained in step (1) was added to a fluidized bed roasting device at a temperature of 500 °C for dehydroxylation roasting. During the roasting process, air atmosphere was continuously introduced at the bottom of the device at a rate of 500 mL / min. After roasting for 5 min, dehydroxylated minerals were obtained;

[0084] Subsequently, the dehydroxylated minerals were placed in a fluidized bed roasting device at a temperature of 500 °C for directional mineral phase transformation under a reducing atmosphere. The reducing gas introduced was 150 mL / min of H2 and 50 mL / min of CO, and at the same time, 400 mL / min of N2 was introduced as a protective gas. After 20 min, mineral phase transformation products were obtained.

[0085] (3) The mineral phase transformation products were cooled to room temperature in cold water and further mechanically activated for 5 min by a ball mill. The particle size of the obtained product < 0.074 mm accounted for more than 75% of the total weight.

[0086] (4) The leaching reagent ammonia water, the complexing reagent ammonium chloride, and water were formulated into a chemical extraction solution. The concentration of ammonia water was 1 mol / L, and the concentration of ammonium ions in the chemical extraction solution was 1.2 mol / L. According to the liquid-solid ratio of 12:1, the mechanically activated products were added for stirring leaching. During the leaching process, the solution temperature was maintained at room temperature, the stirring speed was 500 r / min, and the leaching time was 30 min.

[0087] (5) The products obtained in step (4) were filtered by suction, and the filter cake was washed 3 times with deionized water to obtain copper-rich alkaline leaching solution and iron-rich leaching residue.

[0088] (6) The iron-rich leaching residue was put into a rod mill and ground with water at a liquid-solid ratio of 1:1 for 5 min, and the grinding products were dried in an oven.

[0089] (7) The iron-rich leaching residue dried in step (6) is subjected to magnetic separation in a magnetic separation device. The magnetic field strength is set at 0.15 T, and the magnetic separation time is set at 5 min. The product obtained by magnetic separation is filtered and dried to obtain iron concentrate and magnetic separation tailings.

[0090] In this example, the total copper recovery rate obtained is 80.02%, the iron loss rate is less than 1%, the recovery rate of iron concentrate is 96.39%, and the grade of iron concentrate is 63.61%.

[0091] Comparative Example 1

[0092] A method for comprehensive recovery of valuable metals from a high-iron combined copper oxide ore specifically includes the following steps:

[0093] In this example, the Tibet Yulong high-iron combined copper oxide ore is used as the raw material. By mass fraction, the content of TFe in the raw ore is 48.67%, and the content of Cu is 1.62%.

[0094] (1) The high-iron combined copper oxide ore is subjected to particle fine crushing, particle classification, and material dehumidification using a jaw crusher, a pair-roll crusher, and a disk crusher to obtain ore powder with a particle size < 0.45 mm.

[0095] (2) The ore powder obtained in step (1) is added to a fluidized bed roasting device at a temperature of 500 °C for dehydroxylation roasting. During the roasting process, air atmosphere is continuously introduced at the bottom of the device at a rate of 500 mL / min. After roasting for 3 min, dehydroxylated minerals are obtained;

[0096] Subsequently, the dehydroxylated minerals are placed in a fluidized bed roasting device at a temperature of 500 °C for directional mineral phase transformation under a reducing atmosphere. The reducing gas introduced is H2 at a rate of 150 mL / min, and at the same time, N2 at a rate of 500 mL / min is introduced as a protective gas. After 15 min, mineral phase transformation products are obtained.

[0097] (3) N2 atmosphere is continuously introduced in the fluidized bed roasting device to cool the mineral phase transformation products to below 120 °C. Further, the cooled products are mechanically activated by a ball mill for 4 min, and the particle size of the obtained product < 0.074 mm accounts for more than 70% of the total weight.

[0098] (4) Ammonia water with a concentration of 0.75 mol / L is used as the leaching reagent. According to a liquid-solid ratio of 12:1, the mechanically activated product is added for stirring leaching. During the leaching process, the solution temperature is kept at room temperature, the stirring speed is 400 r / min, and the leaching time is 50 min.

[0099] (5) The product obtained in step (4) is filtered by suction, and the filter cake is washed 3 times with deionized water to obtain copper-rich alkaline leaching solution and iron-rich leaching residue.

[0100] (6) Put the iron-rich leaching residue into a conical ball mill, and carry out wet grinding of ore for 4 min with a liquid-solid ratio of 1:1, and dry the grinding product in an oven.

[0101] (7) Carry out magnetic separation on the iron-rich leaching residue dried in step (6) in a magnetic separation device, set the magnetic field strength at 0.12 T, set the magnetic separation time at 5 min, and obtain iron concentrate and magnetic separation tailings after suction filtration and drying of the products obtained by magnetic separation.

[0102] In this example, the total copper recovery rate obtained is 41.16%, the iron loss rate is less than 1%, the recovery rate of iron concentrate is 97.17%, and the grade of iron concentrate is 63.41%.

[0103] Comparative Example 2

[0104] A method for comprehensive recovery of valuable metals in a high-iron combined copper oxide ore specifically comprises the following steps:

[0105] In this example, the Yulong high-iron combined copper oxide ore in Tibet is used as the raw material. By mass fraction, the content of TFe in the raw ore is 48.67%, and the content of Cu is 1.62%.

[0106] (1) Carry out particle fine crushing, particle classification, and material dehumidification on the high-iron combined copper oxide ore by using a jaw crusher, a pair-roll crusher, and a disc crusher to obtain ore powder with a particle size < 0.45 mm.

[0107] (2) Prepare a chemical extraction solution by mixing the leaching reagent ammonia water, the complexing reagent ammonium chloride, and water. The concentration of ammonia water is 0.75 mol / L, the concentration of ammonium ions in the chemical extraction solution is 0.75 mol / L, and the solution temperature is kept at room temperature during the chemical extraction process; add the ore powder according to a liquid-solid ratio of 12:1, carry out stirring leaching, the stirring speed is 400 r / min, and the leaching time is 50 min.

[0108] (3) Carry out suction filtration on the product obtained in step (2), and wash the filter cake 3 times with deionized water to obtain a copper-rich alkali leaching solution and an iron-rich leaching residue.

[0109] (4) Put the iron-rich leaching residue into a conical ball mill, and carry out wet grinding of ore for 4 min with a liquid-solid ratio of 1:1, and dry the grinding product in an oven.

[0110] (5) Carry out magnetic separation on the iron-rich leaching residue dried in step (4) in a magnetic separation device, set the magnetic field strength at 0.12 T, set the magnetic separation time at 5 min, and obtain iron concentrate and magnetic separation tailings after suction filtration and drying of the products obtained by magnetic separation.

[0111] In this example, the mineral phase transformation process was not adopted. Therefore, the copper minerals in the high-iron combined copper oxide ore were not released, resulting in the inability to effectively recover the copper minerals by chemical wet extraction, and the extraction efficiency of copper was only 16.16%. The iron minerals in the ore still exist in the form of limonite, and the weak magnetic separation process cannot recover them.

[0112] As can be seen from the results of the above examples and comparative examples, the present invention conducts mineral phase transformation on high-iron combined copper oxide ore under a reducing atmosphere and high temperature conditions, so that the weakly magnetic limonite therein is directionally transformed into strongly magnetic iron minerals. This process not only strengthens the magnetic separation characteristics of iron minerals, but also promotes the grain boundary dislocations between copper minerals and iron minerals, thereby significantly improving the copper extraction efficiency of the mineral phase transformation product. During the wet strengthening extraction process of the mineral phase transformation product, under the action of the complexing agent ammonium salt, the complexing dissolution efficiency of copper minerals increases significantly, the solution system is more stable, and the recovery efficiency of copper is significantly improved.

Claims

1. A method for comprehensive recovery of valuable metals in high-iron combined copper oxide ore, characterized in that: The specific steps include: (1) The high iron combined copper oxide ore is crushed, graded and dehumidified by a jaw crusher, a roll crusher and a disc crusher to obtain ore powder with a particle size of less than 0.45 mm; The crushing equipment is a combination of a jaw crusher, a roll crusher and a disc crusher; (2) adding the mineral powder obtained in step (1) into a fluidized roasting device, and performing dehydroxylation roasting in an air atmosphere to obtain a dehydroxylated mineral; then placing the dehydroxylated mineral in a fluidized roasting device, and performing directional mineral phase transformation in a reducing atmosphere to obtain a mineral phase transformation product; (3) cooling the mineral phase transformation product to below 120° C. and further mechanically activating the mineral phase transformation product; (4) preparing a chemical extraction solution by using a leaching agent ammonia water, a complexing agent ammonium salt and water, and adding the mechanical activation product to perform stirring leaching; (5) filtering the product obtained in step (4) and washing the filter cake with deionized water for 2 to 3 times to obtain a copper-rich alkaline leaching solution and an iron-rich leaching residue; (6) putting the iron-rich leached slag into a mill, adding water to grind the ore and then drying it; (7) The iron-rich leaching residue after drying in step (6) is subjected to magnetic separation in a magnetic separation device, and the product obtained by magnetic separation is filtered and dried to obtain iron concentrate and magnetic separation tailings.

2. The method for comprehensive recovery of valuable metals in high-iron combined copper oxide ore according to claim 1, characterized in that: In the step (2), during the dehydroxylation calcination process, the temperature in the fluidized calcination device is 350° C. to 500° C., an air atmosphere is continuously introduced into the bottom at a flow rate of 400 mL / min to 600 mL / min, and the calcination time is 3 min to 5 min.

3. The method for comprehensive recovery of valuable metals in high-iron combined copper oxide ore according to claim 1, characterized in that: In the step (2), the temperature in the fluidized roasting device during the directional mineral phase conversion process is 450° C. to 550° C., and the mineral phase conversion time is 10 min to 25 min.

4. The method for comprehensive recovery of valuable metals in high-iron combined copper oxide ore according to claim 1, characterized in that: In the step (2), the reducing atmosphere is one or more of CO and H2, and the amount of gas introduced is 80mL / min to 200mL / min. At the same time, N2 is introduced at a gas amount of 300mL / min to 500mL / min as a protective gas.

5. The method for comprehensive recovery of valuable metals in high-iron combined copper oxide ore according to claim 1, characterized in that: In the step (3), the cooling method is nitrogen cooling or water quenching cooling, and the particle size of the product after mechanical activation is less than 0.074 mm, accounting for more than 70% of the total weight.

6. The method for comprehensive recovery of valuable metals in high iron combined with copper oxide ore according to claim 1, characterized in that: In the step (4), the concentration of ammonia water is 0.75 mol / L to 1.5 mol / L, the ammonium salt is selected from ammonium chloride, ammonium carbonate, and ammonium sulfate, and the concentration of ammonium ions in the chemical extraction solution is 0.75 mol / L to 1.5 mol / L.

7. The method for comprehensive recovery of valuable metals in high-iron combined copper oxide ore according to claim 1, characterized in that: In the step (4), the liquid-to-solid ratio of the chemical extraction solution to the modified product is (8-12):1, the solution temperature is maintained at room temperature during the leaching process, and the leaching time is 20 min to 50 min.

8. The method for comprehensive recovery of valuable metals in high-iron combined copper oxide ore according to claim 1, characterized in that: In the step (6), the mill is a conical ball mill or a rod mill, and the grinding time is 3 min to 5 min.

9. The method for comprehensive recovery of valuable metals in high-iron combined copper oxide ore according to claim 1, characterized in that: In the step (7), the magnetic field strength of the magnetic separation is set at 0.1T to 0.2T, and the magnetic separation time is set at 3min to 5min.

10. The method for comprehensive recovery of valuable metals in high-iron combined copper oxide ore according to claim 1, characterized in that: The total copper recovery rate is ≥78%, the iron loss rate is less than 1%, the recovery rate of the iron concentrate is ≥95%, and the grade of the iron concentrate is ≥63%.

Images