阅读说明：本技术 一种铜矿选矿尾矿获取铁粉的方法、铁粉及其应用 (Method for obtaining iron powder from copper ore dressing tailings, iron powder and application of iron powder ) 是由 彭同江 罗冰 孙红娟 于 2021-09-01 设计创作，主要内容包括：本发明提供了一种铜矿选矿尾矿获取铁粉的方法、铁粉及其应用,所述获取铁粉的方法包括：氧化煅烧硫化物铜矿选矿尾矿,获得含20％以上质量份的γ-Fe-(2)O-(3)的第一煅烧渣和含氧化硫的气体；按照预定质量比混合第一煅烧渣、煤粉和钙质原料粉体混合均匀后,进行还原煅烧,获得含单质铁的第二煅烧渣；将第二煅烧渣进行粉磨和磁选处理,获得铁粉。本发明的工艺方法简单,处理成本低,获得的全铁的提取率为56％～88％,提取回收率高,得到单质铁粉产品中单质铁的含量为22％～46％,品位高,符合冶炼原料要求。(The invention provides a method for obtaining iron powder from copper ore dressing tailings, iron powder and application thereof, wherein the method for obtaining the iron powder comprises the following steps: oxidizing and calcining the mineral dressing tailings of the sulphide copper ore to obtain the gamma-Fe with the mass part of more than 20 percent 2 O 3 And a gas containing sulfur oxides; mixing the first calcined slag, the coal powder and the calcium raw material powder according to a preset mass ratio, uniformly mixing, and then carrying out reduction calcination to obtain second calcined slag containing simple substance iron; and performing grinding and magnetic separation treatment on the second calcined slag to obtain iron powder. The method has the advantages of simple process, low treatment cost, high extraction recovery rate of the obtained total iron of 56-88 percent, high grade of the obtained simple substance iron powder product with the simple substance iron content of 22-46 percent, and accordance with the requirements of smelting raw materials.)

1. The method for obtaining the iron powder from the copper ore dressing tailings is characterized by comprising the following steps of:

s1, oxidizing and calcining the sulfide copper ore dressing tailings to obtain the gamma-Fe with the mass part of more than 20%₂O₃And a gas containing sulfur oxides;

s2, mixing the first calcined slag, the coal powder and the calcareous raw material powder according to a preset mass ratio, uniformly mixing, and carrying out reduction calcination to obtain second calcined slag containing simple substance iron;

and S3, grinding and magnetically separating the second calcined slag to obtain iron powder.

2. The method for obtaining iron powder from copper ore dressing tailings according to claim 1, wherein the size of the copper sulfide ore dressing tailings is 0.044mm to 0.147mm, and the copper sulfide ore dressing tailings contain sulfide minerals and gangue minerals, the sulfide minerals comprise at least one of pyrrhotite, chalcopyrite, pyrite and amphibole, and the gangue minerals comprise at least one of quartz, biotite, anorthite, muscovite, feldspar, chlorite, lepidolite and carbonate minerals.

3. According to claim 1The method for obtaining the iron powder from the copper ore dressing tailings is characterized in that the first calcined slag comprises 31-50% of SiO in percentage by mass₂、25％～60％Fe₂O₃And 9 to 25% of Al₂O₃。

4. The method for obtaining iron powder from copper ore dressing tailings according to claim 1, wherein the coal powder comprises at least one of lignite, bituminous coal, anthracite and coke, and the calcareous raw material powder comprises at least one of quicklime, slaked lime and carbide slag powder.

5. The method for obtaining iron powder from copper ore dressing tailings according to claim 1, wherein in step S2, 50% -80% of first calcined slag, 10% -30% of coal powder and 5% -15% of calcareous raw material powder are uniformly stirred and mixed, then 3% -30% of deionized water is added for granulation, and after natural drying, reduction calcination is performed.

6. The method for obtaining iron powder from copper ore dressing tailings according to claim 1, wherein the reduction calcination is performed by gradually raising the ambient temperature to a preset temperature, then gradually raising the preset temperature to a reduction temperature, and setting the reduction time of the calcination to be 55min to 75min, wherein the preset temperature ranges from 900 ℃ to 1000 ℃, the reduction temperature ranges from 1000 ℃ to 1250 ℃, the temperature raising rate from the ambient temperature to the preset temperature is 15 ℃/min to 20 ℃/min, and the temperature raising rate from the preset temperature to the reduction temperature is 30 ℃/min to 50 ℃/min.

7. The method for obtaining the iron powder from the copper ore dressing tailings according to claim 1, wherein the grinding is one of dry grinding and wet grinding, and the particle size of the powder is 0.05mm to 0.15 mm; the magnetic separation is one of wet magnetic separation and dry magnetic separation, and the set magnetic field intensity of the magnetic separator is 100-220 mT.

8. The method for obtaining iron powder from copper ore dressing tailings according to claim 7, wherein the mass-to-volume ratio of the wet-ground material to water is 1: 20-1: 30g/mL during wet magnetic separation.

9. An iron powder, which is obtained by the method for obtaining the iron powder by using the copper ore dressing tailings as claimed in any one of claims 1 to 8, and the content of the elementary iron in the iron powder is 22-46%.

10. Use of the iron powder according to claim 9 as a raw material for iron and steel smelting.

Technical Field

The invention relates to the technical field of treatment and resource utilization of copper ore dressing tailings, in particular to a method for obtaining iron powder from copper ore dressing tailings, iron powder obtained by recovery based on the method for obtaining the iron powder from the copper ore dressing tailings and application of the iron powder.

Background

In recent years, the copper yield of China is rapidly increased and becomes the first major refined copper producing country in the world, and the yield approximately accounts for 1/3 worldwide. At present, copper in China is mainly produced by pyrometallurgical smelting, the discharge amount of copper slag exceeds 1000 million tons every year according to the discharge amount of 2.2 tons of copper slag per 1 ton of produced refined copper in the copper smelting process, most of the copper slag is piled up in a slag yard, land is occupied, the surrounding environment is polluted, and meanwhile, huge resource waste is caused. The valuable components in the copper slag are mainly ferrous silicate, the total iron grade is about 40%, the iron mainly exists in the form of fayalite, the embedded particle size is small, and the iron is difficult to recover by adopting the traditional beneficiation method, so that the effective recovery of the iron component in the copper slag has important significance for environmental protection.

The iron in the copper smelting slag mainly exists in the forms of fayalite and ferric silicate, the iron grade is high, the embedded granularity is extremely fine, and the comprehensive utilization difficulty is high. In the prior art, magnetic separation roughing, regrinding, magnetic separation concentration, reverse flotation and other processes are mostly adopted to carry out ore dressing tests for recovering iron ore concentrate and coal dressing heavy medium from copper slag copper dressing tailings.

For example, patent documents entitled method for comprehensively recovering magnetite and copper minerals from copper slag flotation tailings, which is disclosed in 2019, 4, 19 and publication No. CN109647616A, describe a method for comprehensively recovering magnetite and copper minerals from copper slag flotation tailings. Firstly, magnetic roughing is carried out, magnetic separation is carried out on copper slag flotation tailings under the condition of 1800Gs-2200Gs, magnetic rough concentrates and magnetic tailings are obtained respectively, 450g/t-550g/t of water glass and 15g/t-25g/t of Z-200 are added into a stirring barrel for stirring for 5min during table reselection, regrinding and magnetic separation are carried out, the magnetic rough concentrates and the table concentrates are combined and then sent into a ball mill for regrinding, lime is added as a grinding aid, and finally copper minerals are recovered through flotation. The process is complex and high in energy consumption, and only magnetite concentrate is obtained.

The patent document with the publication number of CN112251601A discloses a method for recovering iron by reducing manganese-containing mineral reinforced red mud in 22.1.1.1, which comprises the steps of preparing agglomerates containing red mud, manganese-containing minerals, a binder and water, drying the obtained agglomerates to obtain dried agglomerates, carrying out high-temperature oxidation consolidation on the obtained dried agglomerates to obtain oxidized agglomerates, carrying out reduction roasting on the obtained oxidized agglomerates by using a reducing agent to obtain metallized agglomerates, and finally carrying out ore grinding and magnetic separation on the obtained metallized agglomerates in sequence to obtain metallic iron powder. The method is not only complicated in steps, but also cannot solve the problem of recovering other iron-containing tailings, for example, iron in the desulfurization tailings of the copper mine tailings cannot be recovered by the method.

A beneficiation method for recovering mica from copper ore tailings disclosed in 2018, 1 month and 16 days, and patent document with publication number CN107583764A, which is characterized in that (1) the copper ore tailings are ground to a content of 70-90% of-0.075 mm; (2) carrying out magnetic separation on the obtained substance in the step (1) under the magnetic field intensity of 0.1-0.2T to obtain weak magnetic concentrate and weak magnetic tailings; (3) carrying out magnetic separation on the weak magnetic tailings obtained in the step (2) under the magnetic field intensity of 0.8-1.4T to obtain strong magnetic concentrate and non-magnetic tailings; (4) grading the strong magnetic concentrate obtained in the step (3) into two grades of + 0.051-0.075 mm and-0.051-0.075 mm, and taking the coarse fraction; (5) and (4) reselecting the product obtained in the step (4), during reselection, roughing is firstly carried out to obtain roughed concentrate, roughed middlings and roughed tailings, during scavenging, the selected raw material is roughed middlings to obtain scavenged concentrate and scavenged tailings, and the roughed concentrate and the scavenged concentrate are combined to obtain reselected mica concentrate. The invention has simple process flow structure, equipment investment saving and low mineral dressing cost, but the invention does not solve the problem of iron recovery, and the iron still exists in mica and is more difficult to recover from the mica.

In summary, the existing treatment process or technology needs to add a flotation agent for flotation or add a strong oxidant for reduction reaction, and has the defects of high cost, complex process or impure iron powder obtained after recovery and separation. At present, no method for recovering iron from copper tailings by reduction roasting-magnetic separation after sulfur release is carried out by oxidation roasting.

Disclosure of Invention

The present invention aims to address at least one of the above-mentioned deficiencies of the prior art. For example, one of the purposes of the invention is to provide a method for obtaining iron powder from copper ore dressing tailings with low cost, simple process and high iron powder purity.

In order to achieve the above object, the present invention provides a method for obtaining iron powder from copper ore dressing tailings, comprising the following steps:

s1, oxidizing and calcining the sulfide copper ore dressing tailings to obtain the gamma-Fe with the mass part of more than 20%₂O₃And a gas containing sulfur oxides;

s2, mixing the first calcined slag, the coal powder and the calcareous raw material powder according to a preset mass ratio, uniformly mixing, and carrying out reduction calcination to obtain second calcined slag containing simple substance iron;

and S3, grinding and magnetically separating the second calcined slag to obtain iron powder.

In an exemplary embodiment of the method for obtaining iron powder from copper mine tailings, the size of the copper sulphide ore tailings may be 0.044mm to 0.147mm and contain sulphide minerals and gangue minerals, the sulphide minerals may include at least one of pyrrhotite, chalcopyrite, pyrite and willemite, and the gangue minerals may include at least one of quartz, biotite, anorthite, muscovite, feldspar, chlorite, lepidolite and carbonate minerals.

In an exemplary embodiment of the method for obtaining iron powder from copper ore dressing tailings of the present invention, the first calcined slag may include 31% to 50% of SiO by mass percentage₂、25％～60％Fe₂O₃And 9 to 25% of Al₂O₃。

In an exemplary embodiment of the method for obtaining iron powder from copper ore dressing tailings of the present invention, the pulverized coal may include at least one of lignite, bituminous coal, anthracite and coke, and the calcareous raw material powder may include at least one of quicklime, slaked lime and carbide slag powder.

In an exemplary embodiment of the method for obtaining iron powder from copper ore dressing tailings, in step S2, 50% to 80% of first calcined slag, 10% to 30% of coal powder, and 5% to 15% of calcareous raw material powder are stirred and mixed uniformly, then 3% to 30% of deionized water is added for granulation, and after natural drying, reduction calcination is performed.

In an exemplary embodiment of the method for obtaining iron powder from the copper ore dressing tailings, the reduction roasting may be performed by gradually raising the ambient temperature to a preset temperature, then gradually raising the preset temperature to a reduction temperature, and setting the reduction time of the roasting to 55min to 75min, wherein the preset temperature is 900 ℃ to 1000 ℃, the reduction temperature is 1000 ℃ to 1250 ℃, the temperature raising rate from the ambient temperature to the preset temperature is 15 ℃/min to 20 ℃/min, and the temperature raising rate from the preset temperature to the reduction temperature is 30 ℃/min to 50 ℃/min.

In an exemplary embodiment of the method for obtaining iron powder from copper ore dressing tailings of the present invention, the grinding may be one of dry grinding and wet grinding, and the particle size of the powder may be 0.05mm to 0.15 mm; the magnetic separation can be one of wet magnetic separation and dry magnetic separation, and the set magnetic field intensity of the magnetic separator can be 100-220 mT.

In an exemplary embodiment of the method for obtaining iron powder from the copper ore dressing tailings, the mass-to-volume ratio of the wet-ground material to water during wet magnetic separation can be 1: 20-1: 30 g/mL.

The iron powder is obtained by the method for obtaining the iron powder from the copper ore dressing tailings, and the content of the simple substance iron in the iron powder can be 22-46%.

In a further aspect the present invention provides the use of an iron powder as described above as a raw material for iron and steel smelting.

Compared with the prior art, the beneficial effects of the invention comprise at least one of the following:

(1) the method for producing the elemental iron powder by using the copper ore dressing tailing powder as the raw material realizes resource utilization of the copper tailing solid waste, protects resources and environment and utilizes the resources at a high value, and has important significance for sustainable development of resources, environment and ecology;

(2) the resource utilization of the copper tailings has important ecological and environmental significance on the safety, reclamation and greening of the tailings pond;

(3) the extraction and utilization of iron and sulfur components in tailings are realized by taking copper ore dressing tailing powder as a raw material through an oxidation-reduction two-step method, and the iron dressing tailings can be used for building materials (an implementation mode), have the advantages of simple and convenient production process, no three-waste discharge, high product added value, high ecological environmental benefit and the like, and have important significance for green mine construction and social and economic development;

(4) the invention obtains the gamma-Fe-containing material by calcining treatment in oxygen-containing atmosphere₂O₃The calcined slag powder and a gas containing sulfur oxide; containing gamma-Fe₂O₃Calcining the calcined slag powder in a reducing atmosphere to obtain calcined slag containing simple substance iron, grinding and magnetically separating to obtain a simple substance iron powder product, and using iron selection tailings as a building material; and collecting the gas containing the sulfur oxide, preparing sulfuric acid, and reacting with calcium oxide to prepare the calcium sulfate whisker. All the additives added in the process flow enter the product, so that no harm or three-waste discharge is caused;

(5) the method has the advantages of simple process, low treatment cost, high extraction recovery rate of the obtained total iron of 56-88 percent, high grade of the obtained simple substance iron powder product with the simple substance iron content of 22-46 percent, and accordance with the requirements of smelting raw materials.

Drawings

The above and other objects and/or features of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows the method for obtaining iron powder from copper ore dressing tailings containing gamma-Fe₂O₃The calcined slag of (2) has a schematic diagram of XRD phase change at different calcination temperatures.

Detailed Description

Hereinafter, the method for obtaining iron powder from copper ore dressing tailings, the iron powder and the application thereof according to the present invention will be described in detail with reference to the exemplary embodiments.

It should be noted that "first," "second," and the like are merely for convenience of description and for ease of distinction, and are not to be construed as indicating or implying relative importance. For those of ordinary skill in the art, the term "pressure" in part herein corresponds to pressure.

The inventor finds out through research that: the ore dressing tailings of the blocky sulfide type copper ore are oxidized, roasted and sulfur-released to obtain the ore dressing tailings containing gamma-Fe₂O₃The calcined slag has magnetism with certain strength and high iron content, and can effectively recover iron components in the copper slag. However, in consideration of long process flow and high cost of the flotation separation of valuable components, the gas-based reduction technology has high cost, and in order to save the recovery cost and improve the grade of the recovered iron powder, the invention provides the method which can directly recover the simple substance iron by reduction roasting-magnetic separation after the copper ore dressing tailing powder is oxidized, roasted and released sulfur.

The invention provides a method for obtaining iron powder from copper ore dressing tailings.

In an exemplary embodiment of the invention, a method for obtaining iron powder from copper ore dressing tailings comprises the following steps:

s1, oxidizing and calcining the sulfide copper ore dressing tailings to obtain the gamma-Fe with the mass part of more than 20%₂O₃And sulfur oxide-containing gas.

Wherein the first calcined slag contains iron minerals including at least one of hematite and maghemite. gamma-Fe contained in the first calcined slag₂O₃(maghemite, belonging to hematite), is magnetic and can be separated by direct magnetic separation.

In particular, the copper ore tailings may comprise tailings of lump sulphide copper ores. In the tailings, pyrrhotite, marmatite and chalcopyrite are complexly connected with each other or are distributed in gangue minerals in a tree shape. The pyrrhotite is mostly in the shape of blocks or blocks and mainly concentrated in the size fraction range of-0.20 to +0.05 mm; the chalcopyrite is mostly in a fine particle shape, the granularity is 0.02-0.20 mm, the sphalerite is mostly in an irregular particle shape, and the granularity can reach 0.3-0.8 mm.

Furthermore, the granularity of the sulphide copper ore dressing tailings can be 0.044 mm-0.147 mm, and the sulphide copper ore dressing tailings contain sulphide minerals and gangue minerals. Wherein the sulfide minerals may include at least one of pyrrhotite, chalcopyrite, pyrite, and willemite, and the gangue minerals may include at least one of quartz, biotite, anorthite, muscovite, feldspar, chlorite, lepidocrocite, and carbonate minerals.

It should be noted that the first calcined slag contains γ -Fe₂O₃The first calcined slag may include 31% to 50% SiO by mass₂、25％～60％Fe₂O₃And 9 to 25% of Al₂O₃. For example, in the first calcined slag, SiO₂Can be 30.00%, 34.00%, 38.00%, 41.00%, 54.00%, 58.00% and the like in percentage by mass, Fe₂O₃Can be 6.50%, 33.00%, 38.00%, 44.00%, 48.90%, 53.45% by mass, Al₂O₃The content of (b) may be 11.30%, 13.20%, 16.40%, 17.00%, 18.05%, 18.90% and the like by mass.

The sulfur oxide-containing gas comprises SO₂、SO₃And the collected calcium sulfate whisker can be used for preparing sulfuric acid or reacting with calcium oxide to prepare calcium sulfate whisker.

And S2, mixing the first calcined slag, the coal powder and the calcareous raw material powder according to a preset mass ratio, uniformly mixing, and carrying out reduction calcination to obtain second calcined slag containing simple substance iron.

Specifically, in the calcining process, coal powder is used as a reducing agent, the calcareous raw material powder blocks the combination of iron and silicon and contains gamma-Fe₂O₃The high-valence iron in the first calcined slag can be reduced into an iron simple substance under the action of a reducing atmosphere, so that the second calcined slag containing the iron simple substance with the mass percentage of 10-25% is obtained. For example, the second calcined slag may contain 11%, 13%, 18%, 21% by mass of iron powder. The calcination treatment is carried out in a calcining kiln, and the reduction atmosphere is realized by generating CO through incomplete combustion of coal powder in the ingredients at high temperature.

Further, the pulverized coal may include at least one of lignite, bituminous coal, anthracite and coke, and the calcareous raw material powder may include at least one of quicklime, slaked lime and carbide slag powder.

In step S2, after 50% to 80% of the first calcined slag, 10% to 30% of the coal powder, and 5% to 15% of the calcareous raw material powder are uniformly stirred and mixed, 3% to 30% of deionized water is added for granulation, and the reduction roasting material is obtained after natural drying. It should be noted that the mixing of the first calcined slag, the coal powder and the calcareous raw material powder according to the above ratio is to enable Fe to be generated in the subsequent reduction reaction₂O₃The reduction degree of the iron is increased, the metallization rate of the iron is improved, and the grade of the iron in the concentrate is further improved. If the mixing ratio of the first calcined slag, the coal powder and the calcareous raw material powder exceeds or is lower than the above ratio, the metallization rate of iron in the subsequent reduction reaction is reduced, the grade of iron in the concentrate is reduced, and the recovery rate is reduced. For example, the first calcined slag may be 56.02%, 63.15%, 68.26%, 72.69%, 78.39%, etc., the pulverized coal may be 12.03%, 15.18%, 20.79%, 24.69%, 28.24%, etc., the calcareous raw material powder may be 6.02%, 8.15%, 9.26%, 12.69%, 14.39%, etc., and the deionized water may be 25.93%, 13.52%, 3.71%, 4.69%, etc.

In the process of calcining, reducing and roasting the materials, the environmental temperature can be gradually increased to the preset temperature, then the preset temperature is gradually increased to the reduction temperature, and the reduction time of calcining is set to be 55-75 min. Wherein the preset temperature is 900-1000 ℃, the reduction temperature is 1000-1250 ℃, the heating rate of the temperature from the ambient temperature to the preset temperature is 15-20 ℃/min, and the heating rate of the temperature from the preset temperature to the reduction temperature is 30-50 ℃/min.

The reduction reaction can reduce all oxygen-containing iron in the first calcined slag into metallic iron by a reducing agent, and the metallic iron also comprises gamma-Fe₂O₃Reducing the iron into elemental iron, and mainly reacting as follows:

2Fe₂O₃+3C→4Fe+3CO₂(g)

and S3, grinding and magnetically separating the second calcined slag to obtain iron powder.

Specifically, the powder grinding may be one of dry powder grinding and wet powder grinding, and the particle size of the powder may be 0.05mm to 0.15 mm.

The magnetic separation can be one of wet magnetic separation and dry magnetic separation, and the set magnetic field strength of the magnetic separator can be 100-220 mT, such as 120, 140, 160, 180, 200mT and the like.

During wet magnetic separation, the mass-to-volume ratio of the wet ground material to water can be 1: 20-1: 30 g/mL. For example, 1: 23. 1: 26. 1: 28. 1: 29, etc.

The iron powder is obtained by the method for obtaining the iron powder from the copper ore dressing tailings, and the content of the simple substance iron in the iron powder can be 22-46%.

The method is adopted to obtain the simple substance iron powder from the copper ore dressing tailing powder, the grade of the obtained iron powder is 22-46%, and the recovery rate is 56-88%.

For example, the iron may be present in an amount of 28%, 30%, 31%, etc. by mass, and the recovery rate may be 59.46%, 60.45%, 69.13%, 74.23%, 80.75%, 86.71%, etc.

In a further aspect the present invention provides the use of an iron powder as described above as a raw material for iron and steel smelting.

For a better understanding of the above-described exemplary embodiments of the present invention, reference is made to the following description taken in conjunction with the accompanying drawings and specific examples.

Example 1

The method for obtaining the simple substance iron powder from the copper ore dressing tailing powder comprises the following steps:

(1) the copper ore dressing tailing powder is sent to a calcining kiln to be calcined in oxygen-containing atmosphere to obtain the product containing gamma-Fe₂O₃The first calcined slag powder (namely, the first calcined slag) and gas containing sulfur oxide. The sulfur oxide-containing gas comprises SO₂、SO₃And the sulfuric acid can be prepared by the existing process after collection.

Wherein, contains gamma-Fe₂O₃The calcined slag powder contains maghemite, quartz and biotite. It is composed ofSiO in chemical composition₂Can be 35.00 percent by mass and Fe₂O₃33.00 percent of Al₂O₃The mass percentage content is 16.40 percent.

(2) Adding anthracite coal 25%, CaO 14.29%, and grinding to 57% containing gamma-Fe₂O₃The calcined slag powder is uniformly mixed, 3.71 percent of deionized water is added for granulation, and the mixture is naturally dried for later use to obtain dry granules with the particle size of 16.78 mm.

(3) And (3) placing the dried mixed material in a calcining kiln, and gradually heating the ambient temperature to the reduction temperature to obtain the calcined slag (namely the second calcined slag) containing 16.03 mass percent of the iron simple substance.

Under the condition that the calcining kiln furnace adopts electric heating, the reduction temperature of calcining treatment is 1200 ℃, the reduction time is 60min, wherein the temperature rise rate of the low-temperature section from the normal temperature to 1000 ℃ is 15 ℃/min, and the temperature rise rate of the high-temperature section from 1000 ℃ to 1200 ℃ is 30 ℃/min.

(4) Adding water into the calcined slag containing the iron simple substance to form fluid with the mass volume ratio of the material to the water being 1: 28; and the magnetic field strength is set to 160 mT; obtaining iron powder with the mass percentage of 34.56 percent after magnetic separation treatment.

In the example, the obtained iron powder with the mass percentage of 34.56 percent can be directly sold as a raw material for iron and steel smelting, and the tailings after the iron powder is magnetically separated can be further used for preparing building materials, such as microcrystalline glass.

Tests show that the method of example 1 produces an iron powder grade of 33.01% with a recovery of 65.47%.

FIG. 1 shows the present exemplary gamma-Fe-containing₂O₃A schematic diagram of the phase change of the calcined slag (i.e. the first calcined slag) in the X-ray diffraction analysis (XRD) at different calcination temperatures, which reflects the phase change process during calcination. In FIG. 1, a represents Quartz (Quartz), b represents Biotite (Biotite), c represents Anorthite (Anorthite), f represents olivine (Fayalite), m represents maghemite (Magnetite), h represents Hematite (Hematite), t represents elemental iron (Ferrite), and w represents Wustite (Wustite); the curve corresponding to A pointsLine represents gamma-Fe₂O₃The phase change process of the calcined slag after calcining for 60min at the calcining temperature of 1200 ℃ meets the curve pointed by B and represents that the calcined slag contains gamma-Fe₂O₃The phase change process of the calcined slag after calcining for 60min at the calcining temperature of 1150 ℃ meets the curve pointed by C and represents that the calcined slag contains gamma-Fe₂O₃The phase change process of the calcined slag after calcining for 60min at the calcining temperature of 1100 ℃ meets the condition that the curve pointed by D represents that the calcined slag contains gamma-Fe₂O₃The phase change process of the calcined slag after calcining at 1050 ℃ for 60min meets the curve pointed by E and represents that the calcined slag contains gamma-Fe₂O₃The phase change process of the calcined slag after calcining for 60min at the calcining temperature of 1000 ℃ meets the curve pointed by F and represents that the calcined slag contains gamma-Fe₂O₃The calcined slag is calcined at the calcination temperature of 0 ℃ for 60min, and then the phase change process is carried out.

In the process of obtaining simple substance iron powder from copper ore dressing tailing powder, as shown in fig. 1, when the temperature is increased to 1200 ℃ and the calcination time is 60min, the phases in the calcination slag mainly comprise quartz and maghemite (gamma-Fe)₂O₃) Mica, anorthite and hematite.

The reduction-magnetic separation method is adopted to separate iron in the copper tailing desulfurization tailings, and has the following advantages: the method is simple and easy to implement, the energy consumption used by the reduction method is low, if the technology is applied in a large scale, the coal-based direct reduction is utilized, the energy structure of 'more coal, less oil and less gas' in China is met, the recovery rate is high, the grade of the obtained iron powder is 22-46%, and the extraction rate is as high as 56-88%; the chemical agents adopted by the technology comprise coal, CaO and ionized water, so that the used chemical agents are few, the corrosion to equipment is small, the harm to human health is small, and the environmental pollution is not easy to cause. The reduction-magnetic separation process has very wide application prospect in separating the copper tailing desulfurization tailings.

Example 2

The method for obtaining the elemental iron powder from the mineral dressing tailing powder of the Liwu copper ore comprises the following steps:

(1) the copper ore dressing tailing powder is sent to a calcining kiln to be calcined under the oxygen-containing atmosphereTo obtain a catalyst containing gamma-Fe₂O₃The first calcined slag powder (namely, the first calcined slag) and gas containing sulfur oxide. The sulfur oxide-containing gas comprises SO₂、SO₃And after collection, the calcium sulfate whisker can be prepared by the reaction of the existing process and calcium oxide.

Wherein, contains gamma-Fe₂O₃The calcined slag powder contains hematite, maghemite, quartz, anorthite and muscovite. Chemical composition of which is SiO₂Can be 41.00 percent by mass, Fe₂O₃40.00 percent of Al₂O₃The mass percentage content is 12.80 percent.

(2) Adding 18 percent of anthracite coal and 12.04 percent of CaO, and mixing with 65.27 percent of ground gamma-Fe₂O₃The calcined slag powder is uniformly mixed, 4.69 percent of deionized water is added for granulation, and the mixture is naturally dried for later use to obtain dry granules with the particle size of 12.56 mm.

(3) And (3) placing the dried mixed material in a roasting furnace, and gradually heating the ambient temperature to the reduction temperature to obtain roasting slag (namely second roasting slag) containing 12.87 mass percent of iron simple substance.

The reduction temperature of the roasting treatment was set at 1100 ℃ and the roasting time was 65 min. Wherein the heating rate of the low-temperature section from the normal temperature to 1000 ℃ is 20 ℃/min, and the heating rate of the high-temperature section from 1000 ℃ to 1100 ℃ is 40 ℃/min.

(4) Adding water into the calcined slag containing the iron simple substance to form fluid with the mass volume ratio of the material to the water being 1: 24; and the magnetic field strength is set to 180 mT; obtaining iron powder with the mass percentage of 28.71 percent after magnetic separation treatment.

In the example, 28.71 mass percent of obtained iron powder can be directly sold as a raw material for iron and steel smelting, and tailings after the iron powder is magnetically separated can be further used for preparing building materials, such as concrete.

Tests show that the method of example 2 produces an iron powder grade of 28.67% with a recovery of 61.25%.

In conclusion, the method for obtaining the iron powder from the copper ore dressing tailings has the advantages that:

(1) the method can realize the high-efficiency recovery of the iron component in the blocky sulfide-type copper ore dressing tailings, wherein the content of iron in the roasting slag can be 10-25 wt%.

(2) The invention uses anthracite, which reduces the cost of the reducing agent compared with other gas-based reducing agents and has no tail gas emission.

(3) The recovery rate of iron in the roasting slag is high and can reach 88%.

(4) The invention has short process flow, simple method and easy implementation.

Although the present invention has been described above in connection with the exemplary embodiments and the accompanying drawings, it will be apparent to those of ordinary skill in the art that various modifications may be made to the above-described embodiments without departing from the spirit and scope of the claims.