阅读说明：本技术 一种从铜渣浮选尾矿回收铁的选冶联合工艺 (Dressing and smelting combined process for recovering iron from copper slag flotation tailings ) 是由 马松勃 王铧泰 赖春华 王鹏程 王景凤 孔德鸿 胡生福 张丽 张慧婷 于 2021-07-19 设计创作，主要内容包括：本发明公开了一种从铜渣浮选尾矿回收铁的选冶联合工艺,通过磨矿磁选的方法获得磁选精矿,再将磁选精矿与煤粉混合后进行深度还原焙烧,控制还原温度和时间,焙烧产物进行磨矿磁选得到还原铁粉,还原铁粉可作为废钢进行销售,磁选尾矿进行脱碳处理,脱除的碳可作为煤粉,除碳后的尾矿与焙烧前的磁选尾矿混合做为最终尾矿,可用于水泥生产,深度还原焙烧收集的粉尘可作为锌冶炼原料。整个工艺具有工艺简单、流程较短、能耗低、经济环保、铁回收效果好、经济效益更高等优点。(The invention discloses a dressing-smelting combined process for recovering iron from copper slag flotation tailings, which comprises the steps of obtaining magnetic separation concentrates by a grinding and magnetic separation method, mixing the magnetic separation concentrates with coal dust, then carrying out deep reduction roasting, controlling the reduction temperature and time, carrying out grinding and magnetic separation on roasted products to obtain reduced iron powder, selling the reduced iron powder as waste steel, decarbonizing the magnetic separation tailings, mixing the decarbonized tailings with the magnetic separation tailings before roasting to obtain final tailings, wherein the final tailings can be used for cement production, and dust collected by the deep reduction roasting can be used as a zinc smelting raw material. The whole process has the advantages of simple process, shorter flow, low energy consumption, economy, environmental protection, good iron recovery effect, higher economic benefit and the like.)

1. A dressing and smelting combined process for recovering iron from copper slag flotation tailings is characterized by comprising the following steps: the recovery process is carried out as follows,

1) carrying out stage grinding and magnetic separation on the copper slag flotation tailings to obtain magnetic separation concentrate;

2) mixing the magnetic concentrate obtained in the step 1) with pulverized coal, performing deep reduction roasting, and collecting dust to obtain soot, wherein the mass ratio of the magnetic concentrate to the pulverized coal is 1.5-2.5: 1;

3) carrying out ore grinding and magnetic separation on the roasted product obtained in the step 2) to obtain reduced iron powder and magnetic separation tailings;

4) decarbonizing the magnetic tailings obtained in the step 3) to obtain coal powder and coal-removed tailings.

2. The combined beneficiation and metallurgy process for recovering iron from copper slag flotation tailings according to claim 1, wherein: in the step 1), the stage ore grinding magnetic separation process comprises magnetic separation I → ore grinding I → magnetic separation II → ore grinding II → magnetic separation III → ore grinding III → magnetic separation IV, the magnetic field intensity of the magnetic separation I, the magnetic separation II, the magnetic separation III and the magnetic separation IV is 1900Oe, 1700Oe and 1400Oe, and the ore grinding fineness is-400 meshes accounting for 90%, minus 500 meshes accounting for 90% and minus 600 meshes accounting for 90%.

3. The combined beneficiation and metallurgy process for recovering iron from copper slag flotation tailings according to claim 1, wherein: in the step 2), the magnetic concentrate and the coal powder are mixed according to the mass ratio of 2:1, the reaction temperature is 1150-1250 ℃, and the reaction time is 40 minutes.

4. The combined beneficiation and metallurgy process for recovering iron from copper slag flotation tailings according to claim 1, wherein: in the step 3), the grinding fineness is controlled to be-325 meshes and accounts for 90%, and the magnetic field intensity of magnetic separation is 1700 Oe.

5. The combined beneficiation and metallurgy process for recovering iron from copper slag flotation tailings according to claim 1, wherein: in step 4), the decarburization treatment process is reselection.

Technical Field

The invention relates to the technical field of non-ferrous metal hydrometallurgy, in particular to a process for recovering iron from copper slag flotation tailings.

Background

At present, more than 90% of enterprises adopt a pyrometallurgical process to smelt copper, and a large amount of copper slag (about 3 tons of copper slag are produced in 1 ton of copper) is produced in the pyrometallurgical process of copper, wherein the copper content of the smelting slag is about 3-6%, the copper content of the blowing slag is about 10-12%, and the copper content of the flash smelting slag is about 1%. Aiming at the problem of high copper content in slag, most copper smelting enterprises adopt a flotation process to recover copper, and the process is mature at present. After the copper slag is floated, a large amount of flotation tailings can be generated, wherein the tailings generally contain 40-45% of iron, a small amount of copper, zinc, arsenic and sulfur elements, and the balance of silicate minerals. The copper content of the tailings is generally 0.2-0.4%, and the tailings have no much economic value under the current technical level. At present, copper slag flotation tailings are mainly used as additives of building materials such as cement and concrete, and are generally sold to cement enterprises according to the price of 50-100 yuan/ton.

Because flotation tailings contain a large amount of iron, a process for recovering iron from copper slag flotation tailings is proposed. For example, patent CN104874485B discloses a process for recovering iron from copper smelting slag flotation tailings, which comprises copper smelting slag flotation tailings → low-intensity magnetic separation → reverse flotation → scavenging → thickening → filtration; the patent CN108178532A discloses a method for comprehensively utilizing copper slag flotation tailings, which comprises the steps of crushing and finely grinding the copper slag flotation tailings until the particle size is 0.1-0.4 mm, and then carrying out magnetic separation under the condition that the magnetic separation strength is 200-250 mT to obtain magnetic separation iron ore concentrate and magnetic separation tailings; adding quicklime into the dried magnetic separation tailings, uniformly mixing, and then performing high-temperature sintering treatment for 3-5 hours at the temperature of 900-1100 ℃ to obtain cement clinker. Because the occurrence state of iron in the copper slag flotation tailings is different from that of iron ore in the nature, the iron is mostly in the form of ultrafine magnetite and partially in the form of fayalite, and a small amount of copper, zinc and sulfur elements are mixed and symbiotic with the magnetite or the fayalite, the grade of the obtained iron concentrate is not up to 60 percent, the impurities in the concentrate are out of the limits due to high copper and zinc contents, the concentrate cannot be sold as the iron concentrate, and the purity of magnetic iron of the iron concentrate serving as a heavy medium cannot meet the national standard requirement of the heavy medium; patent CN108754170A discloses a method for comprehensive utilization of all components of copper slag, which comprises the steps of proportioning, mixing, crushing and grinding the copper slag, calcium oxide, aluminum oxide and carbon according to a certain mass ratio, then placing the mixture into a high-temperature reduction furnace for reduction, and separating slag and iron to obtain molten iron and slag. The molten iron can be sent to a steel mill, the slag can be processed by a forming-annealing process, a nucleation process and a crystallization process to obtain microcrystalline glass, and zinc vapor generated in the reduction reaction process is collected and then sent to the zinc mill. Although the process utilizes the copper slag to prepare the zinc oxide dust, the ferroalloy product and the glass ceramics, the process is complex, the flow is long, the energy consumption is high, and the quality of the produced ferroalloy product and the glass ceramics is not explained. Therefore, in order to shorten the process flow and reduce the energy consumption, a process which is short in flow, economical and environment-friendly and is used for recovering iron from copper slag flotation tailings needs to be developed.

Disclosure of Invention

The invention aims to solve the technical problem of providing a selection and metallurgy combined process for recovering iron from copper slag flotation tailings, which has the advantages of simple process, shorter flow, low energy consumption, economy, environmental protection and good iron recovery effect.

In order to solve the technical problems, the invention adopts the following technical scheme: a dressing and smelting combined process for recovering iron from copper slag flotation tailings is characterized by comprising the following steps: the recovery process is carried out as follows,

1) carrying out stage grinding and magnetic separation on the copper slag flotation tailings to obtain magnetic separation concentrate;

2) mixing the magnetic concentrate obtained in the step 1) with pulverized coal, performing deep reduction roasting, and collecting dust to obtain soot, wherein the mass ratio of the magnetic concentrate to the pulverized coal is 1.5-2.5: 1;

3) carrying out ore grinding and magnetic separation on the roasted product obtained in the step 2) to obtain reduced iron powder and magnetic separation tailings;

4) decarbonizing the magnetic tailings obtained in the step 3) to obtain coal powder and coal-removed tailings. The decarbonized tailings can be used as coal powder, the decarbonized tailings and the magnetic separation tailings before roasting are mixed to be used as final tailings, the final tailings can be used for cement production, and dust collected by deep reduction roasting can be used as a zinc smelting raw material.

In the step 1), the stage ore grinding magnetic separation process comprises magnetic separation I → ore grinding I → magnetic separation II → ore grinding II → magnetic separation III → ore grinding III → magnetic separation IV, the magnetic field intensity of the magnetic separation I, the magnetic separation II, the magnetic separation III and the magnetic separation IV is 1900Oe, 1700Oe and 1400Oe, and the ore grinding fineness is-400 meshes accounting for 90%, minus 500 meshes accounting for 90% and minus 600 meshes accounting for 90%.

In the step 2), the magnetic concentrate and the coal powder are mixed according to the mass ratio of 2:1, the reaction temperature is 1150-1250 ℃, the preferable temperature is 1200 ℃, and the reaction time is about 40 minutes.

In the step 3), the grinding fineness is controlled to be-325 meshes and accounts for 90%, and the magnetic field intensity of magnetic separation is 1700 Oe.

In step 4), the decarburization treatment process is reselection.

The invention obtains the iron ore concentrate by determining proper grinding fineness and magnetic separation strength, controls the reduction temperature and time to ensure that zinc in the iron ore concentrate is fully distributed and collected from the soot, and has the following advantages compared with the prior art: 1. magnetic minerals and non-magnetic minerals in copper slag flotation tailings are separated through a physical method of ore grinding and magnetic separation, energy consumption is reduced compared with a process of separating molten iron and slag through pyrometallurgy, and the process is simpler and easier to realize;

2. the method has low requirements on the grade and the impurity content of the iron concentrate, and avoids the problems that the iron grade of the magnetic concentrate is low and the impurities are high and can not be used as blast furnace ironmaking raw materials;

3. the reduced iron particles are controlled to a certain particle size by controlling the deep reduction condition, and then the iron is recovered by a grinding magnetic separation method to obtain iron concentrate with the iron grade of more than 90 percent, and the iron concentrate can be sold as scrap steel, and has high iron recovery rate, simple process and higher economic benefit.

Drawings

FIG. 1 is a flow diagram of the recovery process of the present invention.

Detailed Description

The invention is further illustrated by the following specific embodiments in conjunction with the accompanying drawings:

in this embodiment: the chemical multi-element analysis results of the copper slag flotation tailings in a certain copper smelting plant are shown in the following table 1:

TABLE 1 Multi-element analysis of copper slag flotation tailings chemistry (Unit/%) of a certain copper smelter

The recovery process is carried out according to the following steps:

1) 1kg of copper slag flotation tailings of a certain copper smelting plant are taken and treated according to the processes of magnetic separation I → ore grinding I → magnetic separation II → ore grinding II → magnetic separation III → ore grinding III → magnetic separation IV, the magnetic field intensity in the magnetic separation process is 1900Oe, 1700Oe and 1400Oe respectively, the ore grinding fineness in the ore grinding process is-400 meshes accounting for 90 percent, -500 meshes accounting for 90 percent and-600 meshes accounting for 90 percent respectively to obtain magnetic separation concentrate, and the ore grinding equipment is240X 90 conical ball mill and magnetic separation equipment400 x 240 electromagnetic wet multipurpose drum magnetic separator;

2) mixing 300g of the magnetic concentrate obtained in the step 1) with 150g of coal powder according to a mass ratio of 2:1, continuously and uniformly feeding the materials into an SHY-1 type rotary kiln for a test, controlling the reaction temperature to be 1200 ℃, reacting for 40 minutes, collecting the reduced materials at the discharge end of the rotary kiln, and recovering discharged soot through a guide pipe on the rotary kiln by using a bag dust collector;

3) grinding and magnetically separating the roasted product obtained in the step 2) to obtain reduced iron powder and magnetic separation tailings, wherein the grinding fineness is-325 meshes and accounts for 90%, the magnetic field intensity is 1700Oe, and the grinding equipment is240X 90 conical ball mill and magnetic separation equipment400 x 240 electromagnetic wet multipurpose drum magnetic separator;

4) decarbonizing the magnetic separation tailings obtained in the step 3) on a shaking table, and drying the obtained shaking table tailings and then testing the tailings to directly serve as coal powder.

The results obtained were as follows:

table 2 comparison of magnetic concentrate to standard iron concentrate index (unit/%)

As can be seen from Table 2, compared with the standard iron concentrate, the magnetic concentrate obtained by the process has the advantages that the total iron grade does not meet the requirement, the impurity elements such as silicon dioxide, sulfur, zinc and copper also exceed the standard, and the iron concentrate does not meet the iron concentrate standard of blast furnace iron making. The core of the deep reduction process adopted by the invention is that solid magnetic iron is reduced by CO gas to reduce iron atoms and polymerize and grow into iron particles with smaller granularity in a certain form, mainly the polymerization and growth of the iron atoms, so the requirements on iron grade and impurities are lower than those of standard iron ore concentrate required by high furnace ironmaking. The reaction temperature of the process is 1200 ℃, silicon dioxide is reduced into silicon at the temperature of more than 1300 ℃ and dissolved in pig iron in the form of FeSi, so that the reduction and the fusion of the silicon are avoided. Because of the low volatilization point of zinc, zinc is volatilized into smoke dust mainly in a gaseous state at the temperature of over 1000 ℃.

TABLE 3 reduced iron powder to scrap index comparison (Unit/%)

As can be seen from Table 3, compared with the impurity-containing requirement of the steel scrap, the iron grade and other elements except copper of the reduced iron powder meet the requirement of the steel scrap, and the impurity content of the copper is mainly over standard. Copper exists mainly in the form of copper matte in magnetic concentrate, metal sulfide can not be reduced and still exists in the original form in the deep reduction process, the copper sulfide mainly enters reduced iron powder along with reduced iron in the form of fine particle inclusion in the ore grinding and magnetic separation process after reduction, the reduced iron powder with high copper content can be used as a raw material of weathering resistant steel and antibacterial stainless steel, the copper content in the weathering resistant steel is 0.25-0.45%, and the content in the antibacterial stainless steel is 1.5-3.8%.

The present invention has been described in detail, and it should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.