阅读说明：本技术 一种鞍山式铁尾矿中铁资源的强化回收方法 (Reinforced recovery method of iron resource in Anshan-type iron tailings ) 是由 杨光 高鹏 马自飞 孙永升 金磊 袁立宾 于 2021-08-23 设计创作，主要内容包括：本发明涉及一种鞍山式铁尾矿中铁资源的强化回收方法,其特征在于,对于品位18～26％、单体解离度<40％的铁尾矿的强化回收方法,包括下述步骤：1)强磁预选抛尾提质；2)强磁精矿的搅拌磨机细磨,获得为-0.025mm含量占85～97％的排矿产品；3)排矿产品的流态化焙烧；4)焙烧产品的弱磁选别,获得铁品位62％以上、铁回收率60％以上的弱磁精矿。本发明的优点是：强磁预选抛尾,减少后续流程处理量,节能降耗,提高效率；2)搅拌磨机细磨,减少过磨,增大反应的活性位点,强化还原,提高焙烧反应速率,缩短10％以上的焙烧时间；3)相比于“先焙烧-后细磨”流程,在精矿品位稳定情况下,提高回收率2个百分以上。(The invention relates to a method for strengthening and recovering iron resources in Anshan-type iron tailings, which is characterized by comprising the following steps of: 1) carrying out strong magnetic preselection and tailing discarding for quality improvement; 2) fine grinding the strong magnetic concentrate by using a stirring mill to obtain an ore discharge product with the content of-0.025 mm accounting for 85-97%; 3) fluidized roasting of the ore discharge product; 4) and (3) carrying out weak magnetic separation on the roasted product to obtain weak magnetic concentrate with the iron grade of more than 62% and the iron recovery rate of more than 60%. The invention has the advantages that: the tail is thrown in the strong magnetic preselection process, so that the subsequent process treatment capacity is reduced, the energy is saved, the consumption is reduced, and the efficiency is improved; 2) the stirring mill is used for fine grinding, over-grinding is reduced, active sites of reaction are increased, reduction is enhanced, the roasting reaction rate is improved, and the roasting time is shortened by over 10%; 3) compared with the flow of roasting before fine grinding, the recovery rate is improved by more than 2 percent under the condition of stable concentrate grade.)

1. A method for strengthening and recovering iron resources in Anshan-type iron tailings is characterized by comprising the following steps:

step 1, performing strong magnetic preselection tailing discarding and quality improvement on iron tailings

Feeding the iron tailings into a strong magnetic separator for preselection, tailing discarding and quality improvement, and discarding the strong magnetic tailings to obtain strong magnetic concentrate with the iron grade of 30-40% and the iron recovery rate of 75-86%;

step 2, fine grinding of the stirring mill of the strong magnetic concentrate

Feeding the strong magnetic concentrate into a stirring mill for narrow-level fine grinding to obtain a stirring mill ore discharge product with the content of-0.025 mm accounting for 85-97%;

step 3, fluidized roasting of ore discharge products of the stirring mill

Feeding the discharged ore products of the stirring mill into a roasting furnace for fluidized roasting to obtain roasted products; the technological parameters of fluidized roasting are as follows: the roasting temperature in the roasting furnace is 500-580 ℃, and nitrogen and CO or H are introduced into the roasting furnace₂In a ratio of 1:1 to 5:1 with Fe₂O₃The main reactions that occur are as follows:

Fe₂O₃+CO/H₂→Fe₃O₄+CO₂/H₂O

step 4, weak magnetic separation of roasted products

And feeding the roasted product into a conventional wet low-intensity magnetic separator or a dry low-intensity magnetic separator for low-intensity magnetic separation, discarding tailings with low intensity magnetism to obtain low-intensity magnetic concentrate with the iron grade of more than 62% and the iron recovery rate of more than 60%, wherein the low-intensity magnetic concentrate is the final concentrate.

2. The method for intensively recovering the iron resources in the Anshan-type iron tailings according to claim 1, wherein the iron tailings are iron tailings with a-0.074 mm fraction content of 50-90%, an iron grade of 18-26%, and an iron mineral monomer dissociation degree of less than 40%.

3. The method for intensively recovering the iron resources in the Anshan-type iron tailings as claimed in claim 1, wherein the magnetic field intensity of the strong magnetic separator is 6000 to 10000 Oe.

4. The method for intensively recycling the iron resource in the Anshan-type iron tailings as claimed in claim 1, wherein the stirring mill is a NEUMM-3 ceramic ball stirring mill.

5. The method for enhanced recovery of iron resources in Anshan-type iron tailings as claimed in claim 1, wherein the magnetic field strength of the conventional wet low-intensity magnetic separator or dry low-intensity magnetic separator is 1000-1800 Oe.

Technical Field

The invention belongs to the technical field of mineral processing, and particularly relates to a method for intensively recovering iron resources in Anshan-type tailings.

Background

The iron ore resources in China are rich and lean, and have the characteristics of low raw ore grade, complex mineral composition, fine disseminated granularity and the like. A large amount of poor iron ore is mined in low efficiency, a large amount of iron tailings are generated, and disordered stacking of the iron tailings not only seriously affects the surrounding environment, but also wastes iron ore resources. The iron tailings have the advantages of high iron content, fine granularity, no mining and crushing cost and the like, so that valuable iron minerals in the iron tailings are recycled, and the method is the best method for treating the iron tailings. The method for recovering iron from the iron tailings not only reduces the discharge amount of the iron tailings, but also creates new economic value for improving the comprehensive utilization rate of iron ore resources.

Because the iron tailings have the characteristics of fine iron mineral embedded particle size, low monomer dissociation degree and the like, the conventional process for recovering iron resources in the iron tailings needs to comprise fine grinding operation to improve the monomer dissociation degree of the iron minerals, and then a conventional beneficiation method is adopted for sorting and recovering. In practical application, however, the conventional beneficiation method has the defects that the gravity separation, the magnetic separation, the flotation and the combined process are difficult to achieve better effects. For example, the fine-ground iron tailings cannot be treated with powdery ores by gravity separation; the magnetic separation field intensity is low, so that the loss of micro-fine iron minerals is easily caused, the recovery rate is reduced, the magnetic agglomeration is easily caused due to the high magnetic separation field intensity, and the product quality is reduced; for flotation, flotation pulp is argillized after fine grinding, the flotation effect is poor, the dosage of flotation reagents is increased sharply, and the cost is increased. In addition, researches show that the process of performing fine grinding and low-intensity magnetic separation after the iron tailings enriched by the high-intensity magnetic separation are magnetized and roasted is better than the process of performing recycling on the iron tailings by a conventional ore dressing method, but the magnetized and roasted method has the defects of higher energy consumption and increased cost.

In summary, the recovery process of iron resources in iron tailings in the prior art has the following two difficulties: firstly, the iron tailings have fine granularity and low dissociation degree of iron mineral monomers, fine grinding is required, and the iron minerals are easy to lose in subsequent operation due to over grinding; and secondly, the magnetic difference between the iron minerals and the gangue is small, the field intensity of the magnetic separator is low, iron is easy to run off, the recovery rate is reduced, the field intensity of the magnetic separator is high, magnetic agglomeration is easy to cause, and the quality of the concentrate is difficult to ensure. The magnetizing roasting process has application prospect, but further research and discussion are needed.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a method for strengthening recovery of iron resources in Anshan-type iron tailings.

The invention is realized by the following technical scheme:

the invention discloses a method for intensively recovering iron resources in Anshan-type iron tailings, which is characterized by comprising the following steps of:

step 1, performing strong magnetic preselection tailing discarding and quality improvement on iron tailings

Feeding the iron tailings into a strong magnetic separator for preselection, tailing discarding and quality improvement, and discarding the strong magnetic tailings to obtain strong magnetic concentrate with the iron grade of 30-40% and the iron recovery rate of 75-86%;

step 2, fine grinding of the stirring mill of the strong magnetic concentrate

Feeding the strong magnetic concentrate into a stirring mill for narrow-level fine grinding to obtain a stirring mill ore discharge product with the content of-0.025 mm accounting for 85-97%;

step 3, fluidized roasting of ore discharge products of the stirring mill

Drying and uniformly mixing the discharged ore products of the stirring mill, and feeding the mixture into a roasting furnace for fluidized roasting to obtain a roasted product; the technological parameters of fluidized roasting are as follows: the roasting temperature in the roasting furnace is 500-580 ℃, and nitrogen and CO or H are introduced into the roasting furnace₂The ratio of the raw materials to the raw materials is 1: 1-5: 1, and the roasting time is 10-30 min. At this stage, the reducing gas and Fe₂O₃The main reaction takes place as follows, producing ferromagnetic magnetite Fe₃O₄：

Fe₂O₃+CO→Fe₃O₄+CO₂

Fe₂O₃+H₂→Fe₃O₄+H₂O

Step 4, weak magnetic separation of roasted products

And feeding the roasted product into a conventional wet-type low-intensity magnetic separator for low-intensity magnetic separation, and discarding tailings of low-intensity magnetic tailings to obtain low-intensity magnetic concentrate with the iron grade of more than 62% and the iron recovery rate of more than 60%, wherein the low-intensity magnetic concentrate is the final concentrate.

Preferably, in the step 1, the iron tailings are iron tailings with a-0.074 mm size fraction content of 50-90%, an iron grade of 18-26%, and an iron mineral monomer dissociation degree of less than 40%.

Preferably, in step 1, the magnetic field intensity of the strong magnetic separator is 6000 to 10000 Oe.

Preferably, in the step 2, the stirring mill is a ceramic ball stirring mill with a specification model of NEUMM-3;

preferably, in step 4, the magnetic field intensity of the conventional wet type weak magnetic separator ranges from 1000 Oe to 1800 Oe.

Compared with the prior art, the invention has the advantages that:

1. according to the invention, through the strong magnetic separation pre-enrichment operation, part of gangue can be thrown out in advance, the subsequent flow treatment capacity is reduced, the energy is saved, the consumption is reduced, the cost is saved, and the production efficiency is improved;

2. the stirring mill mainly adopts a grinding effect to realize narrow-grade fine grinding and superfine grinding of iron minerals, control the granularity range of products and reduce the occurrence of over-grinding phenomenon; meanwhile, the monomer dissociation degree of the iron mineral is improved, the particle size is reduced, the specific surface area and the active sites of the reaction are increased, the roasting reaction rate is improved, and the roasting reaction time is shortened, so that the aim of strengthening reduction is fulfilled;

3. compared with the traditional roasting mode, the gas-solid contact of fluidized roasting is more sufficient, and the mass and heat transfer efficiency is higher.

4. Compared with the original process flow of roasting firstly and then grinding finely, the method can improve the recovery rate of the final concentrate iron by 1-3 percent under the condition of stable concentrate grade, and simultaneously shorten the roasting time by 10-20 percent.

Drawings

FIG. 1 is a process flow for the practice of the present invention.

FIG. 2 shows the original "calcination first-fine grinding" process.

Detailed Description

The invention is further illustrated by the following figures and examples.

The iron tailings have low grade, and are generally characterized by relatively low content of ferromagnetic iron minerals, relatively high content of weakly magnetic iron minerals, relatively low content of monomer iron minerals and enriched intergrowths, and relatively high content of iron mineral depleted intergrowths except for gangue minerals. Therefore, the strong magnetic tailing discarding pre-enrichment operation is firstly carried out on the iron tailing sample, so that the treatment capacity of subsequent operation is reduced, the energy is saved, the consumption is reduced, and the production efficiency is improved.

Example 1

Iron tailings:

selecting certain iron tailings in the Anshan area, wherein useful minerals comprise hematite and magnetite, gangue minerals mainly comprise quartz, the content of the gangue minerals with the granularity of-0.074 mm accounts for 64 percent, the iron grade is 19 percent, the dissociation degree of iron mineral monomers is 35 percent,

test equipment:

the specification and model of the low-intensity magnetic separator adopted in the test are as follows: RK/CRS 400X 300 model roller magnetic separator, Wuhanloke manufacturing Co., Ltd;

the specification and model of the strong magnetic machine are as follows: LGS-1000 vertical induction wet-type high intensity magnetic separator, Shenyang Longji electromagnetic technologies, Inc.;

the specification and model of the stirring mill are as follows: NEUMM-3 model ceramic ball stirring mill, university of northeast;

the model of the fluidization roasting furnace is as follows: OTF-1200X-S-VT vertical suspension furnace, fertilizer combination crystal.

The specific implementation process is as follows:

step 1, performing strong magnetic preselection tailing discarding and quality improvement on iron tailings

Feeding the iron tailings into a strong magnetic separator for preselection tailing discarding and upgrading (magnetic field intensity is 10000Oe), and discarding the strong magnetic tailings to obtain strong magnetic concentrate with the iron grade of 32.21% and the iron recovery rate of 84.10%;

step 2, fine grinding of the stirring mill of the strong magnetic concentrate

Feeding the strong magnetic concentrate into a stirring mill for narrow-level fine grinding to obtain a stirring mill ore discharge product with the content of-0.025 mm accounting for 95%;

step 3, fluidized roasting of ore discharge products of the stirring mill

Drying and uniformly mixing the discharged ore products of the stirring mill, and feeding the dried and uniformly mixed ore products into a roasting furnace for fluidized roasting to obtain a roasted product; the technological parameters of fluidized roasting are as follows: controlling the roasting temperature in the roasting furnace to be between 510 and 530 ℃, and introducing nitrogen and CO or H in the roasting furnace₂The ratio of (A) to (B) is 4:1, and the roasting time is 20 min. At this stage, the reducing gas and Fe₂O₃The main reaction takes place as follows, producing ferromagnetic magnetite Fe₃O₄：

Fe₂O₃+CO→Fe₃O₄+CO₂

Fe₂O₃+H₂→Fe₃O₄+H₂O

Step 4, weak magnetic separation of roasted products

And (3) feeding the roasted product into a wet low-intensity magnetic separator for low-intensity magnetic separation (the magnetic field intensity is 1500Oe), discarding tailings of low-intensity magnetic separation to obtain low-intensity magnetic separation iron concentrate with the iron grade of 62.51% and the iron recovery rate of 61.41%, wherein the low-intensity magnetic concentrate is the final concentrate.

Compared with the technical indexes of 62.45% of final concentrate grade and 60.01% of iron recovery rate in the process of roasting firstly and then finely grinding, the method can improve the iron recovery rate by 1.41% under the condition of stable concentrate grade, and simultaneously shorten the roasting time by 15%.

Example 2

Example 2 the equipment and procedure used were the same as in example 1, except that:

the iron tailing sample has an iron grade of 23 percent, the iron mineral monomer dissociation degree of 31 percent and the content of-0.074 mm of 67 percent.

Pre-selecting and tailing discarding upgrading by strong magnetism (magnetic field intensity 8500Oe) to obtain strong magnetic concentrate with the total iron grade of 36% and the iron recovery rate of 81%;

the granularity of the fine ground product of the stirring mill is 91 percent of minus 0.025 mm;

the fluidized roasting temperature is maintained at 540-560 ℃, and nitrogen and CO or H2 with the ratio of 3.5:1 are introduced into the furnace body;

and (3) carrying out magnetic separation on the roasted product by adopting a common wet type low-intensity magnetic separator (the magnetic field intensity is 1200Oe), and finally obtaining the low-intensity magnetic separation iron concentrate with the iron grade of 63.23% and the iron recovery rate of 60.67%.

Compared with the technical indexes of 63.16% of final concentrate grade and 58.52% of iron recovery rate in the process of roasting firstly and then finely grinding, the method can improve the iron recovery rate by 2.15% under the condition of stable concentrate grade, and simultaneously shorten the roasting time by 12%.