Method for extracting reduced iron powder by using zinc kiln slag

Abstract

The invention relates to the technical field of metal smelting, in particular to a method for extracting reduced iron powder by using zinc kiln slag, and aims to solve the problems that in the current recycling process of metals such as iron in the zinc kiln slag, a large number of chemical reaction reagents are generally required to be added in the conventional preparation of reduced iron, the reduction link is relatively single, and the cost is high. And finally, the extraction recovery rate of the reduced iron is relatively low. According to the method for extracting the reduced iron powder from the zinc kiln slag, an iron extraction and preparation link is added, so that high-ratio extraction of iron elements in the zinc kiln slag is effectively realized, and the iron content in the reduced iron powder and the recovery rate of elemental iron are further improved; meanwhile, a magnetic-gravity separation-table flotation purification combined mode is adopted, effective separation of the iron-silver concentrate is achieved according to the specific gravity, magnetism and floatability differences of useful elements, and therefore the reduced iron powder and the silver concentrate are obtained, and under the condition that reduced addition of chemical reagents for extracting the reduced iron powder from the zinc kiln slag is greatly avoided, the yield of the reduced iron powder is increased. And the extraction rate of the reduced iron in the zinc kiln slag is obviously improved.

Description

Technical Field

[0001] The invention relates to the technical field of metal smelting, and in particular to a method for extracting reduced iron powder by utilizing zinc kiln slag. Background Art

[0002] Zinc kiln slag is a valuable resource, mainly used for paving roads and as cement fillers, etc. Most of it has not been recycled and used reasonably, but has been piled up in zinc smelting plants, which not only occupies a large area of ​​land resources, but also easily causes environmental pollution and waste of resources, making it difficult to achieve effective comprehensive recycling. Therefore, how to recover economically valuable metal resources such as iron and silver from zinc kiln slag in a low-cost, environmentally friendly and efficient manner has become increasingly important. At present, the method of extracting metallic iron and valuable metals from zinc kiln slag mainly uses zinc kiln slag and graphite rods as cathode and anode electrodes, respectively, and inserts them into a molten salt system composed of a mixture of sodium chloride and potassium chloride in a protective gas atmosphere to carry out a molten salt constant-tank electrolysis reaction. Finally, the cathode is cleaned and dried to obtain metallic iron. However, in the process of preparing metallic iron, this method requires the addition of a large amount of chemical reagents, which poses a greater risk of environmental pollution and certain safety risks in operation, which is not conducive to large-scale promotion. At the same time, it can also be used After the blast furnace gas ash falls from the kiln head, it is flushed with water to extinguish the fire, granulated, and then sinks to the bottom of the slag pool. The cooled granulated kiln slag at the bottom of the slag pool is transported out to obtain granulated rotary kiln slag. Water is added to the granulated rotary kiln slag, mineral powder and desulfurized gypsum mixture, pressed into shape, cured and dried to become steelmaking charge. This method does not directly prepare metallic iron, but prepares it into steelmaking charge. It still needs to be further smelted in a blast furnace to prepare metallic iron. The recycling method of this type of zinc kiln slag generally has the problem of a relatively single reduced iron powder preparation link and a low extraction rate. Summary of the invention

[0003] The present invention provides a method for extracting reduced iron powder by using zinc kiln slag, so as to solve the problems that the preparation process of zinc kiln slag reduced iron powder is relatively single and the extraction rate is low in the above background.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: A method for extracting reduced iron powder using zinc kiln slag, comprising the following process: Step 1: The zinc kiln slag is subjected to magnetic separation to obtain iron-silver concentrate and iron tailings.

[0005] Step 2: The iron tailings obtained in step 1 are subjected to a flotation decarbonization to obtain carbon concentrate and carbon tailings.

[0006] Step 3: subjecting the carbon tailings obtained in step 2 to a secondary flotation sulfur extraction process to obtain silver concentrate, crude iron ore and tailings slag.

[0007] Step 4: The iron-silver concentrate obtained in step 1 is subjected to mineral property analysis and determination, and it is determined that the gravity separation particle size of the iron-silver concentrate is 150-200 mesh, the proportion is greater than 60%, the pH value of the gangue component CaO / SiO2 is greater than 1, and the grindability is 80%-150%.

[0008] Step 5: Gravity separation is performed on the iron-silver concentrate according to the gravity separation parameters determined in step 4 to obtain silver concentrate and coarse iron powder.

[0009] Step 6: The crude iron ore obtained in step 3 is reselected to obtain crude iron powder.

[0010] Step 7: Finally, the crude iron powder obtained in step 5 and step 6 is dried to obtain reduced iron powder.

[0011] Furthermore, the mineral property analysis and determination of the iron-silver concentrate in step 4 includes multi-element analysis, phase analysis, gold assay analysis, mineral composition analysis, embedding characteristics, particle size composition, silver occurrence state, grindability and Bond work index.

[0012] Furthermore, the magnetic field intensity of the zinc kiln slag magnetic separation treatment in step 1 is 1200 Gs-2000 Gs.

[0013] Furthermore, in the step 2, the reagents used for the primary flotation decarbonization of the iron tailings are 2000 g / t-3000 g / t of emulsified kerosene and 300 g / t-500 g / t of 2# flotation oil.

[0014] Furthermore, in the step 3, the carbon tailings are subjected to a secondary flotation process for sulfur separation and silver extraction, and the reagents used in the roughing process are 400 g / t-600 g / t of isobutyl potassium xanthate, 200 g / t-400 g / t of aniline black, and 250 g / t-350 g / t of 2# flotation oil, and the amount of reagents used in the scavenging process is half of the amount of the roughing reagents.

[0015] Furthermore, in step 3, the first concentrating agent is 200 g / t-400 g / t of isobutyl potassium xanthate, 50 g / t-70 g / t of aniline black, and 40 g / t-60 g / t of 2# flotation oil, and the second concentrating is blank concentrating to obtain silver concentrate and crude iron ore, and the crude iron ore is then re-selected to obtain crude iron powder.

[0016] Furthermore, the gravity separation particle size of the iron-silver concentrate is controlled to 150-170 meshes, accounting for 65%-75%, the pH value of the gangue component is CaO / SiO2=1.3-1.7, and the gravity separation can be carried out after the fineness is 100%-120% to obtain coarse iron powder.

[0017] The present invention has the following beneficial effects: The present invention adopts a combined method of magnetic gravity separation and multiple flotation purification, and realizes effective separation of iron-silver concentrate according to the difference in specific gravity, magnetism and floatability of useful elements, thereby obtaining reduced iron powder and silver concentrate.

[0018] The present invention effectively realizes the high-ratio extraction of iron elements in zinc kiln slag by adding the characteristic determination and re-selection links of iron-silver concentrate.

[0019] The present invention effectively avoids the addition of a large amount of reaction chemical reagents in the extraction of reduced iron powder from zinc kiln slag through physical separation methods such as magnetic separation and multiple flotation, thereby effectively reducing the pollution risk to the working environment and the safety risk of working operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall process flow of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0022] Example 1 A method for extracting reduced iron powder using zinc kiln slag, the steps are as follows: A zinc kiln slag was selected, the main components of which were metallic iron with a grade of 16.81% and silver with a grade of 263.84 g / t.

[0023] Zinc kiln slag is magnetically separated under a magnetic field strength of 2000Gs to obtain iron-silver concentrate and iron tailings containing 65.21% iron.

[0024] The iron tailings are subjected to a flotation carbon separation process. The carbon separation process adopts a primary flotation roughing process. The reagents and dosages used are 2000g / t of emulsified kerosene and 300g / t of 2# flotation oil to obtain carbon concentrate and carbon tailings.

[0025] The carbon tailings enter the secondary flotation process for sulfur separation and silver extraction. This process adopts a one roughing, two refining and two scavenging process. The reagents and dosages used for roughing are 400g / t of isobutyl potassium xanthate, 200g / t of aniline black, and 250g / t of 2# flotation oil. The dosage of the reagents used for scavenging is half of the dosage of the roughing reagents; the first refining reagents are 200g / t of isobutyl potassium xanthate, 50g / t of aniline black, and 40g / t of 2# flotation oil; the second refining is blank refining to obtain silver concentrate and crude iron ore, and the crude iron ore is then re-selected to obtain crude iron powder.

[0026] The iron-silver concentrate is then ball-milled to -0.074mm, accounting for 92.17%. The gravity separation particle size is determined to be 150 mesh, accounting for 65%. The pH value of the gangue component is CaO / SiO2=1.3. The fineness can be 100% before gravity separation to obtain coarse iron powder.

[0027] Finally, the crude iron powder obtained in the above step is dried to obtain reduced iron powder. The iron content of the reduced iron powder is detected to be 92.37%, and the recovery rate of elemental iron is 90.13%.

[0028] Example 2 A method for extracting reduced iron powder using zinc kiln slag, the steps are as follows: A zinc kiln slag was selected, the main components of which were metallic iron with a grade of 16.81% and silver with a grade of 263.84 g / t.

[0029] Zinc kiln slag is magnetically separated under a magnetic field strength of 1500Gs to obtain iron-silver concentrate and iron tailings containing 66.47% iron.

[0030] The iron tailings are subjected to flotation carbon selection process. The carbon selection process adopts a primary flotation roughing process. The reagents and dosages used are 2500g / t of emulsified kerosene and 400g / t of 2# flotation oil to obtain carbon concentrate and carbon tailings.

[0031] The carbon tailings enter the secondary flotation process for sulfur separation and silver extraction. This process adopts a one-roughing, two-fine and two-sweeping process. The reagents and dosages used for roughing are 500g / t of isobutyl potassium xanthate, 300g / t of aniline black, and 300g / t of 2# flotation oil. The dosage of the reagents used for scavenging is half of the dosage of the roughing reagents; the first fine reagent is 300g / t of isobutyl potassium xanthate, 60g / t of aniline black, and 50g / t of 2# flotation oil; the second fine selection is blank selection to obtain silver concentrate and crude iron ore, and the crude iron ore is then re-selected to obtain crude iron powder.

[0032] The iron-silver concentrate is then ball-milled to -0.074mm, accounting for 94.58%. The gravity separation particle size is determined to be 160 mesh, accounting for 70%. The pH value of the gangue component is CaO / SiO2=1.5. The grinding degree is 115% and then gravity separation is carried out to obtain coarse iron powder.

[0033] The crude iron powder obtained in the above step is dried to obtain reduced iron powder, the iron content of the reduced iron powder is 92.11%, and the elemental iron recovery rate is 90.51%.

[0034] Example 3 A method for extracting reduced iron powder using zinc kiln slag, the steps are as follows: A zinc kiln slag was selected, the main components of which were metallic iron with a grade of 16.81% and silver with a grade of 263.84 g / t.

[0035] Zinc kiln slag is magnetically separated under a magnetic field strength of 1200Gs to obtain iron-silver concentrate and iron tailings containing 65.37% iron.

[0036] The iron tailings are subjected to a flotation carbon separation process. The carbon separation process adopts a primary flotation roughing process. The reagents and dosages used are 3000g / t of emulsified kerosene and 500g / t of 2# flotation oil to obtain carbon concentrate and carbon tailings.

[0037] The carbon tailings enter the secondary flotation process for sulfur separation and silver extraction. This process adopts a one roughing, two refining and two scavenging process. The reagents and dosages used for roughing are 600g / t of isobutyl potassium xanthate, 400g / t of aniline black, and 350g / t of 2# flotation oil. The dosage of the reagents used for scavenging is half of the dosage of the roughing reagents; the first refining reagents are 400g / t of isobutyl potassium xanthate, 70g / t of aniline black, and 60g / t of 2# flotation oil; the second refining is blank refining to obtain silver concentrate and crude iron ore, and the crude iron ore is then re-selected to obtain crude iron powder.

[0038] The iron-silver concentrate is then ball-milled to -0.074mm, accounting for 93.22%. The gravity separation particle size is determined to be 170 mesh, accounting for 75%. The pH value of the gangue component is CaO / SiO2=1.7. The grinding degree is 120% and then gravity separation is carried out to obtain coarse iron powder.

[0039] The crude iron powder obtained in the above step is dried to obtain reduced iron powder, the iron content of the reduced iron powder is 92.23%, and the elemental iron recovery rate is 90.37%.

Claims

1. A method for extracting reduced iron powder using zinc kiln slag, characterized in that: The following processes are included: Step 1: The zinc kiln slag is subjected to magnetic separation to obtain iron-silver concentrate and iron tailings; Step 2: flotation and carbon removal of the iron tailings obtained in step 1 to obtain carbon concentrate and carbon tailings; Step 3: subjecting the carbon tailings obtained in step 2 to a secondary flotation sulfur extraction process to obtain silver concentrate, crude iron ore and tailings slag; Step 4: Analyze and determine the mineral properties of the iron-silver concentrate obtained in step 1, and determine that the gravity separation particle size of the iron-silver concentrate is 150-200 mesh, the proportion is greater than 60%, the pH value of the gangue component CaO / SiO2 is greater than 1, and the grindability is 80%-150%; Step 5: Gravity separation is performed on the iron-silver concentrate according to the gravity separation parameters determined in step 4 to obtain silver concentrate and coarse iron powder; Step 6: reselect the crude iron ore obtained in step 3 to obtain crude iron powder; Step 7: Finally, the crude iron powder obtained in step 5 and step 6 is dried to obtain reduced iron powder.

2. The method for extracting reduced iron powder from zinc kiln slag according to claim 1, characterized in that: The magnetic field intensity of the zinc kiln slag magnetic separation treatment in step 1 is 1200 Gs-2000 Gs.

3. The method for extracting reduced iron powder using zinc kiln slag according to claim 1, characterized in that: In the step 2, the reagents used for the primary flotation decarbonization of the iron tailings are 2000 g / t-3000 g / t of emulsified kerosene and 300 g / t-500 g / t of 2# flotation oil.

4. The method for extracting reduced iron powder using zinc kiln slag according to claim 1, characterized in that: In the step 3, the carbon tailings are subjected to secondary flotation to select sulfur and extract silver. The reagents used in the roughing process are 400g / t-600g / t of isobutyl potassium xanthate, 200g / t-400g / t of aniline black, and 250g / t-350g / t of 2# flotation oil. The amount of reagents used in the scavenging process is half of the amount of the roughing reagents.

5. The method for extracting reduced iron powder using zinc kiln slag according to claim 4, characterized in that: In the step 3, the first concentrating agent is 200 g / t-400 g / t of isobutyl potassium xanthate, 50 g / t-70 g / t of aniline black, and 40 g / t-60 g / t of 2# flotation oil. The second concentrating is blank concentrating to obtain silver concentrate and crude iron ore, and the crude iron ore is then re-selected to obtain crude iron powder.

6. The method for extracting reduced iron powder using zinc kiln slag according to claim 1, characterized in that: The gravity separation particle size of the iron-silver concentrate is controlled to 150-170 meshes, accounting for 65%-75%, the pH value of the gangue component is CaO / SiO2=1.3-1.7, and the gravity separation can be carried out after the fineness is 100%-120% to obtain coarse iron powder.

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