Method for recycling iron-containing metallurgical dust and sludge

Abstract

The invention discloses an iron-containing metallurgical dust and sludge recycling method which comprises the following steps: classifying different types of iron-containing metallurgical dust and sludge, and then respectively determining chemical elements and contents of the chemical elements in the various types of iron-containing metallurgical dust and sludge; according to the requirements of the chemical components of the sintered ore, the iron-containing metallurgical dust and mud are utilized for ore blending, and it is ensured that the percentage of the components of the sintered ore meets the standard; according to the control requirements of the chemical components, various types of iron-containing metallurgical dust and mud are subjected to premixing ore blending according to the ore blending structure, and a pre-blended material is obtained; mixing the pre-prepared pre-prepared materials with auxiliary materials for pelletizing, and then pelletizing to obtain material pellets; and sintering the prepared material pellets to obtain the sintered ore. The invention provides a high-efficiency, environment-friendly and economical method for cleaning, recycling and reusing iron-containing metallurgical dust and sludge, which overcomes the problems of tedious technological process, high recycling cost, difficulty in waste residue treatment, low resource utilization efficiency and the like in the existing iron-containing metallurgical dust and sludge recycling method, namely a wet process.

Description

Technical Field

[0001] The present invention relates to the technical field of clean recycling and utilization of iron-containing metallurgical dust and sludge in iron and steel plants, and in particular to a method for recycling and reusing iron-containing metallurgical dust and sludge. Background Art

[0002] As an important pillar of the national economy, the iron and steel industry inevitably generates a large amount of solid waste during its production process, such as blast furnace tapping dust, steelmaking dust, and rolling mill cleaning mud. These wastes are collectively referred to as metallurgical dust and sludge. Metallurgical dust and sludge contain a large amount of valuable metal elements such as iron, nickel, and chromium, but may also contain substances harmful to the environment. Therefore, how to efficiently and cleanly recycle and treat these metallurgical dust and sludge is of great significance for promoting the green development of the iron and steel industry, realizing resource recycling, and reducing environmental pollution.

[0003] At present, although the commonly used wet process in industry can recycle valuable metals in metallurgical dust and sludge, it has the following main problems: Lengthy process flow: The wet process involves multiple complex steps, including dissolution, precipitation, filtration, electrolysis, etc., resulting in a long recovery process, and requiring a large amount of manpower, material resources, and financial resources.

[0004] High recovery cost: Since the wet process requires a large amount of chemical reagents and water resources, and the equipment investment and maintenance costs are relatively high, the recovery cost is relatively high and the economy is not good.

[0005] Difficult slag treatment: The slag generated during the disposal of the wet process is often difficult to meet the harmless standard, which may cause secondary pollution to the environment.

[0006] Low resource utilization efficiency: When the wet process recovers valuable metals, it often cannot fully utilize other valuable components in metallurgical dust and sludge, resulting in low resource utilization efficiency.

[0007] In view of the problems existing in the above-mentioned existing method for recycling and treating iron-containing metallurgical dust and sludge - the wet process, there is an urgent need for an efficient, environmentally friendly, and economical method for cleaning recycling and reusing metallurgical dust and sludge. Summary of the Invention

[0008] The purpose of the present invention is to provide an efficient, environmentally friendly, and economical method for cleaning recycling and reusing iron-containing metallurgical dust and sludge, so as to overcome the problems of long process flow, high recovery cost, difficult slag treatment, low resource utilization efficiency, etc. existing in the existing method for recycling and treating iron-containing metallurgical dust and sludge - the wet process.

[0009] In order to solve the above problems, the technical solution adopted by the present invention is: It includes the following steps: (1) Chemical composition analysis: Classify different types of iron-containing metallurgical dust and sludge, and then determine the chemical elements and their contents in each type of iron-containing metallurgical dust and sludge respectively; (2) Ore blending structure: According to the requirements of the chemical composition of sinter, use the above various types of iron-containing metallurgical dust and sludge for ore blending to ensure that the component percentages of sinter meet the following standards: nickel content is not less than 0.6 - 0.7%, chromium content is not less than 2.8%, total iron content is not less than 45.0%, silicon dioxide content is about 6.00 - 8.00%, and alkalinity is 1.50 ± 0.15; (3) Pre-blending: According to the above chemical composition control requirements, pre-mix and blend various types of iron-containing metallurgical dust and sludge according to the above ore blending structure to obtain pre-blended materials; (4) Pelletizing: Mix the pre-blended materials with pelletizing auxiliary materials, and then pelletize to obtain material pellets; (5) Sintering: Sinter the made material pellets to obtain sinter.

[0010] In the above technical solution, a more specific technical solution can also be: In the pelletizing process of step (4) above, flux and fuel are used as pelletizing auxiliary materials.

[0011] Further, in the sintering process of step (5) above, control the material layer thickness to be 700 mm - 800 mm, the thickness of the bottom layer material to be 30 mm - 50 mm, the ignition temperature to be 1050 ± 50 °C, the ignition negative pressure to be 5 Kpa - 8 Kpa, the negative pressure of the main flue to be 10 ± 1 Kpa, the sintering time to be 40 ± 5 minutes, and the end point temperature to be 330 ± 20 °C.

[0012] Further, in the sintering process of step (5) above, control the material layer thickness to be 750 mm, the thickness of the bottom layer material to be 40 mm, the ignition temperature to be 1050 ± 50 °C, the ignition negative pressure to be 5 Kpa, the negative pressure of the main flue to be 10 ± 1 Kpa, the sintering time to be 40 ± 5 minutes, and the end point temperature to be 330 ± 20 °C.

[0013] Further, in the pelletizing process of step (4) above, use a cylindrical granulating mixer to mix and pelletize the pre-blended materials and pelletizing auxiliary materials.

[0014] Further, in the sintering process of step (5) above, use a belt sintering machine to sinter the material pellets.

[0015] Further, in the sintering process of step (5) above, use an annular cooler to cool the sinter for 50 - 60 minutes Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art: 1. With many advantages such as the simplicity of its steps, strong operability, and low production cost, the present invention has shown significant application value in the field of industrial solid waste treatment and metal resource recovery.

[0016] 2. The present invention conducts ore blending by using various types of iron-containing metallurgical dusts according to the requirements of the chemical composition of sinter, optimizes its ore blending structure, and precisely controls the blending ratio to ensure that various metal elements can fully react during the sintering process and reduce the generation of harmful substances.

[0017] 3. The present invention improves the sintering process steps. By optimizing key parameters such as sintering temperature, time, and atmosphere, the material pellets can fully react during the sintering process, thereby improving the strength and wear resistance of the product.

[0018] 4. The present invention effectively improves the environmental protection benefits and economic benefits of the factory, and has broad application prospects in the field of industrial solid waste treatment and metal resource recovery: by realizing the harmless treatment of industrial solid waste, it effectively reduces the environmental pressure and makes a positive contribution to sustainable development; at the same time, by comprehensively recycling valuable metal resources, it can also reduce the production cost of enterprises and improve economic benefits. Specific Embodiments

[0019] The present invention will be further described in detail below in conjunction with embodiments: Embodiment

[0020] The objects of recycling and reuse in this embodiment are steel rolling cleaning mud (i.e., the mud generated from steel rolling cleaning) and metallurgical powder materials (i.e., the powder materials formed during the metallurgical process). These two types of substances are both classified into the category of iron-containing metallurgical dust. The specific methods for their recycling and reuse include the following steps: (I) Chemical composition analysis: First, determine the chemical elements and their contents of the steel rolling cleaning mud and metallurgical powder materials respectively. The results are shown in Table 1; Table 1 (II) Ore blending structure: According to the requirements of the chemical composition of sinter, use the above-mentioned steel rolling cleaning mud and metallurgical powder materials for ore blending to ensure that the component percentages of sinter meet the following standards: the nickel content is not less than 0.5 - 0.7%, the chromium content is not less than 2.8%, the total iron content is not less than 45.0%, the silica content is about 5.00 - 8.00%, and the basicity is 1.50 ± 0.15; (III) Pre-blending: First, process the steel rolling cleaning mud through a rotary dryer to obtain pellets with a water content of less than 15%, and then pre-mix and blend the metallurgical powder materials according to the above ore blending structure to obtain pre-blended materials; (4) Pelletizing: The pre-prepared materials are evenly mixed with the auxiliary materials for pelletizing - fluxes and fuels, and then homogenized through a cylindrical granulating mixer to obtain small material balls. (5) Sintering: The small material balls are sintered using a Lurgi-type belt sintering machine to obtain sintered ore. During sintering, the thickness of the material layer is controlled at 750 mm, the thickness of the bottom material layer is 40 mm, the ignition temperature is 1050 ± 50 °C, the ignition negative pressure is 5 Kpa, the negative pressure of the main flue is 10 ± 1 Kpa, the sintering time is 40 ± 5 minutes, the end temperature is 330 ± 20 °C, and finally, the sintered ore is cooled for 50 - 60 minutes using a ring cooler to obtain the final sintered ore product.

[0021] In the actual production operation environment, the recovery and treatment process of iron-containing metallurgical dust and sludge is usually continuous and uninterrupted, aiming to efficiently utilize materials in different batches. In this process, the treatment cycle for each batch is generally set at 2 hours. Based on this cycle arrangement, the production department will regularly, that is, approximately every 2 hours, extract samples from the obtained sintered ore products and then analyze the chemical composition of the samples. The results are shown in Table 2 (only a part of the table is shown).

[0022] Table 2 .

[0023] The above two consecutive sampling products are combined and subjected to a physical analysis (i.e., detecting their strength and particle size composition). The results are shown in Table 3 (similar to Table 2, only a part of the table is shown).

[0024] Table 3 .

[0025] From the data in Table 2 and Table 3 above, it can be seen that the chemical composition and performance of the sintered ore products obtained through the treatment of this embodiment have reached the indicators for industrial production and utilization, achieving the purpose of recycling and reuse.

[0026] The present invention aims to solve the problem of recycling and reuse of various iron-containing metallurgical dust and sludge. Among them, the rolling mill cleaning sludge and metallurgical powdery materials in the above embodiment are only described as two specific examples among many iron-containing metallurgical dust and sludge. It should be clear that the application scope of the present invention is not limited to these two types of dust and sludge. In fact, the technical solution proposed by the present invention has wide applicability and can handle more types of iron-containing metallurgical dust and sludge. These dust and sludge, regardless of their composition, source or physical properties, as long as they follow the same treatment principle as the rolling mill cleaning sludge and metallurgical powdery materials, can be efficiently recycled and reused through the method of the present invention. Therefore, the present invention not only provides innovative ideas for the recycling and reuse of rolling mill cleaning sludge and metallurgical powdery materials, but also brings new solutions to the entire field of treatment of iron-containing metallurgical dust and sludge.

[0027] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for recycling iron-containing metallurgical dust and mud, characterized in that The following steps are involved: (i) Chemical composition analysis: Classify different types of iron-containing metallurgical dust and mud, and then determine the chemical elements and their contents in each type of iron-containing metallurgical dust and mud; (II) Ore blending structure: Based on the requirements of the chemical composition of the sintered ore, the above-mentioned various types of iron-containing metallurgical dust and mud are used for ore blending to ensure that the composition percentages of the sintered ore meet the following standards: nickel content is not less than 0.6-0.7%, chromium content is not less than 2.8%, total iron content is not less than 45.0%, silicon dioxide content is about 6.00-8.00%, and basicity is 1.50±0.15; (III) Pre-batching: Based on the above chemical composition control requirements, various types of iron-containing metallurgical dust and mud are pre-mixed and blended according to the above ore blending structure to obtain pre-batched materials; (iv) Pelletizing: mixing the pre-mixed materials with the pelletizing auxiliary materials, and then pelletizing to obtain material pellets; (V) Sintering: Sinter the prepared material pellets to obtain sintered ore.

2. The method for recycling and reusing iron-containing metallurgical dust according to claim 1, characterized in that: In the pelletizing process of step (iv) above, flux and fuel are used as auxiliary materials for pelletizing.

3. The method for recycling iron-containing metallurgical dust according to claim 1 or 2, characterized in that: In the sintering process of the above step (v), the material layer thickness is controlled to be 700mm~800mm, the base material thickness is 30mm~50mm, the ignition temperature is 1050±50℃, the ignition negative pressure is 5Kpa~8Kpa, the large flue negative pressure is 10±1Kpa, the sintering time is 40±5 minutes, and the final temperature is 330±20℃.

4. The method for recycling and reusing iron-containing metallurgical dust according to claim 3, characterized in that: In the sintering process of step (v) above, the material layer thickness is controlled to be 750 mm, the base material thickness is 40 mm, the ignition temperature is 1050±50°C, the ignition negative pressure is 5 Kpa, the large flue negative pressure is 10±1 Kpa, the sintering time is 40±5 minutes, and the final temperature is 330±20°C.

5. The method for recycling iron-containing metallurgical dust and sludge according to claim 4, characterized in that: In the pelletizing process of step (iv) above, a cylindrical granulating mixer is used to mix the pre-mixed materials and the auxiliary materials for pelletizing to form pellets.

6. The method for recycling and reusing iron-containing metallurgical dust according to claim 5, characterized in that: In the sintering process of step (v) above, a Lurgi belt sintering machine is used to sinter the material pellets.

7. The method for recycling and reusing iron-containing metallurgical dust according to claim 6, characterized in that: In the sintering process of step (v) above, the sintered ore is cooled for 50 to 60 minutes using a ring cooler.

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