Method for preparing converter cold charge from copper slag

Abstract

The invention relates to the technical field of ferrous metallurgy, and discloses a method for preparing a converter cold charge by using copper slag, which comprises the following steps: weighing the following raw materials in percentage by weight: 30-55% of copper slag, 10-30% of oxide scale, 20-35% of converter fly ash, 3-10% of magnetic separation tailings and 3-5% of binder; mixing the weighed raw materials, adding water, and mixing; the mixture obtained in the second step is fed into a ball rolling machine to be pressed into a wet block mass, and the converter cold material is obtained after the wet block mass is dried; according to the method, iron and copper in the copper slag are directly utilized, so that the dependence on traditional cold materials (such as sintered ore, pellet ore and waste steel) is reduced, the step of additionally using materials such as copper plates as alloy raw materials is omitted, and the cost of the steelmaking procedure is remarkably reduced; zinc in the copper slag escapes in the form of Zn steam and is finally condensed into zinc oxide or secondary zinc oxide in the flue; and by recovering the zinc element in the converter ash, a steel mill can sell the zinc element to a zinc recovery manufacturer, so that the economic benefit is further improved.

Description

Technical Field

[0001] The invention relates to the technical field of iron and steel metallurgy, and in particular to a method for preparing converter cold material by utilizing copper slag. Background Art

[0002] The existing technologies and processes for comprehensive utilization of copper slag can be mainly divided into recycling and extracting valuable metal elements such as iron and copper or directly using them as building materials. The former has a long process and large investment for recycling valuable elements, while the latter does not fully recycle the valuable metal elements in the copper slag.

[0003] At present, the steel industry is facing the challenge of sustainable development of iron ore resources. Steel companies have been committed to reducing costs and increasing efficiency in production, and the efficient use of various cost-effective iron-containing resources using reasonable technologies and processes has always been pursued by steel companies. On the other hand, the metallurgical industry also needs to actively deal with a large amount of stockpiled iron-containing non-ferrous metallurgical slag. For example, the copper slag in this application contains about 40% iron, which is much higher than the selected grade of 27% of general iron ore. Therefore, adopting a reasonable method to recover metallurgical slag, especially the valuable elements such as iron, copper, and zinc in the copper slag in this application, can reduce the environmental problems caused by the stockpiling of copper slag, which is of great significance. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a method for preparing converter cold material using copper slag.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preparing converter cold material using copper slag comprises the following steps:

[0007] Step 1: weigh the raw materials according to the following weight percentages: copper slag 30%-55%, iron oxide scale 10%-30%, converter dust ash 20%-35%, magnetic separation tailings 3%-10%, and binder 3%-5%;

[0008] Step 2: Mix the weighed raw materials and add water to mix;

[0009] Step 3: Load the mixed material obtained in step 2 into a roller ball press to press out wet lumps. After the wet lumps are dried, the converter cold material is obtained.

[0010] Preferably, the copper content in the copper slag in step 1 is 0.14%-0.52%.

[0011] Preferably, in step 2, water is added until the moisture content of the mixture is 7.5%-8.5%.

[0012] Preferably, in step 3, the drying method includes drying and air-drying.

[0013] Preferably, in step 3, the moisture content of the wet mass obtained by drying is 1.3%-1.9%, and the compressive strength is 866N-1299N.

[0014] The beneficial effects of the present invention are:

[0015] 1. Reduce the cost of steelmaking process: The direct use of iron and copper in copper slag reduces the dependence on traditional cold materials (such as sintered ore, pelletized ore, scrap steel, etc.), eliminates the step of using additional materials such as copper plates as alloy raw materials, and significantly reduces the cost of the steelmaking process.

[0016] 2. Improve resource utilization efficiency: The iron and copper elements in copper slag directly enter the molten iron through redox reactions. The copper element can be used as an alloy raw material for producing weathering steel or copper-containing stainless steel, while the iron can be directly used as a component in the molten iron.

[0017] 3. Shorten the process flow and reduce process costs: Compared with the traditional process of recovering iron from copper slag by reduction grinding, this patented technology simplifies the process and directly completes the recovery of iron and copper in the converter, with a shorter process flow and lower costs.

[0018] 4. Zinc recycling and value-added: The zinc in copper slag mainly exists in the form of ZnO, ZnS or ZnFe2O4. In the converter steelmaking process, ZnO, ZnS or ZnFe2O4 is first reduced to Zn metal by carbon in molten iron, and escapes in the form of Zn steam, and finally condenses into zinc oxide or secondary zinc oxide in the flue. By recycling the zinc element in the converter ash, the steel mill can sell it to zinc recycling manufacturers to further improve economic benefits.

[0019] 5. Utilization of multi-source materials: This method effectively utilizes waste materials with low moisture content and high iron content in steel mills (such as iron oxide scale, converter dust removal ash, and magnetic separation powder) and combines them with copper slag to replace traditional converter cold materials, making waste resources and further promoting the efficient recycling of resources.

[0020] 6. Environmental benefits: Through the recycling of copper slag and converter ash, the pressure of waste treatment and emission is reduced, which helps the green development goals of the steel industry and achieves the dual improvement of cost reduction and efficiency improvement and environmental benefits. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0022] Example 1: The following material proportions were calculated by planning and solving: 30% copper slag, 30% iron oxide scale, 35% converter dust ash, and 5% magnetic separation tailings. The amount of binder A was 3%, and water was added to the mixture until the moisture content was 7.5%. The mixture was pressed into wet agglomerates by a roller press. The obtained wet agglomerates were then left for 72 hours, and the moisture content of the agglomerates dropped to 1.9%, and the compressive strength was 866N. The copper content in the molten steel was 0.14%.

[0023] Example 2: The following material proportions were calculated by planning and solving: 35% copper slag, 25% iron oxide scale, 35% converter dust ash, and 5% magnetic separation tailings. The amount of binder A was 4%, and water was added to the mixture until the moisture content was 7.8%. The mixture was pressed into wet agglomerates by a double-roll ball press. The obtained wet agglomerates were then left for 72 hours, and the moisture content of the agglomerates dropped to 1.5%, and the compressive strength was 978N. The copper content in the molten steel was 0.18%.

[0024] Example 3: The following material proportions were calculated by planning and solving: 40% copper slag, 25% iron oxide scale, 30% converter dust ash, and 5% magnetic separation tailings. The amount of binder B was 3%, and water was added to the mixture until the moisture content was 8.0%. The mixture was pressed into wet agglomerates by a double-roll ball press. The obtained wet agglomerates were then left for 72 hours, and the moisture content of the agglomerates dropped to 1.8%, and the compressive strength was 1056N. The copper content in the molten steel was 0.24%.

[0025] Example 4: The following material proportions were calculated by planning and solving: 45% copper slag, 15% iron oxide scale, 22% converter dust ash, and 8% magnetic separation tailings. The amount of binder B was 4%, and water was added to the mixture until the moisture content was 8.2%. The mixture was pressed into wet agglomerates by a double-roll ball press. The obtained wet agglomerates were then left for 72 hours, and the moisture content of the agglomerates dropped to 1.7%, and the compressive strength was 1012N. The copper content in the molten steel was 0.33%.

[0026] Example 5: The following material proportions were calculated by planning and solving: 50% copper slag, 15% iron oxide scale, 32% converter dust ash, and 3% magnetic separation tailings. The amount of binder A was 5%, and water was added to the mixture until the moisture content was 8.3%. The mixture was pressed into wet agglomerates by a double-roll ball press. The obtained wet agglomerates were then placed for 96 hours, and the moisture content of the agglomerates dropped to 1.3%, and the compressive strength was 1299N. The copper content in the molten steel was 0.41%.

[0027] Example 6: The following material proportions were calculated by planning and solving: 55% copper slag, 10% iron oxide scale, 20% converter dust ash, and 10% magnetic separation tailings. The amount of binder A was 5%, and water was added to the mixture until the moisture content was 8.5%. The mixture was pressed into wet agglomerates using a double-roll ball press. The obtained wet agglomerates were then left for 96 hours, and the moisture content of the agglomerates dropped to 1.4%, and the compressive strength was 1145N. The copper content in the molten steel was 0.52%.

[0028] In Examples 1-6, binder A and binder B were purchased from Hebei Yanxing Chemical Co., Ltd., and were both organic-inorganic composite binders, with models of CMB and CMS, respectively.

[0029] In the method for preparing converter cold material using copper slag provided by the present invention, copper slag is mainly used to mix and briquette with steel mill materials with low moisture content and high iron content, such as iron oxide scale, converter dust removal ash and magnetic separation tailings, and the obtained agglomerates are used as converter cold materials. First, based on the chemical composition of each material, the composition of the mixed material after mixing is made to meet the requirements of coolant for steel mill converter (for example, TFe≥50%, CaO / SiO2≥2, etc., which can be adjusted according to actual production conditions) through a planning solution method. Under reasonable particle size distribution, an appropriate amount of water is added according to the moisture demand, and an appropriate amount of binder is added for mixing, and then the mixture is pressed into agglomerates by a double-roll ball press. The obtained agglomerates can be dried or air-dried according to the actual production conditions to obtain dry agglomerates, and the strength required for converter cold materials (≥800N) is achieved. The dry agglomerates are then sent to the converter for use as cold materials.

[0030] The iron oxides and copper matte in the copper slag undergo redox reactions in the molten iron to generate metallic iron and copper, which then enter the molten iron. The copper element in the molten iron can be used as an alloy raw material for adjusting the elements in the molten steel later (for example, the production of weathering steel and copper-containing stainless steel requires a certain amount of Cu in the steel). The Zn in the copper slag mainly exists in the form of ZnO, ZnS or ZnFe2O4. During the converter steelmaking process, ZnO, ZnS or ZnFe2O4 is first reduced to Zn metal by carbon in the molten iron, and escapes in the form of Zn vapor. After entering the flue, it is oxidized to zinc oxide or zinc suboxide, which is cooled and condensed in the flue, or attached to dust particles and recovered.

[0031] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing converter cold material using copper slag, characterized in that: The following steps are involved: Step 1: weigh the raw materials according to the following weight percentages: copper slag 30%-55%, iron oxide scale 10%-30%, converter dust ash 20%-35%, magnetic separation tailings 3%-10%, and binder 3%-5%; Step 2: Mix the weighed raw materials and add water to mix; Step 3: Load the mixed material obtained in step 2 into a roller ball press to press out wet lumps. After the wet lumps are dried, the converter cold material is obtained.

2. The method for preparing converter cold material using copper slag according to claim 1, characterized in that: The copper content in the copper slag in step 1 is 0.14%-0.52%.

3. The method for preparing converter cold material using copper slag according to claim 1, characterized in that: In step 2, water is added until the moisture content of the mixture is 7.5%-8.5%.

4. The method for preparing converter cold material using copper slag according to claim 1, characterized in that: In step 3, the drying method includes drying and air-drying.

5. The method for preparing converter cold material using copper slag according to claim 1, characterized in that: In step 3, the moisture content of the wet mass obtained by drying is 1.3%-1.9%, and the compressive strength is 866N-1299N.