Method for preparing iron powder from cold-rolled acid regenerated iron oxide powder

Abstract

The invention relates to the technical field of powder metallurgy, and provides a method for preparing iron powder from cold-rolled acid regenerated iron oxide powder, which comprises the following steps: S1, preheating, mixing and granulating the cold-rolled acid regenerated iron oxide powder and petroleum coke powder to obtain iron oxide reduced balls; and S2, the iron oxide reduction balls are subjected to calcination, reduction, winnowing and ball milling, and iron powder is obtained. According to the technical scheme, the problems of low grade and poor compression performance of iron powder prepared from cold-rolled acid regenerated iron oxide powder in related technologies are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of powder metallurgy, and specifically, to a method for preparing iron powder from oxidized iron powder for cold rolling acid regeneration. Background Art

[0002] In the cold rolling industry, the high-value utilization of by-product oxidized iron powder from acid regeneration and the pollution problem of hydrogen-containing waste gas discharged from cold rolling annealing furnaces are important challenges faced by the industry.

[0003] Oxidized iron powder, commonly known as iron red, is a by-product of cold rolling acid regeneration units. In the cold rolling process, after strip steel is pickled, hydrochloric acid rich in ferrous chloride is generated. When these waste acids are regenerated by methods such as spray roasting, oxidized iron powder is by-produced. A cold rolling production line with an annual output of one million tons can produce nearly ten thousand tons of oxidized iron powder every year. However, at present, the performance and grade of oxidized iron powder produced by many cold rolling plants are relatively low, making it difficult to meet the requirements of high-end fields such as high-performance magnetic materials and catalysts. At the same time, there is a demand for high-performance oxidized iron powder in the high-end market, but due to factors such as product performance and price, the market acceptance is limited.

[0004] During the cold rolling production process, strip steel often needs to be annealed to improve its mechanical properties and processing performance. During the annealing process, hydrogen is often used as a protective atmosphere to prevent strip steel from being oxidized at high temperatures. However, in this process, some hydrogen fails to participate in the reaction completely and is discharged with the tail gas, becoming one of the main sources of waste hydrogen. Cold rolling waste hydrogen often contains various impurities such as dust, oil, oxygen, hydrocarbons, and water vapor. The presence of these impurities seriously affects the purity of hydrogen. Even with various filtration methods such as membrane filtration, washing filtration, and ceramic filtration, the impurities cannot be completely removed, and the problem of fouling of the filtration medium leads to difficulties in recycling hydrogen, and enterprises have many concerns about this and are reluctant to invest in the above purification process.

[0005] Reduced iron powder is a gray or black powder mainly containing elemental iron, which is an aggregate of fine particles of metallic iron obtained through a chemical reduction reaction. It has characteristics such as high purity, high activity, good electrical conductivity, and thermal conductivity, and has a wide range of applications in many fields. For example, reduced iron powder is an important raw material for powder metallurgy products, and its consumption accounts for about 60% - 80% of the total iron powder consumption; in the manufacture of welding electrodes, reduced iron powder is used as an additive to the coating, which can improve the welding process and deposition efficiency of the electrode; using its characteristics of absorbing moisture and oxygen, reduced iron powder is often used as a food preservative; in chemical production and laboratory operations, reduced iron powder is also commonly used as a high-quality reducing agent; in processes such as flame cutting, it can be used as a propellant, etc.

[0006] The domestic market capacity of reduced iron powder alone reaches more than one million tons. Moreover, the raw materials for high-end reduced iron powder are magnetite, iron ore concentrate powder, steel mill scale, etc. Under high-temperature conditions, iron oxides are reduced to fine particles of metallic iron using reducing agents such as hydrogen and carbon monoxide. This provides a broad outlet for the high-value utilization of iron oxide powder by-products from acid regeneration in the cold rolling industry. Coupled with the by-product hydrogen in the cold rolling industry, it can significantly reduce production costs, and related technologies urgently need to be developed and engineered. Summary of the Invention

[0007] The present invention provides a method for preparing iron powder from iron oxide powder by-products of cold rolling acid regeneration, which solves the problems of low grade and poor compression performance in the preparation of iron powder from iron oxide powder by-products of cold rolling acid regeneration in related technologies.

[0008] The technical solution of the present invention is as follows: The present invention provides a method for preparing iron powder from iron oxide powder by-products of cold rolling acid regeneration, comprising the following steps: S1. Preheat and mix cold rolling acid regeneration iron oxide powder and petroleum coke powder, and granulate to obtain iron oxide reduction pellets; S2. Calcinate, reduce, air-separate, and ball-mill the iron oxide reduction pellets to obtain iron powder.

[0009] As a further technical solution, the Fe2O3 content in the cold rolling acid regeneration iron oxide powder is 97.5 wt% - 99.5 wt%, and the average particle size is 0.5 - 2.0 μm.

[0010] As a further technical solution, the fixed carbon content of the petroleum coke powder is 80% - 90%, and the average particle size is 10 - 20 μm.

[0011] As a further technical solution, the mass ratio of the cold rolling acid regeneration iron oxide powder to the petroleum coke powder is 10 - 15:1.

[0012] As a further technical solution, the temperature of the preheating and mixing is 80 - 150 °C.

[0013] As a further technical solution, the iron oxide reduction pellets are elliptical balls, with the long side diameter being 10 - 30 mm and the short side diameter being 0.5 times that of the long side.

[0014] As a further technical solution, the calcination temperature is 950 - 1000 °C, and the time is 1 - 2 h.

[0015] As a further technical solution, the reduction reaction is carried out under cold rolling hydrogen-containing waste gas; the volume content of hydrogen in the cold rolling hydrogen-containing waste gas is 5% - 25%, and the air separation accounts for 20% - 30% of the total amount.

[0016] As a further technical solution, a ball milling agent is added during ball milling; the ball milling agent comprises polyether modified polysiloxane and 3-mercapto-1-propanesulfonic acid sodium with a mass ratio of 8:1 to 5.

[0017] In the present invention, polyether modified polysiloxane and 3-mercapto-1-propanesulfonic acid sodium are used as the ball milling agent. During the ball milling process, polyether modified polysiloxane, relying on its surface activity and lubricating properties, ensures the uniform dispersion of iron powder particles, improves the ball milling efficiency, and at the same time makes the particle surface smooth. 3-mercapto-1-propanesulfonic acid sodium, through chemical modification and inhibition of oxidation, effectively removes impurities and prevents the oxidation of iron powder, improving the iron powder grade. The two work together to obtain higher grade iron powder, and the iron powder has higher compressive strength when it can withstand pressure during the pressing process.

[0018] As a further technical solution, the time of the reduction reaction is 8 to 12 h.

[0019] The working principle and beneficial effects of the present invention are as follows: In the present invention, different from the problems of complex process, high cost, poor safety, etc. existing in the preparation of iron powder by using cold rolling acid regeneration iron oxide powder in the prior art, the present invention adopts the method of preheating and mixing cold rolling acid regeneration iron oxide powder and petroleum coke powder, granulating, and then calcining, reducing, and air separating, which has significant advantages. First of all, preheating and mixing enables the iron oxide powder and petroleum coke powder to be fully contacted, providing a basis for the subsequent reduction reaction. The carbon in the petroleum coke powder can effectively reduce iron oxide, and compared with some methods that require special reducing gases, the cost is lower and the operation is more convenient. The formed iron oxide reduction balls by granulation are beneficial to the uniform transfer of heat during the calcination and reduction process, ensuring the stability and uniformity of the reaction, making the reduction reaction more complete, and greatly improving the iron grade. At the same time, high-temperature calcination and reduction not only fully reduce iron, but also make the arrangement of iron atoms more orderly, reducing lattice defects, thereby improving the compression performance of iron powder. Finally, the air separation operation uses the density and particle size differences of substances to accurately separate impurities in the iron powder, further purifying the iron powder to ensure the acquisition of high-grade products. In practical applications, the high-grade and high-compression performance iron powder prepared by this method can be widely used in fields such as powder metallurgy and electronic materials, improving the performance and quality of products. Specific embodiments

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of the present invention.

[0021] Example 1 A method for preparing iron powder from cold-rolled acid regeneration iron oxide powder, comprising the following steps: S1. Preheat and mix cold-rolled acid regeneration iron oxide powder and petroleum coke powder, and granulate to obtain iron oxide reduction pellets; S2. Calcinate the iron oxide reduction pellets (the calcination temperature is 950 °C and the time is 2 h), reduce for 8 h, perform air separation, and ball mill to obtain iron powder (the grade is 97.8%, and the compression performance is 6.6 g / cm 3 )

[0022] The content of Fe2O3 in the cold-rolled acid regeneration iron oxide powder is 97.5 wt%, the average particle size is 0.5 μm, the fixed carbon content of the petroleum coke powder is 80%, and the average particle size is 10 μm. The mass ratio of the cold-rolled acid regeneration iron oxide powder to the petroleum coke powder is 10:1. The preheating and mixing temperature is 80 °C. The iron oxide reduction pellets are elliptical balls, the long side diameter is 10 mm, and the short side diameter is 0.5 times that of the long side. The reduction reaction is carried out under cold-rolled hydrogen-containing waste gas. The volume content of hydrogen in the cold-rolled hydrogen-containing waste gas is 5%, and the air separation accounts for 20% of the total amount.

[0023] Example 2 A method for preparing iron powder from cold-rolled acid regeneration iron oxide powder, comprising the following steps: S1. Preheat and mix cold-rolled acid regeneration iron oxide powder and petroleum coke powder, and granulate to obtain iron oxide reduction pellets; S2. Calcinate the iron oxide reduction pellets (the calcination temperature is 1000 °C and the time is 1 h), reduce for 12 h, perform air separation, and ball mill to obtain iron powder (the grade is 98.0%, and the compression performance is 6.0 g / cm 3 )

[0024] The content of Fe2O3 in the cold-rolled acid regeneration iron oxide powder is 99.5 wt%, the average particle size is 2.0 μm, the fixed carbon content of the petroleum coke powder is 90%, and the average particle size is 20 μm. The mass ratio of the cold-rolled acid regeneration iron oxide powder to the petroleum coke powder is 15:1. The preheating and mixing temperature is 150 °C. The iron oxide reduction pellets are elliptical balls, the long side diameter is 30 mm, and the short side diameter is 0.5 times that of the long side. The reduction reaction is carried out under cold-rolled hydrogen-containing waste gas. The volume content of hydrogen in the cold-rolled hydrogen-containing waste gas is 25%, and the air separation accounts for 30% of the total amount.

[0025] Example 3 A method for preparing iron powder from cold-rolled acid regeneration iron oxide powder, comprising the following steps: S1. Preheat and mix cold-rolled acid regeneration iron oxide powder and petroleum coke powder, and granulate to obtain iron oxide reduction pellets; S2. Calcinate the iron oxide reduction pellets (the calcination temperature is 1000 °C and the time is 1.5 h), reduce for 10 h, perform air separation, and ball mill to obtain iron powder (the grade is 98.2%, and the compression performance is 6.3 g / cm3 ).

[0026] The Fe2O3 content in the cold-rolled acid regeneration iron oxide powder is 98 wt%, the average particle size is 1 μm, the fixed carbon content of the petroleum coke powder is 85%, and the average particle size is 15 μm. The mass ratio of the cold-rolled acid regeneration iron oxide powder to the petroleum coke powder is 13:1. The temperature of preheating and mixing is 120 °C. The iron oxide reduction balls are oval balls, with the long side diameter being 20 mm and the short side diameter being 0.5 times that of the long side. The reduction reaction is carried out under cold-rolled hydrogen-containing waste gas. The volume content of hydrogen in the cold-rolled hydrogen-containing waste gas is 20%, and the amount separated by air selection accounts for 25% of the total amount.

[0027] Example 4 A method for preparing iron powder from cold-rolled acid regeneration iron oxide powder, comprising the following steps: S1. Preheat and mix the cold-rolled acid regeneration iron oxide powder and the petroleum coke powder, and granulate to obtain iron oxide reduction balls; S2. Calcinate the iron oxide reduction balls (the calcination temperature is 1000 °C and the time is 1.5 h), reduce for 10 h, separate by air selection, and ball mill under a ball milling agent of polyether-modified polysiloxane and 3-mercapto-1-propanesulfonic acid sodium with a mass ratio of 8:6 to obtain iron powder (the grade is 99.0%, and the compression performance is 7.5 g / cm 3 ).

[0028] The Fe2O3 content in the cold-rolled acid regeneration iron oxide powder is 98 wt%, the average particle size is 1 μm, the fixed carbon content of the petroleum coke powder is 85%, and the average particle size is 15 μm. The mass ratio of the cold-rolled acid regeneration iron oxide powder to the petroleum coke powder is 13:1. The temperature of preheating and mixing is 120 °C. The iron oxide reduction balls are oval balls, with the long side diameter being 20 mm and the short side diameter being 0.5 times that of the long side. The reduction reaction is carried out under cold-rolled hydrogen-containing waste gas. The volume content of hydrogen in the cold-rolled hydrogen-containing waste gas is 20%, and the amount separated by air selection accounts for 25% of the total amount.

[0029] Example 5 A method for preparing iron powder from cold-rolled acid regeneration iron oxide powder, comprising the following steps: S1. Preheat and mix the cold-rolled acid regeneration iron oxide powder and the petroleum coke powder, and granulate to obtain iron oxide reduction balls; S2. Calcinate the iron oxide reduction balls (the calcination temperature is 1000 °C and the time is 1.5 h), reduce for 10 h, separate by air selection, and ball mill under a ball milling agent of polyether-modified polysiloxane and 3-mercapto-1-propanesulfonic acid sodium with a mass ratio of 9:1 to obtain iron powder (the grade is 99.0%, and the compression performance is 7.4 g / cm 3 ).

[0030] The Fe2O3 content in the cold-rolled acid regeneration iron oxide powder is 98 wt%, the average particle size is 1 μm, the fixed carbon content of the petroleum coke powder is 85%, and the average particle size is 15 μm. The mass ratio of the cold-rolled acid regeneration iron oxide powder to the petroleum coke powder is 13:1. The temperature of preheating and mixing is 120 °C. The iron oxide reduction ball is an elliptical ball, the long side diameter is 20 mm, and the short side diameter is 0.5 times that of the long side. The reduction reaction is carried out under cold-rolled hydrogen-containing waste gas. The volume content of hydrogen in the cold-rolled hydrogen-containing waste gas is 20%, and the amount of air separation accounts for 25% of the total amount.

[0031] Example 6 A method for preparing iron powder from cold-rolled acid regeneration iron oxide powder, comprising the following steps: S1. Preheat and mix the cold-rolled acid regeneration iron oxide powder and the petroleum coke powder, and granulate to obtain iron oxide reduction balls; S2. Calcinate the iron oxide reduction balls (the calcination temperature is 1000 °C and the time is 1.5 h), reduce for 10 h, perform air separation, and ball mill under a ball milling agent of polyether-modified polysiloxane and 3-mercapto-1-propanesulfonic acid sodium with a mass ratio of 8:5 to obtain iron powder (the grade is 99.8%, and the compression performance is 8.0 g / cm 3 )

[0032] The Fe2O3 content in the cold-rolled acid regeneration iron oxide powder is 98 wt%, the average particle size is 1 μm, the fixed carbon content of the petroleum coke powder is 85%, and the average particle size is 15 μm. The mass ratio of the cold-rolled acid regeneration iron oxide powder to the petroleum coke powder is 13:1. The temperature of preheating and mixing is 120 °C. The iron oxide reduction ball is an elliptical ball, the long side diameter is 20 mm, and the short side diameter is 0.5 times that of the long side. The reduction reaction is carried out under cold-rolled hydrogen-containing waste gas. The volume content of hydrogen in the cold-rolled hydrogen-containing waste gas is 20%, and the amount of air separation accounts for 25% of the total amount.

[0033] Example 7 A method for preparing iron powder from cold-rolled acid regeneration iron oxide powder, comprising the following steps: S1. Preheat and mix the cold-rolled acid regeneration iron oxide powder and the petroleum coke powder, and granulate to obtain iron oxide reduction balls; S2. Calcinate the iron oxide reduction balls (the calcination temperature is 1000 °C and the time is 1.5 h), reduce for 10 h, perform air separation, and ball mill under a ball milling agent of polyether-modified polysiloxane and 3-mercapto-1-propanesulfonic acid sodium with a mass ratio of 8:1 to obtain iron powder (the grade is 99.8%, and the compression performance is 8.2 g / cm 3 )

[0034] The Fe2O3 content in the cold-rolled pickling regenerated iron oxide powder is 98 wt%, the average particle size is 1 μm, the fixed carbon content of the petroleum coke powder is 85%, and the average particle size is 15 μm. The mass ratio of the cold-rolled pickling regenerated iron oxide powder to the petroleum coke powder is 13:1. The temperature of preheating and mixing is 120 °C. The iron oxide reduction pellets are elliptical balls, with the long side diameter being 20 mm and the short side diameter being 0.5 times that of the long side. The reduction reaction is carried out under cold-rolled hydrogen-containing waste gas. The volume content of hydrogen in the cold-rolled hydrogen-containing waste gas is 20%, and the amount of air separation accounts for 25% of the total amount.

[0035] Example 8 A method for preparing iron powder from cold-rolled pickling regenerated iron oxide powder, comprising the following steps: S1. Preheat and mix the cold-rolled pickling regenerated iron oxide powder and the petroleum coke powder, and granulate to obtain iron oxide reduction pellets; S2. Calcinate the iron oxide reduction pellets (the calcination temperature is 1000 °C and the time is 1.5 h), reduce for 10 h, perform air separation, and ball mill under 3-mercapto-1-propanesulfonate ball milling agent to obtain iron powder (the grade is 98.9%, and the compression performance is 6.9 g / cm 3 )

[0036] The Fe2O3 content in the cold-rolled pickling regenerated iron oxide powder is 98 wt%, the average particle size is 1 μm, the fixed carbon content of the petroleum coke powder is 85%, and the average particle size is 15 μm. The mass ratio of the cold-rolled pickling regenerated iron oxide powder to the petroleum coke powder is 13:1. The temperature of preheating and mixing is 120 °C. The iron oxide reduction pellets are elliptical balls, with the long side diameter being 20 mm and the short side diameter being 0.5 times that of the long side. The reduction reaction is carried out under cold-rolled hydrogen-containing waste gas. The volume content of hydrogen in the cold-rolled hydrogen-containing waste gas is 20%, and the amount of air separation accounts for 25% of the total amount.

[0037] Example 9 A method for preparing iron powder from cold-rolled pickling regenerated iron oxide powder, comprising the following steps: S1. Preheat and mix the cold-rolled pickling regenerated iron oxide powder and the petroleum coke powder, and granulate to obtain iron oxide reduction pellets; S2. Calcinate the iron oxide reduction pellets (the calcination temperature is 1000 °C and the time is 1.5 h), reduce for 10 h, perform air separation, and ball mill under polyether-modified polysiloxane ball milling agent to obtain iron powder (the grade is 98.6%, and the compression performance is 7.1 g / cm 3 )

[0038] The Fe2O3 content in the oxidized iron powder from cold rolling acid regeneration is 98wt%, the average particle size is 1μm, the fixed carbon content of the petroleum coke powder is 85%, and the average particle size is 15μm. The mass ratio of the oxidized iron powder from cold rolling acid regeneration to the petroleum coke powder is 13:1. The temperature of preheating and mixing is 120°C. The iron oxide reduction pellet is an elliptical sphere, with the long side diameter being 20mm and the short side diameter being 0.5 times that of the long side. The reduction reaction is carried out under the cold rolling hydrogen-containing waste gas. The volume content of hydrogen in the cold rolling hydrogen-containing waste gas is 20%, and the amount of air separation accounts for 25% of the total amount.

[0039] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing iron powder from oxidized iron powder in cold rolling acid regeneration, characterized in that, It includes the following steps: S1. Preheat and mix cold-rolled acid regeneration iron oxide powder and petroleum coke powder, and granulate to obtain iron oxide reduction pellets; S2. Calcinate, reduce, air-separate, and ball-mill the iron oxide reduction pellets to obtain iron powder.

2. The method for preparing iron powder from oxidized iron powder in cold rolling acid regeneration according to claim 1, characterized in that, The Fe2O3 content in the cold-rolled acid regeneration iron oxide powder is 97.5wt% - 99.5wt%, and the average particle size is 0.5 - 2.0μm.

3. The method for preparing iron powder from oxidized iron powder in cold rolling acid regeneration according to claim 1, characterized in that, The fixed carbon content of the petroleum coke powder is 80% - 90%, and the average particle size is 10 - 20μm.

4. A method for preparing iron powder from oxidized iron powder in cold rolling acid regeneration according to claim 1, characterized in that The mass ratio of the cold-rolled acid regeneration iron oxide powder to the petroleum coke powder is 10 - 15:

1.

5. A method for preparing iron powder from oxidized iron powder in cold rolling acid regeneration, according to claim 1, characterized in that, The temperature of the preheating and mixing is 80 - 150°C.

6. A method for preparing iron powder from oxidized iron powder in cold rolling acid regeneration according to claim 1, characterized in that, The iron oxide reduction pellets are ellipsoidal, with the long side diameter being 10 - 30mm and the short side diameter being 0.5 times that of the long side.

7. A method for preparing iron powder from oxidized iron powder in cold rolling acid regeneration according to claim 1, characterized in that, The temperature of the calcination is 950 - 1000°C, and the time is 1 - 2h.

8. A method for preparing iron powder from oxidized iron powder in cold rolling acid regeneration according to claim 1, characterized in that, The reduction reaction is carried out under cold-rolled hydrogen-containing waste gas; the volume content of hydrogen in the cold-rolled hydrogen-containing waste gas is 5% - 25%, and the air-separated part accounts for 20% - 30% of the total amount.

9. A method for preparing iron powder from oxidized iron powder in cold rolling acid regeneration according to claim 1, characterized in that, A ball-milling agent is added during ball-milling; the ball-milling agent includes polyether-modified polysiloxane and 3-mercapto-1-propanesulfonic acid sodium with a mass ratio of 8:1 - 5.

10. A method for preparing iron powder from oxidized iron powder in cold rolling acid regeneration according to claim 1, characterized in that, The time of the reduction reaction is 8 - 12h.