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Method for increasing yield of molten steel chromium in chromium ore direct-alloying

A technology of alloying and molten steel chromium, which is applied in the field of direct alloying molten steel with chromium ore, can solve the problems of prolonged processing time, difficulty in wide application, and complicated equipment, and achieve the effects of shortening refining time, promoting contact area, and reducing production cost

Active Publication Date: 2015-09-02
CENT IRON & STEEL RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Add chromium ore and reducing agent into the converter, but because the converter is an oxidizing atmosphere, the reduction of chromium ore is poor, the recovery rate of chromium is only about 50%, and the utilization rate of chromium ore is low
[0005] (2) In the converter or electric furnace, chromium ore powder is sprayed in the form of powder spraying from the top or bottom, and the recovery rate of chromium is increased, but a special top-blowing spray gun or powder spraying device is required, and the equipment is relatively complicated and the cost is high. Difficult to maintain and difficult to apply widely
However, the existing problem is that after adding chromium ore in the converter tapping process, the temperature drop of molten steel is relatively large, and the temperature of molten steel drops rapidly. At the same time, the content of chromium oxide in the slag increases after the addition of chromium ore, and the viscosity of the slag is relatively high, and the melting point is relatively high. It brings great difficulty to heating, deoxidation and removal of inclusions in molten steel in the subsequent refining process, resulting in prolonged processing time and increased power consumption
[0007] Since the above-mentioned problem of direct alloying of chrome ore has not been solved, the application of this technology is less at present

Method used

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  • Method for increasing yield of molten steel chromium in chromium ore direct-alloying
  • Method for increasing yield of molten steel chromium in chromium ore direct-alloying

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] Chromite (TCr=32.85%, SiO 2 =9.55%, TFe=15.1%, MgO=15%, Al 2 o 3 =11.81%), limestone, coke, ferrosilicon as raw material after drying, crushing and grinding, and the batching composition (weight %) is: 70% of chrome ore powder, 5% of limestone, 15% of coke, 2% of water glass, Ferrosilicon powder 8%.

[0047] The prepared material is used as a spare material for the chrome ore mixture after mixing. Wrap the prepared chrome ore mixture together with a thin steel strip, and then press it tightly to make a cored wire with a diameter of 40mm, a length of 500mm, and a weight of 2.5kg.

[0048] Put 200kg of steel scrap into a 500kg level converter thermal simulation test furnace, heat up to 1650°C by induction heating, take the initial steel sample, and measure [C]=0.3%, [Si]=0.4%, [Cr]=0.02%, [ P] = 0.02%, [S] = 0.02%. Insert 2 cored wires into the molten pool, and blow argon gas at the bottom of the molten pool with a strength of 0.03Nm 3 / t.min, steel samples were tak...

Embodiment 2

[0050] Chromite (TCr=32.85%, SiO 2 =9.55%, TFe=15.1%, MgO=15%, Al 2 o 3 =11.81%), limestone, anthracite, and ferrosilicon are used as raw materials after drying, crushing, and grinding, and the batching composition (weight %) is: 75% of chrome ore powder, 5% of limestone, 10% of coke, 2% of water glass, Ferrosilicon powder 8%.

[0051] The prepared material is used as a spare material for the chrome ore mixture after mixing. Wrap the prepared chrome ore mixture together with a thin steel strip, and then press it tightly to make a cored wire with a diameter of 40mm, a length of 500mm, and a weight of 2.5kg. In a 500kg-class converter heat simulation test furnace, load 200kg of scrap steel, induction heating to 1650 ° C, take the initial steel sample, measured [C] = 0.38%, [Si] = 0.35%, [Cr] = 0.06%, [ P] = 0.02%, [S] = 0.02%.

[0052] Insert 2 cored wires into the molten pool, and blow argon gas at the bottom of the molten pool with a strength of 0.02Nm 3 / t.min, steel sa...

Embodiment 3

[0054] Chromite (TCr=32.85%, SiO 2 =9.55%, TFe=15.1%, MgO=15%, Al 2 o 3 =11.81%), lime and coke are used as raw materials after drying, crushing, and ferrosilicon grinding. The ingredients (weight%) are: 65% of chrome ore powder, 5% of limestone, 15% of coke, 2% of water glass, silicon Iron powder 13%.

[0055] The prepared material is used as a spare material for the chrome ore mixture after mixing. Use a thin steel strip to mix and pack the prepared chrome ore together, and then press it tightly to make a cored wire with a diameter of 40mm, a length of 500mm, and a weight of 2.5kg. In a 500kg level converter thermal simulation test furnace, load 200kg of scrap steel, induction heating to 1650 ℃, take the initial steel sample, measured [C] = 0.28%, [Si] = 0.43%, [Cr] = 0.02%, [ P] = 0.02%, [S] = 0.02%. Insert 3 cored wires into the molten pool, and blow argon gas at the bottom of the molten pool with a strength of 0.05Nm 3 / t.min, steel samples were taken after 5 minute...

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Abstract

The invention relates to a method for increasing yield of molten steel chromium in chromium ore direct-alloying and belongs to the technical field of molten steel chromium alloying in steelmaking. The method includes making chromium ore, limestone, anthracite or coke and silicon iron into powder, adding water glass to obtain mixture according to a certain proportion, making into core-spun wires, feeding the core-spun wires into molten steel in the process of refining of steelmaking and reducing to obtain chromium. The method can ensure quick reaction of the mixture in the high-temperature molten steel and promote reaction balance and contact area of powder and molten steel and is conducive to increasing recovery rate of chromium.

Description

technical field [0001] The invention belongs to the field of chromium alloying in converter or electric furnace steelmaking, and in particular relates to a method for directly alloying molten steel with chromium ore to improve the yield of chromium. Background technique [0002] Chromium is an important alloy of stainless steel, heat-resistant steel, alloy tool steel, and alloy structural steel. Chromium in steel can increase the hardenability of steel and improve the physical and chemical properties of steel. Therefore, chromium is an alloy that must be added in the above steel types. The way to add chromium in the steelmaking process is to add chromium alloys. However, since the manufacture of chromium alloys consumes a large amount of coke and discharges dust and carbon dioxide and other harmful substances to the environment, it is a process of high energy consumption and high pollution. It can realize the direct alloying of chromium ore in steelmaking and cancel the man...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/00
Inventor 吴伟刘跃谭明祥吴东俊戴诗凡
Owner CENT IRON & STEEL RES INST
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