Refining titanium removal slag and low-titanium ferrochrome refining titanium removal method

Abstract

The invention discloses refined titanium-removed slag which is prepared from the following raw materials in parts by weight: 52-56 parts of lime, 20-23 parts of silica and 20-25 parts of laterite. Liquid slag formed during titanium removal of the refined titanium-removed slag comprises the following components: 50%-55% of CaO, 25%-30% of SiO2, 12%-16% of Al2O3 and 6%-10% of FeO. The low-titanium ferrochrome refining titanium removal method is characterized by comprising the following processes: (1) adding ferrochrome molten iron and refining titanium removal slag, (2) melting slag, (3) removing titanium, and (4) removing slag. The method has the advantages that the lime, the silica and the laterite are reasonably proportioned and mixed to form the refined titanium-removed slag, and low-melting-point substances can be formed through mutual reaction, so that the formation of liquid slag is accelerated. The refined titanium-removed slag is added into the ferrochrome molten iron to form low-melting-point titanium-removed slag liquid, the interface between the slag liquid and the ferrochrome molten iron is large, arc heating is carried out in the titanium-removing process, the furnace temperature is high, the viscosity of the slag liquid and the ferrochrome molten iron is small, and the floating resistance of inclusions is small, so that the titanium-removing effect is good, and the titanium-removing rate is high.

Description

Technical field: [0001] The invention relates to the technical field of low-titanium ferrochromium de-titanium, in particular to a refining and de-titanium slag for ferrochromium molten iron and a method for refining and de-titanium of low-titanium ferrochromium. Background technique: [0002] Chromium is the main alloying element for the production of stainless steel, bearing steel and high-strength structural steel, and ferrochromium is an important raw material for the production of these steels. Ordinary high-carbon ferrochromium contains 0.2%-0.3% of titanium, usually mainly in the form of high melting point non-metallic inclusions such as TiC and TiN. Using high-carbon ferrochromium as raw material, the smelted low-carbon ferrochromium and various alloy steels inevitably contain high melting point non-metallic inclusions such as TiC and TiN with edges and corners, which will have strong cracking and stress on the metal matrix. Concentrated action will seriously damage...

AI Technical Summary

Problems solved by technology

However, due to the high content of titanium in ferrochrome in my country, the bearing steel smelted by secondary refining has a titanium content in the range of 72-112ppm, and the fatigue resistance of the bearing is poor. Raw materials, a new method of producing low-titanium ferrochrome, has become one of the current urgent tasks

[0003] There are two conventional methods for the production of low-titanium ferrochrome: the first is to select raw materials with as low a titanium content as possible, and to control the amount of carbon to limit the amount of TiO in the raw materials. 2 Reduction in the electric furnace, it is more difficult to realize these two measures in production. First, the low-titanium high-quality raw materials are increasingly scarce and the cost is high; secondly, limit TiO 2 It is more difficult to restore in the furnace

The second method is to use oxygen blowing to remove titanium outside the high-temperature ferrochromium furnace. Not only is the equipment complex and expensive, but also the cost is high, and the operation is large, the metal loss rate is high, and the safety risk is large, so it is difficult to use in production; while blowing oxygen to remove titanium , is to use CO bubbles to absorb titanium-containing inclusions, float to the slag liquid and remove them; but at the same time, the high-pressure oxygen flow continuously crushes the slag liquid and molten iron, and they mix with each other, and part of the titanium-containing inclusions will return to the iron Liquid iron presents a certain dynamic balance. When the original titanium content in molten iron is too high, its equilibrium value (that is, the amount of residual titanium) is also relatively high.

Therefore, the addition of the oxidizing agent in this patent has no effect on detitanium removal, and the amount of slagging agent added is small, which cannot achieve the claimed effect of detitanium removal

In addition, the electric furnace used in this patent is an intermediate frequency induction electric furnace. The intermediate frequency furnace is used as the refining furnace, chromite is added as the oxidant, and CaO is used as the main slagging agent to carry out titanium removal; The intermediate frequency furnace uses a knotted lining inside the intermediate frequency coil. At such a high temperature, if the maintenance time is too long, the lining will be further sintered, causing shrinkage and cracking, and accidents will occur. In addition, the ferrochrome molten iron must be heated To such a high temperature, the energy consumption is large, not to mention that the oxidant and slagging agent must be made into powder, and sprayed into molten iron through a heat-resistant mixer. The process and equipment are complicated, the cost is high, and the economic benefit is low.

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