Premelting type desulfurizing agent suitable for high-aluminum silicon steel and preparation method thereof

Abstract

The invention provides a premelting type desulfurizing agent suitable for high-aluminum silicon steel and a preparation method thereof. The desulfurizing agent comprises the following components by weight percent: 80-85 percent of calcium oxide (CaO), 13-18 percent of aluminum oxide (Al2O3), not greater than 1.5 percent of magnesium oxide (MgO), not greater than 1.5 percent of silicon dioxide (SiO2), not greater than 0.02 percent of all titanium (Ti) and not greater than 0.02 percent of all carbon (C). The preparation method comprises the following steps: (1) weighing 87-90 percent of limestone of which the granularity is not greater than 10mm and 10-13 percent of Al2O3 of which the granularity is not greater than 10mm by weight percent; (2) putting the raw materials in a mixer and evenly mixing; (3) adding a mixture to a smelting furnace, then, blowing fuel oil for heating, and smelting; and (4) discharging, cooling and crushing for later use. The desulfurizing agent provided by the invention is easy to store, has high desulfurizing rate and has low erosion on the refractory of a vacuum slot body; and in the desulfurizing process, molten steel carburetion and titanizing can be controlled to be under 5 parts per million (ppm), and the desulfurizing rate can reach at least 60 percent on the premise of not increasing the refining time.

Description

technical field [0001] The invention belongs to the technical field of steel-making vacuum refining, and in particular relates to a RH vacuum-treated pre-melting desulfurizer for high-alumina silicon steel and a preparation method thereof. Background technique [0002] Silicon steel is a kind of steel for electrical engineering. Using silicon steel sheets with good performance to make iron cores of transformers and motors can not only save energy, reduce iron loss, but also reduce noise pollution. The core technology of its steelmaking process is the full removal of harmful elements and the reasonable control of its inclusions. Sulfur is a harmful element for most steel types, and desulfurization of molten steel during the RH refining process is a common method to control the sulfur content in steel. [0003] In the 1960s and 1970s, RH devices developed rapidly. Its main functions are degassing, alloying, chemical heating, removal of inclusions, desulfurization, etc. Amon...

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Problems solved by technology

When the above pre-slag is prepared, in order to reduce the content of titanium and carbon in the pre-slag, the raw materials are high-quality limestone and high-purity Al 2 o 3 powder, but did not explain all titanium, because all valences and forms of titanium in the desulfurizer may be reduced to titanium by the aluminum in the aluminum-containing silicon steel, thus causing the titanium content in the steel to exceed the standard

In addition, the SiO in the desulfurizer 2 The content is also higher, SiO 2 The content of silicon steel is 2.5-6.0%, plus SiO formed by silicon steel during RH vacuum treatment 2 , will also aggravate the erosion of magnesia-chrome refractory bricks on the RH vacuum treatment device

On the other hand, Al in the desulfurizer 2 o 3 content is also higher, Al 2 o 3 The content of aluminum is 33-43%. When aluminum-containing silicon steel is deoxidized by aluminum, more Al will be generated. 2 o 3 , so that Al in slag 2 o 3 An increase in content is not conducive to the formation of calcium aluminate with a low melting point, resulting in a decrease in desulfurization performance

[0005] As mentioned above, the existing desulfurizers cannot meet the desulfurization requirements of aluminum-containing silicon steel, and will cause carburization and titanium increase in molten steel during use. At the same time, the Al generated during the refining process of aluminum-containing silicon steel is not considered 2 o 3 and SiO 2 Influence on the properties of slag

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