CN104726643B - Process for applying calcium carbonate carbon spheres to LF (ladle furnace) steelmaking - Google Patents

Abstract

The invention discloses a process for applying calcium carbonate carbon spheres to LF (ladle furnace) steelmaking, which comprises the steps of grinding limestone to a particle size of below 1mm, mixing the limestone with graphite carbon uniformly, and pressing the mixture into calcium carbonate carbon spheres by using a dry powder ball press; every 100kg of calcium carbonate carbon spheres are produced, wherein the addition amount y of limestone is as follows: y =83(100 β -51) ÷ (83 β -12 γ); the adding amount of the graphite carbon is as follows: 100-y; in the formula: beta is the carbon content in graphite,%; gamma is the content of calcium carbonate in the limestone,%; when the aluminum killed steel is smelted in the converter, the calcium carbonate carbon balls are added according to the principle that the equivalent quantity replaces the adding quantity of the traditional calcium carbide, and the aluminum killed steel can be used according to the traditional steelmaking process.

Description

Process for applying calcium carbonate carbon spheres to LF (ladle furnace) steelmaking

Technical Field

The invention relates to a steelmaking process, in particular to a process for applying calcium carbonate carbon spheres to LF steelmaking.

Background

In the steel-making process, calcium carbide is generally used for deoxidation, and the aim of reducing the oxygen content in molten steel or steel slag is fulfilled mainly by utilizing the reaction between carbon in calcium carbide in the molten steel or steel slag and oxygen or oxide in the molten steel or steel slag after the calcium carbide is decomposed. The deoxidation products of the calcium carbide deoxidation process are CO and CaO, so that the molten steel is not polluted when the molten steel is deoxidized, and the alkalinity of the steel slag is not reduced when the steel slag is deoxidized.

However, calcium carbide used in steel making is easily affected by moisture and deteriorated during transportation and storage, and has negative effects, and calcium carbide production belongs to the high energy consumption industry and the industry of national control development, so that the prospect and cost of using calcium carbide in steel making have certain pressure on steel making.

The search literature discloses: (1) the major academic paper "calcium carbide combined packaging bag railway transportation safety analysis" of zhao xu yang in 2012 of beijing university of transportation "is described with the following contents: the content expression that the calcium carbide belongs to a first-grade wet inflammable explosive product, the main provinces of the national calcium carbide production are inner Mongolia, Xinjiang and Ningxia, and the calcium carbide needs to be transported from the west to economically developed areas such as North China after production is realized; (2) the problem that the Chinese calcium carbide industry association, second harmonic affair, grandfather, announced in the fourth calcium carbide industry health development forum and calcium carbide industry technical council is the introduction of the oxygen method calcium carbide production process, which is described below: the comprehensive energy consumption of the existing electric heating furnace is generally 1.2 tons of standard coal/ton of calcium carbide, and the comprehensive energy consumption of the oxygen method calcium carbide furnace is 2.1-2.3 tons of standard coal/ton of calcium carbide and is higher than that of the electric heating furnace. (3) Shuhaiming, edited by Shuhaiming, published in 2011 by the publisher of metallurgical industry, "the external refining technology of converter molten steel" has the content expressions that calcium carbide is used for slagging, the calcium carbide slag is easy to generate, the molten steel is carburized, and the calcium carbide is mainly used as a diffusion deoxidizer in the LF refining process ".

The descriptions in these documents show that the application of calcium carbide to steel making has many negative effects such as high cost.

Disclosure of Invention

The invention aims to provide a process for applying calcium carbonate carbon spheres to LF (ladle furnace) steelmaking, which is applied to the LF steelmaking process by using limestone instead of calcium carbide, has the same effect as the calcium carbide, reduces the risk of using the calcium carbide, reduces the demand of the metallurgical industry on the calcium carbide, saves energy, reduces consumption and reduces production cost.

The invention aims to realize the process for applying the calcium carbonate carbon spheres to LF (ladle furnace) steelmaking, limestone is ground to the granularity of less than 1mm, then the limestone is uniformly mixed with graphite carbon, and the mixture is pressed into the calcium carbonate carbon spheres by a dry powder ball press;

every 100kg of calcium carbonate carbon spheres are produced, wherein the addition amount y of limestone is as follows:

y=83(100β-51)÷（83β-12γ）；

the adding amount of the graphite carbon is as follows: 100-y;

in the formula: beta is the carbon content in graphite,%; gamma is the content of calcium carbonate in the limestone,%;

when the aluminum killed steel is smelted in the converter, the calcium carbonate carbon balls are added according to the principle that the equivalent quantity replaces the adding quantity of the traditional calcium carbide, and the aluminum killed steel can be used according to the traditional steelmaking process.

The technical principle of the invention is based on the following two innovation points:

1. the limestone is crushed and ground, in the process, the mechanical energy of the ground powder is applied to the limestone, the reactive activity of calcium carbonate powder in the middle of the limestone is increased, the calcium carbonate powder is uniformly mixed with graphite carbon and then the graphite carbon is combined with the calcium carbonate under the action of a powerful ball press machine, the carbon and the calcium carbonate are pressed together under the action of the mechanical energy to form a homogeneous body of the calcium carbonate and the carbon, and the deoxidizer capable of replacing the calcium carbide is formed. Wherein the formula for calculating the addition amount of limestone and the addition ratio of carbon is as follows:

calcium carbide (CaC)₂) The chemical mass percentage of the intermediate carbon is as follows: [24 ÷ (23 + 24)]×100%=51%

In order to realize the function of calcium carbide, the mass percentage of carbon in the middle of calcium carbonate carbon spheres in the calcium carbonate carbon spheres should be balanced with that in the middle of calcium carbide, so the addition amount y of 100kg of calcium carbonate in the middle of calcium carbonate carbon spheres is as follows:

y=83(100β-51)÷（83β-12γ）

the adding amount of the graphite carbon is as follows: 100-y

In the formula: beta is the carbon content in the middle of graphite,%; gamma is the content of calcium carbonate in the middle of limestone,%,

2. the calcium carbonate in the middle of the limestone can be rapidly reacted and decomposed in the LF refining process, and is broken into small particles to directly participate in the reaction, wherein the reaction is as follows:

CaCO₃ →CaO+CO₂↑

the reaction characteristic can have a faster reaction speed than calcium carbide, and the deoxidation reaction process can be optimized. The deoxidizer is the homogeneity of calcium carbonate and carbonThe carbon element reacts to generate CO or CO on one side contacting molten slag or molten steel in the reaction process of the carbon element and the molten steel or the molten slag₂The slag is promoted to foam in the overflowing process, the reaction interface of the steel slag and the molten steel or the steel slag and the steel slag is increased, and CaO generated by decomposing the calcium carbonate participates in the slagging reaction, so that the steelmaking deoxidization process of the LF furnace is optimized. Compared with calcium carbide, the calcium carbonate in the middle of limestone needs to absorb heat for decomposition, so that the power consumption of smelting is increased, but the deoxidant can shorten the deoxidation time through rapid reaction, and CO or CO generated by the reaction₂The submerged arc effect of the foam slag generated by foaming can effectively reduce the radiation loss of the arc heat energy of the LF furnace, and the effect can be balanced with the use effect of the calcium carbide.

The invention has the following beneficial effects:

1. the dependence of the LF steel-making process on the industrial calcium carbide can be reduced, and the implementation of the national environmental protection policy on the compression policy of the high-energy-consumption industry is facilitated.

2. Using CaCO in the middle of limestone₃CO produced during decomposition₂The escaping function expands the reaction interface, so that the deoxidation effect and the submerged arc effect of the LF furnace are superior to those of the process using calcium carbide, and the aim of optimizing the steel-making process of the LF furnace is fulfilled.

3. The cost of the process production is 30% lower than that of calcium carbide, and the process is beneficial to cost reduction and efficiency improvement of steelmaking enterprises.

4. The product does not generate chemical reaction after meeting damp due to the use of the mixture of calcium carbonate and graphite carbon, is convenient for transportation and storage management, and has no any potential risk and risk factor in safety compared with the use of calcium carbide.

Detailed Description

The invention is further illustrated below with reference to the example of producing 5 tonne calcium carbonate carbon spheres.

1) Procurement of 2.37 tons of local limestone, CaCO therein₃The content was 53%, and 2.63 tons of graphite powder having a local carbon content of 90% was purchased.

2) Adding the two raw materials into a crusher, crushing at first, then grinding the raw materials in a Raymond mill until the granularity is below 1mm, mixing the raw materials uniformly, adding a high-pressure ball press, pressing the mixture into balls, and then pulling the balls to an LF refining furnace station for later use.

When the aluminum killed steel is smelted in the converter, the calcium carbonate carbon balls are added according to the principle that the traditional calcium carbide is replaced by the same amount, and the aluminum killed steel is used according to the traditional steelmaking process.

Claims (1)

1. A process for applying calcium carbonate carbon spheres to LF steel making is characterized by comprising the following steps: grinding limestone to a particle size of below 1mm, then uniformly mixing the limestone with graphite carbon, and pressing the mixture into calcium carbonate carbon spheres by using a dry powder ball press;

every 100kg of calcium carbonate carbon spheres are produced, wherein the addition amount y of limestone is as follows:

y=83(100β-51)÷（83β-12γ）；

the adding amount of the graphite carbon is as follows: 100-y;

in the formula: beta is the carbon content in graphite,%; gamma is the content of calcium carbonate in the limestone,%;

when the aluminum killed steel is smelted in the converter, the calcium carbonate carbon balls are added according to the principle that the equivalent quantity replaces the adding quantity of the traditional calcium carbide, and the aluminum killed steel can be used according to the traditional steelmaking process.