CN112661421A

CN112661421A - Calcination mode and transportation mode of active lime

Info

Publication number: CN112661421A
Application number: CN202011554564.1A
Authority: CN
Inventors: 李志勇; 李朝辉; 李志钢
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-12-25
Filing date: 2020-12-25
Publication date: 2021-04-16

Abstract

The invention relates to a calcination mode and a transportation mode of active lime for steelmaking and a mode of adding the active lime into a steel furnace, belonging to the technical field of metallurgical energy conservation. The invention changes the calcination mode and the operation mode of the active lime of the existing steel-making enterprises and the mode of adding the active lime into the steel-making furnace, changes the existing continuous lime calcination mode into the accurate firing mode with small specification, changes the mode of transporting the cooled active lime into heat preservation transportation, and changes the mode of adding the cooled lime into the steel-making furnace into the mode of adding the heat preservation fiery high-temperature active lime into the steel-making furnace.

Description

Calcination mode and transportation mode of active lime

Technical Field

The invention relates to a calcination mode and a transportation mode of active lime, which can be applied to steel-making enterprises and belong to a metallurgical process.

Background

At present, the kiln types for producing active lime by each steel enterprise are divided into two categories: the rotary kiln is adopted as one type, and the shaft kiln is adopted as the other type, such as a parallel flow type double-chamber shaft kiln, a double-beam type shaft kiln, an annular sleeve shaft kiln and the like. The activity of the burnt lime is about 350 ml. The technological process includes preheating lime, moving the preheated lime downwards to fast calcining zone, fast calcining for certain time and moving the lime downwards to air cooling zone, air cooling lime to obtain lime, conveying the cold lime from the kiln to lime storing chamber with belt, conveying the lime to lime bin of steel smelting furnace in steel smelting plant with belt, and adding the lime into steel smelting furnace for slagging and steel smelting according to the required weight of steel smelting furnace. 1. The two lime kiln shapes both utilize the fact that the relationship between the temperature of waste gas in the kiln and the calcination system is close, and the contradiction between the ideal preheating temperature and the ideal calcination temperature is difficult to achieve, so that the heating and heat-preserving temperature of limestone is difficult to control within the ideal temperature, and the lime activity is low. 2. The calcination temperature of the lime kiln is uneven, and the calcination heat transfer is slow due to the fact that the calcination time is long, so that the lime activity is influenced. 3. Quantitative active lime cannot be accurately and quantitatively fired. 4. Quantitative lime can not be directly discharged in a thermal state at the calcining temperature, the quantitative high-temperature lime is transported in a heat preservation mode, and the high-temperature active lime is added into a steel-making furnace, so that the steel-making energy consumption is high, the lime can not be rapidly melted into slag, the smelting time is prolonged, the fluorite consumption is increased, and the effect of branch coating P, S is influenced. And the scrap steel ratio of steel making is reduced, the benefit is reduced and the cost is increased. 5. The lime ash rate is high in the transportation process, and in the process of adding the lime ash into a steel furnace, particularly a top-blown converter, the lime ash under small particles is blown away, so that the blowing loss rate of the lime is as high as about ten percent.

Disclosure of Invention

The invention aims to provide a calcination mode and a transportation mode of active lime, which can be applied to steel-making enterprises and can greatly improve the suburb benefit of the steel-making enterprises.

The invention is realized by the following technical scheme. After the amount of lime required by each steelmaking is determined according to the planned steelmaking time and yield of a steelmaking enterprise, the active lime required by each steelmaking is accurately fired, the active lime is directly discharged at the hot state of the calcination temperature, and the active lime is immediately subjected to heat preservation and transportation to directly add the high-temperature active lime into a steelmaking furnace for steelmaking; the process of accurately burning the active lime is also continuous, and a batch of quantitative active lime is burned, which corresponds to the amount of the active lime required by each steelmaking of a steelmaking enterprise. The method is different from the existing calcining mode that the active lime with the calcining temperature required by each steelmaking is precisely calcined and then is immediately added into a steel furnace for steelmaking instead of adding into the steel furnace for steelmaking after a large amount of lime is calcined and cooled at present, and the transportation mode is heat preservation transportation instead of transporting after the lime is cooled at present. The method has the advantages that the energy consumption for steelmaking can be reduced, the active lime can be quickly melted into slag, the smelting time can be shortened, the fluorite consumption can be reduced, the effect of removing P, S elements can be improved, the scrap steel ratio of steelmaking can be increased, the benefit can be increased, and the cost can be reduced.

Advantageous effects

(1) The active lime for steelmaking with the calcination temperature has the temperature of more than 1050 ℃, is higher than the temperature of the active lime added into a steelmaking furnace by more than 1000 ℃ compared with the traditional active lime, has the specific heat capacity of 1.0416KJ/kg ℃, so that the adding amount of the lime for steelmaking is about 5 percent, which is equivalent to adding 5 percent more steel scrap during steelmaking, namely, the steel scrap ratio of the steelmaking is increased by 5 percent, and obvious economic benefit is generated.

(2) Compared with the traditional lime, the lime with thermal activity for steelmaking at the temperature of more than 1050 ℃ does not generate condensed slag crust because of low lime temperature in the early stage of converter steelmaking, so that the lime melting speed is accelerated, the lime with the temperature of more than 1050 ℃ is easier to melt slag in the earlier stage, the lime is quicker than cold ash slagging by 2-3 minutes, the oxygen blowing time for steelmaking can be shortened, fluorite required by slag melting in the middle stage is reduced, the corrosion to a steelmaking lining is reduced, the removal of p and s elements in steelmaking is facilitated, the environmental protection is facilitated, and the economic benefit is high.

(3) The traditional lime transportation and adding mode of the lime into the steel furnace causes high lime powder rate. The traditional lime has low temperature and long slagging time, the blown away small-particle lime is more during oxygen blowing and steel making, the lime blowing loss rate is about 5-10% according to the data of each factory, the novel technology is directly added into a steel making furnace by a crane-mounted lime heat-insulating groove and then oxygen blowing and steel making are carried out, and the blowing loss rate of the lime in the adding process is almost zero.

Detailed Description

The first embodiment is as follows:

at present, 100 tons of molten iron is smelted in a domestic 100-ton converter, about 6 tons of active lime is consumed averagely, and the adding temperature is about 50 ℃. When the method is used for steelmaking, taking 100 tons of converter steelmaking (the temperature of molten steel is about 1600 ℃) as an example, the temperature of the added active lime is about 1050 ℃, which is 1000 ℃ higher than the temperature of 50 ℃ of the active lime added in the prior steelmaking, obviously, the method brings more heat into the converter, and under the condition that other conditions are not changed, the method means that more scrap steel can be added in the steelmaking process. The comparison is calculated as follows: specific heat of lime is 1.0416KJ/kg, specific heat of the waste steel is 0.46KJ/kg, specific heat of molten steel is 0.69KJ/kg, and more waste steel is to be added, the heat is required to be provided when the solid is changed into molten steel liquid (1600 ℃), the heat required in the process is provided by the added 1050 ℃, and the heat required in the process can be considered to be provided by the added active lime at 1050 ℃, and the calculation shows that about 5.7 tons of waste steel can be added into 100 tons of molten iron each time, namely, 5.7 tons of waste steel can be added into each 100 tons of molten iron in each smelting furnace, and the data of the specific implementation process really realizes the process. Moreover, the blowing loss rate of the added active lime in the existing steelmaking method is about 10 percent, while the blowing loss rate implemented by the method is about 3 percent, so that the loss of the active lime can be reduced; in addition, the original method uses fluorite for slagging, about 200kg of fluorite is needed for each smelting of one furnace steel, and only about 50kg of fluorite is needed for each smelting of one furnace steel by adopting the method, so that the consumption of the fluorite can be greatly reduced.

Claims

1. The calcining mode and the transportation mode of the active lime change the calcining mode and the operation mode of the active lime of the existing steel-making enterprises, change the large-scale calcining lime mode into the small-specification precise firing, and change the transportation mode after the active lime is cooled into the heat preservation transportation mode.

2. The calcination manner as claimed in claim 1, wherein the amount of lime required for each steelmaking is determined according to the planned steelmaking time and yield of the steelmaking enterprise, and the active lime required for each steelmaking is precisely burnt and directly discharged in a hot state at the calcination temperature.

3. The calcination manner as claimed in claim 1, characterized in that the active lime is continuously and precisely burnt according to the requirements of steel-making enterprises.

4. The mode of transportation of claim 1, wherein the activated lime in the hot state at the calcination temperature of the firing is transported for holding, either directly or otherwise added to the steelmaking of the steelmaking furnace.