阅读说明：本技术 提高连续加料电炉冶炼效率的方法 (Method for improving smelting efficiency of continuous charging electric furnace ) 是由 操龙虎 徐永斌 于 2019-11-29 设计创作，主要内容包括：本发明提供了一种提高连续加料电炉冶炼效率的方法,包括以下步骤：将废钢原料先切割为一定尺寸范围的小尺寸废钢,然后以特定的进料速度加入到冶炼炉内,保证废钢全程浸没在钢液中；冶炼过程中冶炼炉内采用大量留钢,保证加料过程中无需断电。本发明提供的这种提高连续加料电炉冶炼效率的方法,可以显著提高电炉的冶炼效率,废钢切割到一定较小的尺寸范围,有利于提高废钢熔化速率,同时以合理的进料速度加入到电炉中,保证废钢全程浸没在钢液中,有利于降低铁的氧化,而大量留钢则可以提高单位时间废钢进料质量。采用上述方法,易于实现全程泡沫渣操作,可显著提高连续加料电炉冶炼效率,降低电耗,缩短冶炼周期,并提高金属收得率。(The invention provides methods for improving smelting efficiency of a continuous charging electric furnace, which comprise the following steps of cutting a steel scrap raw material into small-size steel scrap with a size range of , then adding the small-size steel scrap into the smelting furnace at a specific feeding speed, ensuring that the steel scrap is immersed in molten steel in the whole process, and ensuring that power-off is not needed in the charging process because a large amount of steel is left in the smelting furnace in the smelting process.)

1, A method for improving smelting efficiency of a continuous charging electric furnace, which is characterized by comprising the following steps:

the method comprises the steps of cutting a scrap steel raw material into small-size scrap steel with the size range of , adding the small-size scrap steel into a smelting furnace at a specific feeding speed, ensuring that the scrap steel is immersed in molten steel in the whole process, and ensuring that a large amount of steel is left in the smelting furnace in the smelting process and power failure is not needed in the feeding process.

2. The method for improving the smelting efficiency of the continuous charging electric furnace according to claim 1, characterized in that: the size range of the cut scrap steel is 20-80 mm.

3. The method for improving the smelting efficiency of the continuous charging electric furnace according to claim 1, wherein the feeding speed of the scrap steel is ± 20% of the optimum feeding speed, and the specific algorithm of the optimum feeding speed is as follows:

(1) according to the amount of retained steel and the size of furnace meltV _Σ，V _ΣThe maximum volume of the steel scrap which can be occupied when the steel scrap is immersed in the retained molten steel is m³；

(2) Determining the influence coefficient of molten steel temperature on scrap steel meltingK _L；

(3) Determining the influence coefficient of the preheating temperature of the scrap steel on the melting of the scrap steelK _ts；

(4) Determining the influence coefficient of the porosity of the scrap on the melting of the scrapK _P；

(5) Determining the coefficient of influence of the stirring action on the melting of the scrapK _α；

(6) Determining the influence coefficient of scrap size on scrap meltingK _s；

(7) Determination of scrap bulk Densityρ _s；

(8) Calculating the scrap melting timeτ _m=38*K _p*K _L*K _s/K _ts*K _α；

(9) Calculating the optimum scrap feed ratev=V _Σ·ρ _s/τ _m。

4. The method for improving the smelting efficiency of the continuous charging electric furnace according to claim 1, characterized in that: the steel remaining amount in the smelting furnace is 40 to 80 percent of the steel tapping amount.

5. The method for improving the smelting efficiency of the continuous charging electric furnace according to claim 1, characterized in that: preheating the scrap steel before adding the scrap steel into a smelting furnace, wherein the preheating method comprises the following steps:

1) pretreating the scrap steel to be fed into the furnace to remove oil stains on the surface of the scrap steel;

2) spraying an inhibitor for inhibiting the formation of dioxin on the surface of the steel scrap treated in the step 1);

3) and (3) loading the scrap steel treated in the step 2) into a material basket, and adding the scrap steel into a preheating system for electric furnace steelmaking to preheat the scrap steel.

6. The method for improving the smelting efficiency of the continuous charging electric furnace according to claim 5, characterized in that: in the step 1), the waste steel pretreatment process is to clean the waste steel by adopting an alkaline solution, and ultrasonic oscillation is combined during cleaning by adopting the alkaline solution.

7. The method for improving the smelting efficiency of the continuous charging electric furnace according to claim 6, characterized in that: the alkaline solution is Na₂CO₃Solutions or NaHCO₃And (3) solution.

8. The method for improving the smelting efficiency of the continuous charging electric furnace according to claim 6, characterized in that: the working frequency of the ultrasonic wave is 20-50 kHz.

9. The method for improving the smelting efficiency of the continuous charging electric furnace according to claim 5, characterized in that: the inhibitor is CaCO₃ kinds of CaO and dolomite.

10. The method for improving the smelting efficiency of the continuous charging electric furnace according to claim 9, characterized in that: the particle size of the inhibitor is less than 200 mu m.

Technical Field

The invention relates to the technical field of metallurgy, in particular to methods for improving smelting efficiency of a continuous charging electric furnace.

Background

The short-flow steelmaking process taking electric furnace steelmaking as a core has greatly reduced project investment, ton steel resource consumption, energy consumption, occupied area, carbon dioxide and other pollutant discharge amount compared with the long-flow steelmaking process, and meets the requirements of scientific development and low-carbon economic development of the steel industry, the crude steel yield in recent ten years of China is increased year by year, but the proportion of electric furnace steel shows a descending trend of , by 2016, the proportion of electric furnace steel in China only accounts for 7.3 percent of the total steel output and is far lower than the average level in the world, but along with the continuous improvement of national environmental protection requirements and the increase of scrap steel resources, the government banes medium frequency furnaces and ground strip steel, so that the short-flow quantity and the yield of electric furnace steelmaking are obviously increased, meanwhile, steel enterprises are in the aspects of gradually eliminating electric furnace capacity, so that the requirements of environmental protection are not continuously enhanced, but the current start rate is not high, the price of electric furnace steel is in the aspect of unfavorable smelting efficiency of , and the production cost is a relatively low.

At present, in the method for improving the smelting efficiency of the electric furnace, the improvement is mainly carried out from two aspects:

(1) preheating scrap steel: the heat conduction quantity can be reduced by increasing the temperature of the scrap steel, and the melting time of the scrap steel is obviously reduced, thereby shortening the smelting period. Iron and steel engineering companies such as Purit, Western Mark, SPCO and Mizhongmei Sedi all have independent scrap steel preheating patent technologies, so that the smelting period of an electric furnace is reduced to below 40 min.

(2) Reduction of arc furnace operation: the smelting period of the electric furnace mainly comprises electrifying time and non-electrifying time, and the non-electrifying time can be reduced by reducing the operation of the electric furnace, so that the smelting time is shortened. When the flat molten pool is adopted for smelting, the scrap steel charging electrode does not need to be lifted, the scrap steel is automatically charged, the furnace shell is quickly replaced, and the like.

The horizontal continuous charging electric furnace is furnace types widely applied to domestic markets at present, and is characterized in that continuous charging and scrap steel preheating are carried out, so that the smelting stability of the electric furnace is high, wide is applied to the domestic markets at present, but the period of total scrap steel smelting is about 50min at present, and a large difference exists compared with a converter.

Disclosure of Invention

The invention aims to provide methods for improving the smelting efficiency of a continuous charging electric furnace, which are used for improving the smelting efficiency of the electric furnace by controlling the size, the bulk density and the feeding speed of scrap steel.

The invention is realized by the following steps:

the invention provides methods for improving smelting efficiency of a continuous charging electric furnace, which comprise the following steps:

the method comprises the steps of cutting a scrap steel raw material into small-size scrap steel with the size range of , adding the small-size scrap steel into a smelting furnace at a specific feeding speed, ensuring that the scrap steel is immersed in molten steel in the whole process, and ensuring that a large amount of steel is left in the smelting furnace in the smelting process and power failure is not needed in the feeding process.

, the size range of the cut scrap steel is 20-80 mm.

, the feeding speed of the scrap steel is 20% of the optimal feeding speed, and the specific algorithm of the optimal feeding speed is as follows:

(1) according to the amount of retained steel and the size of furnace meltV _Σ，V _ΣThe maximum volume of the steel scrap which can be occupied when the steel scrap is immersed in the retained molten steel is m³；

(2) Determining the influence coefficient of molten steel temperature on scrap steel meltingK _L；

(3) Determining the influence coefficient of the preheating temperature of the scrap steel on the melting of the scrap steelK _ts；

(4) Determining the influence coefficient of the porosity of the scrap on the melting of the scrapK _P；

(5) Determining the coefficient of influence of the stirring action on the melting of the scrapK _α；

(6) Determining the influence coefficient of scrap size on scrap meltingK _s；

(7) Determination of scrap bulk Densityρ _s；

(8) Calculating the scrap melting timeτ _m=38*K _p*K _L*K _s/K _ts*K _α；

(9) Calculating the optimum scrap feed ratev=V _Σ·ρ _s/τ _m。

, the steel remaining in the smelting furnace is 40 to 80 percent of the steel tapping amount.

preheating the scrap steel before it is charged into the furnace by the following method:

1) pretreating the scrap steel to be fed into the furnace to remove oil stains on the surface of the scrap steel;

2) spraying an inhibitor for inhibiting the formation of dioxin on the surface of the steel scrap treated in the step 1);

3) and (3) loading the scrap steel treated in the step 2) into a material basket, and adding the scrap steel into a preheating system for electric furnace steelmaking to preheat the scrap steel.

, the pretreatment process of the steel scrap in the step 1) is to clean the steel scrap by using an alkaline solution, and ultrasonic oscillation is combined during cleaning by using the alkaline solution.

, the alkaline solution is Na₂CO₃Solutions or NaHCO₃And (3) solution.

, the working frequency of the ultrasonic wave is 20-50 kHz.

Further , the inhibitor is CaCO₃ kinds of CaO and dolomite.

, the particle size of the inhibitor is less than 200 μm.

Compared with the prior art, the invention has the following beneficial effects:

the method for improving the smelting efficiency of the continuous charging electric furnace can obviously improve the smelting efficiency of the electric furnace, scrap steel is cut to to have a smaller size range, the melting rate of the scrap steel is favorably improved, the scrap steel is simultaneously added into the electric furnace at a reasonable feeding speed, the whole process of immersing the scrap steel in molten steel is ensured, the oxidation of iron is favorably reduced, and the feeding quality of the scrap steel in unit time can be improved if a large amount of steel is left.

Detailed Description

The technical solutions in the embodiments of the present invention are described clearly and completely below, and it is obvious that the described embodiments are only some embodiments of of the present invention, rather than all embodiments.

The embodiment of the invention provides methods for improving smelting efficiency of a continuous charging electric furnace, which comprise the following steps:

the method comprises the steps of cutting a scrap steel raw material into small-size scrap steel with the size range of through a scrap steel shearing machine, adding the small-size scrap steel into a smelting furnace at a specific feeding speed, ensuring that the scrap steel is immersed in molten steel in the whole process, reducing the oxidation of iron, and in the smelting process, adopting a large amount of steel in the smelting furnace, ensuring that power-off is not needed in the feeding process, promoting the melting of the scrap steel, reducing the non-power-on time, thereby shortening the smelting period and improving the smelting efficiency of an electric furnace.

The method for improving the smelting efficiency of the continuous charging electric furnace can obviously improve the smelting efficiency of the electric furnace, scrap steel is cut to to have a smaller size range, the method is favorable for improving the melting rate of the scrap steel, meanwhile, the scrap steel is added into the electric furnace at a reasonable feeding speed, the scrap steel is guaranteed to be immersed in molten steel in the whole process, the oxidization of iron is favorably reduced, and the feeding quality of the scrap steel in unit time can be improved if a large amount of steel is left.

Preferably, the size range of the cut scrap steel is 20-80 mm, the cutting is facilitated within the range, and the melting rate of the scrap steel can be guaranteed.

The feeding speed depends on the steel amount, the preheating temperature of the scrap steel, the bulk density of the scrap steel, the temperature of molten steel and the like, in order to reduce the oxidation of iron under the condition of maximally improving the smelting rate, the feeding speed of the scrap steel is +/-20% of the optimal feeding speed, and the specific algorithm of the optimal feeding speed is as follows:

(1) according to the amount of retained steel and the size of furnace meltV _Σ，V _ΣThe maximum volume of the steel scrap which can be occupied when the steel scrap is immersed in the retained molten steel is m³；

(2) Determining the influence coefficient of molten steel temperature on scrap steel meltingK _L；

(3) Determining the influence coefficient of the preheating temperature of the scrap steel on the melting of the scrap steelK _ts；

(4) Determining the influence coefficient of the porosity of the scrap on the melting of the scrapK _P；

(5) Determining the coefficient of influence of the stirring action on the melting of the scrapK _α；

(6) Determining the influence coefficient of scrap size on scrap meltingK _s；

(7) Determination of scrap bulk Densityρ _s；

(8) Calculating the scrap melting timeτ _m=38*K _p*K _L*K _s/K _ts*K _α；

(9) Calculating the optimum scrap feed ratev=V _Σ·ρ _s/τ _m。

After the optimal feeding speed is calculated, small-size scrap steel is added into the smelting furnace at the actual feeding speed of +/-20% of the optimal feeding speed, so that the scrap steel is immersed in the molten steel in the whole process under the condition of maximally improving the smelting speed, and the oxidation of iron is reduced.

Preferably, the steel amount remained in the smelting furnace is 40-80% of the steel amount, the fixed steel amount is ensured under the range, power failure is not needed in the charging process, scrap steel melting can be promoted, the non-power-on time is reduced, the smelting period is shortened, and the smelting efficiency of the electric furnace is improved.

The effect of the present invention to improve the smelting efficiency of a continuous charging electric furnace will be described below by way of specific examples.