阅读说明：本技术 一种制备炼钢精炼用石灰的方法 (Method for preparing lime for steelmaking refining ) 是由 张银斌 张兴国 罗桂员 胡显阳 宾鸿伟 张振峰 杨勇攀 程肇红 于 2019-06-29 设计创作，主要内容包括：本发明涉及一种制备炼钢精炼用石灰的方法,其制备步骤如下：S1：遴选粒度合格的高钙石灰石；S2：石灰石经过筛分设备和水洗处理,进一步提升料度合格率和干净度；S3：定量将石灰石通过卷扬机提升设备加料入窑,进行煅烧分解；S4：向窑中通入燃料煤气,对入窑石灰石经过预热、煅烧和冷却,生成优质石灰；S5：将石灰从窑底卸出,输送到筛分设备进行筛分分级；S6：将筛分出的块状物料进仓干燥储存,获得优质炼钢精炼用石灰。能够解决现有技术中缺乏利用石灰石制备炼钢精炼用石灰方法的问题。(The invention relates to a method for preparing lime for steelmaking refining, which comprises the following preparation steps: s1: selecting high-calcium limestone with qualified granularity; s2: limestone is subjected to screening equipment and washing treatment, so that the qualification rate and the cleanliness of the degree of material are further improved; s3: quantitatively feeding limestone into a kiln through a winch lifting device for calcination and decomposition; s4: introducing fuel gas into the kiln, and preheating, calcining and cooling limestone entering the kiln to generate high-quality lime; s5: discharging lime from the kiln bottom, and conveying the lime to screening equipment for screening and grading; s6: and (4) putting the screened blocky materials into a bin, drying and storing to obtain high-quality lime for steelmaking refining. Can solve the problem that the method for preparing the lime for steelmaking refining by using the limestone in the prior art is lacked.)

1. A method for preparing lime for steelmaking refining comprises the following preparation steps:

s1: selecting high-calcium limestone with qualified granularity;

s2: limestone is subjected to screening equipment and washing treatment, so that the qualification rate and the cleanliness of the degree of material are further improved;

s3: quantitatively feeding limestone into a kiln through a winch lifting device for calcination and decomposition;

s4: introducing fuel gas into the kiln, and preheating, calcining and cooling limestone entering the kiln to generate high-quality lime;

s5: discharging lime from the kiln bottom, and conveying the lime to screening equipment for screening and grading;

s6: and (4) putting the screened blocky materials into a bin, drying and storing to obtain high-quality lime for steelmaking refining.

2. The method for preparing lime for steelmaking refining as claimed in claim 1, wherein: in step S1, the CaO content of limestone is not less than 54%, MgO is not more than 0.9%, and SiO2 is not more than 1.5%; the particle size of the limestone is 40-80 mm; the grain size qualified rate is more than or equal to 90 percent.

3. The method for preparing lime for steelmaking refining as claimed in claim 1, wherein: the mesh of the screening device is 40mm in the step S2; the feeding head of the screening equipment is provided with a flushing point, and the flushing point and the materials are subjected to parallel-flow and countercurrent two-way impact.

4. The method for preparing lime for steelmaking refining as claimed in claim 1, wherein: in the step S3, a weighing device is used for quantitative determination, and the quantitative determination is controlled to be 2500-4000 kg per batch.

5. The method for preparing lime for steelmaking refining as claimed in claim 1, wherein: the coal gas has medium and high heat value in step S4Coal gas with heat value more than or equal to 8500KJ/m³。

6. The method for preparing lime for steelmaking refining as claimed in claim 1, wherein: in step S4, preheating is realized by heat exchange between hot flue gas and limestone, the hot flue gas and stone are carried out in a countercurrent mode, and the temperature of the stone is controlled to be not less than 750 ℃ after preheating; calcining, namely mixing and burning coal gas entering the kiln and combustion-supporting air, releasing heat to heat the limestone in a parallel flow manner, and controlling the calcining temperature to be 1000-1150 ℃; during cooling, cooling air is blown from the bottom of the kiln to forcibly cool and blow the calcined lime, and the cooling temperature of the lime is controlled to be less than 200 ℃.

7. The method for preparing lime for steelmaking refining as claimed in claim 1, wherein: in step S4, the amount of gas introduced into the furnace is 7000-12000 m³H, on combustion: the gas combustion and the stone flow direction are in concurrent flow heat exchange; the proportion of combustion-supporting air is 1.00-1.30; the cooling air coefficient is 0.65-0.90; the residence time of the materials in the kiln chamber is controlled to be 23-28 h.

8. The method for preparing lime for steelmaking refining as claimed in claim 1, wherein: in the step S5, the screening device is a double-layer cylindrical screen and/or a vibrating screen, the screen is 10mm or 4mm, and the granules are classified as follows: 10-50mm, 4-10 mm and less than or equal to 4 mm; sieving the block materials by 10-50 mm.

9. The method for preparing lime for steelmaking refining as claimed in claim 1, wherein: in the step S6, the block-shaped materials are sent into a lime block bin, and the lime block bin is sealed and subjected to damp-proof treatment, wherein the storage time of the lime bin is less than or equal to 2 days.

Technical Field

The invention relates to the technical field of metallurgical lime, in particular to a method for preparing lime for steelmaking refining.

Background

With the progress of steelmaking and refining processes, more and more varieties of steel and special steel are smelted, and the high-quality active lime with high calcium is required to be used for controlling the fast pace of steelmaking and the accurate component of refining.

At present, the varieties and preparation methods of lime supplied for steel making and refining in the metallurgical industry are divided into two types:

1. the lime is still common lime, and the preparation method comprises the following steps: the low-heat value gas of coke, coal block, pure blast furnace gas and mixed gas thereof is used as fuel, local or peripheral limestone is used as raw material, simple sprinkling treatment or anhydrous treatment is adopted, the production is continued to use the calcining process and equipment of traditional mechanical vertical kiln, gas-fired vertical kiln and the like, the finished lime generally has the defects of low CaO and SiO₂High impurity content, low lime activity and high scorching and reducing performance. See table below:

when steel is supplied to steel-making and smelting varieties or refined, the effect of the added common lime on Si removal, S removal and P removal is not in an ideal state, so that poor steel-making and refining quality, slow rhythm and high process cost are caused.

2. The production process uses expensive natural gas, special anthracite powder and other mixed gas as fuel, uses local or peripheral limestone as raw material, but has no water washing treatment or simple water spraying treatment, and uses rotary kiln and sleeve kiln process technology and equipment for production, so that the finished product has good quality, and can meet the requirements of steel making and refining.

The process is characterized in that: (1) the fuel has high heat value, and the calorific value is more than or equal to 12000kJ/m³(ii) a (2) The lime has good quality, wherein the CaO is higher, the scorching is lower and the activity is higher; (3) materials and gas streamsThe direction is carried out in a countercurrent way; (4) the heat consumption of the coal gas is higher. See table below:

disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method for preparing lime for steelmaking refining, which can solve the problem that the method for preparing the lime for steelmaking refining by using limestone is lacked in the prior art.

The technical purpose of the invention is realized by the following technical scheme: a method for preparing lime for steelmaking refining comprises the following preparation steps:

s1: selecting high-calcium limestone with qualified granularity;

s2: limestone is subjected to screening equipment and washing treatment, so that the qualification rate and the cleanliness of the degree of material are further improved;

s3: quantitatively feeding limestone into a kiln through a winch lifting device for calcination and decomposition;

s4: introducing fuel gas into the kiln, and preheating, calcining and cooling limestone entering the kiln to generate high-quality lime;

s5: discharging lime from the kiln bottom, and conveying the lime to screening equipment for screening and grading;

s6: and (4) putting the screened blocky materials into a bin, drying and storing to obtain high-quality lime for steelmaking refining.

In conclusion, the invention has the following beneficial effects:

the method is characterized in that high-calcium limestone with certain quality is selected by utilizing peripheral ore resources, the raw material limestone is pretreated by utilizing screening and washing equipment, then the raw material limestone is weighed and quantified and then fed into a kiln, the limestone is decomposed to generate active high-calcium lime under the control of certain calcining temperature, gas flow, air distribution, cooling, reversing and other processes in a double-hearth kiln, and then the active high-calcium lime is screened by utilizing the screening equipment to obtain blocky high-calcium high-quality lime.

The present invention will be described in detail with reference to examples.

1. Raw materials

Selecting high calcium limestone from local or peripheral region, and setting the technical requirements as shown in the following table

2. The heating value of the coal gas is more than or equal to 8500KJ/m³Taken from the local gas pipe network.

3. Device

(1) Screening limestone: model number phi 2100/phi 1200 x 2400

(2) Double-chamber kiln: 500TPD parallel-flow heat accumulating type double-chamber lime shaft kiln

(3) Weighing hoppers: 3.7m³And a capacity of 5000 kg.

(4) Screening a finished product: the mesh size of phi 1200/phi 1800 multiplied by 2400 is 10 multiplied by 30mm, and the mesh size of phi 1800/phi 2400 multiplied by 2000 is 4 multiplied by 20 mm.

Example 1

Selecting limestone with components according with the following table, screening by a limestone cylinder screen (40 mm), washing by water to obtain limestone concentrate with the qualification rate of 40-80mm and 95%, weighing 3.2 t/hopper by a transition bin, lifting by a winch, adding into a parallel-flow heat accumulating type double-hearth lime shaft kiln, introducing coal gas with the calorific value of 9200KJ/m³The three mixed gas of the coke oven, the converter and the blast furnace has the gas content of 9100-³And/h, the combustion-supporting air system is 1.17, the channel temperature is controlled to be 1050-. Discharging the burnt lime from the kiln bottom, conveying the lime to a finished product cylindrical sieve to obtain 10-50mm finished product lime, storing the finished product lime in a warehouse to obtain the lime for steel-making refining, and conveying the lime to steel-making and refining processes after 1 day. The lime components and physical indexes are measured as shown in the attached table 2.

。