CN104818366A - Ladle slag conglomeration agent prepared by boric sludge - Google Patents

Abstract

The invention relates to the technical field of ferrous metallurgy, in particular to a ladle slag conglomeration agent prepared by boric sludge. The slag conglomeration agent is made of raw materials including, in weight percent, 50%-65% of boric sludge, 30%-40% of silica and 5%-10% of emery powder. A preparation method of the slag conglomeration agent mainly includes the steps of grinding, distributing, blending and pelleting. The ladle slag conglomeration agent is added into a ladle slag layer before slag removal and after powder injection desulfurization pretreatment is performed in a ladle, the agglomeration performance of desulfurization slag can be effectively improved, slag collection and slag removal efficiency is increased, slag removal frequency is decreased, slag removal time is shortened, slag removal iron loss can be reduced, molten iron backflow is decreased, desulfurization effects are ensured, and the ladle slag conglomeration agent has remarkable economic and social benefits and is worthy of popularization.

Description

A molten iron-coated slag agent prepared from boron mud

technical field

The invention relates to the technical field of iron and steel metallurgy, in particular to a molten iron-coated slag agent prepared from boron mud.

Background technique

The grade of most boron ores in our country is low. After extracting borax by carbon-alkali method, a large amount of waste boron mud is produced. Due to the complicated treatment process of boron mud, it has been piled up as waste residue. Water resources are seriously polluted, and the comprehensive utilization of boron mud needs to be solved .

In the field of iron and steel metallurgy, hot metal spray powder desulfurization pretreatment has been promoted nationwide; the desulfurization of molten iron in the ladle is mainly by spraying CaO, Mg particles or CaO+Mg. After the molten iron is desulfurized, a large amount of The sulfur-containing slag needs to be removed, but because the iron slag after desulfurization is difficult to gather into agglomerates, the efficiency of slag removal is low, and the slag removal time is long, resulting in a certain degree of molten iron resulfurization, so it is necessary to add a slag removal agent before slag removal Perform metamorphic treatment on iron slag; in the prior art, Chinese Patent Publication No. CN 102560000B and CN 102586516A both disclose a slag-accumulating agent composed of albite, fluorite, salt, etc., by reducing the alkalinity of iron slag to change The melting point and viscosity of slag form sticky massive slag clusters to improve the slag removal effect. However, this type of slag gathering agent is not good for desulfurization because it reduces the slag alkalinity, and the problem of molten iron resulfurization has not been effectively solved; Chinese patent publication No. CN101392309B discloses a high-basic slag gathering agent, which is composed of lightly burned dolomite 85-100% and quicklime 0-15%, but the composition of the desulfurization slag produced by the slag gathering agent of the invention and calcium magnesium powder spraying Similar, it can effectively reduce the resulfurization of molten iron, but the effect of slag accumulation needs to be further improved.

After the molten iron is desulfurized by powder spraying in the ladle or torpedo tank, the slag should be removed as soon as possible to prevent the molten iron from returning to sulfur. The characteristics of slag and slag accumulation must have appropriate sintering strength after being aggregated into slag clusters, and the density should be low and easy to pick out, etc., while the slag gathering agents in the prior art cannot have this characteristic at the same time. The acidic slag gathering agent in the present technology is easy to realize rapid slag formation and slagging, but it is easy to return to sulfur, and the slag is too sticky, and the iron loss increases seriously during the slag removal process; while the basic slag gathering agent in the prior art can prevent the molten iron from returning to the slag. Sulfur, but the effect of agglomeration of slag is not ideal, the sintering strength of slag is low, and the slag is easily scattered, resulting in an increase in the number of slag removal and low efficiency of slag removal.

In summary, in combination with the composition and characteristics of iron slag after desulfurization by powder spraying in ladle, and considering the requirements for slag removal, it is necessary to develop a method that can quickly form slag and aggregate slag with iron slag after powder spray desulfurization, and improve It is a new type of slag gathering agent with beneficial purposes such as improving the efficiency of slag removal, preventing resulfurization of molten iron, reducing the number of times of slag removal, and reducing the iron loss of slag removal.

Contents of the invention

The purpose of the present invention is: to invent a kind of slag gathering agent in molten iron prepared by using waste boron mud to solve the problems of poor slag gathering effect, low slag removal efficiency, many times of molten iron resulfurization and slag removal, etc. The problems such as large iron loss during slag removal can be solved, and at the same time, the waste boron mud can be reused to reduce the production cost of slag removal agent.

The technical scheme for realizing the present invention is: a molten iron-coated slag agent prepared by boron mud, characterized in that: the raw material composition for preparing molten iron-coated slag agent is calculated according to weight percentage: boron mud 50-65%, silica 30-40% %, corundum powder 5-10%.

Its preparation method is characterized in that it is prepared by grinding, batching, mixing and granulating, all the raw materials are dried and then pulverized and passed through a 40-mesh sieve, and then the ingredients are weighed according to the above-mentioned weight percentage, and the mixture is mixed by mechanical stirring. Spray granulation in the drum, the particle size of the finished product is 1-3mm, and then dry and moisture-proof package to get the finished product.

The slag-aggregating agent in molten iron prepared by boron mud of the present invention is characterized in that its use method is: after the powder spraying desulfurization pretreatment in the molten iron ladle is completed, and before slag removal, it is added into the molten iron slag layer, and the addition amount is 0.8-1.2Kg /t iron; the hot metal slag gathering agent of the present invention is preferably suitable for gathering slag after ladle powder spraying desulfurization, especially ladle powder spraying desulfurization is mainly based on spraying CaO powder, CaO powder+Mg grains or pure Mg grains It has the best effect; for molten iron that does not adopt powder spraying pretreatment, the present invention can also be used for removing slag in the ladle, and it is added to the ladle 1-2 minutes before the slag removal, and then mechanical slag removal is implemented.

In order to guarantee the use effect of the present invention, the raw material characteristics of the present invention are prepared as follows:

The composition (mass percentage) of the boron mud used is required to be: MgO 41-50%, SiO ₂ 31-40%, Al ₂ O ₃ 5-8%, and the balance is impurity components, the lower the impurity content, the better.

The composition (mass percentage) of the silica used is required to be: 100% >SiO ₂ >99%, and the remainder is impurity components, the lower the impurity content, the better.

The composition (mass percentage) of the corundum powder used is required to be: 100% >Al ₂ O ₃ >95%, and the remainder is impurity components, the lower the impurity content, the better.

The determination of the ratio of raw materials for preparing the present invention is based on the following:

Boron mud: The addition ratio of boron mud is (parts by weight) 50-65%. The ratio is mainly determined according to the performance indicators required for iron slag accumulation and slag removal. During production, it can be roughly determined according to the situation of powder spraying and desulfurization. The basic principle is that when simple lime injection is used for desulfurization, the amount of boron mud in the slag gathering agent is taken as the lower limit, that is, 50%. 65%, when using lime and magnesium mixed blowing desulfurization, the amount of boron slime in the slag accumulator should be an intermediate value of 50-65%, and the best value is 57%; boron slime and iron slag have good wetting And fast slagging performance, good spreadability, rapid slagging, and the slag group has appropriate sintering strength, easy to realize slag gold separation, reduce slag strip iron, reduce slag iron loss, at the same time, boron mud and CaO, CaS, Both MgS and calcium silicate have good ability to combine into slag. The slag group has low viscosity and low density, which is easy to remove and can reduce the resulfurization of molten iron. In addition, the present invention adds more boron mud, which is an alkaline slag removal agent. Not only is it beneficial to control the sulfur return, but also has a good protective effect on the lining refractory.

Silica: Silica is mainly used to adjust the alkalinity of slag. It is used in conjunction with boron mud. By adjusting the alkalinity of slag, it can adjust the viscosity, melting point and performance of slag sintering into agglomerates, and improve the wettability of boron mud and iron slag. , which is conducive to rapid slag formation and slag agglomeration, and is beneficial to slag removal; the amount of silica added is 30-40%, which can be adjusted according to the type of dusting in practical applications. When single lime is used for dusting, the silica in the slag gathering agent The upper limit of the added amount is 40%. When a single magnesium spray is used for desulfurization, the lower limit of the added amount of silica in the slag gathering agent is 30%. The input amount takes the middle value of 30-40%, and the best value is 35%.

Corundum powder: The amount of corundum powder added (parts by weight) ranges from 5-10%. The main purpose is to adjust the viscosity, melting point and agglomeration performance of slag sintering. In practical applications, it can be adjusted according to the type of powder sprayed. When a single lime powder is used, the upper limit of the amount of corundum powder added to the slag gathering agent is 10%. - When magnesium is mixed and blown, the amount of corundum powder in the slag collector should be an intermediate value of 5-10%, and the best value is 8%.

Compared with prior art, main advantage of the present invention is as follows:

(1) The present invention realizes the reuse of waste boron mud, which not only eliminates the hazard of boron mud, but also turns waste into treasure, reducing the cost of raw materials in the production cost of slag accumulator by more than 50%.

(2) The slagging agent of the present invention is used to remove slag from ladles or molten iron torpedo tanks, and the efficiency of slag removal is significantly improved. The number of slag removal is generally 20-30 times, and the iron slag removal rate reaches 80%. However, with the present invention, the slag removal frequency is 15-20 times, and the iron slag removal rate reaches 95%. In addition, the slag removal time is shortened by about 30%. .

(3), adopt the slag removal agent of the present invention, the usage amount of the slag removal agent is reduced, the general use amount of the slag removal agent in the prior art is 3-5Kg/t iron, when adopting the present invention, the addition amount of the slag removal agent is 0.8 -1.2Kg/t.

(4) The iron loss in the slag removal process is reduced. The iron loss caused by the iron coating in the slag when the general slag gathering agent is used in the existing technology is 3-5kg/t iron. The foreign advanced slag removal technology is wrapped in slag. The iron loss caused by iron is also above 1kg/t iron, but with the present invention, since the slag-iron interfacial tension increases, the slag density decreases, the slag-gold separation is more thorough, and the iron loss caused by iron-coated slag can be reduced to 0.5-0.8 The range of kg/t iron.

To sum up, the advantages of the present invention can be summarized as: low production cost, high efficiency, energy saving and consumption reduction, and at the same time realize waste reuse, which has significant social and economic benefits.

Detailed ways

The average composition of boron mud that embodiment is used is as shown in table 1.

The average composition of table 1 boron mud (mass percentage)

Element SiO ₂ MgO Al ₂ O ₃ Impurities Boron mud 35 45 6 margin

Example 1

The slag-removing and slag-gathering agent of the present invention is prepared by using iron slag after desulfurization by single injection of lime powder for the hot metal pretreatment powder spraying desulfurization process. The raw material composition (weight fraction) of the slag-gathering agent is as follows:

Boron mud 50%, silica 40%, corundum powder 10%.

All raw materials are dried, milled, batched, mixed and granulated to obtain finished products, specifically: all raw materials are dried and ground to pass through a 40-mesh sieve, and then the ingredients are weighed according to the above weight percentage, passed through the mechanical After stirring and mixing, it is sprayed and granulated in the drum, and the particle size of the finished product is 1-3 mm, and then dried and packed in moisture-proof packaging to obtain the finished product.

The product of the present invention is used when removing slag from a 100-ton ladle. The specific practical process is as follows: after the powder spraying desulfurization pretreatment in the ladle is completed, the molten iron slag layer is added before the slag removal, and a single lime powder is sprayed on the molten iron pretreatment. After the desulfurization is completed, add the slag-aggregating agent in molten iron of the present invention, and sprinkle it into the iron slag layer according to the amount of 1.0 kg/t iron. Implement mechanical slag removal, the number of times of slag removal is 15 times, the pull-out rate of iron slag reaches 95%, the rate of iron coating in slag is 0.08 kg/t slag by chemical analysis, the sulfur content of molten iron does not change before and after slag removal, that is, no molten iron occurs back sulfur phenomenon.

Example 2

The slag removal and slag gathering agent of the present invention is prepared by single injection of iron slag after magnesium desulfurization in the powder spraying desulfurization process of molten iron pretreatment. The raw material composition (weight fraction) of the slag gathering agent is as follows:

Boron mud 65%, silica 30%, corundum powder 5%.

All raw materials are dried, milled, batched, mixed and granulated to obtain finished products, specifically: all raw materials are dried and ground to pass through a 40-mesh sieve, and then the ingredients are weighed according to the above weight percentage, passed through the mechanical After stirring and mixing, it is sprayed and granulated in the drum, and the particle size of the finished product is 1-3 mm, and then dried and packed in moisture-proof packaging to obtain the finished product.

The product of the present invention is used when removing slag from a 100-ton ladle. The specific practical process is as follows: after the powder spraying desulfurization pretreatment in the ladle is completed, and before the slag removal, the molten iron slag layer is added, and the molten iron pretreatment is sprayed with single metal magnesium. After desulfurization is completed, add the slag gathering agent in molten iron of the present invention, and sprinkle it into the iron slag layer according to the amount of 0.8 kg/t iron. Implement mechanical slag removal, the number of times of slag removal is 12, the extraction rate of iron slag reaches 95%, the rate of iron coating in slag is 0.10 kg/t slag by chemical analysis, the sulfur content of molten iron does not change before and after slag removal, that is, no molten iron occurs back sulfur phenomenon.

Example 3

The slag-removing and slag-gathering agent of the present invention is prepared by using quicklime-magnesium mixed spraying desulfurized iron slag for the pretreatment of molten iron by powder spraying and desulfurization. The raw material composition (weight fraction) of the slag-gathering agent is as follows:

Boron mud 57%, silica 35%, corundum powder 8%.

All raw materials are dried, milled, batched, mixed and granulated to obtain finished products, specifically: all raw materials are dried and ground to pass through a 40-mesh sieve, and then the ingredients are weighed according to the above weight percentage, passed through the mechanical After stirring and mixing, it is sprayed and granulated in the drum, and the particle size of the finished product is 1-3 mm, and then dried and packed in a moisture-proof package to obtain the finished product.

The product of the present invention is used when removing slag from a 100-ton ladle, and the specific practical process is as follows: After the powder spraying desulfurization pretreatment in the ladle is completed, the molten iron slag layer is added before the slag removal, and the molten iron pretreatment is sprayed with quicklime-magnesium (The mass ratio of quicklime to magnesium is 1:1) mixed and injected, after the desulfurization is completed, add the molten iron-coated slag agent of the present invention, and the amount added is sprinkled into the iron slag layer according to 1.2 kg/t iron, and the slag-accumulated agent is spreadable. Well, the slag is formed quickly, the slag is gathered and formed into agglomerates quickly, and the mechanical slag is removed after about 1 minute. The number of slag removal is 15 times. The extraction rate of iron slag reaches 95%, and the rate of iron coating in slag is 0.06 kg/t according to chemical analysis. Slag, before and after slag removal, the sulfur content of molten iron does not change, that is, the phenomenon of sulfur reversion in molten iron does not occur.

The performance and actual use effect of the covering agent prepared in Examples 1-3 .

For the slagging agent prepared in Example 1-3, the melting point of the slagging agent is 1300-1320°C, the melting time at 1350°C is 30-45s, the surface tension is 0.48N/m, and the melting point is 0.48N/m. Generally, after the desulfurization pretreatment of molten iron for steelmaking pig iron, it is used as a slagging agent. Compared with the use effect of other slagging agent products under the same conditions, it is found that the use of the present invention is better than that of other calcium silicate or calcium aluminate covering agents. The effect is better, which is mainly reflected in that the efficiency of slag removal is significantly improved, the number of slag removal is reduced, and the time of slag removal is shortened. The number of times of slag removal in the prior art is generally 20-30 times, and the iron slag removal rate reaches 80%. The number of slag removal times is 15-20 times, and the iron slag extraction rate reaches 95%; in addition, the slag removal time is shortened by about 30%; in addition, the raw material cost of the slag removal agent is reduced, the usage is reduced, and the iron loss of slag removal is reduced. Statistics show that, The cost of raw materials can be reduced by 50%, the amount of slag removal agent can be reduced by more than 20%, especially the iron loss can be reduced by more than 50%, which has significant social and economic benefits.

Claims (10)

1. A molten iron-coated slag agent prepared by boron mud is characterized in that: the raw material composition of preparing molten iron-coated slag agent is calculated according to weight percentage: boron mud 50-65%, silica 30-40%, corundum powder 5- 10%. 2. The molten iron-coated slag agent prepared by a kind of boron mud as claimed in claim 1 is characterized in that: the composition of said boron mud is calculated as: MgO 41-50%, SiO ₂ 31～40%, Al ₂ O ₃ 5~8%, the rest is impurity components, the lower the impurity content, the better. 3. The molten iron-coated slag agent prepared by a kind of boron mud as claimed in claim 1 is characterized in that: the composition of the silica is calculated as: 100%>SiO ₂ >99%, and the balance is impurity group points, the lower the impurity content, the better. 4. The molten iron-coated slag agent prepared by a kind of boron mud as claimed in claim 1 is characterized in that: the composition of the corundum powder is calculated as: 100% >Al ₂ O ₃ >95%, the balance It is an impurity component, and the lower the impurity content, the better. 5. the preparation method of the molten iron-coated slag agent prepared by a kind of boron mud as claimed in claim 1 is characterized in that the steps are as follows: all raw materials are milled after drying and cross 40 mesh sieves, then weigh the ingredients by weight percentage, After mechanical stirring and mixing, spray granulation in the drum, the particle size of the finished product is 1-3mm, and then dry and moisture-proof package to obtain the finished product. 6. The using method of the molten iron slag-aggregating agent prepared by a kind of boron mud as claimed in claim 1 is characterized in that: after the powder spraying desulfurization pretreatment is completed in the molten iron ladle, add it in the molten iron slag layer before removing slag , the addition amount is 0.8-1.2Kg/t iron. 7. The molten iron-coated slag agent prepared by a kind of boron mud as claimed in claim 1 is characterized in that: the molten iron-coated slag agent is suitable for gathering slag after ladle powder spraying and desulfurization, especially ladle powder spraying The desulfurization has the best effect when mainly spraying CaO powder, CaO powder + Mg particles or pure Mg particles. 8. The molten iron-coated slag agent prepared by a kind of boron mud as claimed in claim 7 is characterized in that: when adopting simple injection lime desulfurization, the proportioning amount of boron mud in the slag-gathering agent gets the lower limit, adopts simple magnesium spraying During desulfurization, the amount of boron slime in the slag gathering agent is taken as the upper limit. When lime and magnesium are used for mixed blowing desulfurization, the amount of boron mud in the slag gathering agent is taken as the middle value of 50-65%, and the best value is 57%. 9. The molten iron-coated slag agent prepared by a kind of boron mud as claimed in claim 7 is characterized in that: when dusting adopts single lime, the add-on of silica in the slag-aggregator gets upper limit i.e. 40%, when adopting single When spraying magnesium for desulfurization, the lower limit of the amount of silica added in the slag gathering agent is 30%. The best value is 35%. 10. The slag-gathering agent in molten iron prepared by a kind of boron mud as claimed in claim 7 is characterized in that: when dusting adopts single lime, the addition of corundum powder in the slag-gathering agent gets upper limit i.e. 10%, when adopting For single magnesium spraying desulfurization, the lower limit of corundum powder in the slag gathering agent is 5%; when lime-magnesium mixed blowing is used for powder spraying desulfurization, the amount of corundum powder in the slag gathering agent is in the middle of 5-10%. value, the best value is 8%.