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CN-122012867-A - Steelmaking slag former produced by utilizing iron-containing dust mud and using method thereof

CN122012867ACN 122012867 ACN122012867 ACN 122012867ACN-122012867-A

Abstract

The invention discloses a steelmaking slag former produced by utilizing iron-containing dust mud and a use method thereof, and aims to solve the problems of low utilization rate of the iron-containing dust mud, difficult slag formation in low-silicon molten iron/semisteel steelmaking, poor dephosphorization effect and the like of iron and steel enterprises. The slag former is prepared by mixing iron-containing dust mud and limestone powder or lime powder uniformly in proportion, directly or pressing balls into a kiln, and roasting at 800-1250 ℃, and ingredients containing SiO 2 or SiO 2 、Al 2 O 3 can be added as required. The invention fully utilizes iron resources and various beneficial components in the iron-containing dust mud, forms the low-melting-point premelting slag-making agent after roasting, has the advantages of high slag-making speed, good dephosphorization effect, low converter blowing temperature, and the like, can partially or completely replace metallurgical lime, is suitable for different blowing scenes such as normal molten iron, low-silicon molten iron, semisteel, and the like, obviously improves the added value of the iron-containing dust mud, reduces smelting cost, reduces metal loss and splashing phenomenon, and has good industrial application value.

Inventors

  • WANG HU

Assignees

  • 王虎

Dates

Publication Date
20260512
Application Date
20251231

Claims (10)

  1. 1. A steelmaking additive is prepared from iron-containing dust mud, and features that the iron-containing dust mud is proportionally mixed with limestone powder or lime powder, and then baked in kiln or directly baked in kiln.
  2. 2. A steelmaking process as claimed in claim 1 wherein the iron-containing sludge is mixed with limestone powder or lime powder in a ratio of 100:0 to 80 or 100:0 to 60.
  3. 3. A process for producing steelmaking as claimed in claim 1, wherein said iron-containing sludge is one or more of converter stucco, head stucco, blast furnace dust stucco, mill scale and other iron oxide-containing waste materials.
  4. 4. A steelmaking process as claimed in claim 1 wherein the iron-containing sludge is mixed with limestone powder or lime powder in a ratio of 100:15 to 60 or 100:10 to 50.
  5. 5. A steelmaking process as claimed in claim 1 wherein said iron-containing sludge is mixed with limestone powder or lime powder to which SiO 2 -containing or SiO 2 、Al 2 O 3 -containing ingredients are added as appropriate.
  6. 6. The process for producing a steelmaking formulation from an iron-containing dust sludge according to claim 1, wherein said SiO 2 -containing formulation is one of silicon-killed steel slag, yellow sand, and quartz sand.
  7. 7. A steelmaking process as claimed in claim 1 wherein said SiO 2 、Al 2 O 3 -containing batch is clay.
  8. 8. A process for producing a steelmaking agent from an iron-containing dust sludge as defined in claim 1 wherein said lime powder comprises CaO-containing fly ash.
  9. 9. A steelmaking process as claimed in claim 1 wherein said in-furnace firing temperature is 800-1250 ℃.
  10. 10. The application method of the steelmaking slag former produced by utilizing the iron-containing dust mud is characterized in that the steelmaking slag former can be used in the whole steelmaking process, especially in the initial stage of blowing.

Description

Steelmaking slag former produced by utilizing iron-containing dust mud and using method thereof Technical Field The invention relates to the field of steel, in particular to the utilization of iron-containing dust mud in a steelmaking process. Background Iron-containing sludge in iron and steel enterprises comprises converter sludge and electric furnace sludge, wherein the dust sludge is produced by a sintering machine head in a sintering process, blast furnace sludge produced in an iron-making process, iron scale produced in a steel rolling process and the like, and the dust sludge components of a certain plant part are shown in Table 1 in detail. TABLE 1 analysis of chemical composition of various fly ashes (%) As can be seen from the above table, some of the dust mud contains up to 40-65% iron, and also contains CaO, zn, C and other components. At present, the steel mill returns the dust-removed dust balls to the converter as a cooling agent or a slag melting agent for use. For example, in the patent application of 'the production process (CN 202310045305.3) for recycling iron element by adding sludge balls into a converter', the sludge balls are pressed into sludge balls by using a binder for converter sludge, dust and iron scale to be used as a steelmaking slag melting agent. The converter dust and mud is easy to burst when the mixing proportion of the CaO content in the pellets is large. The patent 'a cold-bonded pellet and its preparation and use' method (CN 201910310194.8) adopts blast furnace dust, converter dust, lime powder, iron concentrate powder and binder pressed pellets as steelmaking coolant or slag former. The sintering machine head ash, namely the sintering machine dust ash contains Fe 2O3, caO, K, na, zn, pb, cl and other impurities, and is easy to enrich, so that blast furnace nodulation, equipment corrosion and excessive fine dust cannot be directly returned to sintering, the sintering machine head ash usually needs to be washed by water, namely wet process, pyrogenic process and other processes to remove harmful impurities, and the residual Fe 2O3 and other components after impurity removal are either sintered or directly fed into the blast furnace. When the Zn content in the blast furnace cloth bag ash is less than 1%, the blast furnace cloth bag ash can be returned to be used for sintering ingredients, but most of blast furnace cloth bag ash in steel factories is more than 1%, if the blast furnace cloth bag ash is returned to be continuously used in a sintering process, zn in sinter is enriched, so that the Zn load of the blast furnace is over-standard, and the problems of lowering coke strength, corroding refractory bricks, forming furnace tumors, damaging air ports and the like are easily generated. Currently, the zinc is extracted from the blast furnace cloth bag ash by a rotary kiln process. Some iron and steel enterprises have low slag metallization rate, the utilization of slag is problematic, some take-out, and some self-processing balling returns to converter steelmaking, see patent 'method for preparing steelmaking furnace burden by using blast furnace ash to extract zinc slag' (202010042578.9). The steel sheet is used as the cooling agent for converter steelmaking. The converter steelmaking process is a slag making process, and the slag is required to be early and well melted. The converter has low blowing temperature in the early stage, and the distribution ratio of phosphorus in slag and iron is large, so that the converter is more suitable for dephosphorization in the early stage of blowing. The converter has low temperature in the earlier stage of converting, large dephosphorization balance coefficient, easy dephosphorization, but difficult slag melting due to low temperature, good lime melting, raised bath temperature, poor dephosphorization effect and easy re-drying in the middle of converting. For low-silicon molten iron with [ Si ] of 0.4-0.4%, the mass fraction of silicon and manganese elements in the molten iron is low in the early stage of blowing, oxidation is completed within 1-2 minutes, chemical heat release of the molten iron is less, the temperature rise in the early stage of a molten pool is slow, the content of acid oxide SiO in slag is low, the addition amount of lime is less and refractory, and the dephosphorization opportunity in the low-temperature stage is missed. The silicon content in the molten iron is low, the blowing process is carried out earlier into a carbon-oxygen reaction period, at the moment, the decarburization speed is high, and the blown oxygen and ferric oxide in the slag are used for participating in the decarburization reaction, so that the (FeO) content in the slag reaches the minimum value. The content of FeO in slag is reduced, so that the generated high-melting-point phase wraps lime, lime is not easy to melt, the generated slag amount is small, a slag layer cannot cover molten steel well, the conditions of steel sticking of an