CN112522509B - Preparation process of cold-pressed red mud pellets, and product and application thereof - Google Patents
Preparation process of cold-pressed red mud pellets, and product and application thereof Download PDFInfo
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- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/14—Agglomerating; Briquetting; Binding; Granulating
- C22B1/24—Binding; Briquetting ; Granulating
- C22B1/248—Binding; Briquetting ; Granulating of metal scrap or alloys
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
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- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/14—Agglomerating; Briquetting; Binding; Granulating
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Abstract
The invention discloses a preparation process of cold-pressed red mud pellets, and a product and application thereof. The preparation process of the cold-pressed red mud pellets comprises the steps of pretreatment and cold-pressing treatment; the pretreatment comprises the following steps: the method comprises the steps of obtaining a raw material containing the red mud, wherein the water content of the red mud is 20% -25%, adding a mineral heating agent into the raw material, uniformly mixing, curing to reduce the water content to 5.5% -15%, and finally obtaining a mixture; the cold pressing treatment comprises the following steps: and (3) performing cold press molding on the mixture to prepare the red mud pellets, wherein during the cold press molding, the maximum pressure between the pair rollers is 800t-1000t, the maximum linear pressure ratio is 8.00-10.00t/cm, and the linear speed is 0.50-0.80m/s. The red mud pellets in the invention are all manufactured by cold processing, the process flow is simple, no fuel is consumed, no other binder is added, no waste is generated, the production cost is low, the red mud pellets are energy-saving and environment-friendly, the strength is high, the quality is good, and the red mud pellets can bear the external force extrusion in the pellet production, transportation and application processes.
Description
Technical Field
The invention relates to the field of smelting additives, in particular to a slag melting agent and a slag pressing agent used in steelmaking.
Background
The metallurgical industry is a dense consumer of raw materials in the industrial sector of China and is also a producer of a large amount of powdery waste; wherein, the alumina industry in China produces about 1 million tons of industrial waste residue-red mud per year, and the accumulated stock of red mud reaches up to 5 million tons. At present, although the comprehensive utilization approaches of the red mud are various, the comprehensive utilization rate is only about 5%, and most of the rest red mud adopts a direct stockpiling treatment mode, so that resources are wasted, and the environment is more harmful. Therefore, how to reasonably optimize and efficiently utilize the red mud resource is a concern of many researchers.
The red mud contains useful resources such as ferric oxide, aluminum oxide, calcium oxide and the like, and can be applied to steel smelting. However, because of their small size, direct recycling into the furnace can deteriorate the furnace conditions, requiring that the material be first agglomerated to achieve the physicochemical and metallurgical properties required for smelting into the furnace.
In the conventional process, red mud pellets are usually obtained by briquetting in a high-temperature sintering and cold-press molding manner. For example, chinese patent application CN103725825A discloses a dephosphorizing agent for converter steelmaking using aluminum industrial red mud as matrix and a preparation method thereof, which adopts a high temperature consolidation method to carry out agglomeration treatment on red mud, lime, dolomite, binder and other raw materials, and high temperature roasting is needed in the agglomeration process, so that the agglomeration process needs more energy consumption. Compared with the high-temperature sintering block making process, the block making process of cold press molding is simpler in production process and equipment requirements and lower in operation cost, for example, in Chinese patent documents CN106148683A, CN103602805B and CN205907310U, a method for preparing red mud pellets by adopting the block making process of cold press molding is disclosed, in the method, raw materials need to be dried at high temperature to reduce the moisture in the red mud, or the prepared spheres need to be dried to improve the compressive strength of the spheres; therefore, the cost consumption is increased. In addition, in the cold-press molding agglomeration process adopted by the method, a bonding agent is usually added to improve the compressive strength and the balling rate of the molded ball, so that the material return rate is reduced; however, the one-time pelletizing rate of the block making process of cold press molding with the addition of the adhesive is only between 50% and 70%, and the compressive strength of the manufactured pellets is not ideal. Therefore, the preparation method of the red mud pellets needs to be further improved.
Disclosure of Invention
Therefore, the technical problem to be solved by the invention is to overcome the defects of high energy consumption and low compressive strength of the red mud pellets prepared by the cold press molding process in the prior art, so that the preparation process of the cold press red mud pellets, the products and the application thereof can obtain higher compressive strength without any fuel and adhesive.
A preparation process of cold-pressed red mud pellets comprises the following steps:
pretreatment: obtaining a raw material containing red mud, wherein the water content of the red mud is 20-25%, adding a mineral heating agent into the raw material, uniformly mixing, curing to reduce the water content to 5.5-15%, and finally obtaining a mixture;
cold pressing treatment: and (3) performing cold press molding on the mixture to prepare the red mud pellets, wherein during the cold press molding, the maximum pressure between the pair rollers is 800t-1000t, the maximum linear pressure ratio is 8.00-10.00t/cm, and the linear speed is 0.50-0.80m/s.
The mineral heat generating agent comprises, by mass, 40.00% -60.00% of CaO and 40.00% -60.00% of MgO.
The raw materials of the mixture comprise dedusting ash, red mud and a mineral heating agent; the content of the red mud is more than 50 percent of the total weight of all the raw materials added in the pretreatment step;
when the raw material containing the red mud is only the red mud, adding the dedusting ash after the curing step and uniformly mixing to obtain a mixture;
when the raw materials containing the red mud comprise the dedusting ash and the red mud, the mixture can be obtained after the curing step.
Sieving the red mud by a 3mm sieve, wherein the proportion of red mud particles smaller than 2mm is more than 90%; the fly ash passes through a 0.106mm sieve.
The red mud is Bayer process red mud, and the fly ash is blast furnace fly ash.
And performing prepressing and emptying before cold press molding of the mixture.
In the pre-pressing emptying step, the porosity of the material when entering is 34% -45%, and the porosity of the material in the minimum clearance area in the pre-pressing emptying process is 12% -17%.
The length, width and height of the red mud pellets are respectively 38-42mm, 38-42mm and 18-22mm.
The slag melting agent comprises the following raw materials in percentage by weight:
82.00% -92.00% of red mud;
3.00% -9.00% of mineral heating agent;
5.00-9.00% of dust removal ash.
The mineral heat generating agent comprises, by mass, 40.00% -60.00% of CaO and 40.00% -60.00% of MgO.
Sieving the red mud by a 3mm sieve, wherein the proportion of the red mud particles smaller than 2mm is more than 90%; sieving the fly ash by a 0.106mm sieve;
the red mud is Bayer process red mud, and the fly ash is blast furnace fly ash.
The slag pressing agent comprises the following raw materials in percentage by weight:
52.00% -58.00% of red mud;
2.00% -4.00% of mineral heating agent;
38.00-46.00% of dust removal ash.
The mineral heat generating agent comprises, by mass, 40.00% -60.00% of CaO and 40.00% -60.00% of MgO.
Sieving the red mud by a 3mm sieve, wherein the proportion of the red mud particles smaller than 2mm is more than 90%; sieving the fly ash by a 0.106mm sieve;
the red mud is Bayer process red mud, and the fly ash is blast furnace fly ash.
The application of the slag melting agent in converter steelmaking is that the addition amount of the slag melting agent is 5-10 kg/ton steel.
The application of the slag pressing agent in converter steelmaking is used for defoaming slag pressing, and the addition amount of the slag pressing agent is 1.0-1.5kg per ton of steel.
The technical scheme of the invention has the following advantages:
1. the preparation process of the cold-pressed red mud pellets provided by the invention comprises the steps of preprocessing to obtain a mixture and cold-pressing the mixture. In the pretreatment step, firstly, a mineral heating agent is adopted to treat the raw material containing the red mud, wherein after the mineral heating agent is mixed with the red mud, the mineral heating agent and the moisture in the red mud can carry out an exothermic reaction, and then a part of the moisture in the red mud is used as the raw material of the exothermic reaction to realize the consumption of the moisture in the red mud; meanwhile, a large amount of heat released by exothermic reaction can also promote the evaporation rate of moisture in the red mud, and after a period of curing operation, the thermal capillary force of the red mud is increased along with the rise of the temperature of the red mud, so that the evaporation heat transfer of the red mud and an air interface is promoted, and the moisture content in the red mud can be further reduced; therefore, the invention can effectively reduce the moisture content in the red mud from 20-25% to 5.5-15% without external fuel, and effectively reduce the energy consumption. In the step of cold pressing the mixture, the mixture is processed by adopting the cold pressing molding condition that the maximum pressure between the pair rollers is 800t-1000t, the maximum linear pressure ratio is 8.00-10.00t/cm and the linear speed is 0.50-0.80m/s, the friction force and the mechanical gripping force among powder particles in the mixture are destroyed by the processing mode, so that an arch bridge effect is formed, and each particle in the material moves towards the favorable direction of the particle and is rearranged, so that the porosity among the powder particles is reduced, the contact surface among the particles is enlarged, and the interaction force among the particles is continuously increased; when the external pressure is increased continuously, the interaction force among the particles, the lump density and the strength are increased, and finally, pellets with certain size, density and strength are formed; and through the setting of the cold pressing condition, the moisture content can be further reduced, and the red mud pellets with qualified size, moisture content and compressive strength can be formed. In conclusion: the red mud pellets are all manufactured by cold processing, the process flow is simple, no fuel is consumed, no other binder is added, no waste is generated, the production cost is low, the red mud pellets are energy-saving and environment-friendly, the strength is high, the quality is good, and the red mud pellets can bear the external force extrusion in the pellet production, transportation and application processes.
2. The preparation process of the cold-pressed red mud pellets further optimizes the particle size of raw materials, and adds the steps of pre-pressing and emptying before cold-press molding, particularly, in the optimization of the particle size of the raw materials, the red mud passes through a 3mm sieve, and the proportion of the red mud particles smaller than 2mm is more than 90%; the fly ash passes through a 0.106mm sieve. Through the optimization of the parameters and the process steps, the excessive air in the materials can be discharged in advance through the pre-pressing and emptying steps, so that the red mud pellet product after cold pressing treatment has more uniform quality and higher pelletizing rate, and the pelletizing rate can reach more than 90 percent.
3. The preparation process of the cold-pressed red mud pellets further optimizes the composition of the mineral heating agent and the selection of the types of the red mud and the dedusting ash. Specifically, the red mud is Bayer process red mud, the fly ash is blast furnace fly ash, and the mineral heating agent comprises 40.00-60.00% of CaO and 40.00-60.00% of MgO in percentage by mass; by optimizing the components and the proportion, the slag melting agent and the slag pressing agent suitable for converter steelmaking can be effectively prepared.
4. The invention provides a slag pressing agent for converter steelmaking, which comprises the raw materials of 52.00-58.00 percent of red mud, 2.00-4.00 percent of mineral heating agent and 38.00-46.00 percent of dust; the composition and the types of the raw materials are further optimized in the slag pressing agent, and when the red mud pellets prepared from the raw materials are used as the slag pressing agent for converter steelmaking, carbon in the fly ash reacts with iron oxide in slag at the smelting temperature of a converter to generate CO/CO 2 Gas enters the bubbles in the middle of the foamed slag in the overflowing process, the gas pressure in the bubbles is increased, and the foamed slag is broken, and the reaction equation is as follows:
2FeO+C→2Fe+CO 2 (g)↑，
FeO+Fe 2 O 3 +4C+→3Fe(s)+4CO(g)↑；
SiO in red mud 2 And Al 2 O 3 Can react with high-melting-point tricalcium silicate and RO in the slag to form a low-melting-point substance, reduces high-melting-point suspended matter particles which are beneficial to slag foaming, is beneficial to defoaming and plays a role in pressing the slag, and the reaction equation is as follows:
SiO 2 +3CaO·SiO 2 +MgO·2FeO→Fe 2 O 3 ·2CaO+MgO·CaO·SiO 2 ，
3CaO·SiO 2 +mAl 2 O 3 →nCaO·mAl 2 O 3 ·SiO 2 ；
therefore, the slag pressing agent prepared by the invention can replace the traditional slag pressing, the cost is saved, most of carbon in the dust is used as a reducing agent, iron-containing substances in the dust are reduced into metallic iron, the metallic iron enters into molten iron to be converted into molten steel, and the valuable maximization in solid waste is realized.
5. The invention provides a slagging agent for converter steelmaking, which comprises 82.00-92.00% of red mud, 3.00-9.00% of mineral heating agent and 5.00-9.00% of fly ash; the slag melting agent further optimizes the composition and the types of the raw materials, and when the red mud pellets prepared by the raw materials are used as the slag melting agent for converter steelmaking, the specific mechanism is as follows:
the steel making is slag making, and the high-alkalinity and low-melting-point slag system refining and the strong oxidizing smelting atmosphere building are very important for removing impurity elements in molten steel. The Bayer process red mud has high alkali property and simultaneously contains rich Na 2 O and Al 2 O 3 And the two have the effects of rapidly melting slag and promoting lime dissolution, as shown in figures 3 and 4, and Na is shown in figures 3 and 4 2 O and Al 2 O 3 For CaO-FeO-SiO 2 The influence of the slag system on the liquid phase area at 1400 ℃, besides being used as a cosolvent, the red mud also provides good thermodynamic conditions for dephosphorization of molten iron, and the dephosphorization effect is obvious.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a process flow diagram of example 1 of the present invention;
FIG. 2 is a process flow diagram of example 2 of the present invention;
FIG. 3 is Na 2 O to CaO-FeO-SiO 2 The influence of slag system on liquid phase area at 1400 ℃;
FIG. 4 shows Al 2 O 3 For CaO-FeO-SiO 2 The influence of slag system on liquid phase area at 1400 ℃.
Detailed Description
The following examples are provided to better understand the present invention, not to limit the best mode, and not to limit the content and protection scope of the present invention, and any product that is the same or similar to the present invention and is obtained by combining the present invention with other features of the prior art and the present invention falls within the protection scope of the present invention.
The examples do not indicate specific experimental procedures or conditions, and can be performed according to the procedures or conditions of the conventional experimental procedures described in the literature in the field. The reagents or instruments used are not indicated by manufacturers, and are all conventional reagent products which can be obtained commercially.
Example 1
The raw materials of the slag pressing agent comprise, by weight, 55.00% of red mud, 3.00% of mineral heating agent and 42.00% of dedusting ash. Wherein the red mud is Bayer process red mud, and the main component contents are respectively Fe 2 O 3 32.66％、Al 2 O 3 20.30％、SiO 2 13.21％、Na 2 O7.43% and CaO 2.01%; the water content in the red mud is 24%. The dust-removing ash is blast furnace dust-removing ash, and its main component content is C29.56%, T-Fe (total iron) 32.37% and Al 2 O 3 3.17％。
The specific preparation process of the slag pressing agent is shown in figure 1, and specifically comprises the following steps:
(1) preparing the red mud and the dedusting ash which meet the granularity requirement. Crushing and sieving the red mud. The red mud passes through a 3mm sieve, so that the proportion of red mud particles smaller than 2mm is more than 90%, and the dust removal ash passes through a 0.106mm sieve.
(2) The red mud, the mineral heating agent and the dedusting ash in the mass ratio are uniformly mixed to prepare a mixture.
(3) The mixture is aged for 12 hours to reduce the water content to 7.4 percent.
(4) The mixture is pressed into red mud pellets with the length, width and height of 40mm and about 20mm by a high-pressure ball press. The step of pressing the mixture by the high-pressure ball press comprises a pre-pressing emptying step and a cold-pressing treatment step; specifically, the high-pressure ball press machine in this embodiment includes two pairs of jade, one pair of jade is used for the pre-compaction evacuation, another pair of jade is used for the cold pressing treatment. Wherein, the porosity of the material entering the pair rolling for prepressing evacuation in the prepressing evacuation step is 34 percent, and the porosity of the material in the minimum clearance area between the two rollers is 12 percent; in the cold pressing treatment step, the maximum pressure between the rollers is 800t, the maximum linear pressure ratio is 8t/cm, and the linear speed is 0.6m/s.
(5) Screening and inspecting the red mud pellets to be qualified to obtain a slag pressing agent; and returning the sieved undersize product to a high-pressure ball press for cold press molding again.
Example 2
The slag melting agent comprises, by weight, 87.00% of red mud, 6.00% of mineral heating agent and 7.00% of dedusting ash. Wherein the red mud is Bayer process red mud, and the main component contents are respectively Fe 2 O 3 32.66％、Al 2 O 3 20.30％、SiO 2 13.21％、Na 2 O7.43% and CaO 2.01%; the water content in the red mud is 23%. The dust-removing ash is blast furnace dust-removing ash, and its main components are C29.56%, T-Fe 32.37% and Al 2 O 3 3.17 percent; the mineral exothermic agent comprises 50.00 CaO and 50.00% MgO.
The specific preparation process of the slagging agent is shown in fig. 2, and specifically comprises the following steps:
(1) preparing the red mud and the dedusting ash which meet the granularity requirement. Crushing and sieving the red mud. The red mud passes through a 3mm sieve, so that the proportion of red mud particles smaller than 2mm is more than 90%, and the dust removal ash passes through a 0.106mm sieve.
(2) Uniformly mixing the red mud and the mineral heating agent in the slag melting agent mass ratio to prepare a premix.
(3) The premix is aged for 18h to reduce the water content to 14.0%.
(4) The premix and the dedusting ash of the steel and iron works in the mass ratio are prepared into a mixture.
(5) The mixture is pressed into red mud pellets with the length, width and height of 40mm and about 20mm by a high-pressure ball press. The step of pressing the mixture by the high-pressure ball press comprises a pre-pressing emptying step and a cold pressing treatment step; specifically, the high-pressure ball press machine in this embodiment includes two sets of beautiful jade, a set of beautiful jade for prepressing evacuation, another set of beautiful jade for cold pressing treatment. Wherein, the porosity of the material entering the pair rolling for prepressing evacuation in the prepressing evacuation step is 36 percent, and the porosity of the material in the minimum clearance area between the two rollers is 13 percent; in the cold pressing treatment step, the maximum pressure between the rollers is 850t, the maximum linear pressure ratio is 8.5t/cm, and the linear speed is 0.8m/s.
(6) Screening and inspecting the red mud pellets to be qualified to obtain a slagging agent; and returning the sieved undersize to a high-pressure ball press for cold press molding again.
Example 3
The difference between this example and example 1 is that the composition, the ratio and the process parameters of the raw materials are different, and the rest are the same as example 1, and the specific differences are as follows:
the differences of the components and the mixture ratio of the raw materials are as follows: the raw materials comprise 52.00 percent of red mud, 2.00 percent of mineral heating agent and 46.00 percent of dust removal ash; wherein the mineral exothermic agent comprises 40.00 CaO and 60.00 percent MgO.
The differences of the process parameters are as follows: the curing time is 16 hours, so that the water content is reduced to 6.9 percent; in the prepressing and emptying step, the porosity of the material when entering is 45 percent, and the porosity of the material in the minimum clearance area between the two rollers is 17 percent; in the cold pressing treatment step, the maximum pressure between the rollers is 900t, the maximum linear pressure ratio is 9t/cm, and the linear speed is 0.6m/s.
Example 4
The difference between this example and example 1 is that the composition, the ratio and the process parameters of the raw materials are different, and the rest are the same as example 1, and the specific differences are as follows:
the differences of the components and the mixture ratio of the raw materials are as follows: the raw materials comprise 58.00 percent of red mud, 4.00 percent of mineral exothermic agent and 38.00 percent of dedusting ash; wherein the mineral exothermic agent comprises 60.00% CaO and 40.00% MgO.
The differences of the process parameters are as follows: the curing time is 16h, so that the water content is reduced to 5.9%; in the prepressing and emptying step, the porosity of the material when entering is 40 percent, and the porosity of the material in the minimum clearance area between the two rollers is 15 percent; in the cold pressing treatment step, the maximum pressure between the rollers is 1000t, the maximum linear pressure ratio is 10t/cm, and the linear speed is 0.5m/s.
Example 5
The difference between this example and example 2 is that the composition, the ratio and the process parameters of the raw materials are different, and the rest are the same as example 2, and the specific differences are as follows:
the differences of the components and the mixture ratio of the raw materials are as follows: the raw materials comprise 82.00 percent of red mud, 9.00 percent of mineral exothermic agent and 9.00 percent of dedusting ash; wherein the mineral exothermic agent comprises 40.00 CaO and 60.00 percent MgO.
The differences of the process parameters are as follows: the curing time is 15h to reduce the water content to 10.8%; in the pre-pressing and emptying step, the porosity of the material when entering is 42 percent, and the porosity of the material in the minimum clearance area between the two rollers is 16 percent; in the cold pressing treatment step, the maximum pressure between the pair rollers is 950t, the maximum linear pressure ratio is 9.5t/cm, and the linear speed is 0.6m/s.
Example 6
The difference between this example and example 2 is that the composition, the ratio and the process parameters of the raw materials are different, and the rest are the same as example 2, and the specific differences are as follows:
the differences of the components and the mixture ratio of the raw materials are as follows: the raw materials comprise 92.00 percent of red mud, 3.00 percent of mineral heating agent and 5.00 percent of dedusting ash; wherein the mineral exothermic agent comprises 60.00% CaO and 40.00% MgO.
The differences of the process parameters are as follows: the curing time is 24 hours, so that the water content is reduced to 13 percent; in the pre-pressing and emptying step, the porosity of the material when entering is 42 percent, and the porosity of the material in the minimum clearance area between the two rollers is 15 percent; in the cold pressing treatment step, the maximum pressure between the pair rollers is 1000t, the maximum linear pressure ratio is 10t/cm, and the linear speed is 0.56m/s.
The finished products prepared in the above examples 1 to 6 were tested for compressive strength, water content and balling rate by the following methods:
compressive strength: GB/T14201-1993;
water content: GB 7172-1987;
balling rate: the pelletizing balling rate = qualified green pellet flow/(qualified green pellet flow + unqualified green pellet flow).
The results of the measurements are shown in Table 1 below.
TABLE 1
According to the detection results, the red mud pellets which do not consume any fuel, are not added with other binders, do not generate any waste, and have low production cost, energy conservation, environmental protection, high strength and good quality can be effectively prepared by adopting the preparation process and the raw material composition.
Example 7
In this example, the slagging agent prepared in example 2 was used for an industrial test, and the specific test procedures and results are as follows:
an existing 120t top-bottom combined blown converter is selected to carry out an industrial test of cold-pressed pellet converter steelmaking, the slagging agent produced in the embodiment 2 is adopted to replace the original slagging agent in the production process, the consumption of the slagging agent is 8 kg/ton of steel, other conditions are unchanged, and the effect produced by the red mud pellets is verified through the production result. The original slagging agent in the test adopts fluorite.
The red mud in the slagging agent adopted in the implementation has high-alkali characteristic and simultaneously contains rich Na 2 O and Al 2 O 3 And the two have the effects of rapidly melting slag and promoting lime dissolution, as shown in figures 3 and 4, and Na is shown in figures 3 and 4 2 O and Al 2 O 3 For CaO-FeO-SiO 2 The influence of the slag system on the liquid phase area at 1400 ℃ can be used as a cosolvent, and the addition of the red mud also provides good thermodynamic conditions for dephosphorization of molten iron; in the test, the red mud has obvious fluxing and slag melting effects, and the problem of 'drying back' in later steelmaking can be well solved.
The red mud pellets in example 2 were used for a total of 50 converter steelmaking tests, and the overall dephosphorization effect was more ideal. Under the original process, the average end point P of the molten steel is 0.031%, the dephosphorization rate is 75.74%, and the average end point phosphorus of the 50-furnace industrial test is reduced by 0.011% compared with the original process, the dephosphorization rate is improved by 11.86%, and the dephosphorization effect is good.
Example 8
The present example is a specific test procedure and a detection result of an industrial test using the slag pressing agent prepared in example 1:
the slag pressing agent in the embodiment 1 is adopted in a 100t converter, the slag pressing agent is added from a high-level storage bin within 60s before a gun is lifted and a converter is turned over at the smelting end point of the converter, 150kg of the slag pressing agent is used each time, and other smelting processes are carried out according to the traditional process.
The used result shows that the slag pressing effect is obvious, compared with the original process, the defoaming time is shortened by more than 30s, and after the slag pressing defoaming, the subsequent slag splashing furnace protection process is also obviously optimized.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. This need not be, nor should it be exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.
Claims (12)
1. A preparation process of cold-pressed red mud pellets is characterized by comprising the following steps:
pretreatment: obtaining a raw material containing red mud, wherein the water content of the red mud is 20-25%, adding a mineral heating agent into the raw material, uniformly mixing, curing to reduce the water content to 5.5-15%, and finally obtaining a mixture;
cold pressing treatment: performing cold press molding on the mixture to prepare red mud pellets, wherein during cold press molding, the maximum pressure between rollers is 800t-1000t, the maximum linear pressure ratio is 8.00-10.00t/cm, and the linear speed is 0.50-0.80m/s;
the mineral heating agent comprises, by mass, 40.00% -60.00% of CaO and 40.00% -60.00% of MgO;
the raw materials of the mixture comprise dedusting ash, red mud and a mineral heating agent; the content of the red mud is more than 50% of the total weight of all the raw materials added in the pretreatment step;
when the raw material containing the red mud only contains the red mud, adding the dedusting ash after the curing step and uniformly mixing to obtain a mixture;
when the raw materials containing the red mud comprise the dedusting ash and the red mud, the mixture can be obtained after the curing step.
2. The preparation process according to claim 1, wherein the red mud is bayer process red mud, and the fly ash is blast furnace fly ash.
3. The preparation process according to claim 1 or 2, wherein the red mud passes through a 3mm sieve, and the proportion of red mud particles smaller than 2mm is more than 90%; the fly ash passes through a 0.106mm sieve.
4. The preparation process according to claim 1 or 2, characterized in that the mixture is subjected to a pre-pressing evacuation step before cold press forming.
5. The preparation process according to claim 4, wherein in the pre-pressure emptying step, the porosity of the material at the time of entering is 34% -45%, and the porosity of the material in the minimum clearance area during the pre-pressure emptying step is 12% -17%.
6. The preparation process according to claim 1 or 2, wherein the red mud pellets have a length, a width and a height of 38-42mm, 38-42mm and 18-22mm, respectively.
7. The slagging agent prepared by the process for preparing cold-pressed red mud pellets according to any one of claims 1 to 6, which is characterized by comprising the following raw materials in percentage by weight:
82.00% -92.00% of red mud;
3.00% -9.00% of mineral heating agent;
5.00% -9.00% of dedusting ash; the mineral heating agent comprises, by mass, 40.00% -60.00% of CaO and 40.00% -60.00% of MgO.
8. The slagging agent according to claim 7, wherein the red mud is Bayer process red mud, and the fly ash is blast furnace fly ash.
9. The slag pressing agent prepared by the process for preparing cold-pressed red mud pellets according to any one of claims 1 to 6, which is characterized by comprising the following raw materials in percentage by weight:
52.00% -58.00% of red mud;
2.00-4.00% of mineral heating agent;
38.00% -46.00% of dust; the mineral heat generating agent comprises, by mass, 40.00% -60.00% of CaO and 40.00% -60.00% of MgO.
10. The slag pressing agent according to claim 9, wherein the red mud is bayer process red mud, and the fly ash is blast furnace fly ash.
11. Use of a slag-melting agent according to claim 7 or 8 in converter steelmaking in an amount of 5-10 kg/ton of steel.
12. Use of a slag pressing agent according to claim 9 or 10 in converter steelmaking at a level of from 1.0 to 1.5 kg/ton of steel.
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| CN103952515B (en) * | 2014-04-29 | 2017-01-04 | 北京科技大学 | A kind of iron red mud is used as the recycling method of steelmaking slag agent |
| KR101736625B1 (en) * | 2015-12-21 | 2017-05-16 | 주식회사 포스코 | Deslopping agent of converter having waste red mud and method for manufacturing the same |
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| CN106086291B (en) * | 2016-08-04 | 2018-05-29 | 钢铁研究总院 | A kind of method that converter half steel slagging agent is prepared using low-sulfur low titanium blast furnace slag |
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