CN115029169A - Preparation method of sintered solid fuel - Google Patents

Abstract

The invention relates to a preparation method of a sintered solid fuel, which comprises the following steps of (1) preparing materials: according to the mass percentage: 5-10% of converter slag, 61-80% of secondary carbon-containing resources, 11-25% of metal-containing iron powder, 2-5% of rare earth tailings and 2-5% of tar residue; (2) crushing: respectively crushing the converter slag and the secondary carbon-containing resource, wherein the granularity is less than or equal to 3mm, and the weight percentage is more than 95%; (3) mixing; (4) cold press molding: cold-pressing the mixed material on a double-roller press to prepare a composite block with the diameter of 15-50 mm; (5) and (3) high-temperature roasting: placing the composite lumps into a heating furnace for high-temperature roasting at the roasting temperature of less than 300 ℃ for 30-60min, wherein the roasting temperature is more than or equal to 300 ℃ and less than 500 ℃, the roasting temperature is more than or equal to 500 ℃ and less than 1000 ℃, the roasting time is 60-120min, the roasting temperature is more than or equal to 1000 ℃ and less than 1200 ℃, and the roasting time is 20-40 min; (6) and (5) crushing and screening. The invention reduces the generation amount of NOx in the sinter bed and simultaneously fully utilizes secondary carbon-containing resources.

Description

A kind of preparation method of sintered solid fuel

technical field

The invention relates to the field of sintering, in particular to a preparation method of sintered solid fuel.

Background technique

At present, the fuels used in the sintering process are mainly anthracite coal and coke powder produced by the coking process. The use of anthracite or coke powder has the advantages of high yield of sintered ore and low energy consumption for sintering production. However, the content of N element in coke powder or anthracite is relatively high, and the ratio is too high, resulting in excessive NOx emission from sintering flue gas. With the increasingly stringent requirements for ultra-low emission of sintering flue gas, the pressure on environmental protection is increasing, and high-quality low-N anthracite resources are becoming more and more scarce. This also raises the question of whether it is possible to find a substitute for anthracite or coke powder, which can not only realize the role of exothermic agent in the sintering system, but also reduce pollutant emissions and reduce the production cost of ironmaking.

In addition to the conventional anthracite and coke powder, there are also sintered fuels prepared by the following methods. The Chinese patent "A method of using composite carbon-containing blocks for sintering" (application number: CN202010643896.0), which is based on secondary The carbonaceous material and the binder are used as raw materials, and the secondary carbonaceous material is ground, mixed with the binder, and heated and calcined in a heating furnace to obtain a composite carbonaceous block for sintering. Substitute the role of traditional fuel as exothermic agent in sintering process. It only uses secondary carbon resources to replace or partially replace traditional sintered solid fuels, without considering the issue of pollutant emissions, let alone reducing NOx emissions.

Chinese patents "A biomass fuel for iron ore sintering and its preparation method and application" (application number: CN201711370241.5), "The preparation method of biomass fuel for iron ore sintering" (application number: CN201710900016.1) , "a biomass coke composite fuel for iron ore sintering" (application number: CN201510334980.3) and so on. The above patents all use carbonized biomass or improve biomass, and partially replace traditional sintered solid fuel to reduce costs, but most carbonized biomass carbon content far exceeds the content of anthracite or coke powder, and does not achieve the goal of reducing NOx emissions. Effect. The combustion characteristics of charcoal and fossil fuels are quite different. The two fuels show the characteristics of independent combustion successively, resulting in long combustion duration and wide combustion bandwidth, which seriously damages the matching between the combustion front and the heat transfer front of the material layer, resulting in the temperature of the sintered material layer. If it is low, the amount of liquid phase that plays a role in binding is insufficient, and the quality index of sintered minerals is deteriorated.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a preparation method of sintered solid fuel, which overcomes the problem that the solid fuel currently used for sintering causes the NOx emission of sintering flue gas to exceed the standard, and

To achieve the above object, the present invention adopts the following technical solutions to realize:

A preparation method of sintered solid fuel, comprising the following steps:

(1) Ingredients: by mass percentage: converter slag 5%-10%, secondary carbon-containing resources 61-80%, metal-containing iron powder 11%-25%, rare earth tailings 2-5%, tar slag is 2-5%;

(2) Crushing: crush the converter slag and secondary carbon-containing resources respectively, and the particle size is ≤3mm and the weight percentage is greater than 95%;

(3) Mixing: firstly, the secondary carbon-containing resources and tar residues are loaded into the mixer in turn, and the mixing time is 3-5min; then the rare earth tailings are loaded into the mixer, and the mixing time is 2-3min; then Load the converter slag into the mixer, and the mixing time is 5-8min; finally, put the metal-containing iron powder into the mixer, and the mixing time is 4-7min;

(4) cold-pressing molding: cold-pressing the mixed material on a pair of roller presses to obtain a composite agglomerate with a diameter of 15-50 mm;

(5) High-temperature roasting: the composite agglomerates are placed in the heating furnace for high-temperature roasting, the roasting temperature is lower than 300℃, roasting for 30-60min, 300℃≤ roasting temperature＜500℃, roasting 60-120min, 500℃≤ roasting temperature＜1000 ℃, roasting 60-180min, 1000℃≤ roasting temperature＜1200℃, roasting 20-40min;

(6) Crushing and screening: The calcined composite agglomerates are crushed and screened to obtain particles with a particle size range of 1-3 mm as sintered solid fuel.

The secondary carbon-containing resources are one or more of various coking dusts, blast furnace coke tank dust removal, blue carbon, waste tires, and waste plastics;

The metal-containing iron powder is machined steel cutting or waste pure iron powder, and the particle size is less than or equal to 3mm, accounting for more than 90%;

The particle size of the rare earth tailings less than or equal to 3mm accounts for more than 90%.

A method for using sintered solid fuel, the sintered solid fuel is premixed with quicklime, the mixing time is 2-4min, then the mixture is mixed with the sintered return ore with a particle size of less than or equal to 0.5mm, and the mixing time is 3-5min; The powder is mixed and granulated three times, and the mixing time is 4-6 minutes; the obtained sintered raw materials are ignited, sintered, crushed and screened after being distributed in the sintering machine.

Compared with the prior art, the beneficial effects of the present invention are:

The invention reduces the generation amount of NOx in the sintered material layer, and at the same time makes full use of secondary carbon-containing resources, such as various dust removal ash from coking, blast furnace ore coke tank dust removal ash, blue carbon, waste tires, waste plastics, etc. Steel waste converter slag, machined waste machined steel chips, waste pure iron powder, etc., with the advantages of low cost and easy availability, produce a new type of sintered solid fuel for sintering process with low NOx generation, and realize the replacement of traditional fuels in sintering. The function of the process exothermic agent can greatly save valuable coal resources and reduce the NOx emission of flue gas in the sintering process.

Detailed ways

Below in conjunction with embodiment, the present invention is further described:

The following examples illustrate the invention in detail. These examples merely describe the best embodiments of the present invention and do not limit the scope of the present invention.

Example 1

Preparation of a sintered solid fuel:

①Ingredients: 5% of converter slag, 70% of secondary carbon-containing resources, 20% of metal-containing iron powder, 3% of rare earth tailings, and 2% of tar slag by mass percentage. Secondary carbon-containing resources are various dust removal from coking, blast furnace coke tank dust removal, blue carbon, and waste tires.

②Crushing: The converter slag and secondary carbon-containing resources are respectively crushed into a particle size of ≤3mm and a weight percentage greater than 95%.

③Mixing: firstly, the secondary carbon-containing resources and tar residue are sequentially loaded into the mixer according to the above mass percentage, and the mixing time is 3 minutes; then the rare earth tailings are loaded into the mixer according to the mass percentage, and the mixing time is 2 minutes; Then, the converter slag was loaded into the mixer according to the mass percentage, and the mixing time was 5 minutes; finally, the metal-containing iron powder was loaded into the mixer according to the mass percentage, and the mixing time was 4 minutes.

④Cold-press forming: The mixed material is cold-pressed on a roller press to obtain a composite agglomerate with a diameter of 15-50mm.

⑤ High-temperature roasting: The composite agglomerate is placed in the heating furnace for high-temperature roasting. The roasting temperature is lower than 300℃, and the roasting time is 30min. The roasting time is 60min, 1000℃≤ roasting temperature<1200℃, and the roasting time is 20min.

⑥ Crushing and screening: The calcined composite agglomerates are crushed and screened to obtain particles with a particle size range of 1-3 mm as sintered solid fuel.

Use of sintered solid fuel:

The sintered solid fuel is pre-mixed with quicklime, and the mixing time is 2 minutes; then the mixture is mixed with the sintered ore with a particle size of less than 0.5 mm, and the mixing time is 3 minutes; finally, it is mixed with iron ore powder three times for granulation, and each mixing time is 4min; the obtained sintered raw materials are ignited, sintered, crushed and screened after being distributed by the sintering machine.

Example 2

Preparation of a sintered solid fuel:

①Ingredients: 10% of converter slag, 61% of secondary carbon-containing resources, 22% of metal-containing iron powder, 4% of rare earth tailings, and 3% of tar slag by mass percentage. The secondary carbon-containing resources are various dust removal dust from coking, blast furnace coke tank dust removal dust, blue carbon and waste plastics.

②Crushing: The converter slag and secondary carbon-containing resources are respectively crushed, and the particle size is ≤3mm and the weight percentage is greater than 95%.

③Mixing: firstly, the secondary carbon-containing resources and tar residues are sequentially loaded into the mixer according to the above mass percentage, and the mixing time is 4 minutes; then the rare earth tailings are loaded into the mixer according to the mass percentage, and the mixing time is 3 minutes; Then, the converter slag was loaded into the mixer according to the mass percentage, and the mixing time was 6 minutes; finally, the metal-containing iron powder was loaded into the mixer according to the mass percentage, and the mixing time was 6 minutes.

④Cold-press forming: The mixed material is cold-pressed on a roller press to obtain a composite agglomerate with a diameter of 15-50mm.

⑤ High-temperature roasting: The composite agglomerate is placed in the heating furnace for high-temperature roasting. The roasting temperature is lower than 300℃, and the roasting time is 60min. The roasting time is 180min, 1000℃≤ roasting temperature<1200℃, and the roasting time is 40min.

⑥ Crushing and screening: The calcined composite agglomerates are crushed and screened to obtain particles with a particle size range of 1-3 mm as sintered solid fuel.

Use of sintered solid fuel:

The sintered solid fuel is pre-mixed with quicklime, and the mixing time is 4 minutes; then the mixture is mixed with the sintered return ore with a particle size of ≤0.5 mm, and the mixing time is 5 minutes; finally, it is mixed with iron ore powder three times for granulation, and the mixing time is 6 minutes. The obtained sintered raw materials are ignited, sintered, crushed and screened after being distributed by a sintering machine.

Example 3

Preparation of a sintered solid fuel:

①Ingredients: 8% of converter slag, 68% of secondary carbon-containing resources, 20% of metal-containing iron powder, 2% of rare earth tailings, and 2% of tar slag by mass percentage. Secondary carbon-containing resources are various dust removal from coking, blast furnace coke tank dust removal, blue carbon, and waste tires.

②Crushing: crushing converter slag and secondary carbon-containing resources, the particle size is ≤3mm and the weight percentage is greater than 95%.

③Mixing: firstly, the secondary carbon-containing resources and tar residues are sequentially loaded into the mixer according to the above mass percentage, and the mixing time is 5 minutes; then the rare earth tailings are loaded into the mixer according to the mass percentage, and the mixing time is 3 minutes; Then, the converter slag was loaded into the mixer according to the mass percentage, and the mixing time was 8 minutes; finally, the metal-containing iron powder was loaded into the mixer according to the mass percentage, and the mixing time was 7 minutes.

④Cold-press forming: The mixed material is cold-pressed on a roller press to obtain a composite agglomerate with a diameter of 15-50mm.

⑤ High-temperature roasting: The composite agglomerate is placed in the heating furnace for high-temperature roasting. The roasting temperature range is lower than 300 °C, and the roasting time is 40 minutes. , the roasting time is 150min, 1000℃≤ roasting temperature<1200℃, and the roasting time is 30min.

⑥ Crushing and screening: The calcined composite agglomerates are crushed and screened to obtain particles with a particle size range of 1-3 mm as sintered solid fuel.

Use of sintered solid fuel:

The sintered solid fuel is pre-mixed with quicklime, and the mixing time is 2 minutes; the granulated mixture is mixed with the sintered ore with a particle size of ≤0.5 mm, and the mixing time is 3 minutes; finally, it is mixed with iron ore powder for three times. The time is 5 minutes; the obtained sintered raw materials are ignited, sintered, crushed and screened after being distributed by the sintering machine.

Example 4

Preparation of a sintered solid fuel:

①Ingredients: 8% of converter slag, 71% of secondary carbon-containing resources, 11% of metal-containing iron powder, 5% of rare earth tailings, and 5% of tar slag by mass percentage. Secondary carbon-containing resources are various dust removal from coking, blast furnace coke tank dust removal, blue carbon, and waste tires.

②Crushing: crushing converter slag and secondary carbon-containing resources, the particle size is ≤3mm and the weight percentage is greater than 95%.

③Mixing: firstly, the secondary carbon-containing resources and tar residues are sequentially loaded into the mixer according to the above mass percentage, and the mixing time is 4 minutes; then the rare earth tailings are loaded into the mixer according to the mass percentage, and the mixing time is 3 minutes; Then, the converter slag was loaded into the mixer according to the mass percentage, and the mixing time was 6 minutes; finally, the metal-containing iron powder was loaded into the mixer according to the mass percentage, and the mixing time was 5 minutes.

④Cold-press forming: The mixed material is cold-pressed on a roller press to obtain a composite agglomerate with a diameter of 15-50mm.

⑤ High temperature roasting: The composite agglomerate is placed in the heating furnace for high temperature roasting, the roasting temperature is lower than 300℃, the roasting time is 50min, 300℃≤ roasting temperature<500℃, the roasting time is 90min, 500℃≤ roasting temperature<1000℃, The roasting time is 120min, 1000℃≤ roasting temperature<1200℃, and the roasting time is 35min.

⑥ Crushing and screening: The calcined composite agglomerates are crushed and screened to obtain particles with a particle size range of 1-3 mm as sintered solid fuel.

Use of sintered solid fuel:

The sintered solid fuel is pre-mixed with quicklime, and the mixing time is 2min; the granulated mixture is mixed with the sintered ore with a particle size of ≤0.5mm, and the mixing time is 4min; finally, it is mixed with iron ore powder three times for granulation, and the mixing time is 5min; the obtained mixture is ignited, sintered, crushed and screened after being distributed.

Example 5

Preparation of a sintered solid fuel:

①Ingredients: 6% of converter slag, 71% of secondary carbon-containing resources, 13% of metal-containing iron powder, 5% of rare earth tailings, and 5% of tar slag by mass percentage. Secondary carbon-containing resources include various dust removal ash from coking, blast furnace ore coke tank dust removal ash, blue carbon, waste tires, and waste plastics.

②Crushing: crushing converter slag and secondary carbon-containing resources, the particle size is ≤3mm and the weight percentage is greater than 95%.

③Mixing: firstly, the secondary carbon-containing resources and tar residues are sequentially loaded into the mixer according to the above mass percentage, and the mixing time is 5 minutes; then the rare earth tailings are loaded into the mixer according to the mass percentage, and the mixing time is 3 minutes; Then, the converter slag was loaded into the mixer according to the mass percentage, and the mixing time was 7 minutes; finally, the metal-containing iron powder was loaded into the mixer according to the mass percentage, and the mixing time was 5 minutes.

④Cold-press forming: The mixed material is cold-pressed on a roller press to obtain a composite agglomerate with a diameter of 15-50mm.

⑤ High temperature roasting: The composite agglomerate is placed in the heating furnace for high temperature roasting, the roasting temperature is lower than 300℃, the roasting time is 55min, 300℃≤ roasting temperature＜500℃, the roasting time is 85min, 500℃≤ roasting temperature＜1000℃, The roasting time is 100min, 1000℃≤ roasting temperature<1200℃, and the roasting time is 25min.

⑥ Crushing and screening: The calcined composite agglomerates are crushed and screened to obtain particles with a particle size range of 1-3 mm as sintered solid fuel.

Use of sintered solid fuel:

The sintered solid fuel is pre-mixed with quicklime, and the mixing time is 2 minutes; the granulated mixture is mixed with the sintered ore with a particle size of ≤0.5 mm, and the mixing time is 3 minutes; finally, it is mixed with iron ore powder for three times. The time is 4min; the obtained sintered material is ignited, sintered, crushed and screened after being distributed by the sintering machine.

The physical and chemical indicators of sintered solid fuel are shown in Table 1.

Table 1 Physical and chemical indexes of sintered solid fuel wt%

name fixed carbon metal iron calcium ferrite Volatile other ash moisture Example 1 68.12 16.38 3.58 2.42 10.37 0.23 Example 2 63.44 17.56 5.67 1.98 11.01 0.34 Example 3 66.67 16.68 5.28 1.77 9.35 0.25 Example 4 69.12 8.98 5.08 1.86 14.61 0.35 Example 5 68.78 10.44 4.36 1.99 14.10 0.33 coke powder 83.68 0.76 0.46 1.98 13.41 0.35

The effect after sintering of the embodiment is shown in Table 2.

Table 2: Sintering Index and NOx Concentration

Claims (4)

1. A preparation method of a sintered solid fuel is characterized by comprising the following steps:

(1) preparing materials: according to the mass percentage: 5-10% of converter slag, 61-80% of secondary carbon-containing resources, 11-25% of metal-containing iron powder, 2-5% of rare earth tailings and 2-5% of tar residue;

(2) crushing: respectively crushing the converter slag and the secondary carbon-containing resource, wherein the granularity is less than or equal to 3mm, and the weight percentage is more than 95%;

(3) mixing: sequentially loading secondary carbon-containing resources and tar residues into a mixer for 3-5 min; then loading the rare earth tailings into a mixer, and mixing for 2-3 min; then, loading the converter slag into a mixture machine, wherein the mixing time is 5-8 min; finally, filling the metal iron-containing powder into a mixture machine, wherein the mixing time is 4-7 min;

(4) cold press molding: cold-pressing the mixed material on a double-roller press to obtain a composite briquette with the diameter of 15-50 mm;

(5) and (3) high-temperature roasting: placing the composite lumps into a heating furnace for high-temperature roasting at the roasting temperature of less than 300 ℃ for 30-60min, wherein the roasting temperature is more than or equal to 300 ℃ and less than 500 ℃, the roasting temperature is more than or equal to 500 ℃ and less than 1000 ℃, the roasting time is 60-120min, the roasting temperature is more than or equal to 1000 ℃ and less than 1200 ℃, and the roasting time is 20-40 min;

(6) crushing and screening: and crushing and screening the roasted composite lumps to obtain particles with the particle size range of 1-3mm, wherein the particles are used as the sintered solid fuel.

2. The method for preparing the sintered solid fuel according to claim 1, wherein the secondary carbon-containing resource is one or more of various fly ashes in coking, fly ashes in blast furnace coke oven, semi coke, waste tires and waste plastics.

3. The method for preparing sintered solid fuel according to claim 1, wherein said metallic iron-containing powder is machined steel scrap or waste pure iron powder having a particle size of 3mm or less and is 90% or more.

4. The method for preparing the sintered solid fuel according to claim 1, wherein the rare earth tailings have a particle size of 3mm or less and account for 90% or more.