CN103834799A - Method for increasing yield of sintering ore by utilizing siderite - Google Patents

Abstract

The invention discloses a method for increasing the output of sintered ore by using siderite. The siderite is crushed into pellets with a particle size of 16-25 mm, and all or part of the pellets are used to replace the finished sintered ore as a bottoming material. After that, cloth, ignition and sintering are carried out, and the siderite is oxidized and roasted by using the high-temperature flue gas generated by sintering. After adopting the method of the present invention, it can not only avoid the use of finished sintered ore as the base material, effectively increase the output of sintered ore, but also roast siderite, realize the increase and synergistic utilization of siderite, and can also improve sintering desulfurization The output of the equipment has great economic benefits.

Description

A method of improving sinter output by using siderite

technical field

The invention belongs to the technical field of sinter preparation, and more specifically relates to a method for increasing the output of sinter by using siderite.

Background technique

Siderite is an ore containing iron carbonate, its main component is FeCO ₃ , and it appears blue-gray. This kind of ore mostly contains quite high calcium salt and magnesium salt. When there are not many impurities in siderite, it can be used as iron ore to extract iron. Carbon dioxide is released, so this type of ore is usually roasted before utilization.

A kind of siderite in Panxi area has high sulfur content (1-3wt%), TFe content is about 35wt%, SiO ₂ content is about 30wt%, its burning loss value is about 25wt%, and its price is relatively high. Low. If its burning loss value is removed, the TFe content of this siderite can reach 47wt%. But precisely because the siderite has high sulfur content, high burning loss and poor sintering performance, although its price is low, it still cannot be used in large quantities, resulting in a serious waste of resources.

Contents of the invention

In view of the deficiencies in the prior art, the purpose of the present invention is to solve one or more of the above technical problems.

The purpose of the present invention is to provide a method for increasing the output of sintered ore by using siderite, which can increase the output of sintered ore while effectively roasting siderite and improving its utilization rate.

In order to achieve the above object, the present invention provides a method for increasing the output of sintered ore by using siderite ore. The siderite ore is crushed into pellets with a particle size of 16-25 mm, and all or part of the pellets are used as the base material. The finished sintered ore is then distributed, ignited and sintered, and the siderite is oxidized and roasted using the high-temperature flue gas generated by sintering.

According to one embodiment of the method for increasing the output of sintered ore by using siderite ore of the present invention, the TFe content in the siderite ore is 30-40% by weight percentage, and the ignition loss value of the siderite ore is 20% ~30%.

According to an embodiment of the method for increasing the output of sintered ore by using siderite in the present invention, the TFe content in the siderite is 35% by weight percentage, and the ignition loss value of the siderite is 25%.

According to an embodiment of the method for increasing the output of sintered ore by utilizing siderite in the present invention, the amount of the finished sintered ore used as the base material accounts for 2-8% of the output of the finished sintered ore in weight percentage.

According to an embodiment of the method for increasing the yield of sintered ore by utilizing siderite in the present invention, the sintered ore is high-titanium vanadium-titanium sintered ore.

According to an embodiment of the method for increasing the output of sintered ore by utilizing siderite in the present invention, the temperature at the bottom of the sintering machine is controlled to be lower than 600°C.

According to an embodiment of the method for increasing the output of sintered ore by using siderite in the present invention, the proportion of coke powder in the sintering raw material is controlled at 4.5-4.8wt%.

After adopting the method of the invention, not only the use of finished sintered ore as the base material can be avoided, and the output of sintered ore can be effectively increased, but also siderite can be roasted, and the output of sintering desulfurization equipment can also be increased, which has great economic benefits.

Detailed ways

Hereinafter, a method for increasing sinter production by using siderite according to an exemplary embodiment of the present invention will be described. Unless otherwise specified, the content involved in this specification refers to the content in weight percentage.

According to the present invention, the method for increasing the output of sintered ore by using siderite specifically includes the following steps: crushing siderite into pellets with a particle size of 16-25 mm, replacing all or part of the pellets as the base material The finished sintered ore is then distributed, ignited and sintered, and the siderite is oxidized and roasted using the high-temperature flue gas generated by sintering.

Specifically, on the one hand, the present invention uses siderite to partially or completely replace the finished sintered ore as the base material, which reduces the return of sintered ore and improves the yield of finished products; , to promote the decomposition of FeCO ₃ and sulfide in it at low temperature, and improve the quality of burning residue. In the sintering process, part of the finished sintered ore with a particle size of 10-16mm is sieved and returned to the sintering machine and laid on the bottom of the raw material to improve air permeability. However, considering that siderite may be partially pulverized after oxidative roasting and decomposition, Therefore, before using siderite, it needs to be crushed to the required particle size of 16-25mm. The preferred particle size setting is considered and determined according to the experiment with reference to the particle size requirements of the bottoming material and the strength after roasting.

Among them, the main component of siderite is FeCO ₃ , and the thermal decomposition reaction formula of FeCO ₃ in air and at a reaction temperature of 400-560°C is as follows:

4FeCO ₃ +O ₂ =2Fe ₂ O ₃ +4CO ₂ ↑

However, using siderite instead of base material for sintering may also cause some problems. One is that some powdery decomposition products may stick to the bottom of the sintering machine, and the other is that the sulfur content in the sintering flue gas may increase, but At present, all sintering machines are equipped with flue gas desulfurization devices, so the impact is not great. The third is that it may have a certain impact on the uniformity of the entire sintered material, but by controlling the alkalinity of the material, the impact will also become very small . Among them, in order to prevent siderite from adhering to the grate of the sintering machine after melting, it can be avoided by controlling the temperature at the bottom of the sintering machine to be lower than 600°C. Generally speaking, the temperature at the bottom of the sintering machine is controlled according to the amount of carbon in the sintering raw materials. According to the present invention, controlling the proportion of coke powder at 4.5-4.8 wt% can make the temperature at the bottom of the sintering machine lower than 600°C .

The roasted siderite enters the blast furnace along with the finished sinter for smelting, and can be used to replace the lump ore used in the blast furnace. And the roasted siderite is more energy-efficient than unroasted siderite directly entering the blast furnace, because it consumes less metallurgical coke, so while increasing the use and utilization of siderite, it reduces energy consumption. consume.

In terms of weight percentage, the content of TFe in the siderite used in the present invention is 30-40%, and its burning loss value is 20-30%. Preferably, the TFe content is 35%, and the burning loss value is 25%. It is more economical to use the siderite with the above grade conditions, because the ore resources under this condition are large and the utilization rate is high. If the TFe content is too low, its value is not great; if the burning loss value is too high, more heat is required for decomposition, which will increase fuel consumption during sintering.

Among them, the amount of finished sintered ore used as bottoming material accounts for 2 to 8% of the output of finished sintered ore, and the above-mentioned crushed siderite pellets can be used to replace all or part of the bottoming material according to actual working conditions. The replacement ratio can be determined according to the benefits brought about by increasing the output of sintered ore, for example, it will be better to replace more than 50% of the sintered ore, and it is preferable to replace all of them. According to an embodiment of the present invention, the sintered ore is high-titanium vanadium-titanium sintered ore, but the present invention is not limited thereto.

Among them, the sintered iron-containing raw materials can be properly selected and proportioned according to the sintering basic characteristics (meltability, assimilability), gangue type and quantity, ore structure, particle size, and sinter performance of the sintered iron-containing raw materials. The present invention The raw material for sintering is not particularly limited.

Since the ratio of sinter ore and sintering parameters have not changed, the performance of the obtained sinter ore is basically unchanged after using siderite instead of sintering primer.

The method for increasing the output of sintered ore by utilizing siderite of the present invention will be further described below in conjunction with specific examples.

Table 1 shows the sintering raw materials and their proportions in the reference example and examples 1 and 2.

Table 1 Sintering raw materials and their proportions (wt%)

It can be seen from Table 1 that the raw materials for sintering in the benchmark example and examples 1 and 2 specifically include Baima vanadium-titanium magnetite concentrate, domestic high-grade ordinary fine ore, low-grade ordinary fine ore, flux (quicklime, limestone), fuel (coke powder) , Return ore powder, etc.

In the proportioning process of the above-mentioned raw materials, the returning ore powder and the bottom layer are mixed externally, that is, 25% of the total weight of the dry powder and 5.5% of the finished ore are additionally added.

In actual production, only the total weight percentage of iron materials including high-grade vanadium-titanium magnetite concentrate, high-grade ordinary fine ore and low-grade ordinary fine ore is fixed at 80%, and the proportion of the rest of the materials is not fixed, and can be sintered according to production Mineral composition requires appropriate adjustments.

Among them, the main physical and chemical indicators of the raw materials used above are (the proportions of each component are weight percentages):

Baima vanadium-titanium magnetite concentrate: ω(TFe)55.5～57.0%, ω(SiO ₂ )>3.0%, ω(FeO)>30%, ω(TiO ₂ )>10%, ω(particle size<0.074mm)>70%;

Domestic high-grade ordinary fine ore: ω (TFe) 58-62%, ω (SiO ₂ ) 6-9%, ω (Al ₂ O ₃ ) <3%, ω (TiO ₂ ) <0.5%;

Low-grade ordinary fine ore: ω (TFe) 40-49%, ω (SiO ₂ ) 17-25%, ω (Al ₂ O ₃ ) <6%, ω (TiO ₂ ) <0.5%;

Dust: ω (TFe) 35-50%, ω (SiO ₂ ) 6-8%, ω (Al ₂ O ₃ ) <4%, ω (TiO ₂ ) <5%;

Active ash: ω (CaO) 85-90%;

Limestone: ω (main component CaO) 50-53%, ω (particle size < 3mm) = 100%;

Coke powder: ash content 12-15%, ω (particle size <3mm) = 100%;

Return ore powder: ω (TFe) 50%, ω (SiO ₂ ) 5.0-5.5%, ω (CaO) 10.0-11.0%, ω (particle size <5mm) = 100%.

According to the ratio shown in Table 1, mix high-grade vanadium-titanium magnetite concentrate, high-grade common ore powder, low-grade common fine ore, active ash, limestone, dedusting ash, coke powder and returned ore into the mixing bin Add water to a mixer and mix. During the mixing process, the water in the mixture is controlled to be 7.4-7.8%, and the mixing time is 5-6 minutes. Before putting the mixed material into the sintering cup, spread 3.0kg of sieved 10-16mm finished sintered ore (about 5.5% of the finished sintered ore) on the bottom of the sintering cup, and then put the mixed material into the sintering cup Fired and ventilated sintering in the cup. Among them, the diameter of the sintering cup is 300mm, the height is 800mm, the particle size of the primer in the sintering cup is 10-16mm, the thickness is 20mm, and the thickness of the material layer is 650-750mm (including the thickness of the primer).

During sintering, the ignition temperature is 1100～1150℃, the ignition time is 2.0～2.5min, the ignition negative pressure is 5.5～6kPa, the sintering exhaust negative pressure is 11.5～12.5kPa, and the exhaust flow is 5～15m ³ /min, which can be adjusted by The sintering speed of the mixture is controlled by parameters such as the negative pressure of the sintering exhaust and the flow rate of the exhaust. According to the sintering operation process of the present invention: the FeO content range is controlled at 7.0-10wt%, the vertical sintering speed is controlled at 17-20mm/min, the material layer thickness is controlled at 650-750mm, and the sintering temperature is controlled at 1250-1300°C. The temperature of the sintering waste gas at the bottom is controlled to be lower than 600°C. In the sintering process, the bottom temperature of the sintering machine can also be controlled by adjusting the thickness of the material layer under the condition of a certain sintering coke powder ratio. The thicker the material layer, the better the sintering heat storage The better the insulation, the higher the temperature.

During the sintering process, when the exhaust gas temperature of the exhaust pipe at the lower end of the sintering cup rises to the highest (below 600°C) and then drops to 300°C, the sintering process ends. Pour out the sintered cake and perform initial crushing (the distance between the crushers is 50mm), and then perform 3 times of drop treatment (the drop height is 2m), and then press 40~25mm, 25~16mm, 16~10mm, 10~5mm, <5mm Screening is carried out separately, and finally the proportion of sintered ore with a particle size greater than 5mm is calculated, and the drum strength of sintered ore is measured according to the national standard GB3209.

In order to facilitate comparison and understanding of the technical effects of the examples of the present invention, the sintering experiments and results of the benchmark example and examples 1 and 2 are specifically given below.

Benchmark example

The proportion of Baima vanadium-titanium magnetite concentrate is 64%, the proportion of domestic high-grade ordinary fine ore is 11%, the proportion of domestic low-grade ordinary fine ore is 5%, the proportion of active ash is 4.5%, and the proportion of limestone is 6.5%. , The ratio of coke powder is 4.8%, the ratio of dust removal ash is 4%, and the ratio of returned ore powder is 25%. Sinter basicity (CaO/SiO ₂ ratio in sinter) is controlled at 1.85±0.05, the ratio of quicklime digestion water is 2:1, the moisture content of sinter mixture is 7.4±0.1%, the amount of bottom layer is 3.0kg, and the height of material layer is 700mm , The charging capacity is 80kg.

The sintering results show that the sintering waste gas temperature is 580°C, the sintering amount of the mixture is 66kg, the sintering ore with a particle size greater than 5mm is 55kg, and the sintering yield is 78.78% after deducting 3.0kg of the bottom layer.

Example 1

The proportion of Baima vanadium-titanium magnetite concentrate is 64%, the proportion of domestic high-grade ordinary fine ore is 11%, the proportion of domestic low-grade ordinary fine ore is 5%, the proportion of active ash is 4.5%, and the proportion of limestone is 6.5%. , The ratio of coke powder is 4.8%, the ratio of dust removal ash is 4%, and the ratio of returned ore powder is 25%. The sintering basicity (CaO/ _SiO2 ratio in sinter) is controlled at 1.85±0.05, the ratio of quicklime digestion water is 2:1, the moisture content of sintering mixture is 7.4±0.1%, the amount of bottoming material is 3.0kg, and the bottoming material includes 1.5 kg of finished sinter and 1.5kg of crushed siderite (with a particle size of 16-25mm), the height of the material layer is 700mm, and the charging amount is 80kg.

The results show that the sintered amount of the mixture is 65.63kg, the sintered ore with a particle size greater than 5mm is 54.63kg, and the sintered finished product rate is 80.95%, which is 2.17 percentage points higher than that of the reference example.

Example 2

The proportion of Baima vanadium-titanium magnetite concentrate is 64%, the proportion of domestic high-grade ordinary fine ore is 11%, the proportion of domestic low-grade ordinary fine ore is 5%, the proportion of active ash is 4.5%, and the proportion of limestone is 6.5%. , The ratio of coke powder is 4.8%, the ratio of dust removal ash is 4%, and the ratio of returned ore powder is 25%. The sintering basicity (CaO/ _SiO2 ratio in sinter) is controlled to be 1.85±0.05, the ratio of quicklime digestion water is 2:1, the moisture content of sintering mixture is 7.4±0.1%, the amount of bottoming material is 3.0kg, and the bottoming material includes 3.0kg The crushed siderite (particle size is 16-25mm), the material layer height is 700mm, and the charging amount is 80kg.

The results show that the amount of sintered mixture is 65.25kg, the amount of sintered ore with a particle size greater than 5mm is 54.25kg, and the sintered finished product rate is 83.14%, which is 4.36 percentage points higher than that of the reference example.

The processing cost of a ton of sintered ore is about 80 yuan/t, the price of siderite is 160 yuan/t, and the price of lump ore with a TFe of 47% is 450 yuan/t. It is estimated that siderite will replace sintered bottom material by 2 percentage points , the sinter output can be increased by 2 percentage points. The 360m ² sintering machine produces about 3.6 million tons of sinter, which is expected to save processing costs and increase production benefits by about 8 million yuan per year. At the same time, it improves the TFe grade of siderite. In order to improve its cost performance, its value can be increased by 200 yuan/t, the annual processing capacity can reach 70,000 tons, and the value-added of siderite can reach more than 10 million yuan/year, and the total benefit of the two is expected to reach more than 20 million yuan/year.

To sum up, the present invention can not only use the sintering waste heat to roast siderite, but also use the siderite to replace the sintering bottom material. While increasing the output of sintering ore, it can also increase the output of sintering desulfurization equipment, and has a large economic benefits.

The present invention is not limited to the above-described embodiments, and various variations and modifications can be made without departing from the scope of the present invention.

Claims (7)

1. a method of utilizing spathic iron ore to improve Sintering Yield, it is characterized in that, spathic iron ore fragmentation is become to the pellet that particle diameter is 16～25mm, finished product agglomerate using all or part of described pellet replacement as grate-layer material, carry out afterwards cloth, igniting and sintering, the high-temperature flue gas that utilizes sintering to produce carries out oxidizing roasting processing to spathic iron ore.

2. the method for utilizing spathic iron ore to improve Sintering Yield according to claim 1, is characterized in that, by weight percentage, the TFe content in described spathic iron ore is 30～40%, and the scaling loss value of described spathic iron ore is 20～30%.

3. the method for utilizing spathic iron ore to improve Sintering Yield according to claim 2, is characterized in that, by weight percentage, the TFe content in described spathic iron ore is 35%, and the scaling loss value of described spathic iron ore is 25%.

4. the method for utilizing spathic iron ore to improve Sintering Yield according to claim 1, is characterized in that, by weight percentage, the amount of the described finished product agglomerate as grate-layer material accounts for 2～8% of finished product Sintering Yield.

5. the method for utilizing spathic iron ore to improve Sintering Yield according to claim 1, is characterized in that, described agglomerate is high-Ti type V-Ti agglomerate.

6. the method for utilizing spathic iron ore to improve Sintering Yield according to claim 1, is characterized in that, controls the temperature of sinter machine bottom lower than 600 ℃.

7. the method for utilizing spathic iron ore to improve Sintering Yield according to claim 6, is characterized in that, the dosage of coke in raw materials for sintering is controlled to 4.5～4.8wt%.