KR970002117B1 - Blowing method of powered metal - Google Patents

Abstract

The powdered metal from a dust collector or rolling mill in ironworks is blown into a blast furnace, by spraying a slurry mixing the powdered metal and a waste lubricant. The waste lubricant containing a crude Pb and Zn less than 200 ppm having low melting point and a iron powder less than 50 wt.% are mixed to give the slurry. The slurry fuel is sprayed into the blower through a blowing lance.

Description

Blast Furnace Blowing Method of Powdered Iron

The present invention relates to a method of injecting powder iron generated from a dust collecting facility or a rolling mill of a steel mill into a blast furnace, and more particularly, by mixing powder iron with waste lubricating oil to prepare a slurry containing high iron and high calorific value and spraying It is about a method to blow into the blast furnace blast furnace.

In general, powdered iron produced as a by-product from various dust collection facilities or rolling mills in steel mills contains a large amount of iron oxide and is recycled as a raw material for blast furnaces.

Usually, in order to use powder iron in a blast furnace, the method of massifying powder iron by sintering and charging to the upper part of a blast furnace is widely used. In particular, powdered iron contaminated by hydrocarbons such as waste oil is first incinerated to remove contaminants and then agglomerated through sintering to be charged through the upper part of the blast furnace.

However, in order to inject powder iron through the blast furnace portion, there is a disadvantage that a sintering process for bulking should be involved.

One way to solve this drawback is to directly inject the powdered iron into the blast furnace, but if you want to recycle the powdered iron in the blast furnace, it must be mixed with hydrocarbons that can reduce and dissolve the powdered iron. . For this purpose, a method of mixing the powdered iron with uncoated coal or heavy oil may be considered, but in this case, the mixture is difficult to manufacture and transport, and thus it is impossible to blow into the blast furnace.

Therefore, there is a need for a hydrocarbon medium that can melt-reduce powder iron when the powdered iron is blown into the blast furnace vent.

On the other hand, with the development of the industry and the increase of vehicles such as automobiles, the use of lubricating oil is rapidly increasing, which inevitably leads to the generation of waste lubricants. Therefore, recycling of waste lubricating oil is a very important issue in terms of resource utilization as well as environmental pollution prevention. For example, small companies use their own fuel negatively or some companies dump illegally, seriously polluting the air, water and soil environments.

When the waste lubricant is recycled, it is purified by adopting different refining processes depending on the purpose of use. Currently, when regenerating with lubricating oil, decompression distillation process or acid and clay treatment process are adopted.However, these methods are disadvantageous in terms of economic and environmental treatment due to lower lubricating oil price, excessive operating cost, and large amount of acid slurry. It is evaluated as a process.

In particular, when the fuel oil is recycled, a chemical treatment / centrifugation process such as the Salusinszky process (US Pat. No. 4,259,021) is used, which is intended to remove heavy metals and other pollen components present in a large amount of waste lubricant. However, even the refined waste lubricating oil, as shown in Table 1 below, may still cause secondary air pollution when used in heat supply facilities such as industrial boilers or kilns, since various heavy metals and ash are still contained.

Therefore, when using waste lubricant as fuel oil, such as a boiler, there is a problem that the refining process is complicated and the treatment cost increases accordingly.

Accordingly, the present inventors have conducted studies and experiments on the method of using the above-described powdered iron and the adjusted waste lubricating oil in the blast furnace, and the present invention was proposed based on the results, and the present invention suggests that the powdered iron is the blast furnace. The purpose of the present invention is to provide an effective blast furnace blowing method for blowing powdered iron as it is, by using waste lubricant adjusted as a hydrocarbon medium capable of melt-reducing powdered iron when blowing into.

Hereinafter, the present invention will be described.

The present invention relates to a method for blowing blast furnace of powder iron, which is prepared by mixing a crude waste powder of crude oil of 50% by weight or less and then injecting the slurry fuel into the blast furnace tuyere.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

When the conventional adjusted waste lubricating oil used in the present invention is blown into the blast furnace blast furnace, Ca, Mg, sulfur and the like are discharged together with the slag material in the ore, coke and coal, so there is no air pollution problem.

However, if the low melting point metals such as Pb and Zn contained in the waste lubricating oil contain thousands of ppm in the waste lubricating oil, the low melting point materials are condensed in the liquid phase in the lumped zone when blown into the blast furnace. By being deposited in the blast furnace charges, it is difficult to lower the charges or worsen breathability. Therefore, the waste lubricating oil used in the blast furnace should use the adjusted waste lubricating oil. Since the content of Pb and Zn contained in the refined waste lubricating oil is very small, it is circulated in the blast furnace and does not affect the blast furnace contents. It is not discharged.

In particular, Pb and Zn contained in the adjusted waste lubricating oil are more preferably at most 200 ppm.

In order to blow iron powder into the blast furnace using the crude waste lubricating oil as a hydrocarbon medium, it is necessary to prepare the slurry by mixing the iron powder with the waste lubricating oil, wherein the prepared slurry maintains a viscosity that can be pumped. And have a degree of flow that can be sprayed. To this end, in the present invention, it is preferable to add the iron powder to the adjusted waste lubricating oil by adding 50% by weight or less. If the iron powder is mixed in an amount of 50% by weight or more with respect to the crude waste lubricant, the calorific value of the slurry fuel not only decreases, but the sprayability is remarkably lowered, which is not preferable.

The iron particles in the mixed slurry are evenly dispersed in the lubricating oil by various surfactants added in the waste lubricating oil, and there is no sedimentation problem during long-term storage.

The crude waste lubricating oil / powder iron slurry fuel mixed by the above method is blown by installing a blowing nozzle in the blast furnace blast furnace and supplying it to a raceway with hot air.

The blast furnace raceway is a region in which hot air, coke and analytical coal react violently, and have a high temperature range of up to 2000 ° C. When the slurry fuel produced by the present invention is injected into this region, the reduction source and melting process of the iron oxide particles occur rapidly with the combustion of the flammable hydrocarbon. At this time, ash and other sulfur components present in the slurry are slag and discharged together with the other slag. In particular, since the slurry fuel is atomized and blown, combustion and reduction melting of iron particles in the raceway are very fast, and combustibility is much superior to that of the pulverized coal blowing method, which is the current blast furnace technology.

In addition, in terms of economics, even if the combined price of the current waste lubricating oil and the refining cost are lower than raw material prices, considering the pulverization cost of coal when pulverized coal is blown, the slurry fuel blowing method according to the present invention is much more economical. In addition, the blast furnace blowing method of the slurry of the present invention is the most economical in terms of recycling of powdered iron and has excellent advantages in terms of environment because it is used by mixing a large amount of powdered iron.

Hereinafter, the present invention will be described in detail through examples.

Example 1

Slurry was prepared by mixing the same composition as shown in Table 1 waste lubricant and powdered iron in the same formulation as Table 2 below.

At this time, the mixture of the crude oil and the powdered iron were each weighed in a predetermined amount and put in a mixing tank so that the total weight was 30 kg, and the mixture was performed at room temperature for about 30 minutes. After kneading, these slurries were measured and evaluated for viscosity and sprayability, and the results are shown in Table 2 below. At this time, the viscosity of the slurry is Brookfield Co., Ltd. model DV-Ⅱ Measured at 100 rpm.

As shown in Table 2, in the case of Comparative Example (1) (2) in which powder iron is mixed in 50% by weight or more of the crude oil, the sprayability is lowered and spraying is not possible when the blast furnace is blown.

On the contrary, as can be seen in the case of Inventive Example (1-5), it is shown that up to 50% by weight of powdered iron is possible in order to maintain spraying ability to be blown into the blast furnace.

Example 2

Slurry was prepared by adjusting the composition of waste lubricant and powder iron adjusted in the same manner as in Example 1 as shown in Table 3, and the calorific value according to the composition of the prepared slurry fuel and the adiabatic flame temperature during combustion were investigated and the result It is shown in Table 3 below.

As shown in Table 3, in Comparative Example (1) (2) in which powdered iron was mixed with more than 5% by weight of the adjusted waste lubricating oil, the thermal insulation flame temperature was excellent, but the calorific value was insufficient. As can be seen, the spraying property is lowered, which is not preferable.

On the other hand, Inventive Example (5-8), in which powdered iron is mixed to 50% by weight or less of the adjusted waste lubricating oil, not only has good spraying properties but also has high calorific value and high thermal flame temperature. It can be seen that there is no possibility of cooling the way.

Example 3

After spraying and burning the mixed slurry of Inventive Example (5) and (7), a combustibility test was conducted by taking a sample at 0.5 m and 1.0 m from the spray nozzle tip, and the results are shown in Table 4 below. At this time, the combustion rate was calculated by the following formula by the flammable content measurement.

Burn rate (%) = [1- {C (100-C) / C (100-C)}] × 100

Where C is the flammable content (% by weight) in the initial sample and C is the flammable content (% by weight) of the sample taken after combustion.

As shown in Table 4, it can be seen that the slurry according to the present invention is completely burned in a very short combustion zone within 1 m. Particularly, when the slurry is burned, it can be reduced at 1 m and the production of molten iron, which can be directly produced by directly slurrying powdered iron with the lubricated waste lubricating oil when injected into the blast furnace raceway. In addition, it shows that it is possible to supply a high heat generation heat source.

As described above, in the present invention, the powdered iron charged into the upper part of the blast furnace is usually mixed with waste lubricating oil to be prepared as a slurry fuel, and then injected into the blast furnace vent, so that the powdered iron can be used as it is. Compared to the conventional method of recycling the powdered iron through agglomeration accompanied by the sintering process and the blast furnace blowing method of powdered iron is simpler and more efficient than the pulverized coal coal blowing, it is more effective in terms of recycling the powdered iron and waste lubricating oil.

Claims (1)

The slurry was prepared by mixing up to 50% by weight of iron powder with waste lubricant containing Pb and Zn, each of which was adjusted to a low melting point of 200 rpm or less, and then injected into the blast furnace blast furnace by a conventional blowing lance. Blast furnace blowing method of powder iron, characterized in that configured.