KR100320570B1 - A method for treating waste shredder dust in a process for manufacturing cement - Google Patents

Abstract

The present invention relates to a method for treating waste vehicle shredder dust, and to provide a method for properly treating waste vehicle shredder dust in a cement manufacturing process, an object thereof.

The present invention is a method for producing a cement clinker by charging the cement raw material and fuel in the cement kiln, waste car shredder dust treatment in the cement manufacturing process of adding the waste car shredder dust to the cement raw material 10% by weight or less based on the fuel weight That's the point.

Description

A method for treating waste shredder dust in cement manufacturing process {A METHOD FOR TREATING WASTE SHREDDER DUST IN A PROCESS FOR MANUFACTURING CEMENT}

The present invention relates to a method for treating waste vehicle shredder dust in a cement manufacturing process.

The number of cars continues to increase, and the amount of scrapped cars is steadily increasing accordingly.

Therefore, there is an urgent need for development of a response technology for waste disposal such as waste vehicles.

Recently, the use of lightweight materials, such as high-strength reduction special materials to improve crash stability and aluminum and plastic materials to reduce fuel consumption, is gradually increasing.

By the way, looking at the material composition ratio of the car, although slightly different depending on the make and model of the car, it shows a similar ratio.

Based on semi-medium cars, about 60% of ferrous metal materials and about 10% of non-ferrous metal materials are easily recycled, and other materials such as plastics, rubber, glass, etc., which are difficult to recycle, are each About 10%, about 6%, about 3%.

Usually, the used waste vehicle is processed through the following processes.

That is, the waste car is handed over to the treatment plant to preferentially separate / recover parts such as bumpers and fuels, oils, tires, and batteries that are dangerous during dismantling.

Engines and transmissions composed mainly of metal materials are decomposed by disassembly or by hand and separated / recycled into ferrous and nonferrous metals for recycling.Inner / external parts of organic compounds such as plastics and sheets are compressed by large compressors while mounted on the car body. Shredder is used to break down the scrap recovery process.

At this time, the iron raw materials are collected and recovered by a magnetic separator, and expensive non-ferrous materials are generally separated / recovered by a non-ferrous sorter and a manual process.

Some parts and metals recovered during the disposal of scrapped cars are separated / recovered and most of the rubber, glass and plastic materials that make up about 25% of the rest of the vehicle's weight are generated as waste.

At this time, the shredder dust (hereinafter referred to as 'shredder dust') is contaminated by the liquid phase remaining in the car body shredding process.

As mentioned above, the shredder dust (final crushed waste) generated during the disposal of waste vehicles is mostly landfilled, and some methods of pyrolysis or incineration have been attempted. However, when the shredder dust is treated by the pyrolysis method, facility investment and facility operation are performed. There is a problem with economics, and in the case of incineration, there is a problem in that harmful substances are generated by incomplete combustion to pollute the air.

In addition, the landfill method of the shredder dust has a problem that it is difficult to secure a large landfill in a country with a narrow country.

Therefore, in order to secure economic value, it is possible to recover and reuse parts in the pre-crushing process as much as possible, or to recycle materials and recycle them with energy. It is a situation that a method is required.

One of the environmentally friendly methods described above may be a waste incineration method using a cement kiln.

As mentioned above, incineration of wastes using cement kilns has already been carried out in Europe and America for over 20 years, and in Japan, more than 10 years ago, most cement kilns are currently recognized as waste incineration facilities.

In addition, the treatment of waste using cement kiln is a technology widely recognized internationally in terms of treatment efficiency and environmental stability.

In particular, the US EPA has notified the stability of waste disposal with cement kilns and has been proven by several test results.

Wastes processed using cement kilns in the cement manufacturing field include industrial wastes such as steel mill slag and fly ash of power plants.

Moreover, in some developed countries, not only hazardous substances such as waste oil, waste organic solvents, waste synthetic resins, freon gas, etc., but also domestic waste such as sewage sludge and municipal waste are processed in cement plants.

When the wastes are treated in the cement kiln, the organic matter in the waste is completely decomposed and the harmful substances are fixed. Due to the nature of the cement process, waste disposal and recycling in the cement industry reduces social demands and costs to safely and economically treat wastes. The situation is steadily increasing due to the necessity of cement industry.

However, a technique for treating waste automobile shredder dust in the cement manufacturing process which has been continuously increasing has not been proposed.

Therefore, the present inventors have conducted research and experiment on the method of recycling shredder dust, and proposed the present invention based on the result, and the present invention is more environmentally friendly by treating waste automobile shredder dust in the cement manufacturing process. It is to provide a method for treating waste vehicle shredder dust that can not only process the waste automobile shredder dust, but also bring about an alternative effect of the fuel added in the manufacture of cement clinker.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.

The present invention is a method for producing a cement clinker by charging the cement raw material and fuel in the cement kiln, waste car shredder dust treatment in the cement manufacturing process of adding the waste car shredder dust to the cement raw material 10% by weight or less based on the fuel weight It is about a method.

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

In general, the raw materials of cement are limestone, clay, iron ore, and siliceous materials. The raw materials of cement are well mixed and finely pulverized in a mill and treated at 1,450 ° C in a kiln, and the limestone components of the raw materials are silica, alumina, and iron. Combine to form clinker minerals, which harden when reacted with water.

Normally, the maximum flame temperature inside the cement kiln is about 2,000 ° C., and the gas residence time at about 1,000 ° C. or more is about 5 seconds or more, so the cement kiln is suitable for completely detoxifying waste.

In view of the above, the present inventors can not only treat wastes but also use shredder dust as auxiliary fuel if the shredder dust is technically treated within a range that does not affect the quality of cement manufacturing process and cement clinker. It is thought that the hazardous components can be solubilized in minerals during the cement firing process to efficiently treat shredder dust, and the present invention has been completed by conducting studies and experiments.

In order to treat the shredder dust in the cement process according to the invention it is important not to adversely affect the cement manufacturing process and cement clinker quality.

Thus, the inventors conducted research and experiments on the physical, chemical and thermal properties of automobile shredder dust.

First, the process of generating shredder dust is as follows.

When the compressed waste vehicle is loaded on a truck and received at the waste vehicle treatment plant, the waste vehicle is introduced through the waste vehicle crusher inlet.

The used waste cars are put into the shredder through the belt conveyor, and then crushed, and then the fine and light rubber and plastic materials are separated through the cyclone (Fluff line), and the iron raw material in the crushed material is a magnetic separator. It is separated (ferrous line) through, and the remaining non-ferrous material and coarse material that is not separated from the cyclone are separated (non-ferrous line) separately.

Dust generated in the rough lines and the egg-ferous line becomes the cart dust of the junk car.

The experiments and the results of the physical, chemical and thermal characteristics of the used shredder dust are as follows.

1) Physical composition ratio

As a result of measuring the physical composition ratio of the various samples taken from the rough line and the egg-ferroose line, the main components consist of seven kinds of sponge, plastic, rubber, cloth, wire, wood + paper, and dust. Could confirm.

Representative examples of the shredder dust are plastics: 32-36%, sponges: 19-22%, patches: 9-12%, irons: 5-7%, rubbers: 2-8%, papers: 1-2 %, And dust: 22-23%.

In addition, as a result of examining the particle size ratio of one example of shredder dust generated from the rough line, more than 16mm: 56-62%, 16-4.75mm: 12-18%, 4.75-2.8mm: 5-8%, 2.8mm Below: 14-19%.

2) Calorific Value and Elemental Analysis

As a result of measuring the calorific value by using Leco's AC-300 thermal calorific value analyzer by physical composition and particle size, the shredder dust sample collected from the proline was 4,000kcal / kg or more except the fine dust in shredder dust. The calorific value was high, and the plastics, rubbers and cloths showed very high calorific value almost equivalent to the calorific value of bituminous coal of 6,500 kcal / kg.

In particular, in the calorific value of each particle size, especially when having a particle size of 16-4.75mm, it was very high as about 6,500kcal / kg, and when it is 2.8mm or less appeared about 2,000kcal / kg.

3) Calculation of theoretical combustion air volume and combustion gas volume

Shredder dust has less theoretical combustion air than bituminous coal and waste tires, and the theoretical combustion gas per unit calorific value is equivalent to burning bituminous coal and waste tires.

4) Cl content analysis

Among the main components of automobile shredder dust, Cl content in plastics and wood / paper is relatively less than 1,000ppm, but Cl content in rubbers and wire irons is more than 10,000ppm.

On the other hand, the Cl content in the waste tire and bituminous coal is about 450-950 ppm and 60-250 ppm, respectively.

In addition, the difference in the Cl content according to the difference between the different tools.

5) Combustibility Measurement

Combustibility was measured using DT-TGA.

The experimental conditions were measured using the temperature rise rate of 10 ℃ / min, air atmosphere, α-alumina as a standard material, the reaction start temperature, the maximum exothermic peak and the reaction end temperature of the sample obtained.

As a result of measuring the combustibility, the reaction start temperature, the maximum exothermic peak temperature, and the end temperature of the shredder dust were relatively low in comparison with the used tires and bituminous coal, indicating that the reaction characteristics were good.

Particularly, when the particle size was 4.75-2.8mm, the reaction start temperature, the maximum exothermic peak temperature, and the reaction end temperature of the shredder dust were the lowest.

6) Ash analysis

Since the ash generated during the combustion becomes part of the reaction with the raw materials during the clinker firing process, the ash acts like a raw material and a considerable amount of ash can deposit on the reacting raw material and the surface of the clinker in the kiln. However, the ash properties affect the clinkering reaction and the quality.

Shredder dust has a relatively high ash content compared to bituminous coal and waste tires, especially a fine dust and a ash content in fine samples of 2.8 mm or less.

The ash mainly contains SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ , CaO and MgO, and contains a small amount of Na ₂ O and K ₂ O.

In particular, in the ash component, the Fe ₂ O ₃ content is high, Na ₂ O content appeared to have a bad effect on the cement process and quality in the fine dust, because the glass was crushed and crushed during the car crushing process I think.

7) Heavy metals and trace components

Heavy metals and trace components were analyzed using ICP and AA.

According to the analysis results, it was found that the content of Cu and Zn in the shredder dust is very high compared to bituminous coal.

In general, some of the heavy metals and trace components are known to volatilize in the cement manufacturing process and affect the quality.

Therefore, in order to apply shredder dust to the cement process in earnest, it is necessary to grasp the effects of heavy metals and trace elements in the shredder dust ash and to pre-separate heavy metals if necessary.

8) Melting Point

The melting point of the shredder dust ash was measured using a high temperature microscope at a heating rate of 5 ° C / min above 600 ° C. The melting point of the shredder dust ash was similar to that of the waste tire ash and was lower than that of the bituminous coal ash.

Therefore, when the shredder dust is applied to the cement process, the impact on the clinker reaction due to the difference in melting point between the ash and the existing R / Mix is expected to be small.

Factors affecting the kiln process include Cl in the shredder dust, the alkali component content, the amount of the shredder dust, the combustibility of the shredder dust, etc., and the factors influencing the quality of the cement clinker are Cl, The content of an alkaline component, the baking conditions of shredder dust, etc. are mentioned.

As described above, since the reaction start temperature, the maximum heat generation peak temperature, and the reaction end temperature of the shredder dust are relatively low compared to waste tires and bituminous coal, there is no particular problem in combustibility when the shredder dust is treated in a kiln.

However, the content of Cl and alkali components in the shredder dust affects the treatment of the Schulder dust in the kiln as follows.

Cl, Na, K, S and some heavy metal compounds volatilize under high temperature atmosphere in the kiln while the waste is combusted in the rotary cementen kiln.

In other words, the circulating materials supplied from the cement raw materials, fuel and waste are volatilized at the hot part of the kiln and then moved along the gas stream to condense at the kiln inlet and the cold part of the preheating chamber.

The condensed purified materials are mixed with the raw materials entering the kiln through the preheating chamber, and reintroduced into the hot part of the kiln, or partially accumulated and volatilized, causing one circulation phenomenon. This circulation phenomenon affects the quality of the cement process and the production clinker. It will adversely affect.

Therefore, in the present invention, it is preferable that the waste materials contain as few as possible heavy metals and cement dropping properties such as Cl and alkali.

In particular, the Cl content of the plastics and wood / paper among the major components constituting the automobile shredder dust is relatively less than 1000ppm, but the Cl content of rubber and wire iron is very high, 10,000ppm or more in the kiln furnace Before treating the shredder dust, it is preferable to perform pretreatment of the shredder dust which can lower the Cl content, such as lowering the content ratio of rubber and wire iron.

If more than an appropriate amount of shredder dust is injected into the kiln inlet, the kiln rear end temperature rise and CO generation may impair the operation of the kiln.

Therefore, in view of the above point, in the present invention, it is preferable to limit the addition amount of the shredder dust to 10% or less with respect to the weight of the fuel injected with the cement raw material.

More preferably, it is limited to 3-7% by weight.

When the amount of the shredder dust is added, the amount of Cl and alkali components increases, which adversely affects the manufacturing process and the quality of the cement clinker during the manufacture of cement clink in the kiln. It is desirable to limit the content to 10% or less.

When treating shredder dust according to the present invention, it is desirable to bypass the gas in the kiln at a constant rate in order to reduce the effects of Cl and alkali components.

In the present invention, the preferred bypass ratio is 5% or less.

When the Cl content in the shredder dust is 2400-7200 ppm, and the addition amount of the shredder dust is 3-7% by weight based on the weight of the fuel, the bypass ratio is preferably 1-3%.

Shredder dust which can be preferably applied to the present invention includes plastics: 32-36%, sponges: 19-22%, cloth: 9-12%, iron: 5-7%, rubber: 2-8%, Papers include 1-2% and dust: 22-23%.

Meanwhile, as described above, the melting point of the shredder dust ash is similar to that of the waste tire ash and is lower than that of the bituminous coal ash, and thus, when the shredder dust is applied to the cement process, the clinking reaction is caused by the difference in melting point between the ash and the existing R / Mix. The impact is expected to be small.

The shredder dust which can be applied more preferably to this invention is comprised as mentioned above, The shredder dust whose particle size is 2.8 mm or more is mentioned.

Hereinafter, the present invention will be described in more detail with reference to Examples.

(Example)

The shredder dust having a physical composition ratio as shown in Table 1 and having a particle size distribution as shown in Table 2 was treated with 5 wt% of the fuel weight in a kiln as shown in Table 3 in the manufacture of cement clinker, and according to the use of shredder dust. The circulating material and heavy metal content in the clinker was measured, and the results are shown in Table 4 below.

The Cl content in the shredder dust shown in Table 1 is about 7,888 ppm.

division Fluff line (fine) I'm a nonferrous line (coarse) plastic Sponges Cloth Wire, iron Rubber Tree paper Dust Rubber plastic Wire, iron 1st acquisition 36 22 9 7 2 One 23 43 36 21 Second acquisition 32 19 12 5 8 2 22 - - - Average 34.0 20.5 10.5 6.0 5.0 1.5 22.5 43.0 36.0 21.0

division 16 mm or more 16-4.75mm 4.75-2.8mm 2.8mm or less 1st acquisition 68 12 5 15 2nd acquisition 56 18 7 19 3rd acquisition 62 16 8 14 Average 62 15.3 6.7 16

division Kiln Type Clinker Production (Ton / D) Bituminous coal usage (Ton / Y) Fuel replacement rate (%) Kiln number 1 NMFC 7,600 260,040 4.1 6 kilns P-AS 5,200 171,600 6.1 7 kilns P-AT 4,500 150,151 7.0 4 kilns SP 2,000 74,250 14.2 5 kilns NMFC 42,000 149,160 7.1

(Circulating matter and heavy metal content in clinker by using shredder dust) Circulating material (%) Heavy metals (ppm) K ₂ O Na ₂ O Cl Cr Zn Cu Fixtures 1 Present conditions 0.58 0.19 131 410 189 195 Kiln number 1 0.58 0.21 217 398 592 923 6 kilns 0.59 0.22 260 391 793 1285 7 kilns 0.59 0.23 279 389 878 1439 Fixtures 2 Present conditions 1.40 0.20 78 180 141 120 4 kilns 1.45 0.38 372 146 1534 2,619 5 kilns 1.42 0.29 227 166 844 1,379

As shown in Table 4, according to the use of the shredder dust, the content of the alkali component such as K ₂ ONa ₂ O in the clinker did not change significantly, but it can be seen that the content of Cl component increases. This is because the Cl content in the blended raw materials without the shredder dust is 100-200ppm, whereas the Cl content in the shredder dust is 7,800ppm, and the Cl content is excessive. It can be seen.

Meanwhile, except for the conditions of Table 5 and the bypass conditions of Table 6, the shredder dust is treated under the same conditions as described above, and the behavior of the circulating material according to the bypass rate is measured, and the results are shown in Table 6 below. Indicated.

Kiln capacity Heat source unit (kcal / kg Kiln Exit Flux (Nm ³ / Kgcli) 6 kilns 5,200 t / d 730 0.4 5 kilns 4,200 t / d

6 kilns 5 kilns Kiln entrance Clinker K-1 stage Clinker Present conditions 10,885 102 3,427 95 Use of Shredder Dust 19,169 176 7,697 209 By-pass (%) One 11,259 105 5,903 161 2 7,957 76 4,779 131 3 6,144 60 4,010 111 4 4,999 49 3,450 96 5 4,209 42 3,024 84

As shown in Table 6 above, when the by-pass circulating material behavior of each kiln is estimated, when the shredder dust throughput is 24,900 tons per year, in the case of 6 kilns, the concentration at the kiln inlet is not present using the shredder dust. It is expected that as much as 2% bypass will be required to maintain the level.

As described above, the present invention can properly treat the automobile shredder dust, which is a waste, without affecting the manufacturing process and the clinker quality. It has the effect of providing a method for treating automobile shredder dust, which can also bring replacement effects.

Claims (9)

A method of manufacturing a cement clinker by charging a cement raw material and fuel together with a cement kiln, wherein waste automobile shredder dust is added to the cement raw material by 3 to 7% by weight based on the weight of the fuel and the bypass ratio of the gas of the kiln is 1 Waste car shredder dust treatment method in the cement manufacturing process, characterized in that ~ 3% delete delete delete The method of claim 1, wherein the Cl content in the shredder dust is 2400-7200 ppm. The shredder dust according to claim 1 or 5, wherein the shredder dust is plastic: 32-36%, sponges: 19-22%, cloth: 9-12%, iron: 5-7%, rubber: 2-8%. Waste paper shredder dust treatment method in the cement manufacturing process, characterized in that comprises, paper: 1-2%, and dust: 22-23% The particle size of the shredder dust is 16mm or more: 56-62%, 16-4.75mm: 12-18%, 4.75-2.8mm: 2-5%, 2.8mm or less: 14-19% Waste shredder dust treatment in cement manufacturing process delete delete