JP6201973B2 - Manufacturing method of heat-up material for converter - Google Patents

Description

  The present invention relates to a heating material for a converter using a plastic as a raw material for heating molten iron accommodated in the converter.

From the viewpoint of preventing global warming, reducing CO ₂ emissions has become a recent issue. In converters in the steelmaking process in the steel industry, oxygen is blown to molten iron with a high carbon concentration, and decarburization refining is performed by removing carbon in the molten iron as an oxide to produce molten steel. Typical iron sources for molten iron include hot metal and scrap. Since scrap is an iron source manufactured from molten steel that has already undergone decarburization refining, from the viewpoint of reducing the above-mentioned CO ₂ emissions, the amount of scrap out of the iron source that is put into the converter An operation directed to increasing the amount of hot metal and decreasing the amount of hot metal is desired.

  Since the melting of scrap is promoted when the temperature of the molten iron is high, the temperature of the molten iron is better. However, from the viewpoint of material properties required for steel products manufactured from molten steel, prior to charging molten iron into the converter, molten iron preliminary treatment for removing sulfur, phosphorus, etc. in the molten iron is appropriately performed, and the molten iron The temperature of the hot metal is lowered by the pretreatment. Furthermore, the scrap is basically cold iron, and the more the scrap is added to the hot metal, the lower the temperature of the molten iron.

Therefore, conventionally, when decarburizing and refining, it is necessary to heat up the molten iron by putting a heat-up material into the molten iron housed in the converter, which is necessary for refining in the steelmaking process. Heat was supplied by coal. As a method for reducing CO ₂ emissions, it is known to replace conventional coal or the like with a carbon neutral carbon source, and it is known to use biomass as a carbon neutral carbon source. Patent Document 1 proposes a converter heating material using plant-based biomass as a main raw material, and adding a binder and moisture to a carbide obtained by carbonizing plant-based biomass and forming a molded converter heating material. Have been described.

International Publication No. 2013/128786

By substituting the converter heating material of fossil resources such as coal with the converter heating material of Patent Document 1, it becomes possible to reduce CO ₂ emissions. However, in Patent Document 1, starch or corn starch or the like is used as a binder, and a heating material for a converter is manufactured by molding a carbide and a binder. When manufacturing a heating material for a converter, Moisture is required, and a process for heating the molded product after molding (a process for drying the moisture) and equipment are required. Therefore, the cost, that is, the energy for producing the converter heating material is increased, and the amount of energy for manufacturing the converter heating material is larger than the unit mass of the converter heating material. There is also the problem of hanging.

  The present invention has been made in view of the above problems, and the object of the present invention is to produce moisture when producing a converter heat-up material even if plant-based biomass is used as the converter heat-up material. Heating materials for converters that can be manufactured at a lower cost, can be manufactured at a lower cost, and can be manufactured with a lower energy consumption per unit mass than in the past. It is to be.

The gist of the present invention for solving the above problems is as follows.
(1) A heating material for a converter that heats molten iron accommodated in a converter, comprising a plastic and a carbide obtained by carbonizing plant biomass, the plastic and the carbide A heat-generating material for a converter, wherein the mixture is molded with an extrusion molding machine, and the ratio of the carbide in the mixture is 75% by mass or less.
(2) The heating material for a converter according to (1), wherein the crushing strength is 50 kgf / piece or more.
(3) The plant biomass according to (1) or (2), wherein the plant-based biomass is one or more selected from palm coconut shells, empty fruit bunches, trunks, and pruned waste. Reheating material for furnaces.
(4) The heating material for a converter according to any one of (1) to (3), wherein the plastic is waste plastic.

  According to the present invention, even if a carbide obtained by carbonizing plant biomass is used as the converter heat-up material, the ratio of the carbide in the mixture containing plastic and the carbide is 75. By manufacturing the heat-generating material for converters by extruding the mixture at a mass% or less, drying and post-molding processes and equipment are not required. Become. Therefore, in the present invention, the amount of energy required for producing the converter heat-up material can be significantly reduced as compared with the conventional case with respect to the unit mass of the converter heat-up material.

In addition, by mixing and molding carbide and plastic, handling is improved as a converter heat-up material, and cracking of the converter heat-up material is prevented even if it is put into a hopper installed on the converter. . Furthermore, the use of carbides obtained by carbonizing plant neutral biomass with low sulfur content, especially carbon neutrals, as a heat-generating material prevents the sulfur content in molten iron from increasing, and CO ₂ emissions derived from fossil fuels. The amount can also be reduced.

It is a figure which shows an example of the carbonization equipment of plant biomass. It is a figure which shows an example of an extrusion molding machine. It is a graph which shows the relationship between the carbide | carbonized_material ratio [mass%] and crushing strength [kgf / piece] about the molding manufactured in the Example.

  The present invention uses a carbide obtained by carbonizing plant biomass as a main raw material of a heating material that heats molten iron accommodated in a converter, and molds the carbide with plastic. . Hereinafter, an example of an embodiment of the present invention will be described.

  Plant-based biomass refers to any biomass that is pyrolyzed to produce carbides, such as agricultural, forestry, and waste systems. Examples of plant biomass that can be collected in Japan include timber waste generated by demolishing houses, wood-based waste generated by sawmills, pruning waste in forests, and agricultural waste. However, in Japan, there are many sources of timber waste generated by demolishing houses and wood-based waste generated by sawmills, and there are many collection routes that have been established. As demand continues to grow beyond supply, the amount available as an energy source is constrained. In addition, pruning waste, agricultural waste, etc. in forests, etc. are widely distributed in the country, and it is difficult to use as an energy source because of the cost of carrying out and collecting. .

  Particularly suitable as woody biomass is biomass derived from palm palm, which is produced in the process of producing crude palm oil from palm palm (oil palm) cultivated in plantations in both Malaysia and Indonesia. In particular, as palm-derived biomass, one or more selected from palm coconut shells (also referred to as “PKS” as appropriate), empty fruit bunches (also referred to as “EFB” as appropriate), trunks, and pruning wastes are used. It is preferable.

  As described above, it is not easy to use plant biomass as an energy source in Japan. On the other hand, palm oil is produced around 36 million tons annually worldwide, and about 90% of it is produced in Malaysia and Indonesia. Since palm oil is manufactured from palm coconut and is less expensive than soybean oil, it is frequently used for industrial applications such as detergents as well as edible oils. The palm fruit from which the palm oil is collected turns into an aggregate of massive fibers called Bunch. Palm fruit is squeezed to obtain crude palm oil. At that time, PKS which is a shell of palm fruit is by-produced in a crushed state. Further, the Bunch after the palm fruit is collected is an empty fruit bunch (EFB).

  Trunk and pruning waste are produced in the process of growing palm palm, and palm palm PKS and EFB are produced in the process of producing crude palm oil. In particular, EFB has a high alkali content, especially potassium K, and when used as fuel, the alkali rate in ash is high, the ash melting point is low, and ash adheres to furnace walls of combustion facilities. The amount tends to increase. If the amount of ash attached to the furnace wall or the like is large, the ash grows into a lump called a clinker on the furnace wall or the like, which may cause trouble that requires manual grinding. Therefore, palm palm EFB is not generally used as fuel, and in most cases, it is left in the vicinity of palm oil factories to promote global warming due to the generation of greenhouse gases such as methane gas due to corrosion. There are concerns. Previously, palm palm PKS, EFB, trunk, and pruning waste have not been developed for use as industrial raw materials, and have been discarded or left as they are.

  These palm palm PKS (coconut husk), EFB (empty fruit bunch), stem, pruning waste are inexpensive raw materials that do not require collection costs, and these are used for plant biomass in the present invention. It is possible to produce an inexpensive carbide. Moreover, EFB of palm palm can be reduced to 1 mass% or less by washing with water after carbonization, and can be used without any problem as a raw material for a heating material for converters used in steelworks. Become. If carbides obtained from these are used in place of fossil resources used as converter heating materials, fossil resource consumption will be reduced, greenhouse gas emissions will be reduced, and global warming problems will be solved. Can contribute. Note that palm palm PKS (coconut husk), EFB (empty fruit bunch), trunk, and pruning waste have low sulfur content, so even if they are used as converter heating materials, the concentration of sulfur in the molten iron in the converter Can suppress the rise.

  Furthermore, by using palm palm PKS (palm shell), EFB (empty fruit bunch), trunk, and pruning waste as plant-based biomass in the present invention, improvement in profitability of the palm oil industry, Through environmental improvements, it can also contribute to the development of palm oil industry countries centering on Malaysia and Indonesia.

  A method for carbonizing the above plant biomass will be described. In Malaysia, a hole is formed by digging the ground, and PKS is charged into the hole as plant biomass, and PKS is carbonized in a state where the supply of oxygen is restricted by limiting the flow of air. Yes. However, it is desirable to carbonize plant biomass using a carbonization device. Carbonizers include rotary kiln furnaces (externally heated rotary kiln furnaces that obtain the heat necessary for carbonization from the outside, internal heat rotary kiln furnaces that obtain the heat required for carbonization by burning part of the raw materials), batch furnaces, A shaft-type furnace or the like can be used.

  FIG. 1 shows a case where plant biomass is carbonized in an externally heated rotary kiln furnace 11. The carbonization facility 10 includes an externally heated rotary kiln furnace 11, a combustion furnace 12 that supplies high-temperature gas to the externally heated rotary kiln furnace 11, a carbide storage tank 13 that stores carbide from the externally heated rotary kiln furnace 11, A tar recovery tank 14 for recovering gas generated in the thermal rotary kiln furnace 11 and recovering tar from the gas. The recovered gas may be supplied again to the externally heated rotary kiln furnace 11.

  In the carbonization facility 10, first, plant biomass 1 is input into the external heating rotary kiln furnace 11 while the heat of the high temperature gas is supplied from the combustion furnace 12 to the external heating rotary kiln furnace 11 and the supply of oxygen is restricted. Is done. While the plant biomass 1 is passing through the externally heated rotary kiln furnace 11, carbonization 2 is generated by dry distillation (carbonization). The carbide 2 is discharged from the externally heated rotary kiln furnace 11 and stored in the carbide storage tank 13. The tar generated when the biomass raw material 1 is carbonized in the external heating type rotary kiln furnace 11 is recovered in the tar recovery tank 14.

  When the carbide 2 contains a particle having a particle size exceeding a predetermined value, for example, 3 mm (for example, the particle size is distributed in the range of about 1 mm to about 10 mm), Only those having a particle size of 3 mm or less may be selected using a 3 mm screen sieve. When extrusion molding is used for the next process, it is desirable to crush the carbide 2 to such an extent that it can pass through a nozzle provided on a die described later.

  Next, an example of an extrusion molding machine is shown in FIG. The extrusion molding machine 21 includes an extrusion molding machine main body 22, a heater (not shown) arranged around the extrusion molding machine main body 22, a die 23, and a cutter 24. A supply port 22 a is provided at the top of one end of the extruder main body 22, and a die 23 is provided at the other end of the extruder main body 22. The die 23 is provided with a plurality of nozzles 23a. A cutter 24 having a rotary blade 24a is installed on the front surface of the nozzle 23a.

  A mixture containing the carbide 2 and the plastic 3 is extruded, and the plastic 3 is preferably a waste plastic. In recent years, the amount of plastic discarded has increased, and it has become difficult to secure a landfill site for the waste every year, and the development of an effective utilization method of waste plastic that does not adversely affect the environment is desired. The use of waste plastic as a heating material for converters contributes to the effective use of waste plastic.

  The plastic 3 is put into the extruder main body 22 where it is melted and stirred, but it is desirable that the plastic 3 be crushed so that it can be put into the extruder main body 22. First, the plastic 3 and the carbide 2 are put into the supply port 22a, and the mixture containing the carbide 2 and the plastic 3 is heated and melted by a heater with a screw built in the extruder main body 22. Knead. Next, the mixture passes through the nozzle 23 a of the die 23, and the molded product formed into a rod shape is cut by the rotating blades 24 a of the opposing cutter 24, thereby producing a cylindrical molded product (converter heating material) 4. To do.

  The ratio of carbide 2 in the mixture is 75% by mass or less. When the carbide 2 is 75% by mass at the maximum with respect to the mixture, the molded product 4 having a high crushing strength, which will be described later, can be stably produced by extrusion molding. However, if the mass ratio of the carbide 2 in the mixture exceeds 75% by mass, the carbide 2 itself is difficult to melt at least as compared with the plastic 3, and it becomes difficult to stably manufacture the molded product 4. Also, there is a possibility that the strength (crushing strength described later) of the molded product 4 is lowered by the extrusion molding. In addition, although it is not impossible to shape | mold a mixture with the roll type | mold molding machine as described in patent document 1, since the mixture contains the plastic 3, the intensity | strength of the molding 4 will become low, and a converter As a heat-generating material for use, handling properties are significantly reduced.

It is more preferable to add 50% by mass or more of the carbide 2 to the mixture. As the mass ratio of the carbide 2 is increased, the amount of CO ₂ emission derived from fossil fuel is reduced. Therefore, from the viewpoint of further reducing the CO ₂ emission amount derived from fossil fuel, it is preferable that 50% by mass or more, which can be said to be the main raw material in the mixture, be the carbide 2.

  The molded product 4 preferably has a sulfur content of 0.1% by mass or less. Even if waste plastic is used as the plastic 3, the plastic 3 hardly contains sulfur. On the other hand, the carbide 2 may contain a sulfur content. Palm palm husks, empty fruit bunches, trunks, and pruning scraps are originally low in sulfur content. Therefore, any one of them is used as a raw material for the carbide 2 and the sulfur content in the molded product 4 is reduced to 0. 0. It can be suppressed to 1% by mass or less. If necessary, component analysis of the carbide 2 may be performed, and the proportion of the carbide 2 in the mixture may be adjusted according to the sulfur content of the analysis result.

  The crushing strength of the molded product (converter heating material) 4 is preferably 50 kgf / piece or more. . If the crushing strength of the molded product 4 is 50 kgf / piece or more, handling in an actual operation such as storage or dropping in a hopper arranged on the converter is facilitated, and the molded product 4 is raised in the converter. When used as a heat material, the molded product 4 is broken and scattered, and the amount that is not effectively used as a heat-up material can be suppressed. Although the molded product 4 can be manufactured by a roll molding method, as described above, it is easy to manufacture a product having high crushing strength by extrusion molding. Here, “kgf” means a unit of force, and 1 kgf is 9.8 N.

The crushing strength measurement conditions are as follows.
(I) A cutter installed oppositely so that the molded product is cut by the rotary blade 24a when the molded product is extruded from the nozzle 23a by about 50mm using the die 23 having a hole diameter of 30mm in the nozzle 23a. 24, the rotational speed of the rotary blade 24a is appropriately adjusted to produce a plurality of cylindrical molded products (converter heating materials) 4 having a diameter of 30 mm and a constant length.
(II) After the molded product 4 is cooled in the atmosphere and sufficiently cooled to the environmental temperature, the length of the plurality of molded products 4 is unified to 15 mm, and a load is gradually applied in a direction perpendicular to the axis. Record the load (kgf) at which 4 breaks.

  For simplicity, the load in (II) above may be the crushing strength per unit (kgf / piece), but (III) 12 molded products 4 are produced and each molded product 4 is destroyed. The crushing strength (kgf / piece) may be recorded by measuring the load at the time of measurement and recording the average value of 10 measurement values excluding the maximum value and the minimum value of the load.

In addition to the carbide 2 and the plastic 3, the converter heating material may have a desulfurization agent component such as CaO, Na ₂ CO ₃ , CaC ₂ , and Mg. If the heating material for the converter has these, it also functions as a hot metal desulfurization agent.

According to the present invention, even when plant-based biomass is used as the converter heat-up material, the plastic is used as a binder, the ratio of carbide in the mixture containing plastic and carbide is 75% by mass or less, and the mixture is extruded. By producing the heating material for the converter, there is no need for a process and equipment for drying after molding, so that the energy used in the heating material production process is reduced. Therefore, in the present invention, the CO ₂ emission amount in the unit heating amount can be greatly reduced as compared with the prior art.

In addition, by mixing and molding carbide and plastic, handling is improved as a converter heat-up material, and cracking of the converter heat-up material is prevented even if it is put into a hopper installed on the converter. . Furthermore, the use of carbides obtained by carbonizing plant neutral biomass with low sulfur content, especially carbon neutrals, as a heat-generating material prevents the sulfur content in molten iron from increasing, and CO ₂ emissions derived from fossil fuels. The amount can also be reduced.

  Using the extrusion molding machine shown in FIG. 2, the ratio between the carbide 2 and the plastic 3 charged into the extruder main body 22 is changed as appropriate, so that the ratio between the carbide 2 and the plastic 3 is different (converter). Heat-treating material) 4 was produced (Invention Examples 1 to 5). In the inventive examples 1 to 5, the ratio of the carbide 2 in the mixture including the plastic 3 and the carbide 2 was set to 75% by mass or less. As the plastic 3, waste plastic made of polyethylene and polypropylene was used. As the plant biomass 1, palm coconut shell was employed, and as the carbide 2, palm palm coconut carbide was used. Prior to charging into the extruder main body 22, the carbide 2 and the plastic 3 were pulverized to adjust the particle size to 3 mm or less.

  Since polyethylene has a melting point of about 125 ° C. and polypropylene has a melting point of about 165 ° C., the extruder 22 is melted and kneaded by heating with a heater (not shown) set to about 140 ° C. It was. As (I) described in the embodiment, when the die 23 having a nozzle 23a having a hole diameter of 30 mm is used and the molded product is extruded from the nozzle 23a by about 50 mm, the molded product is cut by the rotary blade 24a. A cylindrical molded product 4 having a diameter of 30 mm and a constant length was manufactured by the cutter 24 disposed opposite to the molded product 4, and the molded product 4 having a different ratio between the carbide 2 and the plastic 3 was manufactured.

  In order to compare with Examples 1 to 5 of the present invention, a molded article (converter heating material) 4 was produced in the same manner as the Examples of the present invention except that the ratio of carbide 2 in the mixture exceeded 75% by mass ( Comparative examples 1 and 2). Moreover, the molded object 4 from which the ratio of the carbide | carbonized_material 2 and the plastics 3 differs similarly to the example of this invention except having manufactured not with the extrusion molding machine but with the roll-type molding machine (Comparative Examples 3-5). Furthermore, as a reference example, a molded product made of only plastic 3 was produced in the same manner as in the present invention and the comparative example, except that the carbide 2 was not charged into the extruder main body 22 (reference example).

  In Reference Examples, Invention Examples 1 to 5 and Comparative Examples 1 to 5, the crushing strength (kgf / piece) was measured as described in (III) above. The ratio of the carbide 2 and the plastic 3 and the crushing strength of the molded product 4 in Reference Examples, Invention Examples 1 to 5 and Comparative Examples 1 to 5 are shown in Table 1, and the carbide ratio [% by mass] and crushing strength [kgf / piece] ] Is a graph showing the relationship of

参考例で製造された成型物は、圧潰強度が１１７［ｋｇｆ／個］となり高い。本発明例１〜５で製造された成型物４もまた、圧潰強度が全て５０［ｋｇｆ／個］を上回っており、転炉のホッパーに搬送する際や転炉に投入する際に割れたりすることがなく転炉用昇熱材として正常に機能することが期待される。

The molded product produced in the reference example has a high crushing strength of 117 [kgf / piece]. The molded products 4 produced in Invention Examples 1 to 5 also all have crushing strengths exceeding 50 [kgf / piece], and are cracked when being transported to the converter hopper or when being put into the converter. It is expected to function normally as a heating material for converters.

  In Comparative Examples 1 and 2, the ratio of the carbide 2 was 80% by mass or 90% by mass, exceeding 75% by mass, and the molded product 4 could not be produced continuously. Since the carbide 2 is not melted by heating at about 140 ° C., the carbide 2 exists as a solid in the extruder main body 22, and if the carbide 2 is excessive in the mixture, the carbide 2 is separated between the blades of the screw and the blades. Or sandwiched between the screw shaft and blades and the inner wall of the extruder body 22. Even if the carbide 2 is pulverized because it is inferior in strength to a metal screw or inner wall, the biomass charcoal is compressed in the space between the blade and the blade and between the shaft and the blade and the inner wall. Since it is pushed in and filled, the frictional force increases and the load on the motor that rotates the screw increases. Therefore, a large current exceeding the allowable amount may be supplied to the motor. In such a case, the supply of power is cut off for protection of the motor, and continuous operation becomes impossible.

  In Comparative Example 2, although continuous operation was impossible, a molded product 4 having high crushing strength could be produced by extrusion molding. However, in Comparative Example 1 in which continuous operation was not possible, the molding 4 having a crushing strength close to 50 [kgf / piece] was produced, although the crushing strength exceeded 50 [kgf / piece]. When the ratio of the carbide 2 in the mixture exceeds 75% by mass, the operation for continuously producing the molded product 4 may be impossible. Moreover, since there is too little plastic, the bond strength of the carbide | carbonized_material 2 will become weak, and a thing with low crushing strength may be manufactured.

  In Comparative Examples 3 to 5, the molded product 4 is manufactured by a roll type molding machine. Since the mixture contains the plastic 3, the roll-type molding machine can only produce a heating material for a converter whose strength of the molded product 4 is low and handling properties are significantly reduced.

  From the results of the above examples, the converter heat-up material produced by extruding a mixture containing carbide 2 and plastic 3 having a mass ratio of 75% by mass or less has high crushing strength, and thus has high handling properties. It can be expected that it will not crack even if it is put into a hopper installed on the converter.

  Invention Example 5 in Example 1 is referred to as Invention Example 10. In order to compare with the energy intensity of the converter heating material produced in Invention Example 10, the same carbide 2 as in Invention Example 10 was used, and as described in Example 1 of Patent Document 1, roll molding The converter heat-up material was manufactured by a machine (Comparative Example 10). That is, in Comparative Example 10, 4% by mass of starch (the one that has been pregelatinized) with respect to the mass of the carbide 2 is added to the carbide 2, and further, 14% by mass of water with respect to the mass of the carbide 2 is added. The mixture is stirred and mixed with a mixer, a briquette is molded using a roll-type molding machine, and after molding, dried in a drying furnace at a temperature of 105 ° C. until the water content becomes 1% by mass or less of the briquette mass. A furnace heat-up material was produced.

  In Example 10 of the present invention and Comparative Example 10, the production rate of the molded product 4 was about 5 t / hour, except for the energy required when carbonizing the plant biomass 1 to produce the carbide 2, except for the molded product 4. The energy required to produce 1 ton was evaluated. In Example 10 of the present invention, energy is required to drive the extrusion molding machine 21 and the cutter 24, whereas in Comparative Example 10, energy is required to drive the roll molding machine and operate the drying furnace. Necessary. In Example 10 of the present invention, the basic unit of energy for driving the extrusion molding machine 21 and the cutter 24 was about 100 [MJ / ton]. On the other hand, in Comparative Example 10, the basic unit of energy for driving the roll molding machine is about 180 [MJ / ton], and the basic unit of energy for operating the drying furnace is about 400 [MJ / ton]. When these are added, the result is approximately 580 [MJ / ton].

  From the above results, even if plant-based biomass is used as the converter heat-up material, in the mixture containing plastic and the plastic and carbide, the ratio of carbide is 75% by mass or less, and the mixture is extruded. Thus, it can be seen that when a converter heat-up material is manufactured, there is no need for a drying process or equipment after molding, and the converter heat-up material can be manufactured at a lower cost. Furthermore, since the process and equipment for drying after molding are not required, the energy used in the heating material manufacturing process is reduced, and the amount of energy required for manufacturing is less than the unit mass of the heating material for converters. It becomes possible to manufacture the heat-up material for converters, suppressing it conventionally.

1 Plant-based biomass 2 Carbide 3 Plastic 4 Molded product (heat converter for converter)
DESCRIPTION OF SYMBOLS 10 Carbonization equipment 11 External heating type rotary kiln furnace 12 Combustion furnace 13 Carbide storage tank 14 Tar recovery tank 21 Extrusion machine 22 Extrusion machine body 22a Raw material supply port 23 Dice 23a Nozzle 24 Cutter 24a Rotary blade

Claims (4)

A method for producing a heating material for a converter that heats molten iron contained in the converter,
A mixture comprising a plastic and a carbide obtained by carbonizing plant biomass , wherein a mixture in which the plastic content in the mixture is 25% by mass or more and the carbide content is 75% by mass or less is extruded. A method for producing a heating material for a converter , which does not include a step of extrusion molding with a machine and drying after the extrusion molding . 2. The method for producing a converter heat-up material according to claim 1, wherein a crushing strength of the converter heat-up material is 50 kgf / piece or more. The converter biomass riser according to claim 1 or 2, wherein the plant biomass is one or more selected from palm coconut shells, empty fruit bunches, trunks, and pruned waste. A manufacturing method of a heat material. The said plastic is waste plastic, The manufacturing method of the heating material for converters as described in any one of Claims 1-3 characterized by the above-mentioned.

Images