JPH0361729B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a method for producing charcoal powder briquettes. [Prior Art] Currently, charcoal powder is generated as an unsieved powder after sifting the charcoal at the place where it is used, or during the transportation process, but most of it is discarded and not used effectively. Generally, it is said that 15 to 20% of the fine powder is generated during the transportation process, and about 3% at the destination after transportation, and most of it, except for a small portion, is discarded. In addition, the water content in charcoal is about 4% when taken out of the pot, but it usually reaches a maximum of 7 to 9% because it absorbs moisture during transportation and storage.
It can reach up to 30%. If the moisture content is less than 15%, it can be used in a steelmaking blast furnace with little effect and can be used as is, but if it exceeds that, the rate of steam generation will be faster than the rate of release of evaporated moisture, and the charcoal will become powder in the furnace. This causes the furnace to malfunction. Therefore, moisture management is important, but moisture absorption is an unavoidable problem because the products are transported and stored in an open state as much as possible to prevent dust explosions. Regarding the production of briquettes from fine charcoal powder, in the past, when charcoal was used as fuel at home, the charcoal powder was ground, then a binder such as glue or molasses liquid was added to form briquettes by hand, and then air-dried. It was hardened and used as a heating charcoal block (tadong). However, productivity was low and it could not be used for industrial purposes. On the other hand, as a heating fuel, anthracite is used as the main raw material instead of charcoal powder, and clay, bentonite, glue, molasses liquid, pulp waste liquid, etc. are mixed as a binder, and the mixture is molded with a roll press molding machine. Anamei briquettes are known. In this case, the raw material is coal-based, has low water absorption,
Since it has a higher specific gravity than charcoal and is not fibrous like charcoal, it has a dense structure that allows it to be molded. However, when charcoal powder is treated using the method described above, it has a moisture content of up to 30% and is soft. Medium pitch, asphalt-based, and bituminous binders for coal briquettes have poor spreadability to coat each charcoal particle, and since they absorb a lot of water, the surface has poor moisture retention and is difficult to mold. It has poor properties, breaks down under strong pressure, and is difficult to make into briquettes. Therefore, it is necessary to break the texture of the charcoal by grinding it with the rolls of a fret mill. The following steps are required to make charcoal powder into briquettes. Namely, (1) a powerful mechanical crushing process to destroy the rough structure of the charcoal; (2) a process of mixing and spreading caking agents with different specific gravity and properties evenly on the surface of the charcoal particles; and (3) the caking used. Heating process required depending on the agent (4) Adding or removing water depending on the binder used (5) Powerful compression molding process (6) Improving the hardness of the finished product and adjusting moisture The above six steps are essential Therefore, it was not possible to briquette charcoal powder using conventional anthracite briquetting equipment. Next, in order to thinly spread the binder on the surface of the fine charcoal particles, the surface needs to be moist as described above, but in the case of charcoal that does not have water absorption, the weight ratio is 5 to 6%.
However, in the case of charcoal, economic expansion of the binder cannot be expected unless it is absorbed into the interior and maintains the necessary moisture on the surface. This adjustment cannot be made using the coal briquetting method. [Object of the Invention] The present invention produces charcoal that can be used in charcoal blast furnaces and electric furnaces by turning fine charcoal powder, which has conventionally been discarded and unused, into briquettes of an appropriate size and keeping the moisture content at 15%. To provide a method for manufacturing powder briquettes. [Summary of the invention] In order to achieve the above object, the present invention
``Mixing device with high-speed stirring blades'' (hereinafter referred to as KB mixer) of ``Method for producing strong briquette coal for coke and apparatus used therein'' disclosed in No. 980334
By using the above-mentioned (1) to simplify the process necessary to produce briquettes from conventional charcoal powder as much as possible,
(4) Processing is performed in one step, compression molding and moisture adjustment. That is, the gist of the present invention is to use charcoal powder alone or a mixture of charcoal powder and iron ore powder as a raw material, and in the process of manufacturing briquettes by adding a binder to the raw material, the raw material is pulverized using a mixer having high-speed stirring blades. A method for producing charcoal powder briquettes is characterized in that a series of steps of adding a binder, mixing, and heat treatment are performed in one step, followed by compression molding and moisture adjustment. [Structure of the Invention] Next, the present invention will be explained based on the process chart of the present invention shown in FIG. Subsieved powder or extremely fine powder, usually 10 mm or less in size, is charged in bulk into the raw material supply hopper 1, and then introduced into the high-speed stirring KB mixer 2, where the charcoal is pulverized by the upper and lower blades rotating at high speed. At this time, since the particle size to be finely pulverized differs depending on the charcoal substance, this rotational speed can be arbitrarily changed by the transmission 4. A residence time of 2 to 5 minutes in the high-speed stirring KB mixer 2 is sufficient. Next, the necessary binders include carboxy methylcellulose CMC, polyvinyl alcohol and other synthetic resins, starch, lignin, inorganic bentonite, cement, water glass, pitch,
A single binder or a mixed binder of 2 to 4 of tar, firefly, etc. is supplied from the hopper 5. If water is required, it is simultaneously added from the water tank 6 into the high-speed stirring KB mixer 2. Depending on the charcoal particle structure and characteristics, the above (1), the crushing process (2), and the mixing and spreading process with a caking agent
(3) The heating process can also be performed simultaneously. On the other hand, when the water absorption rate of charcoal is high, heat is supplied from the heat source supply device (steam, thermal oil, waste heat, etc.) 8 to the outer cylinder 7 of the high-speed stirring KB mixer 2, and moisture is released from the exhaust pipe 9 by indirect heating. . According to the method of the present invention, water content can be easily adjusted by adding water in the same high-speed stirring KB mixer 2 at the same time as the grinding process. Further, excess moisture after spreading the binder becomes an obstacle during molding, so after sufficient spreading, the moisture is discharged by heat from the outer cylinder 7 of the high-speed stirring KB mixer 2. Of course, the amount of moisture is related to the characteristics of the binder used, so it is necessary to measure the moisture content of the charcoal and the moisture required by the binder in advance. This moisture adjustment is also carried out in the same container with high-speed stirring (260 r/m) by the KB mixer 2, so that the effective heat transfer area can be widened and carried out effectively. Next, the processed raw material discharged from the lower part is temporarily stored in a hopper 10 and charged into a compression molding machine 10, a roll molding machine 11, or a desk molding machine 12. As shown in FIG. 2, the roll forming machine 11 includes:
Drainage groove 13 that makes it easy to remove excess moisture released during compression
As shown in FIG. 3, the desk type molding machine 12 is provided with a dewatering groove 14 around the mold circumference. Both have good compression efficiency. The compression molded briquettes are passed through a hot air drying oven 15 to adjust the moisture and hardness of the finished product, depending on the properties of the binder used at that time. Hot air drying oven 15
After passing through, the product is temporarily stored in a hopper 16 or directly charged into a charcoal blast furnace 17. An electric furnace may be used instead of a charcoal blast furnace. [Embodiments of the Invention] Next, embodiments of the present invention will be described. Example 1 Raw charcoal was made using domestic soft oak charcoal as the reference charcoal.
Briquettes A were prepared by molding standard charcoal and raw charcoal powder under a sieve of 8 mm, and briquettes B were prepared by changing the combination of each binder, based on the above-mentioned process. The formulation and physical properties of the binder are shown in Table 1.

[Table] As shown in Table 1, there is no big difference between briquette AB and the standard charcoal, so it can be charged into the blast furnace, and the moisture content of briquette AB is less compared to the standard, so it is not caused by moisture. The behavior inside the blast furnace is excellent. Example 2 An example will be described in which briquettes were manufactured by simultaneously mixing raw charcoal powder and iron ore fine powder. Briquettes C, D, and E were manufactured using the same process as in Example 1 and the formulations shown in Table 2 below, and the physical properties of the results are also shown in Table 2.

【table】

[Table] As shown in Table 2, even if iron ore is mixed with charcoal powder, it can be made into briquettes according to this production method, and the strength of the briquettes is also good because the iron ore powder, which has a heavy specific gravity, is mixed. The best mixing ratio of charcoal powder and iron ore powder is 1:1. It is also possible to replace iron ore powder with lime. A characteristic of charcoal blast furnaces is that the blast furnace cannot be raised due to the weak physical strength of charcoal. On the other hand, charcoal has higher reactivity than coke, so it is said that it is difficult to increase the size of the furnace because there is no need to raise the furnace height. Therefore, the effective internal volume of a normal charcoal blast furnace is 40 to 300
The charcoal powder briquette according to the ^present invention can be used satisfactorily since the production amount is about 50 to 500 T/D.
However, if hot crushing of the briquettes is still required depending on the volume of the blast furnace used, the binder may be a thermoplastic acrylic resin or a thermosetting binder alone or in combination with other binders. This can be further improved. [Effects of the Invention] As described above, according to the charcoal powder production method of the present invention, charcoal powder can be made into briquettes, which could not be achieved with the conventional coal briquette production process, by using a mixer with high-speed stirring blades and using a binder. This is an extremely effective method that shortens the process and enables easy and economical production by selectively using charcoal powder. It is an invention.

[Brief explanation of drawings]

FIG. 1 is a process diagram showing the manufacturing method of the present invention, FIG. 2 is a schematic diagram showing a dewatering groove of a roll-type molding machine, and FIG. 3 is a schematic diagram of a mold showing a dewatering groove of a desk-type molding machine. In the figure, 1... Charcoal powder hopper, 2... High speed stirring mixer, 3... Stirring blade, 5... Binder hopper,
7...Outer cylinder, 8...Heat source supply device, 9...Exhaust pipe, 10
...Compression molding machine, 11...Roll type molding machine, 12...Desk type molding machine, 13...Draining groove, 14...Dewatering groove, 1
5... Hot air drying oven, 17... Blast furnace or electric furnace.

Claims (1)

[Claims] 1. In the process of manufacturing briquettes using charcoal powder alone or a mixture of charcoal powder and iron ore powder as a raw material and adding a binder to the raw material, a mixer with high-speed stirring blades is used to crush the raw material and remove the binder. addition, mixing,
A method for producing charcoal powder briquettes characterized by performing a series of heat treatment steps in one step, followed by compression molding and moisture adjustment.