JPS63196689A - Molding method of coke powder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a technique for molding coke breeze and advantageously using it for fuel, metallurgy, and other purposes.

[Conventional technology]

Foundry lump coke has conventionally been used as a fuel for Kiepora etc. This is because lump coke is used as a fuel, and unless it has good ventilation, fuels with low volatile content such as coke cannot be used. On the other hand, for metallurgical coke such as blast furnace coke, the average particle size is 50
~70m, and at least 35 days or more are used.

When these are sieved, the coke powder collected in the dust catch during dry cooling of coke, and the coke powder collected in the cyclone cannot be used as fuel due to poor ventilation. Uses are limited. Therefore, it can be obtained at low cost.

Conventionally, in order to mold coke powder, binder such as coal tar pitch or petroleum pinch has been used to heat mold the coke powder. This molded briquette has a crushing strength of about 136 mm at room temperature, which is sufficient strength, but when heated, the pitch softens and the strength decreases significantly and it collapses. Furthermore, it generates yellow smoke at 50°C and black smoke at 800°C, which poses a pollution problem. A product made by blending, mixing, molding, and hardening coke powder with Portland cement, an inorganic binder, had a sufficient crushing strength at room temperature of 172 kg (surface load, 7 days of curing), but this also had a high temperature of soo'c. The crushing strength decreased to about 50 kg.

When colloidal silica, vinyl acetate emulsion, water glass, viscosity, etc. were used as the binder, the crushing strength at room temperature was low.

Polyethylene oxide (PEO), an organic thickener
, carboxymethyl cellulose (CMC), lignin sulfonic acid, corn starch, etc., cannot be molded, dried, or
It can be molded by curing and has sufficient strength at room temperature, but since it is an organic material, it burns at high temperatures and its strength decreases.

As an example of these conventional techniques, for example,
Publication No. 2-3403 describes a method of caking coke powder with a pinch of sulfuric acid, etc. According to this method,
Although the resulting molded product has high drop strength, the working environment is deteriorated by gas, sulfuric acid mist, etc. generated during manufacturing, so a means to deal with this is required, making the process complicated.

Furthermore, JP-A No. 60-219291 discloses a technique for making briquettes by using cement as a binder for coke powder and adding fine grained oxide mineral components to the coke powder, but the resulting briquettes are In some cases, the crushing strength is not always sufficient at both room temperature and high temperature.

[Problem that the invention seeks to solve]

Instead of foundry lump coke, which is the fuel for cupolas,
If coke powder, which is considered relatively inexpensive, can be molded and used, costs will be reduced. However, in furnaces such as cupolas, because the molding is done to ensure ventilation, and because the load is on the upper layer, the crushing strength is not only high at room temperature, but also crushing when heated to about 800°C. It is also required to have great strength.

Therefore, the objective is to find a molding method that can be molded at room temperature and has high crushing strength at room temperature and high temperature.

As mentioned above, coal tar pitch, polyethylene oxide, CMC, lignin sulfonic acid which is pulp waste liquid,
When using bintart with cornstarch, etc., even if it can be molded at room temperature, and even if the crushing strength is high at room temperature,
When the temperature rises to about soo'c, the binder burns and the crushing strength decreases. Even when cement is used as the binder alone, the crushing strength at room temperature is about 50 to 70 kg after curing for 14 days. However, even when the temperature is raised to 800°C, the strength is 60 to 70 kg, which is insufficient overall.

It is an object of the present invention to solve such problems.

Means for Solving Problem C] The present invention provides coke powder with bentonite alone or in combination with cement and bentonite as a binder, and with one type selected from polyethylene oxide, carboxymethyl cellulose, lignin sulfonic acid, and corn starch as an additive. Alternatively, it is a method of molding coke powder, which is characterized by mixing two or more kinds of coke and water, kneading, molding, drying, and hardening.

The present invention will be explained in detail below.

First, in the present invention, coke powder is defined as having a particle size of 11 or less in an amount of 80% by weight or more.

In particular, cyclone powder with a particle size of 84% by weight or less of 0.8u diameter or less, 63% by weight or more of 0.5u or less, 29% by weight or more of 0.15m or less, grain 11ffi, 66% by weight or more of 0.8n diameter or less, 0.5fi Dust catcher powder having a diameter of 35% by weight or more and 8% or more by weight of 0.15m or less is suitable.

Next, in the present invention, bentonite alone can be used as a binder together with additives,
By making this bentonite coexist with one or more of the specific additives mentioned above, the cold crushing strength of the molded product after drying is dramatically improved compared to when cement is used alone as a binder. Because it will be excellent.

Further, in the present invention, cement and bentonite can be used together as a binder.

In this case, Portland cement is preferable as the cement, but even a Portland cement-based mixed cement has sufficient moldability. As mentioned above, if cement is cured for 7 days or more, it is effective in maintaining a strength of 50 to 70 kg at room temperature, and even at high temperatures, the strength does not increase, but it maintains a strength of 6 kg.
It weighs about 0 to 70 kg, which is insufficient in strength when used alone.

However, when bentonite is mixed with cement, curing 1
The strength at room temperature is about 90 to 110 kg in 4 days, but in the coexistence with the additive, the crystal water of bentonite is dehydrated at about 700 °C and gradually sintered, and as a result, the high temperature strength of the molded product is about 130 kr. It also has a strength of 20 to 3
0 kg, and the high-temperature strength is significantly improved compared to the case where cement is used alone as a binder.

When these cements or bentonites are mixed with coke powder and water, they do not retain their shape well when molded at room temperature.
The adhesiveness of water-soluble binders such as polyethylene oxide (PEO), CMC, and starch allows coke powder to adhere and retain its shape during molding.

Bentonite also becomes slightly sticky due to water absorption and contributes to maintaining the initial shape. In other words, cement is effective in ensuring medium crushing strength at room temperature and hot, and the additives PEO and C
MC, lignin sulfonic acid, and starch are effective for shape retention during molding due to their adhesion when kneaded with water, and bentonite contributes to improving hot strength when used in combination with cement. In either case of using bentonite alone or in combination with cement and bentonite, 5 to 15% by weight of cement and 1 to 5% of bentonite are suitable, particularly 9 to 11% of cement and 2 to 2 to 5% of bentonite.
The additive, which is more preferably 3% by weight, is PE00.
05-0.20% by weight, CMC011-0.5% by weight,
One or more selected from 1.5 to 8% by weight of lignin sulfonic acid and 1 to 5% by weight of course starch are used, particularly P E OO.

08-0.10% by weight, CMC 0.18-0.2% by weight
, 1.8 to 2.2% by weight of ligninsulfonic acid, and 1.5 to 2.0% by weight of cornstarch are preferred. Especially when using cement and bentonite together, PE00.
08-0.10% by weight alone or CMC0.1
8-0.2% by weight and ligninsulfonic acid 1°8-2.2%
When using a mixture of 1.5% to 2.0% by weight of corn starch, the hot crushing strength after drying and curing is 13
0-135- and room temperature crushing strength of 90-11 after curing for 14 days.
While it was 0-, the strength was further increased by about 30-.

This is mainly due to the effect of the compounded bentonite, but it is thought that these organic pressure-sensitive adhesives were effective in maintaining the room temperature strength at about 90 to 110. 5 cement
If it is less than 15% by weight, it is difficult to mold, and if it exceeds 15% by weight, it is not only unnecessary for molding, but also increases the ash content after combustion, which is undesirable. If it is similar, there is no problem. However, in any case, the amount of heat generated will decrease. If bentonite is less than 1% by weight, it is not only insufficient to increase hot strength when used in combination with cement, but also becomes impossible to form if the amount of organic additives added is small. This is because when bentonite is added with water, it absorbs water and acts as an adhesive, contributing to room-temperature molding.

More than 5% by weight is unnecessary for increasing hot strength and will instead lead to an increase in strength. PEO is less than 0.05%,
The adhesive molding effect during molding is insufficient, and PEO is expensive, so more than 0.20% by weight is uneconomical, CMC0.1
If it is less than 0% by weight, the adhesive molding effect during molding is insufficient;
．． More than 5% by weight is not only unnecessary for molding, but also P.
Although it is not as expensive as EO, it will increase the cost. If the lignin sulfonic acid is less than 1.5% by weight, the adhesive molding effect will be insufficient, if it exceeds 8% by weight, the sulfur content will increase, which is undesirable, if the corn starch is less than 1% by weight, the adhesive molding effect will be insufficient, and if it exceeds 5% by weight, the adhesive molding effect will be insufficient. It is unnecessary for molding.

The above additives are all organic adhesives that are added for the purpose of maintaining the adhesive shape of the molded product, but one or more other additives may be added for other purposes as necessary. I won't prevent you from doing that.

When mixing wires, it is preferable to add 8 to 15% by weight of water and knead with a kneading machine such as a fret mill (H Runner).If the water is less than 8% by weight, kneading is difficult, and if it exceeds 15% by weight, it will be difficult to mix the mixture after molding. Not only does moisture evaporation require extra heat, but shape retention also deteriorates. Molding is done at low pressure (about 1-2 T/cd)
A briquetting machine is sufficient, and the mold size is preferably a masesoku type, an elag type, a spherical type, etc. with a typical length of about 45 to 65 cranes. For example, 50 x 50 x 39 cranes, 65 x 6
Mold into a 5x44m, 45x45x26 crane shape. After cement curing and molding, a curing period of at least 7 days is necessary to increase the strength at room temperature, and the organic binder as an additive is hardened by heating and drying to evaporate water.

The effects of the present invention will be illustrated in more detail with reference to Examples below.

〔Example〕

Coke powder having the following particle size distribution was molded.

(Table 1) The natural content of this coke powder is 10.1 to 13.3%, volatile content 0.4 to 0.8%, total sulfur content 0.5 to 0.6%, and total calorific value 6.800. To this coke powder, which had a concentration of ~7.100 Kcal/-, various combinations of binders and additives as shown below were added, and a fret mill (II runner, drum diameter 1
, 830 Tsuruφ×330 Tsuru HX15RPM, roller 1.
200m#X350mWx12RPM, batch 20kg
, mixing time 10 minutes). This kneaded material is passed through a briquetting machine with rolls of 700 mm diameter x 700 mm diameter x 5 mm.
RPM, mold size 49 x 49 x 39 dragon).

The relationship between curing period and crushing strength is that the strength is approximately reached after 5 to 7 days of curing, but depending on the formulation, the strength may gradually increase by the 14th day.

There is a correlation that as the absolute dry density increases, the crushing strength also increases.

The survival rate of particles with a particle size of 40 or more in the drop test also increases linearly with the crushing strength.

〔Effect of the invention〕

According to the method of the present invention, molded coke powder can be used in place of the foundry lump coke that has conventionally been used as fuel for cupolas, and it depends on how much cheaper coke powder can be obtained than lump coke. The use of binders and additives can also significantly reduce fuel costs.

Furthermore, according to the molding method of the present invention, it is possible to obtain not only a molded product with high crushing strength at room temperature but also a molded product with high strength under hot conditions.
It does not obstruct ventilation and can be used as an alternative fuel to lump coke, which greatly contributes to cost reduction.

By making effective use of coke powder, which was previously being searched for,
This is an industrially useful invention because it can further reduce costs.

Claims (5)

[Claims] (1) Blended coke powder with bentonite alone or in combination with cement and bentonite as a binder, one or more selected from polyethylene oxide, carboxymethyl cellulose, lignin sulfonic acid, and cornstarch as additives, and water. A method of molding coke powder that is characterized by kneading, molding, drying, and hardening. (2) The method for molding coke powder according to claim 1, wherein 80% by weight or more of the coke powder has a particle size of 1 mm or less. (3) The powder according to claim 1, item 2, which uses 1 to 5% by weight of bentonite alone or a combination of 5 to 15% by weight of Portland cement and 1 to 5% by weight of bentonite as a binder. Coke molding method. (4) As an additive, polyethylene oxide 0.05
~0.20% by weight, carboxymethyl cellulose 0.1
~0.5% by weight, ligninsulfonic acid 1.5-8% by weight
, one or two selected from 1 to 5% by weight of corn starch
Claims 1, 2, and 3 that use more than one species
Method for molding coke powder as described in section. (5) The method for molding coke powder according to claims 1, 2, 3, and 4, wherein the amount of water added is 8 to 15% by weight.