LEE WON HUI (KP)
KIM UHN HI (KP)
JUONG HYO RIM (KP)
LEE WON HUI (KP)
KIM UHN HI (KP)
| DE4244382A1 |
CLAIMS:
1. A fuel mixture consisting of fly ash of coal, cement dust and wad or red clay, which easily catches fire and rapidly carries out thermite reaction.
2. The fuel mixture of claim 1 containing between 30 and 70% of said fly ash of coal, between 13 and 33% of said cement dust and between 13 and 33% of wad or red clay. 3. The fuel mixture of claim 1 having a square shape or a globular shape wherein the granule sizes of said fly ash, said cement dust and said wad are all below 0.5mm.
4. A process of making a fuel mixture consisting of fly ash of coal, cement dust and wad or red clay, which easily catches fire and rapidly carries out a thermite reaction, said process comprising mixing, shaping and drying,
5. The process of claim 4, wherein said mixing comprises fully dissolving wad in water, and adding thereto said fly ash of coal and then said cement dust wherein the ratio of material to water is between 1 :0.4 and 1:0.5, said drying being performed either by a natural drying or in a drying in a 250-300 0 C furnace. |
A FUEL MIXTURE FORMED OUT OF FLY ASH OF COAL AND CEMENT DUST
The present invention relates to a substitute fuel for heating and cooking, in more particular, a fuel mixture consisting of industrial by-products such as fly ash of coal, cement dust and wad(red clay), and to a process of making the same.
In these days, a variety of substitute fuels are developed and utilized for multiple purposes,
KP patent 46417 discloses technique of making a fire-to-easy briquette by mixing 30 to 35% by weight of anthracite, 30 to 35% by weight of sawdust, 5 to 10% by weight of cement dust and 5 to 30% by weight of a binder.
KP patent 12348 discloses technique of making a fire-to-easy briquette by admixing 60 % by weight of anthracite with 40% by weight of weathered granite. Technique is also known in China of making a ball-shaped coal by mixing 38.5 % of charcoal, 38.5% of hemp stalk powder, 15% of anthracite, 20 to 30% of strontium nitrate and 7 to12% of kalium perchlorate.
It is known that a study is being made of obtaining a thermite effect by pulverizing and mixing 6 to 7% of siderite, 40 to 45% of low- grade coal and 48 to 57% of limestone.
The first disadvantage with prior art fuels is that a study has been mainly made in an attempt to reduce anthracite consumption and to obtain the main heat from the oxidizing reaction heat of carbon.
The second disadvantage with prior art is that in case of the use of thermite reaction heat, lots of equipment and power are required for mining and cracking ores, it being difficult to kindle.
Therefore, it is an object of the present invention to provide a substitute fuel that contains no anthracite and is easy to kindle.
In one aspect the present invention provides a fuel mixture consisting of fly ash of coal, cement dust and wad or red clay, which easily catches fire and rapidly carries out thermite reaction.
Preferably, the fuel mixture contains between 30 and 60% by weight of said fly ash of coal, between 13 and 33% by weight of said cement dust and between 13 and 33% by weight of said wad or red clay.
Preferably, the fuel mixture has a square shape or a globular shape, wherein the granule sizes of said fly ash of coal, said cement dust and said wad are respectively below 0.5mm.
In another aspect the present invention provides a process of making a fuel mixture consisting of fly ash of coal, cement dust and wad or red clay, which easily catches fire and rapidly carries out thermite reaction, said process comprising mixing, shaping and drying.
Preferably, said mixing comprises fully dissolving said wad in water, and adding thereto said fly ash of coal and then said cement dust, wherein the ratio of material to water is between 1 :0.4 and 1 :
0.5, said drying being performed either by natural drying or in a drying at a 250 - 300°C furnace.
The thermite reaction is a strong exothermic reaction.
The general equations for the thermite reaction are as follows:
MenOm+mSi=nMe+1/2mSiO 2
MenOm+2/3mAI=nMe+ 1 /2mAI 2 O 3
MenOm+mMg=nMe+ nMgO MeO+CO=Me+CO 2 0+O 2 =CO 2 CO 2 +C=2CO C+H 2 O=CO+H 2
Thermite reaction occurs at 1400-2OfJO 0 C and produces a heat value of 100-300cal/g. For such thermite reaction, the active carbon
(18-20%) is used that is contained in the cement dust. With the aid of substances, such as, but not limited to, C, CO and H 2 , metals are obtained from FeO, MnO, SiO 2 and the like that are metallic oxides apt to be deoxidized at a low temperature. The metals thus obtained provide a reaction condition to deoxidize another metallic oxides, thus the deoxidized metals causing a continuous oxidizing reaction, whereby a large quantity of heat is generated.
Meanwhile, the active matters contained in the fuel mixture of the present invention are mixed at an adequate rate so that the CO produced during the reaction is entirely used up for the reaction, and thus the reaction produces little harmful gas such as CO. Thermite reaction generally occurs at a high temperature of over 100O 0 C .
However, in the fuel mixture according to the present invention, reaction begins at a comparatively low temperature, which is because the activity level of the metal oxides contained in cement dust has already become higher by the heat applied thereto in the boiler firebox and cement kiln.
The fuel mixture according to the present invention comprises: Fly ash of coat consisting of: C, AI 2 O 3 , SiO 2 Fe 2 O 3 , CaO, MgO;
Cement dust consisting of:
SiO 2 , AI 2 O 3 , Fe 2 O 3 , C aθ, MgO 1 K 2 O; Wad consisting of:
MnO 2 , mMnO, nH 2 O, SiO 2 , AI 2 O 3 , Fe 2 O 3 The process according to the present invention comprises:
Mixing
Mixing is performed in such a way that wad is first put, and fully dissolved, in water, then the fly ash of coal and the cement dust being added thereto in order, wherein the mixing ratios (weight ratio) of the components are as follows: Fly ash of coal: 30 - 70% Cement dust: 13 - 33% Wad: 13 - 33%
Water: quantity suitable for shaping Mixing may be effected by means of a screw mixer.
Shaping
Fteferably, the fuel mixture is made in the shape of a ball with a diameter of from 20 to 30mm. It may be in the form of a square.
Drying Drying is conducted by either natural drying or preferably drying at 250- 300 0 C.
The present invention has the following advantages: First, the fuel mixture of the present invention is merely made by mixing industrial by-products without using anthracite, which makes it possible to entirely use the energy latent in the active matters contained in industrial by-products.
Secondly, as fly ash of coal and cement dust can be used without any special processing, the fuel mixture of the present invention is easy to produce, and low in production cost.
Thirdly, as the fuel mixture of the present invention is formed from industrial by-products generated separately, the ash of the fuel mixture is an efficient microelement fertilizer and can be effectively used, for its low alkalinity (PH=7.5), to prevent acidification of soil, q
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