Compositions: ceramic – Ceramic compositions – Clay containing
Reexamination Certificate
1999-10-14
2002-01-29
Marcheschi, Michael (Department: 1755)
Compositions: ceramic
Ceramic compositions
Clay containing
C501S155000, C588S009000, C588S010000, C588S256000, C588S901000
Reexamination Certificate
active
06342461
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a ceramic composition by a composite stabilization process and by using waste materials including heavy metals for recycling the waste materials and a method for manufacturing the same, more particularly the present invention relates to the ceramic composition made from various waste materials such as an electric arc furnace (EAF) dust, a steel slag, an aluminum dross, a fly ash, a paper ash or other industrial dusts in order to utilize the ceramic composition for building materials or engineering materials and the method for manufacturing the ceramic composition.
2. Description of the Prior Art
Various waste materials generated from the industrial activities are generally divided into two groups. One group consists of specific waste materials which include hazardous elements and the other group consists of ordinary waste materials having little harmful elements.
Many heavy metals like iron (Fe), magnesium (Mg), titanium (Ti), lead (Pb), chrome (Cr), copper (Cu), nickel (Ni) or manganese (Mn). The heavy metals are erupted from the specific waste materials when the specific waste materials are buried in the ground according to an ordinary treating method, so fatal environment pollution may occur due to the heavy metals. Also, a cost and a reclaimed land for the waste materials become serious problems though the heavy metals are partially removed from the specific waste materials or the ordinary waste materials are buried in the ground. Therefore, a method for treating and recycling the waste materials is urgently demanded at present.
Hereinafter, several patents for recycling the waste materials will be mentioned as follows.
Japanese Patent No. 53-127,511 discloses one method for manufacturing a block by mixing an EAF dust with the conventional row materials. The block includes the EAF dust of 30 to 50 by weight percent and a sintering process is executed at a temperature of 630 to 830° C. However, the block has a poor compressive strength of about 690 psi.
Another method for manufacturing a block is disclosed at U.S. Pat. No. 5,278,111 issued to Frame. The block contains an EAF dust of 30 to 60 by weight percent around the conventional row material after zinc (Zn) and lead (Pb) in the EAF dust are considerably volatilized through a calcination process. Though the block meets the permissible eruption limits of the heavy metals, the mechanical strength of the block decreases according as the amount of the EAF dust increases.
Also, a method for manufacturing a clinker is suggested at U.S. Pat. No. 5,672,146 issued to Aota et al. The clinker comprises an EAF dust and an alumina and heavy metals are hardly erupted from the clinker. The clinker is used as a row material to produce a tile or a block after it is grinded. The method, however, demands the milling process after a sintering step and the mechanical strength is not mentioned in that Patent.
As it is described above, those patents have the problem that the sintered bodies or the blocks have poor mechanical strength because homogeneous mixture is not formed during mixing the waste materials with the conventional row materials. Also, those patents mention only the specific waste materials except the ordinary waste materials such as the fly ash or the paper ash. Furthermore, a liquid phase excessively increases and the softening of the sintered body occurs since the main ingredients of the EAF dust likewise metals or metal oxides react with the conventional row materials such as a clay and they together form the liquid phase.
Therefore, in case of treating solid state waste materials having the hazardous heavy metals and the harmful ingredients, a treating and recycling method should be developed so as to manufacture a ceramic composition which has a high mechanical strength and can be available for various building materials or engineering materials by sufficiently mixing the ingredients of the waste materials while the heavy metals are not erupted from the ceramic composition.
SUMMARY OF THE INVENTION
Considering the above-mentioned problems, the present inventors have researched and developed a method for effectively treating and recycling waste materials having hazardous ingredients. As a result, the present inventors have accomplished a ceramic composition which can be available for a building material or an engineering material by a composite stabilization method without the eruption of hazardous heavy metals from the ceramic composition.
It is a first object of the present invention to provide a ceramic composition made from waste materials by a composite stabilization process in order to recycle waste materials such as an electric arc furnace dust, a steel slag, a fly ash, paper ash, an aluminum dross and so on.
It is a second object of the present invention to provide a method for manufacturing a ceramic composition made from waste materials by a composite stabilization process in order to recycle the waste materials.
To achieve the first object of the present invention, a ceramic composition comprises between about 5 and about 75 by weight part of a solid state waste material including heavy metals, between about 15 and about 45 by weight part of a fly ash and between about 5 and about 55 by weight part of a clay.
The solid state waste material is at least one selected from the group consisting of an electric arc furnace dust, a steel slag and a paper ash. Preferably, the ceramic composition further comprises between about 5 and about 15 by weight part of an aluminum dross.
According to one embodiment of the present invention, a ceramic composition comprises between about 5 and about 55 by weight part of an electric arc furnace dust, between about 15 and about 45 by weight part of a fly ash and between about 15 and about 55 by weight part of a clay. Preferably, the ceramic composition further comprises between about 5 and about 15 by weight part of a paper ash and the ceramic composition additionally comprises between about 5 and about 15 by weight part of an aluminum dross.
According to another embodiment of the present invention, a ceramic composition comprises between about 25 and about 40 by weight part of a fly ash, between about 15 and about 55 by weight part of a paper ash and between about 15 and about 50 by weight part of a clay.
According to other embodiment of the present invention, a ceramic composition comprises between about 15 and about 55 by weight part of a steel slag, between about 15 and about 45 by weight part of a fly ash, and between about 5 and about 45 by weight part of a clay. Preferably, the ceramic composition further comprises between about 15 and about 35 by weight part of an electric arc furnace dust or between about 15 and about 35 weight part of a paper ash.
Also, to achieve the second object of the present invention, a method for manufacturing a ceramic composition made from waste materials comprises the steps of:
a) forming a homogeneous slip by mixing a ceramic composition with a water wherein the ceramic composition comprises between about 5 and about 75 by weight part of a solid state waste material including heavy metals, between about 15 and about 45 by weight part of a fly ash and between about 5 and about 55 by weight part of a clay;
b) forming a shaped body having a predetermined shape by using said slip;
c) drying said shaped body; and
d) forming a sintered body by sintering said shaped body.
The step a) is performed after analyzing chemical constitutions of ingredients of the ceramic composition and measuring particle size distributions of the ingredients of the ceramic composition.
Preferably, the step a) is performed by primarily mixing an ingredient of said ceramic composition with a water considering volume ratios of particles having diameters of below about 10 &mgr;m wherein the ingredient includes a volume ratio of the particles of 10 &mgr;m which is larger than other ingredients of the ceramic composition and by mixing the ingredients with a water in the order of included particle
Kim Jung-Hwan
Lee Ki-Gang
Marcheschi Michael
Rabin & Berdo
LandOfFree
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