JP3800467B2 - Method for producing stone by melting waste - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing stone by melting waste, and more particularly to a method for producing stone using silica-based waste as a raw material.
[0002]
[Prior art and problems to be solved by the invention]
With increasing interest in environmental conservation, recycling and incineration of construction and industrial waste is highly effective in reducing the volume of waste, reducing harmful organic substances, and reducing the generation of spoilage substances. Utilization is increasing as an essential process in material processing. For example, many wastes such as general waste, that is, municipal waste, sewer sludge, paper sludge, food sludge, etc. are incinerated and safely disposed of.
Incineration ash is generated after such incineration, but this incineration ash sometimes contains heavy metals and the like, and its effective use is limited.
In addition, construction sludge other than incinerated ash has not been effectively used.
In order to improve such a situation, various investigations are underway, and among them, the use of silica-based waste is becoming a direction to proceed through slagging (melting treatment).
One reason for this is that the soil environment standards announced by the Environment Agency in 1993 employ very strict elution control values, which are often not achieved by conventional cement solidification.
The reason for shifting to slag, which is more expensive than solidification by cement mixing treatment, is that even if harmful substances are contained by melting silica-based waste at a high temperature. This is because it can be made difficult to elute.
[0003]
By the way, the cost becomes a problem when slagging silica-based waste.
The main costs are the heat energy source to raise the waste to above the melting temperature and the construction cost of the melting furnace.
As a method for lowering the melting temperature, there was a method realized by increasing the basicity of slag by adding a CaO component such as limestone or quicklime, but it was a waste of resources such as limestone, and the cost related to processing There was a problem of increasing.
Further, depending on the type of waste, gas may be generated during slag formation. When the viscosity of the slag melt is high, a large amount of bubbles remain in the slag after cooling. If a large amount of bubbles remain, depending on the use of the solidified slag product, there is a possibility that it will hinder the use, and the volume reduction rate will be greatly reduced.
As described above, in the conventional processing method, only the heat is forcibly heated and melted, and despite the fact that a great amount of energy is consumed, the melt can only produce a heterogeneous material containing bubbles. Therefore, (1). In the slag processing of silica waste, it is necessary to lower the melting temperature of the object at low cost, and (2). It was necessary to reduce the viscosity of the melt to form a dense slag.
[0004]
[Means for Solving the Problems]
The present inventors have conducted various studies and studies to solve the above-mentioned problems, and have come to achieve the present invention having the following configuration.
(1) Coal ash, paper sludge, the silica-based waste such as construction sludge, by adding gypsum or calcium sulfite or containing waste thereof melts, and the addition amount thereof to the silica mass of molten sample A method for producing a stone material by melting waste, characterized in that it is added in an amount of 10 to 150 mass% in terms of CaO , and then cooled and hardened to form a stone material.
(2) Add gypsum or sulfite gypsum or waste containing them to solid waste such as coal ash, paper sludge, construction sludge, etc., and add solidification material such as cement and quicklime, and the amount added is dissolved. A method for producing a stone by melting waste, characterized in that an amount of 10 to 150% by mass in terms of CaO is added to the silica mass in a fused sample , and then cooled and hardened to form a stone.
(3) 30 the sum of the added amount of gypsum or calcium sulfite or containing waste thereof, the silica mass of molten sample, as calculated as CaO, and Ca O ingredient contained in the silica-based waste The method for producing a stone material by melting the waste according to any one of (1) to (2) above, wherein the method is ˜150 mass%.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described.
In the present invention, waste made of the same component as soil, such as silica and alumina (for example, limestone, paper sludge incineration ash, municipal waste incineration ash, construction sludge, etc.) is melt-treated to produce artificial stone or artificial stone panels. In manufacturing, in order to improve the quality of manufactured products and reduce manufacturing costs, the main component is gypsum, sulfite gypsum, or their contents for the purpose of reducing the viscosity of molten materials, reducing bubbles, and lowering the melting temperature. The compound is mixed with silica waste and melt processed.
That is, (1). Add gypsum, sulfite gypsum, or wastes containing them (for example, desulfurized gypsum and gypsum pod waste) to silica-based waste so that the silica content in the molten sample is 10 to 150% by mass in terms of CaO. Melt. By passing through this process, the viscosity of the silica-based waste in the molten state can be reduced, so that residual bubbles due to the generated gas can be almost removed from the melt.
(2). Gypsum, sulfite gypsum or waste containing them (for example, desulfurized gypsum and gypsum pod waste) in silica-based waste, 10 to 150 mass% in terms of CaO with respect to silica in the molten sample, cement, lime, etc. The solidified material is added and mixed to solidify, and then the mixed solidified material is melted. By going through this process, (1). In addition, the silica-based waste and gypsum, sulfite gypsum or waste containing them (for example, desulfurized gypsum and gypsum pod waste) are melt-processed in an evenly mixed state. The time to reach the melting temperature is short, and a homogeneous melt and cured product (stone) are obtained.
In addition, it is preferable to make the total amount of Ca component in desulfurization gypsum etc. to add and silica-type waste etc. into 10-150 mass% with respect to the silica mass in molten slag in CaO conversion. If the amount exceeds 150% by mass, the amount of gas generated during melting becomes large, the volume reduction is greatly impaired, and the use is also greatly limited due to a decrease in the strength of the cured product (slag). On the other hand, when the amount is less than 30% by mass, the melting point increases and the viscosity increases, and a stable melt cannot be obtained.
Therefore, the addition amount of desulfurized gypsum and the like is preferably 10 to 150 mass% with respect to the silica mass in the coal ash in terms of CaO.
[0006]
The embodiment of the present invention will be described with reference to examples.
In the incineration facility, a large amount of desulfurized gypsum is discharged with the processing of the SOx gas. This desulfurized gypsum is effectively used as a raw material for gypsum pods, but there is a limit to its use and a new method of use is required. The same applies to gypsum pod waste generated from the construction industry. In addition, it is necessary to effectively use desulfurized gypsum generated in incineration of waste.
[0007]
【Example】
Flue gas desulfurization gypsum was added to silica ash (fly ash) in various proportions and melted by heating.
Melting conditions were maintained at 1500 ° C. for 30 minutes.
The viscosity of the melt at the time of melting was confirmed by the method shown in FIG. That is, 1 g of an object to be melted (sample) T is placed on one end side of a high-melting point refractory flat plate P having a length of 8 cm, and a high-melting point refractory rod H having a height of 5 mm is inserted on the lower surface of the one end side portion. It was heated and melted in the state.
The sample T melted by heating flows down according to the gradient, but the flow length L becomes longer when the viscosity at the time of melting is lower and becomes shorter when the viscosity is higher.
The flow length L of the sample T melted after cooling was measured, and the viscosity of the molten mixed material was simply grasped.
The test results are shown in FIG.
In the figure, material A is a sample in which limestone is added, and material B is desulfurized gypsum added to coal ash.
The flow length of the molten material is increased by the increase in basicity, which is the ratio of calcium oxide (CaO) and silica (SiO ₂ : silicon dioxide). And the tendency is the same result, even if it uses only A material, only B material, and the mixture of A material and B material as an additive.
As described above, flue gas desulfurization gypsum can be used as a basicity adjusting material in the melting process, but its possible addition rate is limited. In other words, if a large amount of desulfurized gypsum is added to the silica mass in the coal ash in terms of CaO, the amount of gas generated during melting increases, volume reduction is greatly impaired, and the use of slag is greatly limited. It will become like.
Gas is considered to be a low-boiling component, a component that cannot be dissolved in molten slag such as carbon dioxide, but the substance has not been specified. For this reason, the addition rate of desulfurized gypsum is preferably in the range of 5 to 100% by mass in terms of gypsum and sulfite gypsum. Particularly preferably, it is 5 to 60% by mass in which no bubbles are generated.
[0008]
When the coal ash is melt-processed, solidification (briquetting) is a prerequisite for preventing particle scattering.
Cement and lime are used to solidify the coal ash, but adding flue gas desulfurization gypsum here can increase the strength. The addition of flue gas desulfurization gypsum is highly useful from the viewpoint of cost because the necessary amount of solidifying material such as cement can be reduced to obtain a certain strength.
Although flue gas desulfurization gypsum has the property of not easily decomposing even at high temperatures, it may generate sulfurous acid gas or hydrogen sulfide depending on the melting conditions. Therefore, the amount of gas generated during the melting process was analyzed. As a result, when desulfurized gypsum-added coal ash was melted at 1500 ° C., it was confirmed that the sulfur mass in the cracked gas was 5% or less of the sulfur mass contained in the original sample.
From the above results, it was found that the added desulfurized gypsum effectively reduced the melting temperature and viscosity of coal ash and continued to exist stably in the melt.
[0009]
【The invention's effect】
As described above, according to the present invention,
By adding gypsum, sulfite gypsum, or waste containing them to silica-based waste and melting it, an excellent stone can be easily produced.
Volume reduction of the waste sample is also achieved, and the amount of bubbles is small, and a high-strength hardened stone can be produced.
Therefore, gypsum such as gypsum board waste that is waste, sulfite gypsum, or waste containing them can be advantageously used for the production of stone.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a method for measuring viscosity (flow length) when desulfurized gypsum is added to coal ash and melted at 1500 ° C. FIG.
FIG. 2 is a graph showing the relationship between the basicity (CaO / SiO ₂ ) of molten material and the flow length when desulfurized gypsum is added to coal ash and melted at 1500 ° C.
[Explanation of symbols]
T: object to be melted (molten sample), H: high melting point refractory rod, L: flow length of melt,
P: High melting point refractory flat plate

Claims (3)

Coal ash, paper sludge, the silica-based waste such as construction sludge, by adding gypsum or calcium sulfite or containing waste thereof melts, and the addition amount thereof is calculated as CaO the silica mass of molten sample A method for producing a stone by melting waste, characterized in that it is added in an amount of 10 to 150% by mass , and then cooled and hardened to form a stone. Coal ash, paper sludge, the silica-based waste such as construction sludge, gypsum or calcium sulfite or containing waste thereof and cement with the addition of solidifying material such as quicklime melted, and added amount of molten sample thereof A method for producing a stone by melting waste, characterized in that an amount of 10 to 150% by mass in terms of CaO is added to the silica mass of the product, and then cooled and hardened to form a stone. Amount of gypsum or calcium sulfite or containing waste thereof, the silica mass of molten sample, as calculated as CaO, 30 to 150 mass in total amount of Ca O ingredient contained in the silica-based waste The method for producing a stone material by melting the waste according to any one of claims 1 to 2 , characterized in that the percentage is%.

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