JP2002180146A - Method for recovering mercury from waste fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recover mercury in the form of metal mercury from waste fluorescent lamps at a low cost. SOLUTION: In a hermetically sealed box, the waste fluorescent lamps are crushed, pulverized and screened by the dry process. The resultant gas containing gaseous mercury is passed by suction through an aqueous solution and successively passed through a packed layer of material which reacts with or adsorbs mercury, e.g. gold, silver, copper or aluminum, by which mercury can be adsorbed by or allowed to react with the material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering mercury of a waste fluorescent lamp for recovering mercury of a waste fluorescent lamp as metallic mercury.

[0002]

2. Description of the Related Art Conventionally, the following method has been used for mercury treatment of used waste fluorescent lamps. 1) Treat gaseous mercury with activated carbon or chelating resin. 2) Crushing of waste fluorescent lamps in water and washing of glass with water. 3) Use of sulfides and various chemicals 4) Amalgam treatment of mercury with metal is carried out by carrying gold and silver on fibers such as quartz wool, by coating silver on copper wire nets, or by metal-plated plastic. There are methods.

In the method of (1) for treating gaseous mercury with activated carbon or chelating resin, the activated carbon or chelating resin adsorbing mercury cannot be regenerated. 2) Disruption of the waste fluorescent lamp in water and washing of the glass with water involve fine phosphors in the water together with mercury, so that filtration and drying are very expensive. 3) The use of sulfides and various chemicals also increases the cost of converting mercury into metal. 4) The amalgam treatment of mercury with a metal is not preferable to be used directly when a large amount of mercury is discharged like a waste fluorescent lamp.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a mercury recovery method in which mercury is recovered as metallic mercury at a low cost and in a simple process when a waste fluorescent lamp is recycled.

[0005]

The mercury of the fluorescent lamp chemically reacts with the constituent materials of the lamp during operation to produce mercury oxide,
It becomes a compound such as amalgam. Metallic mercury is thermally decomposed at 260 ° C. or less, mercury oxide at 350 ° C. or less, and amalgam at 350 ° C. or more to release mercury.

Therefore, mercury-containing gas is passed through an aqueous solution in which mercury does not change except for mercury oxide and amalgam, and most of mercury, mercury oxide and amalgam are recovered in the aqueous solution. Is gold, silver,
Mercury is recovered by passing through a packed layer of a substance that reacts or adsorbs with mercury such as copper and aluminum.

[0007] Gold, silver, copper, which has reacted or adsorbed with mercury,
Aluminum is separated from mercury by a well-known method such as a vacuum heating device and condenser in the same way as fluorescent powder and other materials that need to recover mercury, and the exhaust of a vacuum pump is passed through an aqueous solution, followed by gold. It passes through a packed layer of a substance that reacts or adsorbs with mercury such as silver, copper, and aluminum, and adsorbs and reacts with mercury to recover mercury. By this method, all mercury in the waste fluorescent lamp is recovered as metallic mercury.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS When a waste fluorescent lamp is treated in a dry manner, it can be divided into two types according to the method of recovering the fluorescent powder. 1) A method in which the electrode portion is cut with a hydrogen burner or mechanically, and the fluorescent powder is blown off with air or collected by suction. 2) JP-A-2000-202319 and JP-A-11-30
0332, a method of reducing the flow of gas and collecting fluorescent powder through a sieve. The difference between the two is that the amount of gas containing mercury is greatly different.

In the case of 1), since the amount of gas containing mercury is large, contact with an aqueous solution for recovering mercury is carried out using a wet dust collector disclosed in Japanese Unexamined Patent Publication No. 9-49627, a device for removing soot and toxic gas, a venturi scrubber, a jet scrubber, and the like. It is necessary to use a scrubber system, such as a high-performance wet waste gas washing tower mixing scrubber system mu scrubber tower of Mu Company Limited.

In the case of 2), since the amount of gas containing mercury is small, a method of fixing an aqueous solution such as a method of recovering mercury using a combined use of a fluidized filter and a diffuser plate as disclosed in JP-A-10-165716 is sufficient. .

FIG. 1 shows a process chart of a waste fluorescent lamp processing plant in the case of 2). The whole is surrounded by a transparent plate 1 and only the inlet of the waste fluorescent lamp is open. The gas containing mercury is sucked from several other places under the pulverizer so that gas containing mercury does not blow out. Since the inside of the fluorescent lamp is depressurized, the suction amount is small.

FIG. 2 shows an example of a mercury recovery apparatus. Various other wet dust collectors can be used for the mercury recovery device.

FIG. 3 shows an apparatus for removing the mercury in which the gas from which most of the mercury has been removed is made uniform by the current plate. The exhaust body is led to the inlet of the waste fluorescent lamp.

The mercury recovery apparatus shown in FIG. 2 will be described. The housing has a two-part structure consisting of an upper housing 6 of a closed container and a lower housing 7 connected to the bottom. A male screw 8 is formed on the outer edge of the lower end of the upper housing 6, and a female screw 9 for screwing the male screw 8 of the upper housing 6 is provided above the lower housing 7. The two housings 6 and 7 are integrated by screwing. The first separating portion 2 having a conical shape that is convex downward is sandwiched between the bottom of the upper housing 6 and the top of the lower housing 7. The lower surface of the first separation unit 2 has a structure in which a separation surface 10 from which an exhaust body is blown to separate mercury is provided with a through hole 11 formed of a vertical slit continuous from the lower end to the upper end in the circumferential direction. . In addition, the separation surface of the first separation portion may be formed of a porous member such as a net instead of having the slit hole structure. Note that the first separation surface 2 is not limited to the conical shape. A diffuser plate is provided on the upper part 13 of the separation surface. Mercury accumulates in the lower part 14 and is discharged from 15.

In the upper housing 6, a large number of spherical materials 12 made of inorganic fibers are sealed. The inorganic fiber may be ceramic fiber or glass fiber,
Quartz wool coated with gold or silver or fibers of gold, silver, aluminum or the like may be used. The sphere is used in a flowing state. The upper part 16 of the upper housing 6 is provided with a water drop separating part.

A gas containing mercury is introduced from 3, and a gas from which most of the mercury has been removed is removed from 5.

Although not shown, a blower that blows in a gas containing mercury from the inlet of the gas containing mercury is connected, or a gas containing mercury is discharged from the outlet of the gas. Connect a suction machine that sucks in.

FIG. 3 is based on Japanese Patent Application Laid-Open No. 9-276634. The gas from which most of the mercury has been removed in FIG. 2 makes the flow of the exhaust body uniform in the apparatus of FIG. 3, and the remaining mercury is removed by filling the sphere. For the filling of the sphere, use is made of quartz wool coated with gold or silver or fibers of gold, silver, aluminum or the like.

Reference numeral 21 denotes an inlet for a gas containing mercury. 2
Reference numeral 2 denotes a mesh plate or a perforated plate holding a packing of 23 spheres. Reference numeral 24 denotes a gas outlet from which the mercury has been removed through the filling of the 23 spheres. 25 is the inlet 21
A current plate disposed below the 23 spherical packing so that the gas containing mercury rises uniformly and parallel to the spherical packing, and 26 does not contain mercury passing through the spherical packing. A current plate disposed above the 23 spherical packing so that gas flows in parallel. Reference numeral 27 denotes a rectifying plate provided at the inlet 21, and reference numeral 28 denotes a rectifying plate provided at the outlet 24.

Although not shown, a blower for blowing a gas containing mercury from an inlet for mercury-containing gas 21 is connected, or a gas is sucked from an outlet 24. In some cases, a simple suction device may be connected. In any of the means, the suction force or the blowing force is adjusted so that the gas flows at a low speed.

When the processing of the waste fluorescent lamp is completed or when the machine is maintained, the inlet of the waste fluorescent lamp is closed, and FIG.
Air is sent from a discharge port 24 of the exhaust body to a waste fluorescent lamp processing plant, and mercury in the apparatus is recovered while circulating.

Gold, silver, copper, which has reacted or adsorbed with mercury,
Aluminum is separated from mercury by a known method such as a vacuum heating device and condenser in the same manner as fluorescent powder and other materials that need to recover mercury. The flow of the exhaust body is made uniform in a substance that reacts or adsorbs with mercury, such as silver, copper, and aluminum, and is passed through a packed bed to adsorb and react with mercury to recover mercury. By this method, all mercury in the waste fluorescent lamp is recovered as metallic mercury.

The present invention is not limited to such an embodiment at all, and can be implemented in various modes without departing from the gist of the present invention.

[0024]

As described above, in the present invention, most of mercury, mercury oxide, and amalgam are passed through an aqueous solution in which mercury is generated by the crushing treatment of a waste fluorescent lamp and the mercury is not changed except for mercury oxide and amalgam. Mercury, mercury oxide, and amalgam that were collected and removed in gold, silver, copper,
The flow of the exhaust body is made uniform through a packed layer of a substance that reacts with or adsorbs mercury such as aluminum, and the mercury is recovered.
Gold, silver, copper, aluminum, etc., which have absorbed and reacted with fluorescent powder and mercury, recover the mercury with a vacuum heater and condenser. As a result, all mercury is recovered as metallic mercury.

[Brief description of the drawings]

FIG. 1 is an example of a processing diagram of a waste fluorescent lamp.

FIG. 2 shows an example of a method for recovering mercury-containing gas generated by crushing of a waste fluorescent lamp in an aqueous solution.

FIG. 3 shows an example of an apparatus for removing mercury by making the flow of most of the mercury-removed gas uniform with a flow straightening plate.

[Explanation of symbols]

 1 Transparent plate surrounding the waste fluorescent lamp processing plant 2 First separating part 3 Gas inlet containing mercury 4 Inlet of aqueous solution 5 Outlet 6 Upper housing 7 Lower housing 8 Male screw 9 Female screw 10 Separation surface 11 Through hole 12 spherical Object 13 diffuser plate 14 mercury storage unit 15 mercury outlet 16 water drop separator 21 inlet for gas containing mercury 22 mesh plate or perforated plate holding packing of sphere 23 filling of sphere 24 gas from which mercury is removed Outlet 25, 26, 27, 28 Rectifier plate

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C22B 9/02 B09B 3/00 Z H01J 9/50 303A 5/00 ZABZ

Claims (5)

[Claims] In a closed box, waste fluorescent lamps are crushed, crushed and sorted in a dry manner, and the generated gas containing mercury gas is passed through an aqueous solution by suction, followed by gold, silver,
A mercury recovery method for waste fluorescent lamps that adsorbs and reacts with mercury by passing it through a packed layer of substances that react or adsorb with mercury such as copper and aluminum. 2. A method for recovering mercury from a waste fluorescent lamp for adsorbing and reacting with mercury according to claim 1, wherein a substance which reacts with and adsorbs mercury such as gold, silver, copper and aluminum is mixed in the aqueous solution. . 3. The method for recovering mercury of a waste fluorescent lamp for adsorbing mercury according to claim 1, wherein a fluorescent powder having a small amount of exhaust is separated by a sieve. 4. A process for recovering mercury in a packed bed of a substance which reacts with or adsorbs mercury such as gold, silver, copper, aluminum or the like, wherein a flow of a gas containing mercury is made uniform by a current plate. The method for collecting mercury of a waste fluorescent lamp for adsorbing mercury according to claim 1. 5. When the mercury such as gold, silver, copper, and aluminum used for the adsorption of the mercury, the glass, the electrode, and the mercury is vacuum-heated and collected by the condenser, the exhaust of the vacuum pump is carried out in the aqueous solution. A method of collecting mercury from a waste fluorescent lamp that adsorbs and reacts with mercury by passing through a packed layer of a substance that reacts or adsorbs with mercury such as gold, silver, copper, and aluminum.