JPS6134129A - Method for recovering mercury from waste material - Google Patents

Abstract

PURPOSE:To recover efficiently mercury from waste material contg. mercury, to prevent environmental pollution and to conserve resources by crushing the waste material, heating indirectly the resulting powdery substance contg. mercury to evaporate the mercury, and condensing the mercury vapor. CONSTITUTION:The waste material contg. mercury such as waste dry cells is crushed and introduced into a heating furnace 20 as the powdery substance 11 contg. mercury. The furnace 20 is heated from the outside with an electric heater 21 to evaporate the mercury, and the resulting gas contg. the mercury vapor is introduced into a condenser 24 by suction with a fan 22 through a duct 23. In the condenser 24, the mercury vapor is condensed by cooling with a cooling medium 25 circulating through the condenser 24, and it is recovered as mercury in a mercury collecting port 27 through a duct 26. The remaining mercury-free gas is returned to the furnace 20 through the fan 22 and a return pass 28.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to wastes containing mercury such as municipal waste and other waste dry batteries, mercury lamps, thermometers (hereinafter referred to as "waste dry batteries, etc."),
Or, it relates to a method for recovering mercury from waste dry batteries, etc. that are collected separately.

[Prior Art 1] In recent years, environmental pollution caused by mercury contained in waste dry batteries has become a problem, and many local governments have begun to separate and collect waste dry batteries. However, separate collection at each household cannot be expected to have a high recovery rate, and many waste dry batteries are disposed of in municipal waste, incinerated, or landfilled. However, when incinerated, vaporized mercury is emitted from chimneys and pollutes the air, and when disposed of in landfills, the outer cylinders of used batteries corrode in the ground, causing mercury to leach out. The soil is contaminated, leading to pollution problems.

Up until now, waste batteries discarded in municipal garbage and other waste have not been collected, and have been left unchecked. In addition, a small amount of waste dry batteries that are collected separately from households are stored in containers and temporarily stored, and then processed in a single trowel, such as solidified with concrete, solidified with asphalt, or transported to a mercury processing factory.

[Problem to be Solved by the Invention 1] However, in the conventional technology, waste dry batteries have a large capacity in their original form, have poor processing efficiency in storage and solidification, and have high transportation costs when sent to processing plants. There was a point.

The present invention aims to solve these conventional problems and efficiently recover mercury from waste dry batteries, thereby contributing to pollution prevention and resource conservation.

[Means for Solving the Problems] The present invention, as a means for solving the above-mentioned problems, crushes waste containing mercury and indirectly heats the obtained powdery material containing mercury to remove mercury. This method of recovering mercury from waste is characterized by evaporation, condensation, condensation, and recovery.

[Embodiment 1] An embodiment of the present invention, in which mercury is recovered from waste dry batteries disposed of in municipal waste, will be described below with reference to the drawings.

In Figure 1, municipal waste 1 is sometimes stored in bags such as paper bags or plastic bags, and if necessary, the bag is torn open by a bag tearing machine 2 to expose the contents, making subsequent separation more efficient. Make sure you can do it well. City garbage that has been broken into bags is
A magnetic separator 3 separates ferrous metals 4 including waste dry batteries. At this time, button-shaped small batteries are also separated and sent to the first vibrating sieve 5 to be sieved, while non-magnetic materials such as paper, plastic, fibers, earth and sand that are not absorbed by the magnetic separator 3 are separated. 6 will be incinerated or disposed of in a landfill.

In the first vibrating sieve 5, the ferrous metals 4 are separated into large metals 7 such as beverages, etc., and small metal pieces 18 including waste dry batteries, and the large metals 7 are subjected to processing such as melting with a trowel outside the system.
Small pieces of metal 8 including waste dry batteries are sent to a crusher 9 and crushed, and powdery substances such as fine pieces and powder containing mercury that were sealed in the outer cylinder of the waste dry battery come out. . Next, by sending this to the second vibrating sieve 10, it is separated into a powdery material 11 containing mercury and a material 12 with a large particle size that does not contain mercury, such as an outer cylinder, positive electrode, etc. The large material 12 can be treated together with the large metals 7.

The mercury-containing powder substance 11 thus separated and recovered is introduced into a heating furnace 20, as shown in FIG. 2, and heated by an electric heater 21 from the outside of the heating furnace 20.

This electric heater 21 can also be replaced by a heating source such as a microwave. The mercury heated in the furnace 20 evaporates and is drawn into the condenser 24 via the conduit 23 by the fan 22 . The mercury vapor is transferred to the condenser 24
It is cooled and condensed by the cooling medium 25 circulated within the
It is collected via conduit 26 into mercury collection pot 27. Next, the gas from which the mercury has been removed is returned from the 7 amp 22 to the return passage 2.
8 and then circulated to the heating furnace 20.

FIG. 3 shows another embodiment of the present invention, in which an external heating method using a burner 29 is adopted as the heating method for the heating furnace 20, and further, the 7-ring 22 in the example in FIG. 2 is replaced with a vacuum pump 30. The pressure inside the heating furnace 20 is reduced to promote evaporation of mercury.

Furthermore, a mercury concentration meter 31 is installed in the return passage in the system, or in the gas passage or outlet of the heating furnace 20 or condenser 24,
By appropriately detecting the mercury concentration in the part, the safety of the treatment operation can be ensured by opening the system after the mercury concentration in the system has sufficiently decreased.

In this way, the present invention indirectly heats waste containing mercury, and unlike the direct heating method, combustion gas does not enter the heating furnace, and the amount of gas generated in the heating furnace can be reduced. This makes it possible to downsize the device.

In addition, in the present invention, as described above, not only the powdery substance containing mercury is separated and treated, but also the constituent parts of waste dry batteries, etc., including the crushed outer cylinder etc., are not separated and are all indirectly heated. is also possible.

[Effect of the invention 1] As described above, the present invention efficiently recovers mercury from waste dry batteries, etc. by crushing the waste dry batteries, etc. and then indirectly heating them to evaporate, condense, and recover the mercury. This has the extremely beneficial effect of solving the problem of pollution caused by waste mercury and also leading to resource conservation.

[Brief explanation of drawings]

The drawings are all system explanatory diagrams, and FIG. 1 shows a municipal waste separation system, and FIGS. 2 and 3 each show an embodiment of the present invention. 1-11 City Garbage, 2-11 Habukuro Iso, 3-11 Porcelain Sorting Iso,
4-11 ferrous metals, 5-11 vibrating sieve, 6--nonmagnetic materials, 7--large metals, small pieces of metals, 9-m-
crusher, 10-11 second vibrating sieve, 11--1 powdery substance containing mercury, 12-m-material with large particle size that does not contain mercury, 20-m-heating furnace, 21--1 electricity Heater, 2
2--7 ann, 23.26--conduit, 24--condenser, 25--m = cooling medium, 27--mercury collection pot, 28--11 return passage, 29--burner, 30-m-
Vacuum pump, 31--mercury concentration meter. Patent applicant: Ebara Corporation Patent attorney: Tadashi Takagi Yori Yukima 1) Kojibe

Claims (1)

[Claims] 1. Mercury recovery from waste, characterized by crushing waste containing mercury and indirectly heating the obtained powdery substance containing mercury to evaporate, condense, and recover mercury. Method. 2. The method for recovering mercury from waste according to claim 1, wherein the mercury concentration in the gas within the system is detected during the indirect heating. 3. The method for recovering mercury from waste according to claim 2, wherein the mercury concentration detection is performed in the indirect heating step. 4. The method for recovering mercury from waste according to claim 2, wherein the mercury concentration detection is performed in the condensation step.