JPH0413033B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for treating waste dry batteries.

[Prior Art] Waste dry batteries have suddenly become a social problem recently, because environmental pollution is expected due to the electrolyte layer containing mercury.

Estimating from published statistics, there are approximately 50 in Japan.
It would be a problem if tons of mercury per year were to be mixed into municipal waste and disposed of, and if it were to be mixed into general incinerators and landfills.

In addition, manganese, alkaline and
If we estimate the components of manganese batteries in the same way as the mercury mentioned above, approximately 13,000 tons of manganese oxide, 15,000 tons of zinc, and 10,000 tons of iron will be dumped every year without being recycled.

Currently, technology is being developed to recycle such useful metals together with mercury, and the Clean Japan Center has published the ``Survey Report on the Development Status of Recycling Technology (Batteries)'' (published in March 1982). ” has the first
Three methods for disposing of used manganese dry batteries are introduced as shown in Figures 3 to 3.

The method shown in Figure 1 uses a low-frequency or high-frequency electric heating furnace to heat the crushed primary battery at 400 to 500°C for several hours in an electric heating furnace to separate the solid phase, liquid phase, and gas phase. Roughly divided into three phases,
The solid phase portion is subsequently heated to around 800℃ and then recovered as an iron, carbon, and manganese sulfate solution through magnetic separation and filtration.The liquid phase portion is crude zinc, and after other components are removed, it is recovered as a zinc chloride solution. ,
The gaseous phase contains mercury, cadmium, etc., and is recovered by capturing it with chelate resin.

In the method shown in FIG. 2, lime is added and mixed using a roasting furnace, roasted in a reducing atmosphere, and separated into each component by appropriate treatment.

The method shown in FIG. 3 uses a roasting furnace and roasts in an oxidizing atmosphere.

[Object of the Invention] The present invention proposes a method different from the above-mentioned processing method, and its purpose is to provide an economical and practical method for processing waste dry batteries that can save energy.

[Structure of the Invention] In the method for processing waste dry batteries according to the present invention, a vertical shaft furnace having a melting furnace at the bottom of the furnace is divided into two areas via a valve such as a rotary valve, and the upper part of the furnace is placed in an oxidizing atmosphere. The lower part of the furnace is a reducing atmosphere area, the upper part of the furnace processes mercury, and the lower part of the furnace processes zinc and manganese iron alloys. The phlegm is taken out of the furnace, subjected to necessary processing, and then introduced into the upper stage of the furnace, making it possible to use energy effectively and process and recover useful metals at relatively low cost.

[Example] The present invention will be described below based on an illustrative example.

As shown in Figure 4, first, waste dry batteries (all primary batteries except silver oxide batteries, which are collected separately) B are crushed in a crusher 1, and the contents are thoroughly absorbed into the atmosphere in the furnace. After being exposed, it is classified by a classifier 2, and the powdery substances P that are likely to generate dust in the furnace under the sieve are kneaded and granulated in advance, and the solid substances S (mainly metals and electrode graphite) on the sieve are mixed and granulated. rods) and charged into the shaft furnace 4 from the charge hopper 3.

The shaft furnace 4 is a rigid type having a melting furnace 7 such as an induction electric furnace or an electric resistance furnace at the bottom, the upper part of the furnace is an oxidizing atmosphere area 5, and the lower part of the furnace is a reducing atmosphere area having the melting furnace 7 at the bottom. It is in area 6.

Furthermore, a rotary valve 8 or a double bell, etc. that can maintain airtightness is installed at the inlet of the charge hopper 3, and at the connection between the oxidizing atmosphere area 5 and the reducing atmosphere area 6, mixing of both atmospheres is avoided. For this reason, a valve such as a rotary valve is installed to separate the area into an oxidizing atmosphere area and a reducing atmosphere area, and at the same time, an inert gas Go is introduced for gas sealing.

In such a shaft furnace 4, mercury Hg is treated in the upper oxidizing atmosphere zone 5, zinc Zn is treated in the lower reducing atmosphere zone 6, and manganese iron alloy FeMn is melted and reduced in the bottom melting furnace 7. The reducing gas CO generated during the melting reduction is immediately taken out of the furnace, subjected to necessary treatment to become an oxidizing gas G ₁ , and this gas G ₁ is introduced into the oxidizing atmosphere region 5 .

That is, the charge is heated and oxidized in the oxidizing atmosphere area 5 by high-temperature oxidizing gas _G1 rising countercurrently from below, and the mercury compound becomes mercuric oxide HgO, which is further decomposed at 500°C or higher. metal mercury vapor
It becomes Hg and is taken out of the area along with other gases.

Therefore, the gas outlet temperature here needs to be at least 500°C or higher.

The mercury vapor gas G ₂ taken out of the area is led to the incinerator 9 in order to burn the combustible content in the gas with a sufficient amount of oxygen to complete the production of mercuric oxide.

The mercury vapor gas G ₂ discharged from the incinerator 9 is condensed and removed in a mercury condenser 10 similar to conventional mercury refining, and further passed through a gas cleaning tower 11 and a dust collector 12 to a detoxification equipment 13. be led to. Although various types of abatement equipment 13 can be considered, adsorption using activated carbon is effective, and activated carbon that has adsorbed mercury can be recycled to the shaft furnace 4 together with the processed materials of the dust collector 12 and the dust collector 14, thereby achieving a complete closed system. is possible.

Next, the workpiece that has been demercurized in the oxidizing atmosphere zone 5 enters the reducing atmosphere zone 6 through a rotary valve, etc., where the reducing gas CO rising from below first reduces zinc, and the metal zinc is reduced. When the temperature inside the furnace exceeds the boiling point of , it evaporates and leaves the furnace together with the reducing gas CO.

For this reason, the temperature at the top of the reducing atmosphere area where the gas outlet is located must be at least 907°C (zinc boiling point) or higher, preferably 1000°C or higher, and the temperature of the workpiece coming from the oxidizing atmosphere area 5 must be 950°C or higher. is necessary.

The workpiece charged into this reducing atmosphere area 6 is melted in a melting furnace 7 at the bottom of the furnace while being reduced.

In the melting furnace 7, manganese oxide and iron in the unreduced material undergo a direct melt-reduction reaction with the remaining carbon to generate ferromanganese FeMn and generate carbon monoxide gas CO. The gas is used as reducing gas CO in the reducing furnace 6.

The reducing gas CO coming out of the reducing atmosphere area 6 is led to the zinc condenser 15 together with metal zinc vapor.

In the zinc condenser 15, metallic zinc Zn is removed as molten zinc, and the remaining gas is cooled in a cooler 16, washed and desulfurized in a desulfurizer 17, and then
It is burned in a combustion furnace 18 and supplied to the lower part of the oxidizing atmosphere area 5 as an oxidizing gas G ₁ that serves as a heat source and an oxidizing agent for the oxidizing atmosphere area 5 .

[Effects of the Invention] As described above, according to the present invention, since the vertical shaft furnace is separated into the oxidizing atmosphere area and the reducing atmosphere area by a valve such as a rotary valve, the workpiece is completely protected in the oxidizing atmosphere area. After demercury treatment, it is sent to a reducing atmosphere area, where zinc and manganese iron alloys are reduced, and the zinc reduced in the reducing atmosphere is taken out of the furnace together with the reducing gas and removed from the reducing gas. It was separated and recovered as metallic zinc, and the reducing gas was burned in a combustion furnace and used as a heat source in the oxidizing atmosphere.
Energy can be used effectively and useful metals can be recovered at relatively low cost, making it extremely economical and practical.

[Brief explanation of drawings]

FIGS. 1, 2, and 3 are flowcharts showing the conventional processing method, and FIG. 4 is a flowchart showing the method for processing waste dry batteries according to the present invention. 1... Crusher, 2... Classifier, 3... Charge hopper, 4... Shaft furnace, 5... Oxidizing atmosphere area, 6... Reducing atmosphere area, 7... Melting furnace, 8...
... Rotary valve, 9 ... Incinerator, 10 ... Mercury condenser, 11 ... Gas cleaning tower, 12 ... Dust collector, 13 ... Hazard removal equipment, 14 ... Shitsukuna, 15
... Zinc condenser, 16 ... Cooler, 17 ... Desulfurizer, 18 ... Combustion furnace.

Claims (1)

[Scope of Claims] 1. A vertical shaft furnace having a melting furnace at the bottom of the furnace is divided into two zones via a valve such as a rotary valve, and the upper part of the furnace is an oxidizing atmosphere area, and the lower part is a reducing atmosphere area. The upper part of the furnace processes mercury, and the lower part of the furnace processes zinc and manganese iron alloy, etc., and the reducing gas generated in the lower part of the furnace is immediately taken out of the furnace to remove zinc. A method for processing waste dry batteries, which comprises separating them, burning them in a combustion furnace, and introducing them into the lower part of the oxidizing atmosphere area in the upper part of the furnace as a heat source for the oxidizing atmosphere area. 2. Claim 1, characterized in that a mercury compound is oxidized to form mercuric oxide in an oxidizing atmosphere area in the upper stage of a vertical shaft furnace, and then decomposed and taken out of the furnace as metallic mercury vapor. Disposal method for waste batteries as described in section. 3 Zinc is reduced in the reducing atmosphere area in the lower part of the vertical shaft furnace, and is taken out of the furnace as zinc vapor, and
2. The method for disposing of waste dry batteries according to claim 1, wherein the remaining manganese oxide and iron are directly reduced and melted to be taken out of the furnace.