JP2000026924A - Method for separating and removing non-ferrous metals in waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for separating and removing non-ferrous metals from waste which is capable of efficiently separating the non-ferrous metals in the waste and decomposing org. chlorine compds. without the generation of dioxin. SOLUTION: The method for separating and removing the non-ferrous metals from the waste consists in mixing the waste and the org. chlorine compds. in such a manner that the total molar number of the non-ferrous metals in the waste and the chlorine molar number in the org. chlorine compds. attain 1:1 to 5, more particularly 1:2 in conversion. The non-ferrous metals in the waste are brought into reaction with the chlorine and carbon in the org. chlorine compds. under a reducing atmosphere under which the quantity of the oxygen existing during the reaction stage attains the theoretical quantity necessary for conversion of all the carbon-components in the supplied org. chlorine compds. to CO or below at a reaction temp. of 500 to 1200 deg.C, by which the non-ferrous metals are evaporated away in the form of metal chlorides. One or more kinds among vinyl chloride, vinylidene chloride, PCB, CNP, PCP, 2, 4, 5-T, 2, 4-D, PCDD and PCDF are usable as the org. chlorine compds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for separating and removing non-ferrous metals from waste, and more particularly to dust discharged from a manufacturing process such as steel making, incinerated ash discharged from a waste treatment process, and Non-ferrous metals that can recover useful components such as irons and non-ferrous metals from wastes such as incineration fly ash, used refractory materials and used catalysts, and can safely treat difficult-to-treat substances such as organochlorine compounds. The present invention relates to a method for separating / removing species.

[0002]

2. Description of the Related Art As a conventional valuable material recovery technique from dust and the like, a process of reducing and melting Zn contained in dust using an electric furnace dust by using a weltz kiln or a plasma generator. F using ultra-high temperature
e and Zn separation techniques are known. As a method for treating incinerated fly ash, a high-temperature melting method is known. On the other hand, as a method for treating an organic chlorine compound, a high-temperature combustion method, a low-temperature dechlorination method, and the like are known. In the above-mentioned method of recovering Zn from electric furnace dust using a Welz kiln, coke is added to the dust.
This is a technique of mixing about 0%, reducing and volatilizing and separating at about 1200 ° C., oxidizing an exhaust gas containing Zn and Pb, and separating and recovering it as crude zinc oxide using a bag filter or the like. According to this technique, Fe contained in dust is almost “entangled” and is not useful. In addition, since coke and heavy oil are used for dust reduction, there remains a problem as a resource recycling technique such as not being suitable for processing dust having a low Zn content in terms of cost.

[0003] A valuable resource recovery method using a plasma heating apparatus is to perform reduction and volatilization separation of Zn and Pb in dust by melting the dust at 1500 to 1600 ° C in a reducing atmosphere using electric energy. Although molten iron and slag can be obtained together with Zn, Pb, etc., there are problems such as high processing equipment costs and high running costs. Also,
As a method of treating incinerated fly ash, there is a high-temperature melting method (burner type, plasma type, coke bed type), but this method also requires external energy (electricity, kerosene, coke, etc.) to be heated and melted at 1500 ° C. Accordingly, the processing is performed with a primary focus on containing heavy metals contained in fly ash in slag. For this reason, there are problems such as high processing cost and no consideration for recovery of metal resources.

[0004] Further, it is difficult to suppress dioxins (abbreviated as DXNs) by a normal temperature combustion method with an organic chlorine compound, and high temperature combustion (1100 ° C or higher) is encouraged. Even in this high-temperature combustion, re-synthesis of DXNs is concerned,
Exhaust gas is quenched or neutralized HCl in exhaust gas,
Released to the atmosphere. In other words, we concentrate on the decomposition process, not only do not effectively use the energy and Cl held by the organic chlorine compound as resources, but also need auxiliary agents such as slaked lime and alkaline solution for the treatment of hydrogen chloride. And so on.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and solves the problem of valuable resources in waste, especially C
Separation and removal of non-ferrous metals in wastes that can be efficiently and inexpensively separated into u, Zn, Pb and Fe and that can decompose organic chlorine compounds, which are difficult-to-treat wastes, without generating dioxins It is an object to provide a method.

[0006]

According to the present invention, there is provided a method for separating and removing non-ferrous metals from waste containing non-ferrous metals. The total mole number of non-ferrous metals in the product and the mole number of chlorine in the organic chlorine compound are mixed so that the ratio is 1: 1 to 5 and preferably 1: 2, and the reaction temperature is 500 to 1
At 200 ° C., preferably 600-900 ° C., under a reducing atmosphere in which the amount of oxygen present during the reaction step is less than the theoretical amount required to convert all the carbon content in the supplied organochlorine compound to CO. A method for separating and removing non-ferrous metals in wastes by reacting non-ferrous metals in wastes with chlorine and carbon in an organic chlorine compound and evaporating them off as metal chlorides. is there. In the present invention, as the organic chlorine compound, vinyl chloride, vinylidene chloride, PCB (polychlorinated biphenyl), CNP (chloronitrophenol), PCP (pentachlorophenol), 2,4,5-T (2,4,4) One or more of 5-trichlorophenoxyacetic acid), 2,4-D (2,4-dichlorophenoxyacetic acid), PCDD (polychlorodibenzodioxin), and PCDF (polychlorodibenzofuran) can be used.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a high-temperature reduction treatment of non-ferrous metals such as copper, zinc and lead and useful components such as iron contained in wastes such as dusts using organochlorine compounds which are difficult to treat. By doing so, the organic chlorine compounds are decomposed without generating dioxins to make them harmless, and at the same time the useful components are efficiently separated and reused as resources, for example,
This is a separation / removal method in which iron can be used as a metal and the recovered non-ferrous metal can be used as a smelting material. The present invention
The vapor pressure difference between the chlorides of zinc, lead and copper, which are useful metals in dust, and metallic iron is large, and by specifying the reaction conditions (reducing atmosphere, ratio of non-ferrous metal to chlorine and reaction temperature), almost completely iron It was conceived based on the principle that it can be separated into non-ferrous metals, which are volatilized as chlorides and collected by bag filters, direct quench devices, etc.
It is possible to increase the ratio of iron in the residue by collecting it by introducing it into a separation packed tower. FIG. 1 shows vapor pressure curves of chlorides of zinc, lead and copper and metallic iron.

When the chlorine content in the organic chlorine compound to be added is mixed at a supply ratio higher than the theoretical amount for converting non-ferrous metals contained in dust into chloride, or when the reaction temperature exceeds 900 ° C., hydrogen chloride content is reduced. It was clarified that the pressure increased and iron was chlorinated, thereby lowering the separation efficiency. FIG. 2 shows a standard free energy change temperature diagram for chloride formation. In addition, some metal chlorides, such as CuCl ₂ , function as a catalyst for resynthesizing dioxins. However, depending on the reaction conditions, a high-temperature treatment of 1000 ° C. or more and ceramic By providing an exhaust gas treatment process such as a high-temperature bag filter or a direct quench (immersion type direct quenching), the resynthesis of dioxin can be suppressed to a low level.

The molar ratio defined in the present invention is:
The description will be made based on the balance between the zinc content and the chlorine content. In the present invention, the theoretical chlorine amount required for converting zinc contained as zinc oxide (ZnO) into chloride (ZnCl ₂ ) and volatilizing it is Zn: Cl ₂ = 1: 1, and Zn: Cl =
1: 2. That is why "preferably 1: 2" is used. In order to make the salification reaction proceed more rapidly and more, a large amount of chlorine source can be added, and at least the added portion contributes to the reaction. When added in a large amount, hydrogen chloride is generated in the exhaust gas, and when added in a small amount, the zinc recovery rate decreases. If the reaction temperature is too high, there is a concern that the amount of hydrogen chloride (HCl) generated will increase (exhaust gas). According to FIG. 2, the line of H ₂ + Cl ₂ → 2HCl decreases with temperature and is stabilized. Conversely, the line of Zn + Cl ₂ → ZnCl ₂ increases with temperature.

[0010]

The present invention will be described below in more detail with reference to examples. Example 1 FIG. 3 shows a schematic configuration diagram of an apparatus used in an experiment of a separation / removal method of the present invention. In FIG. 3, first, in order to mix and mold the non-ferrous component in the dust 4 and the chlorine in the organic chlorine compound at a predetermined ratio, the respective contents were quantified by the X-ray fluorescence analyzer 1 in advance. The dust 4 and the organochlorine compound 5 are collected at a predetermined ratio and mixed and pulverized by the pulverizer / mixer 2. The mixed sample was molded to about 4 × 6 mm by compression molding 3. The molded pellet is continuously supplied to a quartz reaction tube 7 heated to a predetermined temperature. The quartz reaction tube 7 is provided with an alumina crucible 9 held inside a ceramic support 10 therein.
The outer periphery is covered with a tubular electric furnace 8, the reaction temperature is controlled by the tubular electric furnace 8, and an inlet 6 for a molded pellet of a sample, an inlet 15 for an argon gas, and an outlet 16 for an exhaust gas are provided on the upper part. ing.

In the experiment, an artificial sample (Fe ₂ O ₃ , ZnO; Fe / Z) assuming electric furnace dust using the apparatus shown in FIG.
n: 5: 3) 4 and pulverized PVC (chlorine content about 57
%) 5 was mixed so that the ratio of zinc to chlorine was about 1: 2.
Then, pressure molding 3 was performed. The pellets were continuously charged into a furnace 7 heated to about 870 ° C., and a low-boiling compound produced by the reaction was separated and recovered by an argon stream while passing a predetermined amount of 13 argon gas from an argon cylinder 11. The generated gas is led to the condenser 18 for recovery, and the non-agglomerated gas is discharged through the filter 19 and the absorber 20. The result is shown in FIG.
Shown in In FIG. 4, ● represents the Zn / Fe ratio in the residue;
Indicates the Fe ratio. Almost 100% of the input zinc was discharged from the reactor as a gas, and approximately 90% or more of iron remained in the furnace.

[0012]

According to the present invention, when separating and removing nonferrous metals from waste containing nonferrous metals, the amount ratio of organochlorine compounds such as PVC added to the reaction and the reaction temperature are controlled to reduce By doing so, it is possible to suppress the generation of hydrogen chloride and reduce the remaining non-ferrous metals in iron, and even in wastes of mixed composition that are difficult to separate by magnetic separation, the non-ferrous metals Iron can be used as a raw material for steel.

[Brief description of the drawings]

FIG. 1 is a vapor pressure curve diagram of chlorides of zinc, lead, and copper and metallic iron.

FIG. 2 is a graph showing a change in standard free energy (ΔG) depending on a temperature (K) of chloride production.

FIG. 3 is a schematic configuration diagram of an apparatus used in an experiment of the present invention.

FIG. 4 is a diagram showing a change in Zn / Fe ratio and Fe ratio in a residue according to a change in an argon flow rate (ml / min, STP).

[Explanation of symbols]

1: X-ray fluorescence analyzer, 2: crushing mixer, 3: compression molding,
4: dust, 5: organochlorine compound, 6: sample inlet,
7: quartz reaction tube, 8: tubular electric furnace, 9: alumina crucible, 10: ceramic support, 11: argon cylinder,
12: valve, 13: flow meter, 14: thermocouple thermometer, 1
5: Argon gas inlet, 16: Gas outlet, 18: Condenser, 19: Filter, 20: Absorber,

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hiroshi Nagai 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa F-term in Ebara Research Institute, Ltd. (Reference) 4K001 AA09 AA10 AA20 AA30 BA14 BA22 BA24 CA13 DA08

Claims (2)

[Claims] 1. A method for separating and removing non-ferrous metals from waste containing non-ferrous metals, wherein the waste and the organochlorine compound are separated by the total number of moles of the non-ferrous metal in the waste and the organochlorine compound in the organochlorine compound. Mixing is performed so that the molar number of chlorine is 1: 1 to 5 in terms of a ratio, the reaction temperature is 500 to 1200 ° C., and the amount of oxygen existing in the reaction step is such that the carbon content in the supplied organic chlorine compound is all CO Non-ferrous metals in the waste are reacted with chlorine and carbon in the organic chlorine compound under a reducing atmosphere such that the theoretical amount required for conversion to less than the stoichiometric amount is required to be evaporated and removed as metal chloride. Method for separating and removing non-ferrous metals from waste. 2. The organic chlorine compound is vinyl chloride,
Vinylidene chloride, PCB, CNP, PCP, 2, 4, 5
The method for separating and removing non-ferrous metals in waste according to claim 1, wherein the method is selected from one or more of -T, 2,4-D, PCDD, and PCDF.