JPH07258764A - Method for recovering metal form combustion residue of carbonous fuel - Google Patents

Abstract

PURPOSE:To utilize a difference in stability to the temp. of gaseous phase metals so as to separate the metals by halogenating the combustion residues of fossil fuel, then forming gaseous phase metal complexes by a specific complexing agent and introducing these complexes into cracking zones having a temp. gradient. CONSTITUTION:A vessel 7 contg. AlCl3 which is the complexing agent is arranged at the front end of a quartz reaction tube 1 and a vessel 9 housing the fuel residues of the fossil fuel is arranged in the part succeeding thereto to provide the reaction tube with regions A-1 to A-13 having a temp. gradient. The gaseous mixture composed of N2CCl2 is introduced into the reaction tube from its left end while the reaction tube 1 is kept heated by an electric furnace 35. The AlCl3 is heated to evaporate and the metal components, such as V, in the combustion residues in the vessel 9 are chlorinated. The formed metal chloride reacts with the evaporated AlCl3 and form the respective gaseous phase metal complexes. The gaseous phase metal complexes move together with N2 of a carrier gas to a low pressure side in the reaction phase 1 and are made into metal chlorides in the regions of the cracking temp. of the respective metal complexes. These metal chlorides are separated and precipitated into A-1 to A-13. The valuable metals in the combustion residues are thus effectively separated and recovered.

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 metals from combustion residues of carbon-based fuels such as natural asphalt and coal.

[0002]

2. Description of the Related Art Crude oil, natural asphalt, coal and the like contain various metals or metal compounds as impurities. When these fossil fuels are burned as they are or as heavy oil after collecting light components,
In the combustion residue, the metal (which is considered to be mainly an oxide) remains in a concentrated state.

[0003] For example, natural asphalt (a typical example thereof is orinocotar produced in Venezuela of South America) has abundant resources and is inexpensive, and is therefore regarded as an important fuel resource in the future. . Since such a bituminous material has low fluidity, an emulsion containing water, a surfactant and magnesium as a stabilizer for facilitating handling such as transportation (for example, known as a trade name “Olimuljeon”). It is used as a fuel (hereinafter sometimes referred to as a bituminous mixture). The combustion residue of the bituminous mixture contains a considerable amount of metal components such as V and Ni originally contained in the bituminous material, and also the above-mentioned valuable metals such as Mg.

Further, the combustion residue of a fuel obtained by making a slurry of coal powder (hereinafter sometimes referred to as a coal slurry fuel) also contains various metal components depending on the place of production or the type of coal.

The amounts of combustion residues of such heavy oils, bituminous mixtures and coal slurry fuels have been gradually increasing in recent years, and effective utilization of their useful components or safety treatment has become a major technical issue. is there. Some of these combustion residues are used as cement raw materials, refractory raw materials, etc., but most of them are landfilled or disposed of. One of the problems in this landfill or disposal is the pollution problem due to the elution of the metal components remaining in the combustion residue. Alternatively, from another point of view, the valuable metal remaining in the combustion residue is abandoned without being effectively used.

Conventionally, as a method for recovering the metal component in the combustion residue, a wet method such as a leaching method or a fractional crystallization method has been proposed, and a part thereof is carried out. For example, a wet method is used in which a combustion residue is decomposed with a mineral acid or an alkali to form a solution, and then a metal is recovered as a precipitate. However, the wet method has a drawback in that it requires a large-scale facility because the combustion residue is once dissolved, then separated and then solidified again, so that the cost is high. Further, since the precipitate is obtained as a mixture of a plurality of metals, it is difficult to separate the metals from each other.

[0007]

SUMMARY OF THE INVENTION Therefore, according to the present invention, it is possible to remove a metal component from a combustion residue of a carbon-based fuel without requiring a large-scale facility and a mutual separation step of each metal. The main purpose is to provide a method capable of collecting.

[0008]

As a result of repeated research on a method for recovering metal components from combustion residues of petroleum-based and coal-based fuels, the present inventor exerted a specific complexing agent on halogenated combustion residues. After forming the vapor phase metal complex,
It has been found that when this is introduced into a decomposition zone having a temperature gradient, a specific metal is deposited in a specific temperature region depending on the stability of the produced gas phase metal complex.

That is, the present invention provides the following metal recovery method from the combustion residue of a carbon-based fuel: A method for recovering metals from a combustion residue of a carbon-based fuel, which comprises applying a gas phase complexing agent to a halogenated combustion residue to form a gas phase metal complex, and then decomposing the gas phase metal complex with a temperature gradient. A method for recovering a metal, which comprises sequentially recovering each metal decomposed and deposited at a predetermined temperature by introducing the metal into a zone.

2. The method according to Item 1, wherein the combustion residue is a combustion residue of an emulsion fuel containing natural asphalt and water.

3. A method for recovering metal from a combustion residue of a carbon-based fuel, in which vanadium in the combustion residue is caused to act with a halogenating agent to form vanadium halide, which is deposited and recovered, and then the remaining amount in the combustion residue A gas phase complexing agent is allowed to act on a metal component to form a gas phase metal complex, and the metal complex is guided to a decomposition zone having a temperature gradient to sequentially recover each metal decomposed and deposited at a predetermined temperature. Method of recovering metal.

4. Item 4. The method according to Item 3, wherein the combustion residue is a combustion residue of an emulsion fuel containing natural asphalt and water.

In the present invention, combustion residues of petroleum-based and coal-based fuels (hereinafter simply referred to as combustion residues) are heated in an inert gas stream in the presence of a halogenating agent to form metal halides.

The metal or metal compound (hereinafter simply referred to as a metal) contained in the combustion residue may vary depending on the type of fuel, the place of production, etc., but is usually V, Ni, Mg, Fe, Mo,
Si, Al, Na, Zn and the like. In particular, the combustion residue of the bituminous mixture contains a considerably large amount of Mg to be blended as a stabilizer. Activated carbon may be mixed with the combustion residue as a deoxidizer in order to accelerate the halogenation reaction described later.

In the present invention, as the halogenating agent which reacts with the metal in the combustion residue to be used, halogen gas such as chlorine gas, bromine gas, iodine gas; hydrogen halide gas such as hydrogen chloride; ammonium chloride, odor Examples thereof include ammonium halides such as ammonium halides; metal halides such as silicon chloride and titanium chloride. When the halogenating agent is a gas, it is usually used as a mixture with a carrier gas consisting of an inert gas such as nitrogen or helium. When a solid halogen source such as ammonium chloride is used, it may be directly mixed with the combustion residue. Among these halogenating agents, chlorine gas is more preferable. The amount of the halogenating agent used is preferably about 2.5 to 30 times (molar ratio) with respect to the metal in the combustion residue. The reaction between the combustion residue and the halogenating agent is preferably carried out at a temperature of about 200 to 1000 ° C. The reaction of this metal with the halogenating agent forms a metal halide containing a plurality of metal components derived from the combustion residue.

Next, the metal halide produced above is reacted with a complexing agent. A metal halide is used as the complexing agent. As such a metal halide,
Aluminum halides such as aluminum chloride, aluminum bromide, aluminum iodide; sodium chloride,
Examples thereof include alkali metal halides such as potassium chloride and mixtures of two or more thereof. In the present invention, a compound capable of being converted into a metal halide as a complexing agent in the presence of the above halogenating agent can also be used as a precursor of the metal halide. Examples of such precursors include alum and cryolite.
These complexing agents may be used alone or in admixture of two or more. The amount of the complexing agent used is preferably about 1 to 40 times (molar ratio) that of the metal halide. The reaction between the metal halide derived from the combustion residue and the complexing agent is preferably performed at a temperature of about 300 to 1000 ° C. This reaction proceeds rapidly to produce a gas phase metal complex. The vapor phase metal complex is composed of a plurality of complex compounds having different decomposition temperatures depending on the metal. The complex compound varies depending on the halogenating agent used, the complexing agent, the type of metal contained in the combustion residue, etc., but is usually a Ni complex (decomposition temperature 3
10 to 450 ° C.), Mg complex (decomposition temperature 170 to 3)
The main one is about 50 ° C.

The produced gas-phase metal complex is introduced into a decomposition zone having a temperature gradient from a high temperature part of about 600 ° C. to a low temperature part of about 50 ° C. along with an inert gas flow, and has a predetermined temperature range. In, the compound is decomposed into a metal halide (for example, nickel chloride, vanadium chloride, magnesium chloride, etc.) corresponding to the kind of the halogenating agent and the complexing agent used and deposited.

Therefore, the temperature distribution and the temperature gradient in the decomposition zone may be set according to the metal halide which is determined by the type of metal contained in the combustion residue and the type of complexing agent used. Further, by changing the temperature distribution in the decomposition zone, the recovery rate of metal and the purity of recovered metal can be improved. For example, vanadium chloride is
Precipitation occurs in a temperature range of about 80 ° C or less, and nickel chloride is about 3
Precipitation occurs in the temperature range of 60 to 410 ° C., and magnesium chloride precipitates in the temperature range of about 170 to 450 ° C. Therefore, by setting the temperature range in which the precipitation amount of each precipitate is the largest, it is aimed. The metal can be efficiently recovered.

Alternatively, in the present invention, the vanadium component in the combustion residue may be first recovered in the form of vanadium chloride, and then the remaining metal component may be recovered by the above method. Vanadium chloride is the easiest to recover because it is volatile and precipitates at relatively low temperatures. Therefore, when the combustion residue is contacted with a chlorine-containing gas (for example, chlorine + nitrogen) at a temperature of about 250 to 600 ° C, vapor-phase vanadium chloride is selectively formed. And deposit. According to this method, the purity is about 95%.
About vanadium is obtained with a yield of about 100%. Therefore, when the combustion residue after vanadium recovery is subsequently treated by the above method, the recovery process can be simplified, and vanadium is hardly mixed with other metals, and the purity of other recovered metals can be improved. You can

Referring to the embodiments shown in the drawings,
The present invention will be described in more detail.

FIG. 1 is a sectional view showing the outline of an example of an apparatus for carrying out the method of the present invention. The entire apparatus comprises a quartz reaction tube 1, two electric furnaces 3 and 5 surrounding the reaction tube 1, an alumina magnetic tube A, a complexing agent (aluminum chloride in the illustrated method) container 7 and a combustion residue container 9. Is the main component. The alumina magnetic tube A is divided into 13 regions A-1 to A-13. Each region is set so that the temperature decreases from the left end to the right end, and the temperature can be controlled independently. Therefore, the temperature in the alumina magnetic tube A is
It is possible to adjust so as to gradually decrease instead of decreasing linearly.

The method of the present invention is carried out, for example, as follows. First, while the complexing agent (aluminum chloride is a specific example) is contained in the container 7 and the combustion residue is contained in the container 9, the reaction tube 1 is heated by the electric furnace 3 and the electric furnace 5 while the reaction tube 1 is being heated. introducing N ₂ -Cl ₂ mixed gas from the left edge. At this time, each area A-1 to A of the alumina magnetic tube A
-13 is kept at a predetermined temperature. The aluminum chloride in the container 7 is vaporized by heating, and at the same time, the metal component (presumed to be an oxide) in the combustion residue in the container 9 is also chlorinated. Formed metal chloride (MCl _x )
Reacts with a vaporized aluminum chloride to form a vapor phase metal complex as shown below.

MCl _x (s or g) + nAl ₂ Cl ₆ (g)
= MAl _2n Cl _{6n + x} (g) This vapor phase metal complex is transported to the low temperature side in the alumina magnetic tube A by N ₂ as a carrier gas and is deposited as a metal chloride when the decomposition temperature is reached. . The gas-phase metal complex contains a plurality of metals, but the decomposition temperature of each complex component varies depending on the metal, so that the regions A-1 to A-13 are different.
It is possible to separate metals from each other due to the difference in the deposition position leading to.

Aluminum chloride produced by the decomposition of the gas phase metal complex can be taken out of the system together with the carrier gas and recovered, and can be reused.

[0025]

The metal in the combustion residue can be efficiently recovered with high purity by a simple operation.

When the combustion residue from which the metal components have been removed is subjected to disposal or landfill treatment, it is possible to reduce the amount of disposal by reducing the amount of the combustion residue.

[0027]

EXAMPLES Examples will be shown below to further clarify the features of the present invention.

Example 1 The present invention was carried out using the apparatus shown in FIG.

In other words, AlCl ₃ as a complexing agent is added to the container 7.
In a state of containing 10 g and containing 0.5 g of combustion residue of a bituminous mixture (trade name “Olimuljeon”) in the container 9,
While heating the quartz reaction tube 1 (inner diameter 25 mm x length 1000 mm x thickness 1.5 mm), N as a carrier gas
A mixed gas of 30 ml / l and Cl ₅ ml / l as a chlorinating agent was flowed in.

The composition of the combustion residue is as shown in Table 1. On the right side of the container 9 inside the reaction tube 1, the inner diameter 1
6mm x 2.5mm thick alumina magnetic tube with a length of 3c
Thirteen cylindrical bodies cut into m are arranged to form regions A-1 to A-13 in which the temperature can be adjusted arbitrarily.

[0031]

[Table 1]

The temperature in the container 9, that is, the reaction temperature, is set to 60.
FIG. 2 shows the temperature distribution in each region when the temperature is 0 ° C., 500 ° C., and 400 ° C. However, in this case, the temperature was adjusted so that the temperature changed substantially linearly from the high temperature side to the low temperature side. In FIG. 2, the temperature measurement positions (horizontal axis) are simply shown as 1 to 13 in order to simplify the description, but these indicate regions A-1 to A-13, respectively.

Table 2 shows the relationship between the transportation conditions and the yield of metal components.
3 and the tendency of precipitation of vanadium, nickel and magnesium under the conditions of a reaction temperature of 600 ° C. and a transportation time of 12 hours are shown in FIG. From these results, the following matters became clear.

[0034]

[Table 2]

Note: Yield = total precipitation amount / (metal remaining in container 9 + total precipitation amount) × 100 (%) (a) Vanadium is 80 ° C. or lower, nickel is 360 to 360
In the temperature range of 410 ℃, magnesium is 170-450 ℃
Precipitation was observed in the temperature range of.

(B) Reaction temperatures of 500 ° C. and 400 ° C.
In that case, the yield of metals other than vanadium was low regardless of the transportation time.

(C) When the transportation time was 6 hours, the yield of metals other than vanadium was low even when the reaction temperature was 600 ° C.

(D) On the other hand, when the reaction temperature is 600 ° C. and the transportation time is 12 hours, the yield of nickel is a little low at 60%, but the yields of vanadium and magnesium are close to 100%. It was

Example 2 When the combustion residue was treated in the same manner as in Example 1 except that the complexing agent was not used, vanadium was precipitated in the temperature range of 80 ° C. or lower, and the yield was about 95% and the yield was about 95%. Recovery at about 100% was possible.

It is speculated that this is because vanadium was converted into a low boiling point compound such as chlorine oxide and transported. Therefore, the combustion residue after recovering vanadium was used in Example 1
It is considered that the temperature conditions can be simplified and nickel and magnesium can be recovered in high purity when treated in accordance with the above.

Example 3 From the results obtained in Example 1, it was found that the precipitation temperature regions of nickel and magnesium overlap each other. Therefore, near the midpoint of the precipitation peak temperatures of nickel and magnesium (3
An attempt was made to increase the purity of nickel by setting a constant temperature region at 80 ° C, 390 ° C, 400 ° C and 410 ° C. Figure 4 shows the temperature distribution in each temperature range in these cases.
Shown in. 5 and 6 show the precipitation tendency of vanadium, nickel and magnesium under the conditions of a reaction temperature of 600 ° C. and a transportation time of 12 hours.

From these results, the following matters were clarified.

(A) When a constant temperature region is provided at 380 ° C. or 390 ° C., nickel and magnesium are not separated well, so the nickel purity is at most 53.
% (See FIG. 5 showing an example in which a constant temperature region is provided at 390 ° C.).

(B) When a constant temperature region is provided at 400 ° C. or 410 ° C., the regions A-2 to A-6 (temperature 540
It was found that high-purity nickel of about 83 to 90% was obtained at (~ 410 ° C), and the ability to separate nickel and magnesium was improved (a diagram showing an example in which a constant temperature region was provided at 410 ° C). 6).

The recovered nickel chloride contains aluminum chloride derived from the complexing agent. However, it is possible to separate the two by utilizing the difference between the ascending point of nickel chloride (about 970 ° C.) and the ascending point of aluminum chloride (about 190 ° C.).

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an outline of an example of an apparatus for carrying out the method of the present invention.

FIG. 2 shows a reaction temperature of 600 ° C. and 500 in Example 1.
It is a graph which shows the temperature distribution of each area | region when it was set to 40 degreeC.

FIG. 3 is a graph showing the tendency of vanadium, nickel and magnesium to precipitate in Example 1.

FIG. 4 is a graph showing a temperature distribution when a constant temperature region is provided in the reactor in Example 3.

5 is a graph showing the tendency of vanadium, nickel and magnesium to precipitate when a constant temperature region of 390 ° C. is provided in the reactor in Example 3. FIG.

FIG. 6 is a graph showing the tendency of vanadium, nickel, and magnesium to precipitate when a constant temperature region of 410 ° C. is provided in the reactor in Example 3.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Quartz reaction tube 3 ... Electric furnace 5 ... Electric furnace 7 ... Container 9 ... Container A ... Alumina magnetic tube

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Takanobu Hirayama, 3-3-22 Nakanoshima, Kita-ku, Osaka City, Kansai Electric Power Co., Inc. (72) Taiichiro Suda 3--22, Nakanoshima, Kita-ku, Osaka Kansai Denryoku Co., Ltd. (72) Inventor Zenji Hotta 3-3-22 Nakanoshima, Kita-ku, Osaka City Kansai Denryoku Co., Ltd. (72) Inventor Ginya Adachi Mikage Taki, Mikage-cho, Higashinada-ku, Kobe-shi, Hyogo Prefecture No. 1345-9 (72) Inventor Kuniaki Owase 1-5-13, Sonehigashi-cho, Toyonaka-shi, Osaka (72) Inventor Teruaki Fukami 1668-113, Shirane-cho, Nakakoma-gun, Yamanashi Prefecture (72) Kenichi Machida 1-5-5 A-Magaya Nishi, Minoh-shi, Osaka Prefecture A-206 (72) Kenichi Nishikawa 3-2-12-1 Yamada Higashi, Suita City, Osaka Prefecture

Claims (4)

[Claims] 1. A method for recovering metal from a combustion residue of a carbon-based fuel, which comprises reacting a metal component in a halogenated combustion residue with a gas phase complexing agent to form a gas phase metal complex, A method for recovering a metal, which comprises sequentially recovering each metal decomposed and precipitated at a predetermined temperature by introducing a phase metal complex into a decomposition zone having a temperature gradient. 2. The method according to claim 1, wherein the combustion residue is a combustion residue of an emulsion fuel containing natural asphalt and water. 3. A method for recovering metal from a combustion residue of a carbon-based fuel, which comprises reacting vanadium in the combustion residue with a halogenating agent to form vanadium halide, precipitating and recovering it, and then combusting it. A vapor phase complexing agent acts on the remaining metal components in the residue to form a vapor phase metal complex, which is then introduced into a decomposition zone having a temperature gradient, so that each metal that decomposes and precipitates at a predetermined temperature is sequentially recovered. A method for recovering a metal, comprising: 4. The method according to claim 3, wherein the combustion residue is a combustion residue of an emulsion fuel containing natural asphalt and water.