MX2007014417A - Process for recovering valuable metals from waste - Google Patents

Abstract

A process for recovering valuable metals, namely, at least one element (M) selected from the group consisting of Mo, Ni and Co and V from waste containing the valuable metals in the form of iron ally, which comprises the step (a) of roasting the waste to form a roasted ore containing oxides of the valuable metals, the step (b-1) of heating the roasted ore together with an iron source and a flux to form a molten ion-base alloy, the step (b-2) of adding a reducing agent exhibiting an oxygen affinity higher than that of V at reduction temperature to the molten ion-base alloy to reduce the oxides and form a molten Fe-M-V alloy, the step (c) of oxidizing substantially only V contained in the molten Fe-M-V alloy to form a slag containing V oxide and a molten Fe-M alloy, and the step (d) of separating the slag from the molten Fe-M alloy. A process for recovering valuable metals, namely, at least one element (M) selected from the group consisting of Mo, Ni and Co and V from waste containing the valuable metals in the form of iron ally, which comprises the step (a) of roasting the waste to form a roasted ore containing oxides of the valuable metals, the step (b-1) of heating the roasted ore together with an iron source and a flux to form a molten ion-base alloy, the step (b-2) of adding a reducing agent exhibiting an oxygen affinity higher than that of V at reduction temperature to the molten ion-base alloy to reduce the oxides and form a molten Fe-M-V alloy, the step (c) of oxidizing substantially only V contained in the molten Fe-M-V alloy to form a slag containing V oxide and a molten Fe-M alloy, and the step (d) of separating the slag from the molten Fe-M alloy. Provided is a high frequency amplifier having two amplification elements of different element sizes connected in parallel and switching the amplification elements depending on the magnitude of output power. The high frequency amplifier is provided with an output matching circuit for matching the characteristic impedance (50Ω) both when the output power is high and low, and increasing the impedance when the amplification element in off state is viewed from the output side joint of two amplification elements. Consequently, high output high efficiency characteristics can be achieved and leakage of an amplified high frequency signal to the matching circuit on the amplification element side in off state can be suppressed.

Description

METHOD FOR RECOVERING VALUABLE WASTE METALS FIELD OF THE INVENCIOf The present invention relates to a method for recovering valuable metals from wastes such as desulphurisation catalysts used for oil refining, boiler ash generated in thermal power plants, etc.

BACKGROUND OF THE INVENTION The desulfurization catalysts used for oil refining, etc. and boiler mud, boiler ash, etc. generated from petroleum fuels in thermal eriergy plants, etc. They contain high concentrations of valuable metals such as Mo, Ni, V, etc. Since these valuable metals are rare and extremely expensive, it is desirable to recover them in the form of iron-based alloys in high concentration, so that the waste can be reused as resources. Japanese Patent 3705472 describes a method for heating a waste containing Ni, Mo and V at 450-950 ° C to remove S, N and C; Mix it with an iron source such as scales, etc. and a reducing agent such as coke, etc .; pulverize and granulate the mixture; heat the resulting granules at 150-150 ° C to perform the solid phase reduction of the oxides of Fe, Ni and Mo; melt them to form a molten material containing mainly Fe, Ni and Mo and a flux rich in V oxide; subjecting the molten material to a dephosphorylation treatment to form a low phosphorus (Ni, Mo) -Fe alloy; and mix the flux with iron and the reducing agent and heat it to reduce the V oxide in the flux, thereby forming a Fe-V alloy. Since the separation of Ni and Mo from V is carried out by a solid phase reduction method to reduce the Ni and Mo oxides without reducing the V oxide in this method, a mixture of the waste, the iron source and the agent of reduction is heated to relatively low temperatures of 1150-1350 ° C. However, the previous solid phase reduction method does not completely separate Ni and Mo from V, resulting in an alloy of Fe-Ni-Mo containing a relatively large amount of V, and an Fe-V alloy containing relatively long amounts of Ni and Mo. Also when a waste containing a large amount of P is used, V and P do not separate completely, resulting in a large amount of P contained in the Fe-V alloy. In an attempt to remove only P from this molten Fe-V alloy material, V would predominantly oxidize, resulting in an extremely large loss of V by oxidation. Thus, if P were dissolved in the Fe-V alloy, it would currently be difficult to remove P from the Fe-V alloy. Additionally, since the oxides of Fe, Ni and Mo are reduced in solid phase with a carbonaceous reducing agent such as coal or coke finely pulverized, etc., the Fe-V alloy contains C and an attempt to remove C by oxidation just as P would oxidize V simultaneously. Japanese Patent 3450779 describes a method for recovering metal components from a used catalyst containing V, Mo, Ni and Co with an AI2O3 carrier, comprising the steps of (a) calcining the used catalyst at 500-800 °. C to oxidize the metal components (b) add Si and / or Al in an amount of 20-120% by mass based on the stoichiometric amount to reduce the oxides of Mo, Ni and Co to metals, together with CaO, ( c) reduce them by heat to form a Mo-Ni-Co alloy and a CaO-Al2O3 slag containing V oxide, (d) add Si and / or Al in such amount to sufficiently reduce the V oxide contained in the slag separated from the Mo-Ni-Co alloy, (e) form a V-Si alloy or a V-AI alloy and a CaO-AI203 slag by heat reduction, and (f) separate the V-Si alloy. -Yes or the V-AI alloy of the slag. However, it is currently difficult to control the amount of a reducing agent (Si and / or Al) to reduce only the oxides of Mo, Ni and Co without reducing the oxide of V. For example, when much is added Si and / or Al, a large amount of the V-oxide is reduced and V is dissolved in the Mo-Ni-Co alloy. On the other hand, when very small amounts of Si and / or Al are added, part of the oxides of Mo, Ni and Co do not oxidize, remaining in the slag that contains V. Since there is no uniform reduction environment In a real operation, Si and / or Al can be partially oxidized before to participate in the reduction reaction, even if they are weighed accurately. Thus, the amounts of Si and / or Al that act as reduction agents would be insufficient, causing the above problems. It is evident from the foregoing that the method of Japanese Patent 3450779 fails to separate V from Mo, Ni and Co sufficiently. Recently, the desulfurization catalysts used for oil refining contain an increasing amount of P to show better performance, but it is difficult to remove only P from an alloy of V containing P because P and V have a higher oxidability. Accordingly, when the method of Japanese Patent 3450779 is carried out in the used desulfurization catalysts containing a large amount of P, the formed V-Si alloy or V-AI alloy contains too much P to reduce its concentration by example at a level corresponding to the ISO FeV40 standard, whereby the concentration of P is 0.1 mass% or less in an iron-based alloy containing 35-50 mass% of V. Japanese Patent 3705498 describes a method for recover valuable metals of V, Mo and Ni from a waste containing the valuable metals comprising the steps of (a) calcining the waste at 800-950 ° C to form the oxides of V, Mo and Ni, (b) reduce the oxides of Mo and Ni in the waste with Fe to form an alloy of Fe-Mo-Ni and a slag containing oxides of V, and (c) add a reducing agent to the slag containing V oxide to form an Fe-V alloy. However, like that Japanese patent 3450779, a weak reduction with Fe fails to separate Mo and Ni from V sufficiently, which results in large amounts of Mo and Ni contained in the slag containing V oxide. Even more, when this method is performed in desulfurization catalysts used with a lot of P a considerable quantity of P remains in the slag containing capitalized V oxide, in the Fe-V alloy formed in a later step, which causes deterioration in quality.

OBJECTS OF THE INVENTION Accordingly, an object of the present invention is to provide a method for recovering valuable metals, which includes at least one selected from the group consisting of Mo, Ni and Co and V, in the form of iron-based alloys of High quality (low in phosphorus) from a waste that contains valuable metals efficiently in a high yield. Another object of the present invention is to provide a method for recovering valuable metals and simultaneously collecting a slag produced secondarily in the form of calcium alumina.

BRIEF DESCRIPTION OF THE INVENTION As a result of intense research in virtue of the above objects, the inventor discovered that all the oxides of Mo, Ni and Co and V they are reduced by reducing agents that have high affinity for oxygen, such as Al, Si, C, at temperatures high enough for the valuable metals to diss in iron-based melts. Paying attention to the fact that P has an oxidability close to that of Mo, Ni and Co, the inventor also found that when valuable metal oxides are reduced so that all metals diss in an iron (or iron) -based alloy together with P, and that when the iron-base alloy is oxidized, substantially only V is only oxidized and transferred into a slag. The present invention has been completed based on such findings. Thus, the first method of the present invention for recovering valuable metals including V in the form of iron-base alloys from a waste containing the valuable metals comprises the steps of calcining the waste; reduce calcined waste while melting with an iron source, thus forming a molten iron-based alloy material containing valuable metals; oxidize the molten material to form a slag containing V oxide; and separating the slag containing V oxide from the remaining melting material. The second method of the present invention for recovering valuable metals including V in the form of iron-base alloys from a waste holding the valuable metals comprises repeating, once the slag containing V oxide is separated, at least one cycle comprising the steps of adding again a calcined waste to the remaining melting material, subjecting the resulting melting material to reduction and then oxidation, and separating a freshly formed slag containing V oxide. In a preferred embodiment of the present invention, the first method for recovering valuable metals, which includes at least one element of M selected from a group consisting of Mo, Ni and Co and V, in the form of an iron-based alloy from a waste containing the valuable metals, comprises the steps of (a) calcining the waste to form a calcined ore containing oxide of the valuable metals; (b) heating the calcined ore with an iron source, a flux and a reducing agent having a greater affinity for oxygen than V at a reduction temperature, to reduce the oxides of the valuable metals, thereby forming a molten material of Fe-MV alloy, (c) substantially only oxidize V in the Fe-MV alloy melt material to form a slag containing V-oxide and a Fe-M alloy melt; and (d) separating the V-oxide-containing slag from the passage of molten Fe-M alloy material. In another preferred embodiment of the present invention, the first method for recovering valuable materials, which includes at least one element of M selected from the group consisting of Mo, Ni and Co, and V, in the form of iron-based alloys to Starting from a waste comprising the valuable metals comprises the steps of (a) calcining the waste to form a calcined ore containing oxides of the valuable metals; (b-1) heat the calcined ore together with an iron source and a flux, to form a cast iron alloy material; (b-2) adding a reducing agent having greater affinity for oxygen than V at a reaction temperature to the molten material, thereby reducing the oxides of the valuable metals to form a molten Fe-M alloy material; (c) substantially oxidizing only V in the Fe-M-V alloy melt material to form a slag containing V-oxide and a Fe-M alloy melt material; and (d) separating the V-oxide-containing slag from the passage of molten Fe-M alloy material. In a further preferred embodiment of the present invention, the second method comprises repeating, after step (d), at least one cycle comprising the steps of (e) adding a fresh calcined mineral, a flux and a reducing agent having greater affinity for oxygen than V at a reaction temperature to the molten material of Fe-M alloy, thereby reducing the oxides of the valuable metals, so that valuable metals dissolve in the molten material of Fe-M alloy; (f) substantially oxidizing only V in the resulting Fe-M-V alloy melt material to form a slag containing V-oxide and a molten Fe-M alloy material; and (g) separating the slag containing V oxides from the molten material of Fe-M alloy. In a further preferred embodiment of the present invention, the second method comprises repeating, after step (d), at least one cycle comprising the steps of (e-1) adding a fresh calcined mineral and a flux to the alloy melting material of Fe-M, so that the ore fresh calcined is dissolved in the molten material; (e-2) add a reducing agent that has greater affinity for oxygen than V at a melting temperature, thereby reducing valuable metal oxides, so that valuable metals dissolve in the alloy melt material Fe-M; (f) substantially oxidizing only V in the resulting Fe-M-V alloy melt material to form a slag containing V-oxide and a Fe-M alloy melt; and (g) separating the V-oxide-containing slag from the passage of molten Fe-M alloy material. The reducing agent preferably comprises Al and / or Si. The reducing agent preferably further comprises C. To oxidize V in the Fe-M-V alloy, it is preferable to add quicklime as the flux and an oxygen gas and / or iron oxide scale as the oxidizing agent to the molten material. A dephosphorylation treatment is preferably performed on the molten Fe-M alloy material after the slag containing V oxide is separated. The dephosphorylation treatment preferably comprises adding quick lime, silica sand and a western agent. The dephosphorylation treatment converts the Fe-M alloy to one of low carbon and low phosphorus. It is preferable to reduce the V oxide to form an alloy of Fe-V by adding a source of iron and a reducing agent that has higher affinity for oxygen than V at a reaction temperature to the slag containing V oxide and then heating it.

Using A as the reducing agent and quicklime as a flux, it is possible to form slags substantially composed of calcium oxide and alumina. Such slag is obtained after the reduction of the calcined ore and after the reduction of the slag containing V. oxide.

BRIEF DESCRIPTION OF THE DRAWING Figure 1 is a graph schematically showing the change in affinity for oxygen (oxidability) with temperature with respect to Ni, Mo, Co, P, Fe, V, C, Si and Al. Figure 2 (a) is a diagram of flux showing steps in the method of the present invention to recover valuable metals. Figure 2 (b) is a flux diagram showing the steps for producing an Fe-V alloy from a slag containing V-oxide. Figure 3 (a) is a schematic view showing a melting furnace and reduce a calcined mineral. Figure 3 (b) is a schematic view showing a homo to oxidize a molten iron-based alloy material containing valuable metals. Figure 3 (c) is a schematic view showing an oven for reducing slag containing V. oxide.

Figure 4 is a graph schematically showing the change in amount with respect to the time of a slag and a molten material from cycle to cycle in the second given memento of the present invention. Figure 5 is a graph showing the concentration change over time of Mo, Ni, V and P when the molten Fe-Mo-Ni-V alloy material containing P is oxidized in reference example 1. The Figure 6 is a graph showing the change in concentration over time of Mo, Ni, V and P in the molten Fe-Mo-Ni-V alloy material containing P in the second method of the present invention. Figure 7 is a graph showing the change in concentration over time of Mo, Ni, C and P when the molten Fe-Mo-Ni-V alloy material containing P is dephosphorylated in Reference Example 2.

DETAILED DESCRIPTION OF THE INVENTION The method of the present invention is characterized by metallurgically recovering valuable metals including V, particularly valuable metals, including at least one element of M selected from the group consisting of Mo, Ni and Co, and V, in the form of base-based alloys. iron from a waste containing valuable metals. First, with reference to figure 1, which is a graph (Ellingham diagram) schematically showing the affinity of Fe, Mo, Ni, Co, V, P, Al, Si and C for oxygen, the metallurgical method principle of the present invention it is explained in comparison with conventional methods. Mo, Ni, Co and V are valuable metals, Al, Si and C are reducing agents, Fe is a matrix element that has a reduction function and is capable of alloying valuable metals and P is an imty contained in the waste. Valuable metals in the form of oxides in the calcined ore are easily reduced by reducing agents, so that they are taken up in the molten iron-based alloy material. The use of Al as a reducing agent is taken, for example, to simplify the explanation. Reduction rations occur as shown in the following formulas (1) - (4). (Mo03) +2 [AI] = [Mo] + (AI203) ... (1), 3 (NiO) +2 [AI] = 3 [Ni] + (AI203) (2), 3 (CoO) + 2 [AI] = 3 [Co] + (AI203) (3), and where the parentheses indicate components in the slag and the brackets indicate components in the molten material. When the reduction with Fe is carried out as in the method described in Japanese Patent 3705498, the reduction reaction of Mo, Ni and Co proceeds but the V oxide having greater affinity for oxygen is not reduced, remaining in the slag. P, whose affinity for oxygen is more close to that of Faith, it also remains in the scum, because it is extremely difficult to reduce P oxide with Fe. Since V has greater affinity for oxygen than P, it is impossible to have only V from a slag containing V and P by reduction. Accordingly, the method of Japanese Patent 3705498 failed to obtain a high purity Fe-V alloy. In the method of the present invention, on the other hand, the calcined ore is reduced with a reducing agent that has a greater affinity for oxygen than that of V, so all the valuable metals are dissolved in a molten alloy material with a base of iron. At this time, the P oxide is similarly reduced so that P dissolves in the molten iron alloy material. After this, when the oxidation of the molten material is carried out, only V is sufficiently oxidized and transferred to the slag, because V has an extremely greater affinity for oxygen than that of the valuable metals and P. Since a slag containing High purity V oxide is obtained, its reduction provides a high purity Fe-V alloy. Thus, when V is oxidized after all valuable metal oxides are reduced, there is no restriction in the V reduction and oxidation reactions as shown in the above formulas (1) - (4), resulting in a stabilized operation and efficient to provide products with extremely improved purity and uniformity. [11 First method for recovering valuable metals The first method of the present invention corresponds to a first cycle that is shown in Fig. 2 (a). Fig. 2 (a) shows a case where the element M is composed of only Mo and Ni for simplicity but is not substantially different from a case where the element M is composed of Mo, Ni and Co, because Co has substantially the same affinity For the oxygen that Mo. Accordingly, specific explanation will be made below in a case where the element M is composed of Mo and Ni, but this explanation is applicable to a case where the element M is composed of Mo, Ni and Co. (a) Calcining step Waste containing valuable metals can be used as desulphurisation catalysts, boiler ash, boiler mud, nickel mud, etc., which are calcined alone or in combination. When the waste is calcined at 700 ° C or more, for example, 800-100 ° C, not only valuable metals are oxidized but the removal of heavy oil, water, volatile components, etc., and desulfurization occur. When the calcination temperature is lower than 700 ° C, the removal of volatile components and carbonaceous components and desulfurization are insufficient. On the other hand, when it is higher than 1000 ° C, molybdenum trioxide (MoO3) is sublimated extremely. (b) Foundry step / reduction. The method of loading the calcined ore, quick lime and iron source and a reducing agent in a furnace is not particularly restricted. Any of a method (1) comprising heating a mixture of the calcined ore, the flux and the iron source to form molten material and a slag, and then adding the reducing agent, and a method (2) comprising heating a mixture of the calcined ore, flux, iron source and reducing agent, causing melting and reduction simultaneously to form a molten material and slag, can be used, although method (1) is more preferable. Fig. 2 (a) shows method (1). In any case, a molten iron-based material can be formed before loading the calcined ore, etc. All calcined ore, etc. it does not need to be added at the same time, but additional calcined ore, flux, iron source and reducing agent can be gradually added after the molten material and slag are formed. When a sufficiently large amount of the slag, a mixture of calcium oxide and alumina, is formed, part of it can be removed from the furnace. The reducing agent must have a greater affinity for oxygen than V at a reduction temperature and specifically is preferably Al and / or Si. If necessary, a highly reductive low cost C can also be used. Al and Si are preferably simple substances (metals), and C is preferably coke, etc. The amount of C added should be equal to or less than a stoichiometric amount to reduce metal oxides valuable, preferably 75% by mass or more and less than 100% by mass of the stoichiometric amount. When too much C is added, a large amount of C is taken into the molten iron-based alloy material, so that a subsequent decarburizing step was conducted for a long period of time. The flux is preferably calcium, which, when used together with a reducing agent composed of metallic Al, provides a high purity mixture of calcium oxide and alumina (so-called "calcium aluminate" depending on its composition) containing little P When the slag is removed during the reduction step, the flux as quicklime, etc., can be supplemented if necessary. Substantially all of Mo, Ni, V and P and impurity formed by reduction are dissolved in a molten material of an iron or iron based alloy. The resulting iron-base alloy is simply called "Fe-Mo-Ni-V alloy". With the total amount of valuable metals in the ore calcined being 100% by mass, a reduction reaction is preferably conducted until the total amount of valuable metals transferred in the molten material reaches 90% by mass or more. The total amount of valuable metals transferred to the molten material is more preferably 95% by mass or more. The reduction temperature is preferably 1500 ° C or higher, more preferably 1600-2000 ° C, more preferably 1600-1800 ° C, particularly 1600-1700 ° C.

The casting / reduction step can be carried out, for example, in the furnace 1 shown in Fig. 3 (a). Furnace 1 has an inlet 1a to supply an Ar gas at the bottom and there is a means 2 such as a conveyor belt, etc., to charge the calcined ore, the flux, the iron source and the reduction agent in the furnace 1 from above. Provided above the furnace 1 is an alternating current graphite heater electrode 3. The graphite electrode 3 is lowered to a position in contact with the flux to generate arc for heating. With the bubbling of a molten material 20 and a slag 21 with an Ar gas charged in the furnace 1 through the inlet 1a, the molten material 20 and the slag 21 are agitated, causing a reduction reaction efficiently. (c) Oxidation step When a molten material of Fe-Mo-Ni-V alloy in which substantially all valuable metals and P in the calcined ore dissolve, it is put under an oxidation condition, only V is oxidized to forming a slag containing V-oxide (hereinafter "slag containing V-oxide"). The oxidation of the molten material can be carried out by a method of blowing an oxygen gas in the molten material, or a method of adding an oxidizing agent such as iron oxide flakes, etc. Of course, these methods can be combined. As shown in Fig. 3 (b), while stirring the molten material 20 upon bubbling with an Ar gas, an oxygen gas is blown into the molten material 20 through a tube that supplies oxygen gas 4, thus oxidizing only V. Of course, the tube supplying oxygen gas 4 can be inserted into the molten material 20 to bubble with an oxygen gas. The oxidation temperature can be essentially the same as the reduction temperature and specifically is preferably 1500 ° C or higher, more preferably 1600-2000 ° C, more preferably 1600-1800 ° C, particularly 1600-1700 ° C. The most preferred oxidation and reduction temperature scales are shown in Figure 1. (d) Step of separating slag containing V oxide from alloy melt material To form an Fe-V alloy, the slag containing V oxide is separated from the Fe-Mo-Ni alloy. The separation of the slag containing V-oxide can be carried out, for example, by transferring the oxide-containing slag V formed on the molten material of Fe-Mo-Ni alloy to another container when tilting the furnace. [21 Second method to recover valuable metals By virtue of the fact that the Fe-Mo-Ni alloy obtained by the first method does not contain Mo and Ni in high concentrations, the second method comprises the reduction and oxidation by adding a fresh calcined mineral. to the molten material of Fe-Mo-Ni alloy to increase the concentrations of Mo and Ni in the Fe-Mo-Ni alloy. Specifically after the same steps (a) - (d) as in the first method, the second method repeats at least one cycle comprising the steps of (e-1) adding fresh calcined ore to the molten Fe-Mo alloy material. Ni, (e-2) reduce the calcined ore to form a molten Fe-Mo-Ni-V alloy material, (f) oxidize only V in the molten material of Fe-Mo-Ni-V alloy to form a slag containing V-oxide and (g) separate the molten material of Fe-Mo-Ni alloy from the slag containing V-oxide. Of course, steps (e-1) and (e-2) can be carried out in one step. To agree to the explanation, steps (b) - (d) are called "first cycle", and steps (e) - (g) are called "second cycle", "third cycle" ... The second and subsequent Cycles are preferably repeated until the total concentration of Mo and Ni in Fe-Mo-Ni alloy reaches 40% by mass or more, particularly 50% by mass or more. However, since P is distributed between the molten alloy material and the slag in a constant ratio, the concentration of P increases in both the molten material and the slag containing V oxide when the cycles are repeated. Accordingly, it is preferable to keep the Fe-Mo-Ni alloy low by a percentage in phosphorus by repeating the cycles as long as the concentration of P in the slag containing V oxide does not exceed a predetermined level, or by conducting a treatment of dephosphorylation ng the cycle. With reference to fig. 2 (a), steps (e-1) - (g) will be explained below. (e-1) Step of adding fresh calcined ore A fresh calcined mineral is added to the molten Fe-Mo-Ni alloy material obtained in step (d) and a fresh flux such as quicklime etc. is also preferably added. The calcined ore is quickly melted in the presence of the molten material. (e-2) reduction step A reduction agent is added to a slag formed by melting the fresh calcined ore to reduce the oxides of valuable metals (Mo oxide, Ni oxide, V oxide) in the calcined ore, to that the valuable metals dissolve in the molten material of Fe-Mo-Ni alloy. Of course, the P oxide in the calcined ore is also reduced. The reduction agent and the reduction conditions (temperature, etc.) may be the same as in the first method. Incidentally, fresh calcined ore and reducing agent can be added at a time to perform step (e-1) and step (e-2) simultaneously. (f) Oxidation step The oxidation step can be carried out substantially in the same manner as step (c) in the first method. (g) Step of separating slag containing V-oxide from Fe-Mo-Ni alloy material This separation step can be carried out in substantially the same manner as in step (d) in the first method. (h) Change over time of the quantities of molten material and slag. In a case where the second method is carried to the sixth cycle, the change over time of the quantities of molten material and slag is shown schematically in Figure 4. In this example, a calcined mineral, quicklime, powder iron and coke that are charged in the furnace in the melting / reduction steps (b) and (e), and the bubbling is performed with oxygen after the quicklime as the flux is loaded in the oxidation steps (c) and (F). In the dephosphorylation step after the sixth cycle, quicklime, silica sand, iron oxide flakes and oxygen are used. The asterisk in the figure indicates that a slag of CaO | AI2O3 and a slag containing oxides of V are used in the treatment shown in Fig. 2 (b).

[31] Dephosphorylation step Since the molten alloy material formed from Fe-Mo-Ni-V is oxidized to form the V-oxide-containing slag in the method of the present invention, P is not substantially transferred to the slag containing V oxide, but it remains in the alloy molten material of Fe-Mo-N¡. Accordingly, the Fe-Mo-Ni alloy is preferably dephosphorylated in both the first and second methods. Because the dephosphorylation treatment per se is known, its detailed explanation will be omitted. It is preferable to use a flux by easily taking the phosphorous oxide formed. Specifically, lime and silica sand are used. The use of said flux forms a slag of Ca0-S0O2-Fe0, resulting in efficient dephosphorylation in the molten material of the Fe-Mo-Ni alloy. It is preferable to use an oxygen gas and / or iron oxide as the oxidizing agent. The dephosphorylation temperature is preferably 1500X or higher, more preferably 1600-2000 ° C, more preferably 1600-1800 ° C. [41 Step of reduction of the slag containing V-oxide As can be seen in Figure 2 (b), the reduction of slag containing V-oxide in the presence of an iron source forms an alloy of Fe-V . Specifically, after loading the slag containing V oxide, for example, in the furnace 1 shown in Fig. 3 (c) the quicklime (flux), the iron source and the reducing agent are charged. The furnace 11 has an Ar-gas supply inlet 13 in the bottom. To suppress the increase in the concentration of N in the molten Fe-V material in, by N2 in the air, the furnace 1 1 preferably has a cover 12. There is a means 2 (conveyor, etc.) for charging the flux , the source of iron and the reducing agent in the previous 1 1 furnace. There is also a heating electrode of graphite 3 above the oven 1 1. With an Ar gas introduced into the molten material 30 and the slag 31 in the furnace 1 1 through the inlet 13 for bubbling, the molten material 30 and the slag 31 are agitated so that the reduction reaction proceeds efficiently. The reduction temperature of the V oxide is preferably from 1500 ° C or higher, more preferably 1600-2000 ° C, more preferably 1600-1800 ° C. The reducing agent can be Al, Si, C, etc. Specifically, Al, metallic, Al impurity, Si metal, coke, etc. are preferable. In the second method the slag containing V oxide obtained by the plurality of separation steps can be reduced separately or in combination. The reduction of the oxide of V is known per se, and it can be carried out by other methods such as aluminothermia, etc. [51 Calcium aluminate recovery When lime and alumina are used as a flux and a reducing agent, respectively, in the method of the present invention, a CaO-AI203 slag is formed which is useful as a desulfurizing agent for the production of iron, etc. Incidentally, the AI2O3 is transferred from the catalyst carrier used in the slag. The slag of CaO-AI2O3 is recovered mainly in the steps of reduction (b-2), (e-2) and in the reduction step of the slag containing V-oxide. If necessary, quicklime can be added or aluminum to the resulting slag to fit a mass ratio of CaO / AI2O3. The preferred mass ratio of CaO / AI203 is of 0.5-0.7. The recovery of the CaO-AI203 slag contributes to the reduction of secondary industrial waste. The resulting calcium aluminate can be used as a desulfurization agent for the production of iron, an alternative flux for fluorite, etc. The present invention will be described in greater detail with reference to the following examples and reference examples without intending to restrict the present invention to them.

REFERENCE EXAMPLE 1 Oxidation of ¥ in the Fe-Mo-Mn-V alloy Lime was loaded into an oven 1 shown in Figure 3 (b), which contained approximately 6 tons of a Fe-Mo-Ni-V alloy melt comprising 15.0% by mass of V, 18.8% by weight. Ni mass, 20.1% by mass of Mo, and 0.65% by mass of P, the remainder is substantially Fe, and oxygen gas was blown into the molten material at a rate of 7 Nm3 / min. through an inlet pipe 4 attached to an upper portion of the furnace 1, while keeping the molten material at 1650 ° C. Figure 5 shows the concentration changes with time of V, Ni, Mo and P in the molten material. It is verified that only V was oxidized selectively in the molten material of the Fe-Mo-Ni-V alloy, from bed only V decreased as the oxidation time without substantially no change in the concentrations of other elements. Even when the concentration of V in the molten material decreased to 1% by mass, there was only an extremely small decrease in the concentrations of Ni and Mo, with most of P remaining in the molten material. This is verified when the molten material of the Fe-Mo-Ni-V alloy containing P is oxidized, only substantially V is oxidized, resulting in a slag containing V oxide with a small phosphorous content.

EXAMPLE 1 Valuable metals were recovered from various waste mixtures having the compositions shown in Table 1 by a six-cycle treatment according to the flux diagrams shown in Figures 2 (a) and 2 (b) . (1) Calcination step The different wastes that are shown in Table 1 were loaded at speeds that are also shown in the same table, in a rotary kiln with a capacity of 100 tons / day, so that they were calcined at 950 ° C. The oil components, the solid carbonaceous components and the sulfur components that were contained in the waste were all burned. The compositions of minerals The resulting calcined wastes are shown in table 2. The weight of the loaded waste decreased by approximately 1/2 in the calcination step.

TABLE 1 (2) First cycle 8 tons of a calcined ore, 3.6 tons of quicklime and 3.0 tons of iron powder were loaded into a 7,000 kVA homo 1 represented schematically in figure 3 (a), and after the calcined ore, 0.5 tons of coke and 1.1 tons of Al were added as conductive agents to the reduction conduit, thus forming a molten material in which all Mo, Ni, V, Fe and impurity P were substantially dissolved. melting temperature as the Reduction temperature were 600-1700 ° C. The resulting slag was recovered as calcium aluminate. When fresh quick lime was added, an oxygen gas was blown into the molten material at 600-1700 ° C in furnace 1 from above as shown in Figure 3 (b), to carry out an oxidation treatment. As can clearly be seen in Figure 6 showing the change in concentration over time of Mo, Ni, V and P in the molten material in the Fe-Mo-Ni-V alloy, substantially only V was oxidized, and the resulting slag containing V oxide was separated in a molten state from the remaining molten material (Fe-Mo-Ni alloy). (3) Cycles from the second to the sixth Fusion, reduction and oxidation were carried out in the same way as in the first cycle, except that 8 tons of the calcined ore and 3.6 tons of quicklime were added to the molten material of the Fe-Mo-Ni alloy obtained in the first cycle, and the resulting slag containing V-oxide and the Fe-Mo-Ni alloy were separated (second cycle). The same operation as the second cycle was repeated until the total concentration of Mo and Ni in the Fe-Mo-Ni alloy reached 50% by mass or more (from the third to the sixth cycle). (4) Reduction of V-oxide The slag containing V-oxide obtained from each cycle was loaded into an 11,000-kVA furnace 11 which is shown schematically in Figure 3 (c), and then quicklime was added, iron powder and Al. With the reduction of V-oxide, a slag was obtained which was composed of a molten material of the Fe-V alloy and CaO-AI2O3. (5) Dephosphorylation treatment After removing the slag containing V-oxide, quicklime, silica sand and iron oxide were added to the molten material of the Fe-Mo-Ni alloy obtained in the sixth cycle, and He blew oxygen gas in the molten material at 1600-1700 ° C from above to carry out a dephosphorylation treatment. (6) Results The changes in concentration with time of Mo, Ni, V and P in the molten material in furnace 1, in the first to the sixth cycles are shown in figure 6, the composition and weight of the slag [CaO slag · Al203 in fig. 2 (a)] that was obtained after the reduction step in each cycle is shown in Table 3, and the composition, the mass ratio of V / P and the weight of the slag containing V oxide that were obtained in each cycle are shown in table 4.

TABLE 3 Slag obtained in the reduction step TABLE Slag containing V-oxide As is evident from Figure 6 and Tables 3 and 4, (a) the concentrations of Mo, Ni and P in the molten material increased gradually in each cycle, while the concentration of V in the material melt dropped drastically at each oxidation step; (b) the concentration of V on the side containing V oxide was substantially the same in all cycles; (c) the concentration of P in the molten material in furnace 1 gradually increased each cycle, while it was extremely low in the slag obtained after the reduction step in the slag containing V. oxide. The increase in P concentration in the molten material each cycle seems to be a consequence of the fact that P was not substantially transferred to the slag, but it accumulated in the molten material. The slag containing V oxide obtained after the sixth cycle had a V / P mass ratio of more than 300, which indicates that a Fe-V alloy with a low enough phosphorous content was obtained. Table 5 shows the compositions and the weight of the Fe-V alloy and the remaining slag that were obtained by reducing the slag containing V-oxide. As can be clearly seen in Table 5, the concentration of V in the alloy of Fe-V was extremely high, approximately 50% by mass or more. Although the concentration of P in the Fe-V alloy increased gradually in each cycle, it reached the target of 0.15% by mass or less in each cycle. As a result of the first to the sixth cycles, 10 tons of an alloy of Fe-V (corresponding to Fe-50% V) and 80 tons (total slag shown in tables 3 and 5) of calcium aluminate were obtained.

TABLE 5 Compositions of Fe-V alloy and remaining slag Ba Table 6 shows the compositions of the Fe-Mo-Ni alloy before and after dephosphorylation. The concentrations of P and S in the Fe-Mo-Ni alloy (yield: approximately 6.4 tons) after dephosphorylation were extremely low, 0.07% by mass and 0.04% by mass, respectively. This fully met the standards (for example, [P] <0.1% by mass, and [S] = 0.1% by mass) that are generally required for stainless steel materials.

TABLE 6 Composition of the Fe-Mo-Nc alloy REFERENCE EXAMPLE 2 Dephosphorylation of the molten material of the Fe-Mo ° Mi alloy Lime, silica sand and iron oxide were added to approximately 6 tons of a molten material 20 of the Fe-Mo-Ni alloy containing P at about 1600 ° C in furnace 1 shown in Figure 3 ( b), and an oxygen gas was blown into the molten material in the furnace from above. An Ar gas was also blown into the molten material for agitation through an inlet 1 at the bottom of the furnace 1. Figure 7 shows the changes in the concentration with time of Fe-Ni and P in the molten material. In Figure 7 it can be seen clearly that almost all the P were removed from the molten material with the dephosphorylation treatment for 5 minutes. This indicates that the molten material of the Fe-Mo-Ni alloy can be dephosphorylated in a relatively easy manner. The dephosphorylation treatment only slightly reduced the amounts of Ni and Moen the molten material. The dephosphorylation treatment simultaneously removed C, resulting in an Fe-Mo-Ni alloy with a low carbon content and a low phosphorus content.

EFFECT OF THE INVENTION The method of the present invention can efficiently produce an iron base alloy containing V and an iron-based alloy containing other valuable metals with a high purity, since all the oxides of the valuable metals including V are reduced from Thus, valuable metals dissolve first in a molten iron-based material, and only the highly oxidizable V is oxidized to be separated from other valuable metals. In addition, because a molten material containing all valuable metals is oxidized, only V with a high capacity to be oxidized can be oxidized, even if it contains P. As the resulting V oxide does not substantially contain P, the oxide reduction of V in the presence of an iron source provides a high quality Fe-V alloy. By repeating at least one cycle comprising a step of adding a new calcined mineral to the molten material after the slag containing V oxide has been stopped, and the same reduction steps, oxidation and separation that in the first cycle, an iron-based alloy containing Mi, Ni and Co in high concentrations can be obtained. As a high purity mixture of calcium oxide and alumina (which is known as "calcium aluminate") is formed as a secondary product such as slag, it can be recovered to greatly reduce the amounts of secondary waste, and is used as a desulfurization agent for the production of iron, an alternative flux for fluorite, and so on.

Claims (13)

NOVELTY OF THE INVENTION CLAIMS

1. - A method for recovering valuable metals including V in the form of iron-based alloys from a waste containing said valuable metals, comprising the steps of calcining said waste; reduce the calcined waste at the same time as it melts together with an iron source, thus forming a molten material of the iron-based alloy containing said valuable metals; oxidizing said molten material to form a slag containing V oxide; and separating said slag containing V oxide from the remaining molten material.

2. The method for recovering valuable metals according to claim 1, further characterized in that it comprises repeating, after having separated said slag containing V oxide, at least one cycle comprising the steps of adding again a calcined waste. to the remaining molten material, subjecting to reduction the resulting molten material and then to oxidation, and separating a newly formed V-oxide-containing slag.

3. The method for recovering valuable metals according to claim 1 or 2, further characterized in that said valuable metal that is different from V is at least one selected from the group consisting of Mo, Ni and Co.

4. - A method for recovering valuable metals that includes at least one element M selected from the group consisting of Mo, Ni and Co, and V, in the form of iron-based alloys from a waste containing said valuable metals, comprising the steps of: a) calcining said waste to form a calcined mineral containing oxides of said valuable metals; b) heating said calcined ore together with an iron source, a flux, and a reducing agent having a higher affinity for oxygen than V at a reduction temperature, to reduce the oxides of said valuable metals, thereby forming a cast material of Fe-MV alloy; c) oxidizing only substantially V in said molten material of the Fe-MV alloy to form a slag containing V-oxide and a molten material of the Fe-M alloy, and d) separating said V-oxide-containing slag from said cast material of Fe-M alloy.

5. A method for recovering valuable metals, which includes at least one element M selected from the group consisting of Mo, Ni and Co, and V, in the form of iron-based alloys from a waste containing said metals valuable, comprising the steps of: (a) calcining said waste to form a calcined ore containing oxides of said valuable metals; (b-1) heating said calcined ore together with an iron source and a flux, to form a molten material of the iron-based alloy; (b-2) add a reducing agent having a higher affinity for oxygen than V at a reduction temperature to said molten material, thereby reducing the oxides of said valuable metals to form a molten material of the Fe-M-V alloy; (c) oxidizing only substantially V in said molten material of the Fe-M-V alloy to form a slag containing V-oxide and a molten material of the Fe-M alloy; and (d) separating said V-oxide-containing slag from said molten material from the Fe-M alloy.

6. - The method for recovering valuable metals according to claim 4 or 5, further characterized by comprising repeating, after said step (d), at least one cycle comprising the steps: (e) adding a new calcined mineral , a flux, and a reducing agent having a higher affinity for oxygen than V at a reduction temperature to said molten material from the Fe-M alloy, to reduce the oxides of said valuable metals, so that said metals valuable dissolve in said molten material of the Fe-M alloy; (f) oxidizing only substantially V in the molten material of the resulting Fe-M-V alloy to form a slag containing V-oxide and a molten material of the Fe-M alloy; and (g) separating said V-oxide-containing slag from said molten material from the Fe-M alloy.

7. - The method for recovering valuable metals according to claim 4 or 5, further characterized in that it comprises repeating, after said step (d), at least one cycle comprising the steps of: (e-1) adding a new calcined ore and a flux to said molten material from the Fe-M alloy, so that the new calcined ore is dissolve in said molten material; (e-2) adding a reducing agent having a higher affinity for oxygen than V at a reduction temperature to said molten material, to reduce the oxides of said valuable metals in order for said valuable metals to dissolve in said cast material of Fe-M alloy; (f) oxidizing only substantially V in the molten material resulting from the Fe-M-V alloy to form a slag containing V-oxide and a molten material of the Fe-M alloy; and (g) separating said V-oxide-containing slag from said passage of molten material from the Fe-M alloy.

8. The method for recovering valuable metals according to any of claims 1 to 7, further characterized in that the reducing agent comprises Al and / or Si.

9. - The method for recovering valuable metals according to claim 8, further characterized in that said reduction agent also comprises C.

10. The method for recovering valuable metals according to any of claims 1 to 9, further characterized in that Lime is added as the flux and an oxygen gas and / or iron oxide as the oxidizing agent to said molten material of the Fe-MV alloy, to oxidize V in said molten material.

11. - The method for recovering valuable metals according to any of claims 1 to 10, further characterized in that after separating said V-oxide-containing slag, said molten material from the Fe-M alloy is subjected to a dephosphorylation treatment.

12. The method for recovering valuable metals according to any of claims 1 to 11, further characterized in that it also comprises a step of adding a source of iron and a reducing agent having a higher affinity for oxygen than V to a reducing temperature to said slag containing V-oxide and heating them, thereby reducing said V-oxide to form an Fe-V alloy.

13. The method for recovering valuable metals according to any of claims 1 to 12, further characterized in that it comprises using Al as said reducing agent and quicklime as said flux to obtain a slag that is substantially composed of calcium oxide and alumina.