JP2011184763A - Method for treating waste catalyst - Google Patents
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- JP2011184763A JP2011184763A JP2010052735A JP2010052735A JP2011184763A JP 2011184763 A JP2011184763 A JP 2011184763A JP 2010052735 A JP2010052735 A JP 2010052735A JP 2010052735 A JP2010052735 A JP 2010052735A JP 2011184763 A JP2011184763 A JP 2011184763A
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- 239000003054 catalyst Substances 0.000 title claims abstract description 68
- 239000002699 waste material Substances 0.000 title claims abstract description 45
- 238000000034 method Methods 0.000 title claims abstract description 43
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 74
- 238000002386 leaching Methods 0.000 claims abstract description 56
- 239000007788 liquid Substances 0.000 claims abstract description 54
- 229910052751 metal Inorganic materials 0.000 claims abstract description 36
- 239000002184 metal Substances 0.000 claims abstract description 36
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 32
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 32
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims abstract description 30
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 30
- 239000011777 magnesium Substances 0.000 claims abstract description 30
- 239000002244 precipitate Substances 0.000 claims abstract description 30
- 238000000926 separation method Methods 0.000 claims abstract description 27
- 229910052602 gypsum Inorganic materials 0.000 claims abstract description 18
- 239000010440 gypsum Substances 0.000 claims abstract description 18
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims abstract description 17
- 229940043430 calcium compound Drugs 0.000 claims abstract description 6
- 150000001674 calcium compounds Chemical class 0.000 claims abstract description 6
- 238000001556 precipitation Methods 0.000 claims abstract description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 36
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical group [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 35
- 238000011084 recovery Methods 0.000 claims description 9
- 239000004568 cement Substances 0.000 claims description 6
- 239000002994 raw material Substances 0.000 claims description 5
- 238000002485 combustion reaction Methods 0.000 claims description 3
- CBXWGGFGZDVPNV-UHFFFAOYSA-N so4-so4 Chemical compound OS(O)(=O)=O.OS(O)(=O)=O CBXWGGFGZDVPNV-UHFFFAOYSA-N 0.000 claims 1
- -1 platinum group metals Chemical class 0.000 abstract description 5
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 15
- 229910052801 chlorine Inorganic materials 0.000 description 15
- 239000000460 chlorine Substances 0.000 description 15
- 239000007787 solid Substances 0.000 description 15
- 239000000243 solution Substances 0.000 description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 6
- 239000007789 gas Substances 0.000 description 5
- 150000007522 mineralic acids Chemical class 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- QZPSXPBJTPJTSZ-UHFFFAOYSA-N aqua regia Chemical compound Cl.O[N+]([O-])=O QZPSXPBJTPJTSZ-UHFFFAOYSA-N 0.000 description 4
- 238000006386 neutralization reaction Methods 0.000 description 4
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 229910052878 cordierite Inorganic materials 0.000 description 3
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 3
- 230000001590 oxidative effect Effects 0.000 description 3
- 239000000377 silicon dioxide Substances 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- 239000005708 Sodium hypochlorite Substances 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 2
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical class [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 2
- 235000012254 magnesium hydroxide Nutrition 0.000 description 2
- 230000005012 migration Effects 0.000 description 2
- 238000013508 migration Methods 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000003672 processing method Methods 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229940024548 aluminum oxide Drugs 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 235000011116 calcium hydroxide Nutrition 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 239000000292 calcium oxide Substances 0.000 description 1
- 235000012255 calcium oxide Nutrition 0.000 description 1
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000000347 magnesium hydroxide Substances 0.000 description 1
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 238000011946 reduction process Methods 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000000967 suction filtration Methods 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Processing Of Solid Wastes (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
Description
本発明は、廃触媒の処理プロセスにおいて、廃触媒の浸出後液から濾過性のよい沈澱を生成させて湿式処理を容易にした処理方法に関する。より詳しくは、本発明は自動車触媒等の廃触媒から白金族金属を回収する処理プロセス等において、廃触媒に含まれるアルミニウム分およびマグネシウム分を初期段階で濾過性のよい沈澱にして分離し、湿式処理を容易にした廃触媒の処理方法に関する。 The present invention relates to a treatment method that facilitates wet treatment by generating a precipitate having good filterability from a solution after leaching of a waste catalyst in a treatment process of a waste catalyst. More specifically, the present invention is a process for recovering platinum group metals from a waste catalyst such as an automobile catalyst. The present invention relates to a method for treating a waste catalyst that facilitates the treatment.
自動車等の排気ガスを浄化するために、ハニカム構造のセラミックス（コーディエライト）基体に白金族金属を含有したアルミナをコーティングした触媒が一般に使用されている。これらの触媒は一定期間使用された後に使用済み廃触媒となるが、廃触媒に含まれる白金族金属は貴金属であるので、これを回収して有効に再利用することが求められており、従来から幾つかの回収方法が知られている。 In order to purify exhaust gas from automobiles and the like, a catalyst in which an alumina containing a platinum group metal is coated on a honeycomb structure (cordierite) substrate is generally used. These catalysts become used waste catalysts after being used for a certain period of time, but since the platinum group metals contained in the waste catalysts are noble metals, it is required to recover them and reuse them effectively. Several recovery methods are known.
廃触媒から白金族金属を回収する湿式法として、従来、王水または塩酸と過酸化水素の混合溶液のような酸化性の無機酸溶液に廃触媒を浸漬して白金族金属を溶解する方法が知られている。しかし、廃触媒を酸化性の無機酸溶液に浸漬して単純に溶解させる方法では白金族金属の回収率が低いと云う問題がある。 As a wet method for recovering a platinum group metal from a waste catalyst, there is a method of dissolving a platinum group metal by immersing the waste catalyst in an oxidizing inorganic acid solution such as aqua regia or a mixed solution of hydrochloric acid and hydrogen peroxide. Are known. However, there is a problem that the recovery rate of the platinum group metal is low in the method of simply dissolving the spent catalyst by immersing it in an oxidizing inorganic acid solution.
そこで、廃触媒を密閉容器に入れ、無機酸と酸化剤を加え加熱して白金族金属を溶解させる回収方法が知られている（特許文献１）。この回収方法では無機酸として主に塩酸を用い、密閉容器を用いて塩酸の揮発を防止すると共に塩素成分を導入して塩素濃度を高めて溶解を行う。しかし、王水や塩酸によって廃触媒から白金族を溶解する処理方法では残渣に多量の塩素が残留するため、埋立て処分やセメント製造等の他分野に転用して利用することが難しい。一方、残留塩素を除去するには大量の水が必要であるため、除去処理の負担が大きく、また環境への負荷が懸念される。 Therefore, a recovery method is known in which a waste catalyst is placed in a sealed container, an inorganic acid and an oxidizing agent are added and heated to dissolve the platinum group metal (Patent Document 1). In this recovery method, hydrochloric acid is mainly used as an inorganic acid, and a closed vessel is used to prevent volatilization of hydrochloric acid, and a chlorine component is introduced to increase the chlorine concentration for dissolution. However, in the treatment method in which the platinum group is dissolved from the waste catalyst with aqua regia or hydrochloric acid, a large amount of chlorine remains in the residue, so that it is difficult to divert it to other fields such as landfill disposal and cement production. On the other hand, since a large amount of water is required to remove residual chlorine, the burden of the removal process is large and there is a concern about the burden on the environment.
また、従来の湿式処理法では無機酸の使用量が多く、しかも、白金族金属以外の成分（アルミニウム、マグネシウム等）も溶解するのでこれらの分離が難しいなどの問題がある。例えば、アルミニウム等は中和すると水酸化物となり、濾過性が極めて不良な沈澱を生じる。 In addition, the conventional wet processing method has a problem that the amount of inorganic acid used is large and components (aluminum, magnesium, etc.) other than the platinum group metal are also dissolved, so that they are difficult to separate. For example, when aluminum or the like is neutralized, it becomes a hydroxide and precipitates with extremely poor filterability.
浸出工程を二段に分け、一段目に濃硫酸（濃度７５％以上）を用いることによって白金族以外の成分を選択的に浸出させ、次いで、二段目で塩酸浸出または王水浸出を行う方法も知られている（特許文献２）。しかし、この方法でも、浸出後液に含まれる成分を分離するために中和処理を行うと、濾過性の不良な沈澱が生成し、固形分および排水の処理が困難になると云う問題がある。 Dividing the leaching process into two stages, using concentrated sulfuric acid (concentration 75% or more) in the first stage to selectively leach components other than the platinum group, and then performing hydrochloric acid leaching or aqua regia leaching in the second stage Is also known (Patent Document 2). However, even with this method, there is a problem that when the neutralization treatment is performed to separate the components contained in the liquid after leaching, precipitates having poor filterability are generated, and it becomes difficult to treat solids and waste water.
本発明は、従来の処理方法における上記問題を解決したものであり、自動車触媒等の廃触媒から白金族金属を回収する処理プロセス等において、廃触媒に含まれるアルミニウム分およびマグネシウム分を初期段階で濾過性のよい沈澱にして分離し、湿式処理を容易にした廃触媒の処理方法を提供する。 The present invention solves the above-mentioned problems in conventional treatment methods, and in a treatment process for recovering a platinum group metal from a waste catalyst such as an automobile catalyst, an aluminum content and a magnesium content contained in the waste catalyst are in an initial stage. Provided is a method for treating a spent catalyst which is separated by precipitation with good filterability and facilitates wet treatment.
本発明は、以下に示す構成によって上記課題を解決した、廃触媒の処理方法に関する。
〔１〕廃触媒を希硫酸で浸出してアルミニウム分とマグネシウム分を溶出させて固液分離する硫酸浸出工程と、回収した浸出後液にカルシウム化合物を添加して硫酸石膏の沈澱を生成させる沈澱化工程と、該沈澱に取り込まれたアルミニウム分とマグネシウム分を該沈澱と共に固液分離する分離工程とを有することを特徴とする廃触媒の処理方法。
〔２〕硫酸浸出工程において、密閉容器中の希硫酸に廃触媒を浸漬し、１００℃以上に加熱して加圧浸出を行う上記[１]に記載する廃触媒の処理方法。
〔３〕分離工程において回収した硫酸石膏沈澱をセメント原料に利用する上記[１]または上記[２]に記載する廃触媒の処理方法。
〔４〕硫酸浸出工程において固液分離した浸出残渣を塩酸で浸出し、その浸出後液から白金族金属を回収する白金族回収工程を有する上記[１]〜上記[３]の何れかに記載する廃触媒の処理方法。
〔５〕廃触媒が自動車排ガス、または他の内燃機関排ガスの浄化用触媒であって、その使用済み触媒である上記[１]〜上記[４]の何れかに記載する廃触媒の処理方法。
The present invention relates to a method for treating a spent catalyst, which has solved the above problems with the following configuration.
[1] Sulfuric acid leaching process in which the waste catalyst is leached with dilute sulfuric acid to elute the aluminum and magnesium components and solid-liquid separation is performed, and the precipitated calcium sulfate is added to the recovered liquid after leaching to form a sulfate gypsum precipitate. And a separation step of solid-liquid separation of the aluminum content and the magnesium content taken into the precipitate together with the precipitate.
[2] The method for treating a waste catalyst according to the above [1], wherein in the sulfuric acid leaching step, the waste catalyst is immersed in dilute sulfuric acid in a sealed container and heated to 100 ° C. or higher to perform pressure leaching.
[3] The method for treating a spent catalyst according to the above [1] or [2], wherein the sulfate gypsum precipitate recovered in the separation step is used as a cement raw material.
[4] Any one of [1] to [3] above, further comprising a platinum group recovery step of leaching the leaching residue separated in the solid-liquid separation in the sulfuric acid leaching step with hydrochloric acid and recovering the platinum group metal from the liquid after the leaching. A method for treating a spent catalyst.
[5] The method for treating a waste catalyst according to any one of the above [1] to [4], wherein the waste catalyst is a catalyst for purifying automobile exhaust gas or other internal combustion engine exhaust gas, and is a used catalyst.
本発明は、廃触媒を希硫酸で浸出することによって、アルミニウム分とマグネシウム分を選択的に浸出させる。この浸出液を処理するとき、カルシウム化合物で中和することによって硫酸石膏が発生し、これにアルミニウム分およびマグネシウム分が取り込まれることにより、固液分離が容易な実用に適した分離処理を行うことができる。 In the present invention, the aluminum and magnesium components are selectively leached by leaching the waste catalyst with dilute sulfuric acid. When this leachate is treated, it is neutralized with a calcium compound, so that gypsum sulfate is generated, and aluminum and magnesium are taken into this, so that a separation process suitable for practical use that facilitates solid-liquid separation can be performed. it can.
本発明は、廃触媒を希硫酸で浸出することによって、アルミニウム分とマグネシウム分を選択的に浸出させる。この希硫酸浸出では王水や塩酸を用いないので、浸出液にカルシウム化合物を加えて中和したときに生じる硫酸石膏には塩素が殆ど含まれておらず、この硫酸石膏をセメント原料として安定に再利用することができる。さらに排水中にも塩素が含まれないことから排水処理の負担を大幅に軽減することができる。 In the present invention, the aluminum and magnesium components are selectively leached by leaching the waste catalyst with dilute sulfuric acid. In this dilute sulfuric acid leaching, no aqua regia or hydrochloric acid is used, so the sulfate gypsum produced when a calcium compound is added to the leachate and neutralized contains almost no chlorine. Can be used. Furthermore, since chlorine is not contained in the wastewater, the burden of wastewater treatment can be greatly reduced.
本発明は、廃触媒を希硫酸浸出して事前にアルミニウム分とマグネシウム分を選択的に抽出し除去するので、後工程で実施する白金族金属の回収工程が容易かつ効率良く行うことができる。 In the present invention, since the waste catalyst is leached with dilute sulfuric acid and the aluminum and magnesium components are selectively extracted and removed in advance, the platinum group metal recovery step performed in the subsequent step can be performed easily and efficiently.
以下、本発明を実施形態に基づいて具体的に説明する。
本発明の方法は、廃触媒を希硫酸で浸出してアルミニウム分とマグネシウム分を溶出させて固液分離する硫酸浸出工程と、回収した浸出後液にカルシウム化合物を添加して硫酸石膏の沈澱を生成させる沈澱化工程と、該沈澱に取り込まれたアルミニウム分とマグネシウム分を該沈澱と共に固液分離する分離工程とを有することを特徴とする廃触媒の処理方法である。本発明の処理方法の概略を図１に示す。
Hereinafter, the present invention will be specifically described based on embodiments.
The method of the present invention includes a sulfuric acid leaching process in which a waste catalyst is leached with dilute sulfuric acid to elute an aluminum component and a magnesium component and solid-liquid separation is performed. A waste catalyst treatment method comprising: a precipitation step to be formed; and a separation step in which an aluminum component and a magnesium component taken into the precipitate are separated into a solid and a liquid together with the precipitate. An outline of the treatment method of the present invention is shown in FIG.
〔廃触媒〕
本発明の処理対象である廃触媒は、例えば、自動車排ガス、または他の内燃機関排ガスの浄化用触媒であって、その使用済み触媒などである。これらの触媒は、ハニカム構造のセラミックス（コーディエライト）基体に白金族金属（Pt、Pd、Rh）を含有したアルミナをコーティングした触媒が一般に使用されている。白金族金属を回収するには、これらのアルミニウム分およびマグネシウム分を分離する必要がある。
[Waste catalyst]
The waste catalyst to be treated in the present invention is, for example, a catalyst for purifying automobile exhaust gas or other internal combustion engine exhaust gas, such as a used catalyst. As these catalysts, a catalyst in which an alumina containing a platinum group metal (Pt, Pd, Rh) is coated on a ceramic (cordierite) substrate having a honeycomb structure is generally used. In order to recover the platinum group metal, it is necessary to separate these aluminum and magnesium contents.
〔硫酸浸出〕
本発明の処理方法は、廃触媒を希硫酸で浸出してアルミニウム分とマグネシウム分を選択的に溶出させる。触媒の構造体であるシリカ分は浸出残渣として残り、白金族金属も希硫酸には溶解せずに固形分として残る。酸化性の硝酸や濃塩酸を用いると、白金族金属まで溶解するので、白金族金属と他の成分との分離が面倒になるので好ましくない。
[Sulfuric acid leaching]
In the treatment method of the present invention, the waste catalyst is leached with dilute sulfuric acid to selectively elute aluminum and magnesium. Silica which is the structure of the catalyst remains as a leaching residue, and the platinum group metal remains as a solid without being dissolved in dilute sulfuric acid. When oxidizing nitric acid or concentrated hydrochloric acid is used, even the platinum group metal is dissolved, so that separation of the platinum group metal from other components becomes troublesome, which is not preferable.
硫酸浸出は、希硫酸を用い（好ましくは濃度５０wt％以下の希硫酸）、１００℃以上に加熱し、密閉容器を用いて加圧浸出を行うと良い。密閉容器を用いて加熱すると発生した蒸気によって加圧下で浸出が進む。特許文献２の処理方法では、廃触媒を濃度７５％以上の濃硫酸を用い、基体のコーディエライトを溶解せずに、アルミニウム分を選択的に浸出しているが（特許文献２、段落[0012]）、浸出残渣にマグネシウム分が残ると、残渣中の白金族金属を浸出したときにマグネシウムが混在し、その分離が面倒になるので好ましくない。一方、本発明の処理方法は、希硫酸を用い、好ましくは加熱加圧下で、アルミニウム分と共にマグネシウム分を選択的に廃触媒から溶出させる。 For sulfuric acid leaching, dilute sulfuric acid (preferably dilute sulfuric acid having a concentration of 50 wt% or less) is heated to 100 ° C. or higher, and pressure leaching is performed using a sealed container. When heated using a sealed container, leaching proceeds under pressure by generated steam. In the treatment method of Patent Document 2, concentrated sulfuric acid having a concentration of 75% or more is used as a waste catalyst, and aluminum is selectively leached without dissolving the cordierite of the substrate (Patent Document 2, paragraph [ [0012] If a magnesium content remains in the leaching residue, magnesium is mixed when the platinum group metal in the residue is leached, and the separation becomes troublesome. On the other hand, the treatment method of the present invention uses dilute sulfuric acid, and preferably elutes the magnesium component together with the aluminum component from the waste catalyst, preferably under heating and pressurization.
〔沈澱化工程〕
硫酸浸出の後に、その浸出後液にカルシウム化合物を添加して硫酸石膏の沈澱を生成させる。上記浸出後液は硫酸酸性溶液であり、これに生石灰〔CaCO3〕あるいは消石灰〔Ca(OH)2〕のカルシウム化合物を加えて中和すると、液中の硫酸根と添加したカルシウム分が反応して、硫酸石膏〔CaSO４〕の沈澱を生じる。液中に溶存するアルミニウムとマグネシウムの水酸化物はこの硫酸石膏の沈澱に取り込まれて沈澱する。
[Precipitation process]
After the sulfuric acid leaching, a calcium compound is added to the liquid after the leaching to form a sulfate gypsum precipitate. The solution after leaching is a sulfuric acid solution, and when it is neutralized by adding calcium compound of quick lime [CaCO 3 ] or slaked lime [Ca (OH) 2 ], the sulfate radical in the solution reacts with the added calcium content. This causes precipitation of sulfate gypsum [CaSO4]. Aluminum and magnesium hydroxides dissolved in the liquid are incorporated into the sulfate gypsum precipitate and precipitate.
〔分離工程〕
上記沈澱を固液分離してアルミニウムおよびマグネシウムの水酸化物を含む硫酸石膏を回収することができる。また、硫酸浸出を行っているので、浸出後液および回収した硫酸石膏には浸出液に由来する塩素が含まれておらず、従って、回収した硫酸石膏をセメント原料として利用することができる。また、固液分離した液分にはアルミニウムおよびマグネシウムが除去されており、塩素を実質的に含まないので容易に排水することができる。
[Separation process]
The precipitate can be solid-liquid separated to recover sulfate gypsum containing aluminum and magnesium hydroxide. In addition, since sulfuric acid leaching is performed, the liquid after leaching and the recovered sulfate gypsum do not contain chlorine derived from the leached solution, and thus the recovered sulfate gypsum can be used as a cement raw material. In addition, aluminum and magnesium have been removed from the solid-liquid separated liquid, and since it does not substantially contain chlorine, it can be easily drained.
具体的には、例えば、固液分離して回収した硫酸石膏沈殿には廃触媒に含まれているアルミニウムおよびマグネシウムの概ね９０％が移行しており、塩素含有量は極めて少ない。また、固液分離した液分には白金族金属および塩素は殆ど含まれておらず、アルミニウムおよびマグネシウムの移行率も数％である。 Specifically, for example, approximately 90% of aluminum and magnesium contained in the waste catalyst are transferred to the sulfate gypsum precipitate recovered by solid-liquid separation, and the chlorine content is extremely low. Further, the liquid component separated into solid and liquid contains almost no platinum group metal and chlorine, and the migration rate of aluminum and magnesium is several percent.
〔白金族回収工程〕
希硫酸浸出工程において固液分離した浸出残渣から白金族金属を回収することができる。この回収工程を以下に説明する。
[Platinum recovery process]
The platinum group metal can be recovered from the leaching residue that has been solid-liquid separated in the dilute sulfuric acid leaching step. This recovery process will be described below.
イ．塩酸浸出工程
希硫酸浸出の浸出残渣を塩酸に浸漬して白金族金属を浸出する。塩酸は市販濃度（濃度35％HCl）のものを用いることができ、塩素濃度を高めるには、次亜塩素酸ナトリウム（濃度12％NaClO）を添加すると良い。塩酸浸出は密閉容器を用い、１００℃以上に加熱して行うと良い（オートクレーブ）。密閉容器で加熱すると発生する蒸気によって加圧下で浸出が進む。
I. Hydrochloric acid leaching step The leaching residue of dilute sulfuric acid leaching is immersed in hydrochloric acid to leach platinum group metals. Hydrochloric acid having a commercially available concentration (
上記塩酸浸出によって、主に白金族金属が溶出する。触媒基体の主成分であるシリカは残渣に残るので、固液分離して白金族金属が溶出した液分とシリカが主体の固形分に分離する。 The platinum group metal is mainly eluted by the hydrochloric acid leaching. Since silica which is the main component of the catalyst base remains in the residue, it is separated into a liquid component from which platinum group metal is eluted by solid-liquid separation and a solid component mainly composed of silica.
ロ．還元工程
塩酸浸出後液に還元用金属粉を添加して白金族金属を還元し析出させる。還元用金属粉としては鉄粉を用いることができる。白金族金属は鉄粉によって還元されてメタルになり沈澱するので、これを固液分離して回収する。
B. Reduction step Reduction metal powder is added to the solution after leaching with hydrochloric acid to reduce and precipitate the platinum group metal. Iron powder can be used as the reducing metal powder. The platinum group metal is reduced by iron powder to become a metal and precipitates, and is collected by solid-liquid separation.
上記還元工程で回収した固形分には、廃触媒に含まれている白金族金属の大半が含まれており（移行率約９０〜９５wt％）、この固形分を固液分離して白金族金属を回収することができる。また、大部分の塩素もこの沈澱に取り込まれているので、固液分離することによって塩素を液分から除去することができる。 The solid content recovered in the reduction step contains most of the platinum group metal contained in the waste catalyst (migration rate: about 90 to 95 wt%). Can be recovered. In addition, most of the chlorine is also taken into this precipitate, so that it can be removed from the liquid by solid-liquid separation.
ハ．中和工程
還元工程の固液分離によって回収した液分にアルカリを加えて中和処理する。この液分には白金族金属、アルミニウム、およびマグネシウムが殆ど含まれていないので、容易に排水することができる。
C. Neutralization process An alkali is added to the liquid recovered by solid-liquid separation in the reduction process for neutralization. Since this liquid contains almost no platinum group metal, aluminum, and magnesium, it can be easily drained.
以下、本発明の実施例を示す。 Examples of the present invention will be described below.
〔実施例１〕
廃触媒１００ｇ（各成分の含有量を表１に示す）を密閉容器内の希硫酸（濃度96％H2SO4500ml＋水500ml）に浸漬し、１２０℃に２時間加熱した。これを固液分離して液分１０００mlを回収した。固液分離は吸引濾過装置を用いて行い、短時間で濾過分離された。この液分に炭酸カルシウム９００ｇと純水４０００mlを加えてｐＨ７に中和した。この中和処理によって生じた沈澱を固液分離し、硫酸石膏の沈澱１８００ｇ（湿量）を回収し、液分５０００mlを分離した。回収した硫酸石膏中の各成分の含有量を表２に示した。また、液分への各成分の含有量を表３に示した。
[Example 1]
100 g of waste catalyst (content of each component is shown in Table 1) was immersed in dilute sulfuric acid (
表２に示すように、硫酸浸出後液から回収した固形分（硫酸石膏）には塩素が殆ど含まれておらず、これをセメント原料として利用できることが確認された。また、この固形分には廃触媒中の約８８％のアルミニウムおよび約９３％マグネシウムが含まれており、硫酸浸出によって大部分のアルミニウムおよびマグネシウムが浸出残渣中の白金族金属から分離されることが確認された。これらのアルミニウムおよびマグネシウムは硫酸石膏と共にセメント原料として利用することができる。一方、上記固形分を分離した液分には表３に示すように白金族金属および塩素が殆ど含まれておらず、アルミニウムおよびマグネシウムも極めて少ない。 As shown in Table 2, it was confirmed that the solid content (sulfate gypsum) recovered from the solution after leaching with sulfuric acid contained almost no chlorine and could be used as a cement raw material. In addition, this solid content contains about 88% aluminum and about 93% magnesium in the waste catalyst, and most of aluminum and magnesium are separated from platinum group metals in the leaching residue by sulfuric acid leaching. confirmed. These aluminum and magnesium can be used as a cement raw material together with gypsum sulfate. On the other hand, as shown in Table 3, the liquid component from which the solid content has been separated contains almost no platinum group metal and chlorine, and very little aluminum and magnesium.
〔実施例２〕
実施例１の硫酸浸出工程で回収した浸出残渣約５０ｇ（乾量）を密閉容器内の塩酸（濃度35％HCl）２００mlに浸漬し、さらに次亜塩素酸ナトリウム（濃度12％NaClO）１７mlを加え、１４０℃で２時間加熱した。これを固液分離して液分２００mlを回収した。この液分に鉄粉１０ｇを添加して液中の金属イオンを還元し、生成した沈澱約５ｇ（乾量）を固液分離した。この沈澱中の各成分の含有量を表４に示した。この表４から明らかなように、廃触媒に含まれる白金族金属の大部分が回収された。さらに、上記沈澱を分離した液分に水酸化ナトリウム３８ｇと純水２００mlを加えてｐＨ７に中和し、生成した水酸化物沈澱１４０ｇ（湿量）と液分４００mlを固液分離した。この固形分と分離した液分中の各成分の含有量を表５に示した。この表５から明らかなように、固形分、液分ともに白金族金属、アルミニウム、マグネシウムは殆ど含まれていなかった。
[Example 2]
About 50 g (dry weight) of the leaching residue collected in the sulfuric acid leaching process of Example 1 is immersed in 200 ml of hydrochloric acid (
〔実施例３〕
実施例２の塩酸浸出工程で回収した浸出残渣を純水５００mlの水槽に入れて洗浄し、残留塩素を洗い流した後に固液分離した。回収した固形分４６ｇ（湿量）と液分５００mlに含まれる各成分の含有量を表６に示した。何れも白金族金属、アルミニウム、マグネシウムの残量は少なく、固形分の主体はケイ素である。
Example 3
The leaching residue collected in the hydrochloric acid leaching step of Example 2 was washed in a 500 ml pure water tank, and the residual chlorine was washed away, followed by solid-liquid separation. Table 6 shows the content of each component contained in the recovered solid content of 46 g (wet amount) and the liquid content of 500 ml. In all cases, the remaining amount of platinum group metal, aluminum, and magnesium is small, and the main component of the solid content is silicon.
Claims (5)
A sulfuric acid leaching process in which the spent catalyst is leached with dilute sulfuric acid to elute the aluminum and magnesium components and solid-liquid separation; and a precipitation process in which a calcium compound is added to the recovered liquid after leaching to form a sulfate gypsum precipitate. And a separation step of separating the aluminum content and the magnesium content taken into the precipitate together with the precipitate into a solid-liquid separation.
The method for treating a waste catalyst according to claim 1, wherein in the sulfuric acid leaching step, the waste catalyst is immersed in dilute sulfuric acid in a sealed container and heated to 100 ° C or higher to perform pressure leaching.
The method for treating a waste catalyst according to claim 1 or 2, wherein the gypsum sulfate sulfate recovered in the separation step is used as a cement raw material.
The treatment of a waste catalyst according to any one of claims 1 to 3, further comprising a platinum group recovery step of leaching the leaching residue separated by solid-liquid in the sulfuric acid leaching step with hydrochloric acid, and recovering a platinum group metal from the liquid after the leaching. Method.
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