JP2004352900A

JP2004352900A - Method for recovering and recycling phosphor for fluorescent lamp, and fluorescent lamp

Info

Publication number: JP2004352900A
Application number: JP2003153686A
Authority: JP
Inventors: Reiji Otsuka; 礼治大塚
Original assignee: Kasei Optonix Ltd
Current assignee: Kasei Optonix Ltd
Priority date: 2003-05-30
Filing date: 2003-05-30
Publication date: 2004-12-16
Anticipated expiration: 2023-05-30
Also published as: JP4275461B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for recovering and recycling a phosphor for a fluorescent lamp, whereby the phosphor is less affected on luminous characteristics such as luminous colors and color rendering properties when it becomes to a recycled phosphor through the treatment of removing mercury from the phosphor recovered from a fluorescent lamp, and a fluorescent lamp having a high lumen maintenance factor is obtainable without lowering the luminous flux of the fluorescent lamp, when the recycled phosphor is reused as the fluorescent film of the fluorescent lamp; and to provide the fluorescent lamp. <P>SOLUTION: The recycled phosphor is prepared by the followings: after dispersing a mercury-containing recovered phosphor recovered from the fluorescent film of a fluorescent lamp, into a prescribed amount of a phosphor treating liquid composed of pH 2-5 of an acidic aqueous solution and immersing it in the liquid for a prescribed time, the recovered phosphor is separated from the mercury and recovered from the liquid. The fluorescent lamp having a fluorescent film composed of the recycled phosphor, is also provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は蛍光ランプ用蛍光体の回収再生方法及び蛍光ランプに関する。更に詳細には、水銀の放電により発生する紫外線によって発光させるタイプの蛍光ランプの蛍光膜等から回収された蛍光体に付着もしくは混入した水銀および／または水銀化合物（以下、単に「水銀」という）を除去し、再使用可能な蛍光ランプ用蛍光体を再生する回収再生方法及びこの回収再生蛍光体を用いた蛍光ランプに関する。
【０００２】
【従来の技術】
近年来、照明用を主用途とする蛍光ランプは、ハロ燐酸塩蛍光体の単一成分蛍光体からなる蛍光膜を有するタイプに加えて、およそ４５０、５４０及び６１０ｎｍの各波長域に強く、かつ半値幅の狭い発光スペクトルのピークを有する混合蛍光体を蛍光膜とする３波長形蛍光ランプが急速に普及してきた。特に省エネルギーの観点からはこれら３波長形蛍光ランプや高周波点灯形蛍光ランプの普及は著しいものがある。
【０００３】
さらに近年、省資源の観点から家庭用電化製品のリサイクルが行われるようになってきた。しかし使用済みの蛍光ランプは不燃物ゴミとして処理されたり、分別回収されても粉砕して埋没廃棄したり、あるいは蛍光ランプの外囲器であるガラスのみがリサイクルされているのが現状である。３波長形蛍光ランプは比較的高価な混合蛍光体を用いることから、これら蛍光ランプより回収された混合蛍光体（回収蛍光体）を再度利用することが望まれている。そのためには蛍光膜を構成する蛍光体を劣化させることなく蛍光膜に付着した水銀を除去し、蛍光体を回収再生する必要がある。
【０００４】
蛍光ランプから回収された蛍光体の再生方法については余り報告されていないが、従来水銀を除去する方法としては、水銀を溶解することが一般的で、通常は硝酸を用いて溶解させ除去する。しかしこの方法を蛍光ランプから回収された蛍光体の再生処理に適用し、水銀が溶解し得る濃度の硝酸で蛍光ランプからの回収蛍光体を処理すると、水銀は溶解除去されるが、同時に蛍光体の一部も溶解するため蛍光体の結晶構造が変化し発光色度が変化するだけでなく、その蛍光体が紫外線に長時間晒されると次第に蛍光体の輝度低下（紫外線劣化）を起こしたり、その蛍光体を蛍光ランプの蛍光膜として再使用した際、蛍光ランプの継続点灯時に発光輝度が経時的に低下（光束維持率低下）したりするようになる弊害があった。
【０００５】
一方、蛍光体が溶解しないようにするため、回収蛍光体を硝酸ではなく水で処理する方法が考えられるが、この場合蛍光体へのダメージは少なく、発光色度等の変化はないが、水銀の除去が不完全で、そのため回収再生された蛍光体の輝度がもとの蛍光体よりも低かったり、蛍光ランプとした際、そのランプの光束維持率低下が生じるという弊害があった。またこのような処理方法においては、蛍光体から水銀を完全に分離することが出来ないので、蛍光体及び水銀のリサイクル化は出来ず、コスト面及び環境への影響の面で好ましい状況ではなかった。
【０００６】
【発明が解決しようとする課題】
本発明は、上記状況に鑑みてなされたものであり、水銀の放電によって生じた紫外線により蛍光膜を発光させるタイプの蛍光ランプから回収された蛍光体等の、水銀を含む蛍光体から水銀を除去する処理を施して再生蛍光体とした場合、発光色や演色性等の発光特性に影響することなく、また、この再生蛍光体を蛍光ランプの蛍光膜として再使用した際に蛍光ランプの光束の低下がなくて、光束維持率が高い蛍光ランプを得ることのできる回収再生蛍光体を得る方法及び蛍光ランプを提供することを目的とする。
【０００７】
【課題を解決するための手段】
本発明者は、３波長形蛍光ランプ用蛍光体等の紫外線励起用蛍光体やこれらの蛍光体を含む混合蛍光体を蛍光膜とする蛍光ランプから回収された水銀を含む回収蛍光体について、これらの蛍光体を化学的に処理する蛍光体処理液のｐＨ、その種類や添加量、反応時間等の条件を変えて反応させ、得られた蛍光体の輝度および残留水銀の濃度、さらに蛍光体処理液により処理して得られた蛍光体を蛍光膜として用いた蛍光ランプの光束や光束維持率について詳細に調べた結果、蛍光ランプから回収された蛍光体を特定のｐＨ値および量の蛍光体処理液中に分散させて一定時間浸漬し、得られた蛍光体を蛍光膜として用いることによって上記目的を達成し得ることを見出し、本発明に至った。即ち、本発明の蛍光ランプ用蛍光体の回収再生方法及び蛍光ランプは以下の構成からなる。
【０００８】
（１）蛍光ランプの蛍光膜から回収された水銀を含む回収蛍光体をｐＨが２〜５である酸性水溶液からなる蛍光体処理液中に分散させた後、該蛍光体処理液から前記回収蛍光体を前記水銀と分別して回収することを特徴とする蛍光ランプ用蛍光体の回収再生方法。
（２）前記蛍光体処理液の重量が前記回収蛍光体の重量の３〜１０倍であることを特徴とする前記（１）に記載の蛍光ランプ用蛍光体の回収再生方法。
（３）前記回収蛍光体を前記蛍光体処理液中に分散させてから１０〜３０分経過後に前記回収蛍光体を該蛍光体処理液から分別することを特徴とする前記（１）または（２）に記載の蛍光ランプ用蛍光体の回収再生方法。
（４）前記回収蛍光体を分散させている前記蛍光体処理液のｐＨが２〜８に達した時、前記回収蛍光体を該蛍光体処理液から分別することを特徴とする前記（１）〜（３）のいずれかに記載の蛍光ランプ用蛍光体の回収再生方法。
【０００９】
（５）前記回収蛍光体がＹ_２Ｏ_３：Ｅｕ、（Ｓｒ，Ｂａ，Ｃａ，Ｍｇ）_１０（ＰＯ_４）_６Ｃｌ_２：Ｅｕの少なくとも一つを含むことを特徴とする前記（１）〜（４）のいずれかに記載の蛍光ランプ用蛍光体の回収再生方法。
（６）前記蛍光体処理液から分別された後の前記回収蛍光体に含まれる水銀の含有量が該蛍光体処理液中に分散させる前の前記回収蛍光体に含まれる水銀の量の２０％以下であることを特徴とする前記（１）〜（５）のいずれかに記載の蛍光ランプ用蛍光体の回収再生方法。
（７）ガラス管の内壁に蛍光膜を形成してなる蛍光ランプにおいて、前記蛍光膜が前記（１）〜（６）のいずれかに記載の回収再生方法により得られた蛍光体を含むことを特徴とする蛍光ランプ。
【００１０】
【発明の実施の形態】
以下、本発明について詳細に説明する。
本発明の蛍光ランプ用蛍光体の回収再生方法は、先ず、３波長形蛍光ランプをはじめとする水銀の放電により蛍光膜を発光させるタイプの蛍光ランプの蛍光膜より回収された、水銀、その他若干の夾雑物等の発光特性を阻害する物質を含む回収蛍光体の一定量を、所定の酸性度に調整された酸性水溶液からなる蛍光体処理液（以下、単に処理液という）中に分散させて、これを適宜攪拌しながら一定時間処理液と接触させることによって、処理液が水銀と反応してこれを溶解させることなく、蛍光体粒子と徐々に反応して回収蛍光体の粒子に付着している水銀を剥離、脱落させるので、次いでその処理液から回収蛍光体を水銀と分別して分離することにより再生蛍光体を得るものである。
【００１１】
処理液としては酸を希釈した酸性水溶液が用いられる。処理液として用いられる酸の種類については特に制限はないが、環境への影響度が少なく、かつ回収蛍光体が比較的溶解され難い、塩酸、硫酸等の鉱酸や酢酸等の有機酸がより好ましい。上記の酸を、そのｐＨ値が２〜５の範囲になるように調整された酸性水溶液を処理液として用いることによって、再生処理による回収蛍光体へのダメージが少なく、回収再生前の蛍光体の発光特性を保持し得る点で好ましい。
処理液の量は、被処理蛍光体である回収蛍光体に対して３〜１０倍量の範囲とするのが再生効率上望ましい。処理液の量が少な過ぎると水銀の除去が不十分となり、逆に処理液が多すぎると回収蛍光体の種類によりその程度は異なるものの回収蛍光体が過剰に溶解する場合があるのでそれぞれ好ましくない。
【００１２】
また、処理液から回収蛍光体を分離するまでの時間、すなわち、回収蛍光体を処理液中に分散、浸漬させておく時間（回収蛍光体を蛍光体処理液中に投入してから該処理液から分離するまでの時間。以下、この時間を反応時間ともいう）は、処理液のｐＨ値や回収蛍光体の種類にもよるが、反応時間が短かすぎると水銀の除去が不十分になり、逆に長すぎると蛍光体が過剰に溶解する可能性があるので、１０〜３０分の範囲とするのが望ましい。
回収蛍光体の種類によっては反応時間を長くすると処理液の酸が徐々に消費されて処理液のｐＨが次第に上昇し、例えば、回収蛍光体中にＹ_２Ｏ_３：Ｅｕ蛍光体や（Ｓｒ，Ｃａ，Ｂａ，Ｍｇ）_１０（ＰＯ_４）_６Ｃｌ_２：Ｅｕ蛍光体を含有する場合では、これらの蛍光体の溶解が進行して処理液のｐＨが８〜９の範囲にまで変化するので、処理液から回収蛍光体を分離するタイミングのもう一つの目安としては、回収蛍光体を分散させた処理液のｐＨが５〜８の範囲になった時点とすることが必要で、その場合、処理液から回収蛍光体を分離する時点の目安としては上記反応時間よりも処理液のｐＨ値が５〜８の範囲になった時点を優先することが望ましい。
【００１３】
本発明の蛍光ランプ用蛍光体の回収再生方法において、最も重要な要素は、用いる蛍光体処理液の酸性度の設定である。前述のように処理液として蛍光体を比較的溶解し易い硝酸を用いたり、硝酸以外の酸を用いる場合でもその酸濃度がｐＨ２より小さい比較的高濃度の酸性水溶液を用いて回収蛍光体に付着した水銀を直接溶解し分離回収する方法では回収蛍光体本体まで溶解し品質的ダメージを与え易いという弊害があるが、ｐＨ２〜５に調節された、比較的低濃度の酸性度を有する処理液中に分散させて回収蛍光体と処理液とを接触させるようにすれば、回収蛍光体の本体には影響を与えない程度に、蛍光体の最表面をわずかに溶解することにより、蛍光体表面に付着していた水銀が溶解する前にこれを剥離し、処理液中に脱落させることができる。そのため、本発明の蛍光ランプ用蛍光体の回収再生方法によると、再生蛍光体の品質への影響はなく、水銀をメタルの状態のままで回収できるため、コスト的にも品質的にも、また環境面においても好ましい再生方法である。
【００１４】
本発明の回収再生方法により処理される回収蛍光体としては、酸にほとんど溶解しないＬａＰＯ_４：Ｃｅ，Ｔｂ（以下ＬＡＰという）蛍光体、ＢａＭｇＡｌ_１０Ｏ_１７：Ｅｕ（以下ＢＡＭという）蛍光体や、酸に対する溶解度の低いＹ_２Ｏ_３：Ｅｕ蛍光体（以下ＹＯＸという）、（Ｓｒ，Ｃａ，Ｂａ，Ｍｇ）_１０（ＰＯ_４）_６Ｃｌ_２：Ｅｕ蛍光体（以下ＳＣＡという）を含む回収蛍光体が推奨され、回収蛍光体中にハロ燐酸カルシウム系蛍光体のような、ｐＨ２〜５の酸性水溶液に容易に溶解する蛍光体はできるだけ含有しない方が好ましい。ハロ燐酸カルシウム系蛍光体のようなｐＨ２〜５の酸性水溶液に容易に溶解する蛍光体を含む回収蛍光体を処理した場合には再生蛍光体中の残留水銀濃度が高くなり、特にその含有量が２０％以上になると再生蛍光体中の残留水銀の量が著しい。これは処理液中の酸がハロ燐酸カルシウム系蛍光体のようなｐＨ２〜５の酸性水溶液に容易に溶解する蛍光体に消費されてしまい、水銀の除去に利用されなくなるためである。
また回収蛍光体を分散させて処理を終えた処理液は、該処理液中の不純物や回収蛍光体と処理液との反応により生じた不純物を取り除くために、再生蛍光体として該処理液から分離する前に該処理液の電導度がほぼ５０μＳ／ｃｍ以下になるまで純水を加えてデカンテーション法で洗浄し、さらにそのスラリーはオープニング１００μｍ以下のメッシュを通過させることによって蛍光体処理液中に含まれる凝集物を除去しておいても良い。
【００１５】
次いで、一定時間処理液中に分散させて攪拌し、処理を終え、更に必要に応じて洗浄を終えた処理液から回収蛍光体と、蛍光体から剥離、脱落した水銀とを分別して分離される。処理液から蛍光体と水銀とを分別して分離する方法としては、回収蛍光体を含む処理液を攪拌して該処理液中で懸濁させ、回収蛍光体から剥離した蛍光体よりも比重の大きい水銀が最初に沈降し、蛍光体は未だ沈降せずに該処理液中に分散している時に、該処理液と共にスラリー状態で該処理液内に沈降している水銀成分から分別してから、該スラリー（蛍光体成分を含む処理液）を濾過などの手段で固液分離する方法や、回収蛍光体を含む処理液を攪拌してからそのまま静置しておいてこれを沈降させることによって、比重の大きい水銀から先に沈降させ、その上層に蛍光体が沈降してくるのを待って処理液を除去した後に、固形分の中の上層に沈降している蛍光体を分離する等の方法で行われる。
【００１６】
本発明の蛍光ランプは上述の本発明の回収再生方法によって製造された蛍光体がその蛍光膜として使用される外は従来の蛍光ランプと同様であり、使用済みの蛍光ランプの蛍光膜から回収された蛍光体から上述のようにして再生された蛍光体に、必要に応じて新規に製造された未使用の蛍光体を所定量加えた混合蛍光体を外囲器の内面に塗布して蛍光膜とする以外は従来公知の方法によって製造することが出来る。
【００１７】
表１は酸の濃度（ｐＨ値）の異なる塩酸酸性の処理液に主な蛍光ランプ用蛍光体をそれぞれ単独で分散させ、浸漬する処理を施した後、これを該処理液から分離、回収した時の、蛍光体を各処理液から分離する直前の該処理液のｐＨ値（処理後のｐＨ）とその時の蛍光体の回収率（収率）をそれぞれ示したものであり、いずれの蛍光体についても、蛍光体１５０ｇを１．０５ｋｇの処理液中に１０分間浸漬して処理した場合である。なお、表１には３Ｎ硝酸溶液を処理液として用いた時の収率（回収率）も併記してある。
表１から明らかなようにＬＡＰとＢＡＭでは、処理後のｐＨは処理液のｐＨとほぼ同じであるのに対し、ＹＯＸとＳＣＡでは処理後の該処理液のｐＨはおよそ５〜８の範囲まで大きく変化している。またＹＯＸおよびＳＣＡではｐＨが低くなる（酸性度が高くなる）と処理後の収率も低くなっていることから、ＹＯＸおよびＳＣＡは酸と反応し、蛍光体表面が次第に溶解するのに対し、ＬＡＰおよびＢＡＭは酸と反応（酸に溶解）し難いことを示している。従って、ＹＯＸまたはＳＣＡを含有する混合蛍光体をｐＨの低い酸性水溶液で処理した場合、ＳＣＡおよびＹＯＸが溶解し、混合蛍光体中に含まれるＳＣＡおよびＹＯＸの配合量が変化するために混合蛍光体の発光色度が変化し、そのため再度蛍光ランプの蛍光膜用として用いる場合には色度調整の必要が生じ、作業上およびコスト的に不利益になる。
【００１８】
【表１】

【００１９】
表２は表１で示した、酸性度（ｐＨ値）の異なる処理液で処理された各蛍光体を用いてそれぞれ単色の蛍光ランプ（ＦＬ４０Ｓ）の実球を作製し、その光束と光束維持率を未使用の蛍光体（すなわち未だ蛍光ランプに使用されていない同種の蛍光体）を用いた蛍光ランプと比較した結果を示したものである。
【００２０】
【表２】

【００２１】
表２から明らかなようにＬＡＰとＢＡＭを用いた蛍光ランプでは、光束および光束維持率は未処理の蛍光体を用いた蛍光ランプとほぼ同等であり、ＬＡＰおよびＢＡＭは、水銀を溶解除去できるような硝酸溶液でこれを処理しても問題ないこと示している。一方、ＹＯＸとＳＣＡを用いた蛍光ランプでは光束および光束維持率は未処理の蛍光体に比べ大きく低下しており、特にＳＣＡを用いた蛍光ランプの低下率は大きい。これはＹＯＸおよびＳＣＡが酸と反応または酸によって溶解することによって蛍光体が劣化することを示しており、ＹＯＸまたはＳＣＡを含有する回収蛍光体から水銀を除去する際には、ＳＣＡまたはＹＯＸ、特にＳＣＡが酸と反応もしくは酸によって溶解しにくい条件で回収再生しなければならないことを示している。
【００２２】
また、表２においてＹＯＸおよびＳＣＡを用いた蛍光ランプでは処理液のｐＨが低くなると光束および光束維持率が低下しており、特にｐＨ１の処理液で再生処理された蛍光体を用いた蛍光ランプにおいては光束及び光束維持率の低下は著しく、このことは処理液のｐＨが低いほど蛍光体の劣化が大きくなることを示しており、蛍光体処理液のｐＨは２以上であることが望ましい。
このように、蛍光体表面に付着している水銀を除去する際は、酸の濃度の高い処理液で蛍光体を処理すると、蛍光体が劣化し再使用できなくなってしまうため、水銀を直接溶解するのではなく、水銀そのものは溶解せずに蛍光体の最表面層だけをわずかに溶解するだけで蛍光体の本体には影響を与えない程度の酸濃度の低い酸性水溶液で回収蛍光体を処理することにより、蛍光体表面に付着している水銀を剥離、脱落させて除去することができる。
【００２３】
【実施例】
次に、実施例により本発明を説明する。
〔実施例１〕
充分点灯使用され、寿命末期となったＦＬ４０Ｓ／ＥＸ−Ｎ型蛍光ランプからガラス内面に塗布形成された蛍光膜を剥がし取った。剥がし取った蛍光膜を純水に分散させ、オープニング１００μｍのメッシュで篩った後、脱水・乾燥・篩がけの工程を経て蛍光体を回収した。この蛍光体（回収蛍光体）に含まれる水銀濃度は０．３重量％であり、２５４ｎｍの紫外線で励起し、発光させたときの発光色度はｘ＝０．３７４、ｙ＝０．３７４で、相対輝度は９０％であった。なお相対輝度は、ＹＯＸ４０％、ＬＡＰ３２％、ＳＣＡ２８％からなり、発光色度がｘ＝０．３７４、ｙ＝０．３７４の未使用の混合蛍光体（標準蛍光体）の輝度を１００とした時の相対値である。
なお、蛍光体を回収した上記ＦＬ４０Ｓ／ＥＸ−Ｎ蛍光ランプにはＹＯＸとＬＡＰとＳＣＡの混合蛍光体が使用されており、ハロ燐酸カルシウム系蛍光体は含まれていない。
【００２４】
一方、処理液として塩酸でｐＨ３．０に調整した酸性水溶液を調製し、この処理液１０５ｇに上記回収蛍光体１５ｇを攪拌しながら１０秒間で投入して分散させた回収蛍光体のスラリーを、さらに攪拌を１０分間行った。攪拌終了時の処理液のｐＨは６．２であった。攪拌終了後直ちに該スラリーをスラリー容器の底に沈降している水銀を残して濾過し蛍光体成分を回収するとともに、該蛍光体スラリー容器底中に沈降している水銀を金属として回収した。
上記のようにして蛍光体スラリー中から回収された蛍光体を１００ｇの純水に分散させ上澄み液の電導度が５０μＳ／ｃｍ以下になるまで純水でデカンテーションにより洗浄し、さらにそのスラリーをオープニング４０μｍのメッシュを通過させてスラリー中に含まれる凝集物を除去した。その後脱水・乾燥・篩の工程を経て蛍光体を再生し実施例１の再生蛍光体を製造した。
【００２５】
次に、上述のようにして得た実施例１の再生蛍光体に未使用のＹＯＸとＳＣＡを添加し発光色度を標準蛍光体と同一（発光色度ｘ＝０．３７４、ｙ＝０．３７４）にした実施例１の混合蛍光体にニトロセルロースのラッカーと共に酢酸ブチルを添加し十分に混合して蛍光体を懸濁させたスラリーを調製し、このスラリーをガラス管に塗布して乾燥し、通常の方法で色温度５０００Ｋの実施例１の蛍光ランプ（ＦＬ２０Ｓ／ＥＸ−Ｎ）を製造した。
標準蛍光体についても同様の方法で蛍光ランプ（ＦＬ２０Ｓ／ＥＸ−Ｎ）を製造した。
【００２６】
〔比較例１〕
混合蛍光体として実施例１の混合蛍光体に代えて、ＹＯＸ４０％、ＬＡＰ３２％、ＳＣＡ２８％からなる発光色度ｘ＝０．３７４、ｙ＝０．３７４の未使用の蛍光体（標準蛍光体）を用いた以外は実施例１の蛍光ランプと同様にして比較例１の蛍光ランプを製造した。
【００２７】
〔実施例２〜４〕
実施例１の処理液（ｐＨ３．０の酸性水溶液）に代えて、ｐＨ２．０、ｐＨ４．０、ｐＨ５．０の各塩酸酸性水溶液をそれぞれ処理液として用いる以外は実施例１と同様にして実施例２〜４の再生蛍光体を製造した。
また、蛍光膜用の蛍光体として実施例１の再生蛍光体に代えて、実施例２〜４の各再生蛍光体のそれぞれにＹＯＸとＳＣＡを混合していずれの蛍光体も混合後の蛍光体の発光色度が標準蛍光体と同一（発光色度ｘ＝０．３７４、ｙ＝０．３７４）となるようにした実施例２〜４の各混合蛍光体を用いた以外は実施例１の蛍光ランプと同様にして実施例２〜４の蛍光ランプを製造した。
【００２８】
〔比較例２〜４〕
実施例１の蛍光体処理液（ｐＨ３．０の酸性水溶液）に代えて、ｐＨ１．０、ｐＨ６．０、ｐＨ７．０の各塩酸水溶液をそれぞれ処理液として用いた以外は実施例１と同様にして比較例２〜４の再生蛍光体を製造した。
また、混合蛍光体として、実施例１の再生蛍光体に代えて、比較例２〜４の各再生蛍光体のそれぞれに未使用のＹＯＸとＳＣＡを混合してその発光色度が標準蛍光体と同一（発光色度ｘ＝０．３７４、ｙ＝０．３７４）となるようにした比較例２〜４の混合蛍光体を用いた以外は実施例１の蛍光ランプと同様にして比較例２〜４の蛍光ランプを製造した。
【００２９】
表３には上述の実施例１〜４および比較例１〜４の再生蛍光体を製造する際の処理の条件｛処理液のｐＨ、被処理蛍光体に対する処理液の量比、反応時間及び処理後のｐＨ（処理液から回収蛍光体を分離する直前時点での処理液のｐＨ）｝、粉体の特性（再生蛍光体を波長２５４ｎｍの紫外線で励起して発光させた時の発光を視感度フイルターを透過させて輝度計で検出することによって求めた粉体輝度、色度）、蛍光ランプの特性（各再生蛍光体を蛍光膜として用いた実施例１〜４及び比較例１〜４の各蛍光ランプの初期光束、光束維持率）及び各再生蛍光体中に含まれるＨｇ量（Ｈｇ含有量）を示す。
なお表３において、各蛍光ランプの初期光束（表中、「光束」の欄）は標準蛍光体を使用した比較例１の蛍光ランプの初期光束を１００とした時の相対値で示してあり、光束維持率は各ランプを連続点灯した時の１０００時間後における光束を、それぞれの蛍光ランプの点灯直後における光束（初期光束）に対する百分率で表した値である。また、回収蛍光体とは実施例２〜４の回収再生処理に供される前の蛍光体である。
【００３０】
【表３】

【００３１】
表３からわかるように、ｐＨ２〜ｐＨ５の酸性水溶液を処理液として用いて得られた実施例１〜４の各再生蛍光体は、回収蛍光体と比べたとき発光色度の変化が小さく発光輝度（粉末輝度）が改善されており、水銀も十分に除去されていた。また、本発明の方法で再生された実施例１〜４の各蛍光体を色度調整して蛍光膜として用いた本発明の実施例１〜４の蛍光ランプは、未使用の標準蛍光体のみを蛍光膜とする比較例１の蛍光ランプに対する初期光束の低下の程度が少なく、光束維持率は同等であった。
【００３２】
一方、ｐＨ１．０の酸性水溶液を処理液として用いて回収蛍光体を再生することによって得られた比較例２の再生蛍光体では、水銀は十分に除去されているが、回収蛍光体と比べたとき発光色度の変化が大きく、比較例２の蛍光体を色度調整して蛍光膜として用いた比較例２の蛍光ランプは、未使用の標準蛍光体のみを蛍光膜とする比較例１の蛍光ランプや実施例１〜４の本発明の蛍光ランプと比べて初期光束が低く、光束維持率も低くなっていた。
さらにｐＨ６．０およびｐＨ７．０の酸性水溶液を処理液として用い再生された比較例３〜４の再生蛍光体では、回収蛍光体と比べたとき発光色度の変化は小さいが、発光輝度（粉末輝度）が改善されていない上、水銀の除去も不完全であった。さらに比較例３〜４の蛍光体を色度調整して蛍光膜として用いた比較例３〜４の蛍光ランプは、未使用の標準蛍光体のみを蛍光膜とする比較例１の蛍光ランプや実施例１〜４の本発明の蛍光ランプと比べ光束維持率は同等であるが、初期光束は大幅に低くなっていた。
【００３３】
〔実施例５〜７〕
蛍光体処理液として実施例１の酸性水溶液を１０５ｇ（回収蛍光体の７倍量）用いる代わりに、それぞれ４５ｇ（回収蛍光体の３倍量）、７５ｇ（回収蛍光体の５倍量）及び１５０ｇ（回収蛍光体の１０倍量）の酸性水溶液をそれぞれ処理液として用いる以外は実施例１と同様にして実施例５〜７の再生蛍光体を製造した。
また、混合蛍光体として実施例５〜７の各再生蛍光体に未使用のＹＯＸとＳＣＡを混合し、それぞれの発光色度を標準蛍光体と同一（発光色度ｘ＝０．３７４、ｙ＝０．３７４）にした実施例５〜７の混合蛍光体をそれぞれ用いる以外は実施例１の蛍光ランプと同様にして実施例５〜７の蛍光ランプを製造した。
【００３４】
表４に上述の実施例５〜７の再生蛍光体を製造する際の処理の条件、処理後のｐＨ、粉体の特性、蛍光ランプの特性及び再生蛍光体中に含まれるＨｇ量（Ｈｇ含有量）を実施例１及び比較例１と共に示す。なお、表４に示されているこれらの各特性項目の意味するところは表３の場合と同様である。
なお表４において、各蛍光ランプの初期光束及び光束維持率は実施例１〜４と同様にして測定した値である。
【００３５】
【表４】

【００３６】
表４からわかるように、蛍光体に対して３倍量から１０量の酸性水溶液を蛍光体処理液として用いて得られた実施例１および５〜７の各再生蛍光体は、回収蛍光体と比べたとき発光色度の変化が小さく発光輝度（粉末輝度）が改善されており、水銀も充分に除去されていた。また本発明の方法で再生された蛍光体を色度調整して蛍光膜として用いた本発明の実施例１、５〜７の各蛍光ランプは、未使用の標準蛍光体のみを蛍光膜とする比較例１の蛍光ランプと比べて初期光束の低下の程度が少なく、光束維持率は同等であった。
【００３７】
〔実施例８〕
処理液中に回収蛍光体を添加して攪拌する時間（反応時間）を１０分ではなく３０分とする以外は実施例１と同様にして実施例８の再生蛍光体を製造した。
また、混合蛍光体として実施例１の混合蛍光体に代えて実施例８の再生蛍光体に未使用のＹＯＸとＳＣＡを混合して発光色度を標準蛍光体と同一（発光色度ｘ＝０．３７４、ｙ＝０．３７４）にした実施例８の混合蛍光体を用いる以外は実施例１の蛍光ランプと同様にして実施例８の蛍光ランプを製造した。
【００３８】
表５には上述の実施例８の再生蛍光体を製造する際の処理の条件、処理後のｐＨ、粉体の特性、蛍光ランプの特性及び再生蛍光体中に含まれるＨｇ量（Ｈｇ含有量）を実施例１及び比較例１と共に示す。なお、表５に示されているこれらの各特性項目の意味するところは表３の場合と同様である。また、表５において、各蛍光ランプの初期光束及び光束維持率は実施例１〜４と同様にして測定した値である。
【００３９】
【表５】

【００４０】
表５からわかるように、３０分間攪拌し処理液中に浸漬して処理された実施例８の再生蛍光体は、回収蛍光体と比べたとき発光色度の変化が小さく発光輝度（粉末輝度）が改善されており、水銀も除去されていた。また本発明の方法で再生された蛍光体を色度調整して蛍光膜として用いた実施例８の蛍光ランプは、未使用の標準蛍光体のみを蛍光膜とする比較例１の蛍光ランプと比べて初期光束の低下の程度が少なく、光束維持率は同等であった。
【００４１】
〔実施例９〕
実施例１の回収蛍光体１４．２５ｇに５％のハロ燐酸カルシウム蛍光体０．７５ｇを加えた混合蛍光体を回収蛍光体として用いた以外は実施例１と同様にして実施例９の再生蛍光体を製造した。
表６に上述の実施例９の再生蛍光体を製造する際の処理の条件、処理後のｐＨ及び再生蛍光体中に含まれるＨｇ量（Ｈｇ含有量）を実施例１の場合と共に示す。なお、表６に示されているこれらの各特性項目の意味するところは表３の場合と同様である。
【００４２】
【表６】

表６からわかるように、ハロ燐酸カルシウム蛍光体の混合割合が５％の場合の再生蛍光体では水銀は十分に除去されていた。
【００４３】
【発明の効果】
本発明の方法により、使用済み蛍光ランプの蛍光膜から回収された蛍光体を再生処理することにより得られた再生蛍光体を蛍光ランプの蛍光膜として用いた場合、使用前の蛍光ランプの発光色や演色性等の発光特性と同等の発光特性を維持し、また、蛍光ランプの光束の低下がなくて、光束維持率の高い蛍光ランプを得ることが可能となる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for collecting and regenerating a phosphor for a fluorescent lamp and a fluorescent lamp. More specifically, mercury and / or a mercury compound (hereinafter, simply referred to as “mercury”) attached to or mixed with a phosphor recovered from a fluorescent film or the like of a fluorescent lamp of a type that emits light by ultraviolet rays generated by mercury discharge. The present invention relates to a recovery / recovery method for recovering a fluorescent lamp for a fluorescent lamp which can be removed and reused, and a fluorescent lamp using the recovered / regenerated fluorescent material.
[0002]
[Prior art]
In recent years, fluorescent lamps mainly used for illumination have a strong characteristic in each wavelength range of about 450, 540 and 610 nm, in addition to a type having a phosphor film composed of a single component phosphor of a halophosphate phosphor, and A three-wavelength fluorescent lamp using a mixed phosphor having a peak of an emission spectrum with a narrow half-value width as a fluorescent film has rapidly spread. In particular, from the viewpoint of energy saving, these three-wavelength fluorescent lamps and high-frequency lighting fluorescent lamps have become very popular.
[0003]
Furthermore, in recent years, household electric appliances have been recycled from the viewpoint of resource saving. However, at present, used fluorescent lamps are treated as incombustible garbage, crushed and buried and discarded even if they are separately collected, or only the glass that is the envelope of the fluorescent lamp is recycled. Since the three-wavelength fluorescent lamp uses a relatively expensive mixed phosphor, it is desired to reuse the mixed phosphor (recovered phosphor) recovered from these fluorescent lamps. For that purpose, it is necessary to remove mercury adhering to the phosphor film without deteriorating the phosphor constituting the phosphor film, and to recover and reproduce the phosphor.
[0004]
Although there has been little report on a method of regenerating a phosphor recovered from a fluorescent lamp, mercury is conventionally removed as a method of removing mercury, and usually is dissolved and removed using nitric acid. However, when this method is applied to the regeneration treatment of the phosphor recovered from the fluorescent lamp and the phosphor recovered from the fluorescent lamp is treated with nitric acid at a concentration at which mercury can be dissolved, mercury is dissolved and removed, but at the same time, the phosphor is dissolved. Not only dissolves but also changes the crystal structure of the phosphor and changes the emission chromaticity. In addition, if the phosphor is exposed to ultraviolet rays for a long time, the brightness of the phosphor gradually decreases (UV degradation), When the phosphor is reused as the fluorescent film of the fluorescent lamp, there is a problem that the emission luminance is reduced with time (the luminous flux maintenance ratio is reduced) when the fluorescent lamp is continuously lit.
[0005]
On the other hand, in order to prevent the phosphor from dissolving, a method of treating the recovered phosphor with water instead of nitric acid can be considered. In this case, the damage to the phosphor is small, and there is no change in emission chromaticity or the like. Incomplete removal of the fluorescent material causes the luminance of the recovered and regenerated fluorescent material to be lower than that of the original fluorescent material, and when a fluorescent lamp is used, the luminous flux maintenance ratio of the lamp is reduced. Further, in such a treatment method, mercury cannot be completely separated from the phosphor, so that the phosphor and mercury cannot be recycled, which is not a favorable situation in terms of cost and environmental impact. .
[0006]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and removes mercury from a phosphor containing mercury, such as a phosphor recovered from a fluorescent lamp of a type that causes a phosphor film to emit light by ultraviolet rays generated by mercury discharge. When the regenerated phosphor is used as a regenerated phosphor, it does not affect the emission characteristics such as emission color and color rendering, and when the regenerated phosphor is reused as the fluorescent film of the fluorescent lamp, the luminous flux of the fluorescent lamp is reduced. It is an object of the present invention to provide a method and a fluorescent lamp for obtaining a recovered / reproduced phosphor capable of obtaining a fluorescent lamp having a high luminous flux maintenance rate without a decrease.
[0007]
[Means for Solving the Problems]
The present inventor has proposed a phosphor for ultraviolet excitation, such as a phosphor for a three-wavelength fluorescent lamp, and a recovered phosphor containing mercury recovered from a fluorescent lamp using a mixed phosphor containing these phosphors as a phosphor film. The phosphor is treated by changing conditions such as the pH of the phosphor treatment solution for chemically treating the phosphor, the type and amount of addition, the reaction time, etc., and the luminance of the resulting phosphor and the concentration of residual mercury, and the phosphor treatment A detailed examination was conducted on the luminous flux and luminous flux maintenance rate of a fluorescent lamp using a phosphor obtained by treating with a liquid as a fluorescent film. As a result, the phosphor recovered from the fluorescent lamp was treated with a specific pH value and amount of phosphor. The present inventors have found that the above object can be achieved by dispersing in a liquid and immersing the phosphor for a certain period of time, and using the obtained phosphor as a phosphor film. That is, the method of recovering and regenerating the fluorescent substance for a fluorescent lamp and the fluorescent lamp of the present invention have the following configurations.
[0008]
(1) A phosphor containing mercury recovered from a fluorescent film of a fluorescent lamp is dispersed in a phosphor processing solution composed of an acidic aqueous solution having a pH of 2 to 5, and then the recovered fluorescent light is dispersed from the phosphor processing solution. A method of recovering and regenerating a fluorescent substance for a fluorescent lamp, wherein the fluorescent substance is separated and recovered from the mercury.
(2) The method according to (1), wherein the weight of the phosphor treatment liquid is 3 to 10 times the weight of the recovered phosphor.
(3) The above-mentioned (1) or (2), wherein the collected phosphor is separated from the phosphor treatment liquid 10 to 30 minutes after the dispersion of the collected phosphor in the phosphor treatment liquid. The method for recovering and regenerating the fluorescent substance for a fluorescent lamp according to the above item.
(4) When the pH of the phosphor treatment liquid in which the collected phosphor is dispersed reaches 2 to 8, the collected phosphor is separated from the phosphor treatment liquid (1). A method for recovering and regenerating a fluorescent substance for a fluorescent lamp according to any one of claims 1 to 3.
[0009]
(5) The recovered phosphor is Y ₂ O ₃ : Eu, (Sr, Ba, Ca, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : The method for collecting and regenerating a phosphor for a fluorescent lamp according to any one of the above (1) to (4), comprising at least one of Eu.
(6) The content of mercury contained in the collected phosphor after being separated from the phosphor treatment liquid is 20% of the amount of mercury contained in the collected phosphor before being dispersed in the phosphor treatment liquid. The method for collecting and regenerating a fluorescent substance for a fluorescent lamp according to any one of the above (1) to (5), characterized in that:
(7) In a fluorescent lamp in which a fluorescent film is formed on an inner wall of a glass tube, the fluorescent film contains a phosphor obtained by the collection and regeneration method according to any one of (1) to (6). Features fluorescent lamp.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
The method of recovering and regenerating the fluorescent substance for a fluorescent lamp according to the present invention includes firstly mercury recovered from the fluorescent film of a fluorescent lamp of a type that emits a fluorescent film by discharging mercury such as a three-wavelength fluorescent lamp, A certain amount of the recovered phosphor containing a substance that inhibits the emission characteristics such as impurities is dispersed in a phosphor treatment solution (hereinafter simply referred to as a treatment solution) composed of an acidic aqueous solution adjusted to a predetermined acidity. By contacting the treating solution with the treating solution for a certain period of time while appropriately stirring the treating solution, the treating solution does not react with and dissolve the mercury, but gradually reacts with the phosphor particles and adheres to the particles of the collected phosphor. The recovered phosphor is separated and separated from mercury from the processing solution to separate and remove the mercury, thereby obtaining a regenerated phosphor.
[0011]
An acidic aqueous solution obtained by diluting an acid is used as the treatment liquid. There is no particular limitation on the type of acid used as the treatment liquid, but the influence on the environment is small, and the recovered phosphor is relatively difficult to dissolve, and mineral acids such as hydrochloric acid and sulfuric acid and organic acids such as acetic acid are more likely to be used. preferable. By using the above-mentioned acid as the treatment liquid, an acidic aqueous solution whose pH value is adjusted to be in the range of 2 to 5, damage to the recovered phosphor due to the regeneration treatment is small, and the phosphor before the recovery and regeneration is used. This is preferable in that light emitting characteristics can be maintained.
The amount of the treatment liquid is preferably 3 to 10 times the amount of the recovered phosphor, which is the phosphor to be treated, from the viewpoint of regeneration efficiency. If the amount of the processing solution is too small, the removal of mercury becomes insufficient, while if the amount of the processing solution is too large, the degree differs depending on the type of the recovered phosphor, but the recovered phosphor may be excessively dissolved, which is not preferable. .
[0012]
Also, the time until the recovered phosphor is separated from the processing solution, that is, the time during which the recovered phosphor is dispersed and immersed in the processing solution (from the time when the recovered phosphor is introduced into the processing solution for the phosphor, The time until the separation from the solution (hereinafter also referred to as the reaction time) depends on the pH value of the processing solution and the type of the recovered phosphor, but if the reaction time is too short, the removal of mercury becomes insufficient. On the other hand, if the length is too long, the phosphor may be excessively dissolved.
Depending on the type of the recovered phosphor, if the reaction time is extended, the acid of the processing solution is gradually consumed, and the pH of the processing solution gradually increases. ₂ O ₃ : Eu phosphor or (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : In the case where Eu phosphors are contained, the dissolution of these phosphors progresses and the pH of the processing solution changes to the range of 8 to 9, so that another timing for separating the recovered phosphor from the processing solution. As a guide, it is necessary to set the time when the pH of the processing solution in which the collected phosphor is dispersed becomes in the range of 5 to 8. In this case, the standard at the time of separating the collected phosphor from the processing solution is as described above. It is desirable to give priority to the point in time when the pH value of the processing solution is in the range of 5 to 8 over the reaction time.
[0013]
In the method of recovering and regenerating the phosphor for a fluorescent lamp according to the present invention, the most important factor is the setting of the acidity of the phosphor treatment solution to be used. As described above, even when using nitric acid as a treatment liquid, which dissolves the phosphor relatively easily, or when using an acid other than nitric acid, use a relatively high-concentration acidic aqueous solution whose acid concentration is smaller than pH 2 to adhere to the recovered phosphor. The method of directly dissolving and separating and recovering the collected mercury has the disadvantage of easily dissolving the phosphor itself and causing quality damage, but in a processing solution having a relatively low concentration of acidity adjusted to pH 2 to 5. If the collected phosphor is brought into contact with the processing solution by dispersing it in the surface of the phosphor, the outermost surface of the phosphor is slightly dissolved to such an extent that the main body of the collected phosphor is not affected. Before the attached mercury is dissolved, it can be peeled off and dropped into the processing solution. Therefore, according to the method for recovering and regenerating a fluorescent material for a fluorescent lamp of the present invention, there is no effect on the quality of the regenerated fluorescent material, and mercury can be recovered in a metal state. This is also a preferable regeneration method in terms of environment.
[0014]
The recovered phosphor treated by the recovery and regeneration method of the present invention includes LaPO that is hardly soluble in acid. ₄ : Ce, Tb (hereinafter referred to as LAP) phosphor, BaMgAl ₁₀ O ₁₇ : Eu (hereinafter referred to as BAM) phosphor and Y having low solubility in acid ₂ O ₃ : Eu phosphor (hereinafter referred to as YOX), (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : A recovered phosphor containing an Eu phosphor (hereinafter referred to as SCA) is recommended, and the recovered phosphor does not contain a phosphor which is easily dissolved in an acidic aqueous solution of pH 2 to 5, such as a calcium halophosphate-based phosphor. Is more preferred. When a recovered phosphor containing a phosphor that easily dissolves in an acidic aqueous solution having a pH of 2 to 5 such as a calcium halophosphate-based phosphor is treated, the residual mercury concentration in the regenerated phosphor becomes high, and the content thereof is particularly low. If it exceeds 20%, the amount of residual mercury in the regenerated phosphor becomes remarkable. This is because the acid in the treatment liquid is consumed by a phosphor that easily dissolves in an acidic aqueous solution having a pH of 2 to 5, such as a calcium halophosphate phosphor, and is not used for removing mercury.
In addition, the processing solution that has been processed by dispersing the recovered phosphor is separated from the processing solution as a regenerated phosphor in order to remove impurities in the processing solution and impurities generated by a reaction between the recovered phosphor and the processing solution. Before the treatment, pure water is added until the conductivity of the treatment solution becomes approximately 50 μS / cm or less, and the solution is washed by a decantation method. Further, the slurry is passed through a mesh having an opening of 100 μm or less to form a phosphor treatment solution. Aggregates contained may be removed.
[0015]
Next, the phosphor is dispersed in the treatment liquid for a certain period of time and stirred, and the treatment is finished. If necessary, the recovered phosphor is separated from the treated liquid, and the mercury peeled off and dropped off from the phosphor is separated and separated. . As a method of separating and separating the phosphor and the mercury from the treatment liquid, the treatment liquid containing the recovered phosphor is stirred and suspended in the treatment liquid, and the specific gravity is larger than the phosphor separated from the collected phosphor. When the mercury first settles and the phosphor is not yet settled and is dispersed in the processing solution, it is separated from the mercury component settling in the processing solution in a slurry state together with the processing solution, A method of solid-liquid separation of a slurry (a processing liquid containing a phosphor component) by means such as filtration, or a method of stirring a processing liquid containing a collected phosphor and leaving it to stand as it is, thereby allowing the specific gravity to be settled Large amount of mercury, first settle the phosphor in the upper layer, remove the processing solution, and then separate the phosphor that has settled in the upper layer of the solid content. Done.
[0016]
The fluorescent lamp of the present invention is the same as a conventional fluorescent lamp except that the phosphor produced by the above-described recovery and regeneration method of the present invention is used as the fluorescent film, and is recovered from the fluorescent film of the used fluorescent lamp. A mixed phosphor obtained by adding a predetermined amount of a newly manufactured unused phosphor as necessary to the phosphor regenerated as described above from the phosphor thus obtained is applied to the inner surface of the envelope to form a phosphor film. Other than the above, it can be manufactured by a conventionally known method.
[0017]
Table 1 shows that each of the main phosphors for fluorescent lamps was separately dispersed and immersed in a hydrochloric acid treatment solution having a different acid concentration (pH value), and then separated and recovered from the treatment solution. At this time, the pH value (pH after the treatment) of the processing solution immediately before separating the phosphor from each processing solution and the recovery rate (yield) of the phosphor at that time are shown, respectively. The above is also the case where 150 g of the phosphor was immersed in 1.05 kg of the treatment liquid for 10 minutes to carry out the treatment. Table 1 also shows the yield (recovery rate) when a 3N nitric acid solution was used as the treatment liquid.
As is clear from Table 1, the pH of the treated liquid is almost the same as that of the treatment liquid for LAP and BAM, whereas the pH of the treated liquid for YOX and SCA is up to about 5-8. It has changed significantly. In addition, YOX and SCA have a lower pH (increased acidity) and a lower yield after treatment, so that YOX and SCA react with an acid and the phosphor surface gradually dissolves. LAP and BAM have shown that it is difficult to react (dissolve in an acid) with an acid. Therefore, when the mixed phosphor containing YOX or SCA is treated with an acidic aqueous solution having a low pH, SCA and YOX dissolve and the blending amount of SCA and YOX contained in the mixed phosphor changes, so that the mixed phosphor is changed. Changes in the emission chromaticity of the fluorescent lamp, so that when it is used again for the fluorescent film of the fluorescent lamp, it is necessary to adjust the chromaticity, which is disadvantageous in terms of work and cost.
[0018]
[Table 1]

[0019]
Table 2 shows the actual sphere of a single-color fluorescent lamp (FL40S) produced using each of the phosphors treated with the treatment solutions having different acidities (pH values) shown in Table 1, and the luminous flux and the luminous flux maintenance factor. Is a result of comparing a fluorescent lamp with a fluorescent lamp using an unused phosphor (that is, the same kind of phosphor not yet used in the fluorescent lamp).
[0020]
[Table 2]

[0021]
As is clear from Table 2, in the fluorescent lamp using LAP and BAM, the luminous flux and the luminous flux maintenance factor are almost equal to those of the fluorescent lamp using the untreated phosphor, and LAP and BAM can dissolve and remove mercury. It shows that there is no problem in treating this with a mild nitric acid solution. On the other hand, in the fluorescent lamp using YOX and SCA, the luminous flux and the luminous flux maintenance rate are greatly reduced as compared with the untreated phosphor, and the reduction rate of the fluorescent lamp using SCA is particularly large. This indicates that the phosphor is degraded by the reaction or dissolution of YOX and SCA with an acid. When mercury is removed from the recovered phosphor containing YOX or SCA, SCA or YOX, especially This indicates that SCA must be recovered and regenerated under conditions that do not easily react with or dissolve in the acid.
[0022]
Further, in Table 2, in the fluorescent lamp using YOX and SCA, the luminous flux and the luminous flux maintenance ratio decrease as the pH of the processing liquid decreases, and particularly in the fluorescent lamp using the phosphor regenerated with the processing liquid having a pH of 1. Indicates that the luminous flux and the luminous flux maintenance rate decrease remarkably, which indicates that the lower the pH of the processing liquid, the greater the deterioration of the phosphor, and the pH of the phosphor processing liquid is desirably 2 or more.
As described above, when removing the mercury adhering to the phosphor surface, if the phosphor is treated with a treatment solution having a high acid concentration, the phosphor deteriorates and cannot be reused. Instead of dissolving the mercury itself, only the outermost surface layer of the phosphor is slightly dissolved, and the recovered phosphor is treated with an acidic aqueous solution with a low acid concentration that does not affect the phosphor body. By doing so, mercury adhering to the phosphor surface can be removed by stripping and falling off.
[0023]
【Example】
Next, the present invention will be described with reference to examples.
[Example 1]
The fluorescent film applied to the inner surface of the glass was peeled off from the FL40S / EX-N type fluorescent lamp which had been used sufficiently and had reached the end of its life. The peeled-off fluorescent film was dispersed in pure water and sieved with an opening 100 μm mesh, and then the phosphor was recovered through a dehydration, drying and sieving process. The concentration of mercury contained in this phosphor (recovered phosphor) is 0.3% by weight, and the emission chromaticity when excited by 254 nm ultraviolet light and emitted is x = 0.374 and y = 0.374. And the relative luminance was 90%. The relative luminance is composed of 40% YOX, 32% LAP, and 28% SCA. When the luminance of an unused mixed phosphor (standard phosphor) having an emission chromaticity of x = 0.374 and y = 0.374 is set to 100. Is the relative value of
The FL40S / EX-N fluorescent lamp from which the phosphor was recovered uses a mixed phosphor of YOX, LAP, and SCA, and does not include a calcium halophosphate-based phosphor.
[0024]
On the other hand, an acidic aqueous solution adjusted to pH 3.0 with hydrochloric acid was prepared as a treatment liquid, and 15 g of the above-mentioned collected phosphor was added to 105 g of this treated liquid with stirring for 10 seconds to further disperse the recovered phosphor slurry. Stirring was performed for 10 minutes. The pH of the treatment liquid at the end of the stirring was 6.2. Immediately after the completion of the stirring, the slurry was filtered while leaving mercury settled at the bottom of the slurry container to collect the phosphor component, and mercury settled in the bottom of the phosphor slurry container was collected as metal.
The phosphor recovered from the phosphor slurry as described above is dispersed in 100 g of pure water, washed with pure water by decantation until the conductivity of the supernatant becomes 50 μS / cm or less, and the slurry is then opened. Aggregates contained in the slurry were removed by passing through a 40 μm mesh. Thereafter, the phosphor was regenerated through the steps of dehydration, drying, and sieving to produce the regenerated phosphor of Example 1.
[0025]
Next, unused YOX and SCA are added to the regenerated phosphor of Example 1 obtained as described above, and the emission chromaticity is the same as the standard phosphor (emission chromaticity x = 0.374, y = 0.74). To the mixed phosphor of Example 1 prepared in Example 374), butyl acetate was added together with a lacquer of nitrocellulose and mixed well to prepare a slurry in which the phosphor was suspended. This slurry was applied to a glass tube and dried. The fluorescent lamp (FL20S / EX-N) of Example 1 having a color temperature of 5000K was manufactured by a usual method.
For the standard phosphor, a fluorescent lamp (FL20S / EX-N) was manufactured in the same manner.
[0026]
[Comparative Example 1]
An unused phosphor (standard phosphor) having an emission chromaticity of x = 0.374 and y = 0.374 composed of YOX 40%, LAP 32%, and SCA 28% instead of the mixed phosphor of Example 1 as the mixed phosphor A fluorescent lamp of Comparative Example 1 was manufactured in the same manner as the fluorescent lamp of Example 1 except for using.
[0027]
[Examples 2 to 4]
The procedure was performed in the same manner as in Example 1 except that the hydrochloric acid acidic aqueous solutions of pH 2.0, pH 4.0, and pH 5.0 were used as the processing liquids instead of the treatment liquid of Example 1 (the acidic aqueous solution of pH 3.0). The regenerated phosphors of Examples 2 to 4 were produced.
Further, instead of the regenerated phosphor of Example 1 as the phosphor for the fluorescent film, each of the regenerated phosphors of Examples 2 to 4 was mixed with YOX and SCA, and all the phosphors were mixed. Of Example 1 except that each of the mixed phosphors of Examples 2 to 4 in which the emission chromaticity of Example was the same as the standard phosphor (emission chromaticity x = 0.374, y = 0.374) was used. The fluorescent lamps of Examples 2 to 4 were manufactured in the same manner as the fluorescent lamp.
[0028]
[Comparative Examples 2 to 4]
In the same manner as in Example 1 except that the respective hydrochloric acid aqueous solutions of pH 1.0, pH 6.0, and pH 7.0 were used as the processing liquids instead of the phosphor treatment liquid (pH 3.0 acidic aqueous solution) of Example 1, respectively. Thus, the regenerated phosphors of Comparative Examples 2 to 4 were manufactured.
Further, as the mixed phosphor, in place of the regenerated phosphor of Example 1, each of the regenerated phosphors of Comparative Examples 2 to 4 was mixed with unused YOX and SCA, and the emission chromaticity was set to be equal to that of the standard phosphor. Comparative Examples 2 to 4 were made in the same manner as the fluorescent lamp of Example 1 except that the mixed phosphors of Comparative Examples 2 to 4 were made identical (emission chromaticity x = 0.374, y = 0.374). 4 were manufactured.
[0029]
Table 3 shows the processing conditions for manufacturing the regenerated phosphors of Examples 1 to 4 and Comparative Examples 1 to 4 above, ie, the pH of the processing solution, the ratio of the processing solution to the phosphor to be processed, the reaction time, and the processing. PH (the pH of the processing solution immediately before separating the recovered phosphor from the processing solution)｝, the characteristics of the powder (the luminescence when the regenerated phosphor is excited by ultraviolet light having a wavelength of 254 nm to emit light) The powder luminance and chromaticity determined by passing through a filter and detecting with a luminance meter, and the characteristics of the fluorescent lamp (Examples 1 to 4 and Comparative Examples 1 to 4 using each regenerated phosphor as a fluorescent film) The initial luminous flux of the fluorescent lamp, the luminous flux maintenance rate) and the amount of Hg (Hg content) contained in each regenerated phosphor are shown.
In Table 3, the initial luminous flux of each fluorescent lamp (the column of "luminous flux" in the table) is shown as a relative value when the initial luminous flux of the fluorescent lamp of Comparative Example 1 using the standard phosphor is 100. The luminous flux maintenance ratio is a value that represents the luminous flux 1000 hours after the continuous lighting of each lamp with respect to the luminous flux (initial luminous flux) immediately after the lighting of each fluorescent lamp. The recovered phosphor is a phosphor before being subjected to the recovery and regeneration treatments of Examples 2 to 4.
[0030]
[Table 3]

[0031]
As can be seen from Table 3, each of the regenerated phosphors of Examples 1 to 4 obtained by using an acidic aqueous solution of pH 2 to pH 5 as a treatment liquid has a small change in emission chromaticity as compared with the recovered phosphor, and thus has a light emission luminance. (Powder brightness) was improved, and mercury was sufficiently removed. In addition, the fluorescent lamps of Examples 1 to 4 of the present invention in which each of the phosphors of Examples 1 to 4 reproduced by the method of the present invention were adjusted in chromaticity and used as a fluorescent film were only unused standard phosphors. Of the fluorescent lamp of Comparative Example 1 using a fluorescent film as the fluorescent film, the degree of reduction of the initial luminous flux was small, and the luminous flux maintenance factor was equivalent.
[0032]
On the other hand, in the regenerated phosphor of Comparative Example 2 obtained by regenerating the recovered phosphor by using an acidic aqueous solution having a pH of 1.0 as a treatment liquid, mercury was sufficiently removed but compared with the recovered phosphor. When the fluorescent lamp of Comparative Example 2 used the phosphor of Comparative Example 2 as a fluorescent film by adjusting the chromaticity of the phosphor of Comparative Example 2, the fluorescent lamp of Comparative Example 1 used only the unused standard phosphor as the fluorescent film. The initial luminous flux was lower and the luminous flux maintenance rate was lower than the fluorescent lamps and the fluorescent lamps of the present invention of Examples 1 to 4.
Furthermore, in the regenerated phosphors of Comparative Examples 3 and 4 which were regenerated using acidic aqueous solutions of pH 6.0 and pH 7.0 as the treatment liquid, the change in emission chromaticity was small compared to the recovered phosphor, but the emission luminance (powder) Brightness) and mercury removal was incomplete. Furthermore, the fluorescent lamps of Comparative Examples 3 and 4 in which the phosphors of Comparative Examples 3 and 4 were used as fluorescent films by adjusting the chromaticity were the fluorescent lamps of Comparative Example 1 in which only unused standard phosphors were used as the fluorescent films. The luminous flux maintenance factor was the same as that of the fluorescent lamps of the present invention of Examples 1 to 4, but the initial luminous flux was significantly lower.
[0033]
[Examples 5 to 7]
Instead of using 105 g (7 times the amount of the collected phosphor) of the acidic aqueous solution of Example 1 as the phosphor treatment liquid, 45 g (3 times the amount of the collected phosphor), 75 g (5 times the amount of the collected phosphor), and 150 g, respectively. Regenerated phosphors of Examples 5 to 7 were produced in the same manner as in Example 1, except that each of the acidic aqueous solutions (10 times the amount of the recovered phosphor) was used as a treatment solution.
Unused YOX and SCA are mixed with each of the regenerated phosphors of Examples 5 to 7 as a mixed phosphor, and the emission chromaticity of each is the same as that of the standard phosphor (emission chromaticity x = 0.374, y = The fluorescent lamps of Examples 5 to 7 were manufactured in the same manner as the fluorescent lamp of Example 1 except that the mixed phosphors of Examples 5 to 7 were used.
[0034]
Table 4 shows the processing conditions, the pH after the processing, the characteristics of the powder, the characteristics of the fluorescent lamp, and the amount of Hg contained in the regenerated phosphor (Hg content) in the production of the regenerated phosphors of Examples 5 to 7 described above. Amount) is shown together with Example 1 and Comparative Example 1. The meanings of these characteristic items shown in Table 4 are the same as those in Table 3.
In Table 4, the initial luminous flux and luminous flux maintenance factor of each fluorescent lamp are values measured in the same manner as in Examples 1 to 4.
[0035]
[Table 4]

[0036]
As can be seen from Table 4, each of the regenerated phosphors of Examples 1 and 5 to 7 obtained by using an acidic aqueous solution of 3 to 10 times the amount of the phosphor as the phosphor treatment liquid, When compared, the change in emission chromaticity was small, the emission luminance (powder luminance) was improved, and mercury was sufficiently removed. Further, in each of the fluorescent lamps of Examples 1, 5 to 7 of the present invention in which the phosphor regenerated by the method of the present invention is used as a phosphor film by adjusting the chromaticity, only the unused standard phosphor is used as the phosphor film. The degree of reduction of the initial luminous flux was smaller than that of the fluorescent lamp of Comparative Example 1, and the luminous flux maintenance ratio was equivalent.
[0037]
Example 8
A regenerated phosphor of Example 8 was manufactured in the same manner as in Example 1, except that the time (reaction time) of adding the recovered phosphor to the treatment solution and stirring was 30 minutes instead of 10 minutes.
In addition, as a mixed phosphor, an unused YOX and SCA are mixed in the regenerated phosphor of Example 8 in place of the mixed phosphor of Example 1, and the emission chromaticity is the same as the standard phosphor (emission chromaticity x = 0). .374, y = 0.374), except that the mixed phosphor of Example 8 was used to produce a fluorescent lamp of Example 8 in the same manner as the fluorescent lamp of Example 1.
[0038]
Table 5 shows the processing conditions, the pH after the processing, the characteristics of the powder, the characteristics of the fluorescent lamp, and the amount of Hg (Hg content) contained in the regenerated phosphor in Example 8 described above. ) Are shown together with Example 1 and Comparative Example 1. The meanings of these characteristic items shown in Table 5 are the same as those in Table 3. In Table 5, the initial luminous flux and the luminous flux maintenance factor of each fluorescent lamp are values measured in the same manner as in Examples 1 to 4.
[0039]
[Table 5]

[0040]
As can be seen from Table 5, the regenerated phosphor of Example 8 which had been agitated for 30 minutes and immersed in the processing solution to be treated had a small change in emission chromaticity when compared to the recovered phosphor, and thus had emission luminance (powder luminance). Has been improved and mercury has been removed. Further, the fluorescent lamp of Example 8 in which the phosphor regenerated by the method of the present invention was used as a fluorescent film by adjusting the chromaticity was compared with the fluorescent lamp of Comparative Example 1 in which only an unused standard phosphor was used as the fluorescent film. Thus, the degree of reduction of the initial luminous flux was small, and the luminous flux maintenance ratio was equivalent.
[0041]
[Example 9]
The regenerated fluorescence of Example 9 was used in the same manner as in Example 1 except that a mixed phosphor obtained by adding 0.75 g of 5% calcium halophosphate phosphor to 14.25 g of the recovered phosphor of Example 1 was used. Body manufactured.
Table 6 shows the processing conditions, the pH after the treatment, and the amount of Hg (Hg content) contained in the regenerated phosphor in Example 9 together with the case of Example 1 when producing the regenerated phosphor of Example 9 described above. The meanings of these characteristic items shown in Table 6 are the same as those in Table 3.
[0042]
[Table 6]

As can be seen from Table 6, mercury was sufficiently removed from the regenerated phosphor when the mixing ratio of the calcium halophosphate phosphor was 5%.
[0043]
【The invention's effect】
When the regenerated phosphor obtained by regenerating the phosphor recovered from the fluorescent film of the used fluorescent lamp by the method of the present invention is used as the fluorescent film of the fluorescent lamp, the emission color of the fluorescent lamp before use is used. It is possible to obtain a fluorescent lamp having a high luminous flux maintenance ratio without maintaining the luminous characteristics equivalent to the luminous characteristics such as color and color rendering properties, and without reducing the luminous flux of the fluorescent lamp.

Claims

After dispersing the recovered phosphor containing mercury recovered from the fluorescent film of the fluorescent lamp in a phosphor processing solution composed of an acidic aqueous solution having a pH of 2 to 5, the recovered phosphor is separated from the phosphor processing solution by the method described above. A method for collecting and regenerating a fluorescent material for a fluorescent lamp, wherein the fluorescent material is separated and recovered from mercury.

The method of claim 1, wherein the weight of the phosphor treatment liquid is 3 to 10 times the weight of the recovered phosphor.

3. The fluorescent lamp according to claim 1, wherein the collected phosphor is separated from the phosphor treatment liquid after a lapse of 10 to 30 minutes since the collected phosphor is dispersed in the phosphor treatment liquid. 4. Method of collecting and regenerating phosphor for use.

4. When the pH of the phosphor treatment liquid in which the recovered phosphor is dispersed reaches 2 to 8, the recovered phosphor is separated from the phosphor treatment liquid. A method for recovering and regenerating a phosphor for a fluorescent lamp according to claim 1.

The recovery phosphor is _{_{Y 2 O 3: Eu, (}} Sr, Ba, Ca, Mg) 10 (PO 4) 6 Cl 2: any of claims 1 to 4, characterized in that it comprises at least one Eu A method for collecting and reproducing the phosphor for a fluorescent lamp according to claim 1.

The content of mercury contained in the collected phosphor after being separated from the phosphor treatment liquid is 20% or less of the amount of mercury contained in the collected phosphor before being dispersed in the phosphor treatment liquid. A method for recovering and regenerating a fluorescent substance for a fluorescent lamp according to any one of claims 1 to 5.

7. A fluorescent lamp having a fluorescent film formed on an inner wall of a glass tube, wherein the fluorescent film contains a phosphor obtained by the recovery method according to any one of claims 1 to 6. lamp.