Recovery of nickel from waste hydrogenation catalyst
Küçük Resim Yok
Tarih
1997
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Ege Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Sıvı yağların doyurulmasında kullanılmış atık nikel katalizör nikel için önemli bir ikincil kaynaktır. Bu çalışmada atık nikel katalizörlerinden nikelin geri kazanılması incelenmiştir. Atik katalizörün nikel analizi gravimetrik ve atomik absorpsiyon spektrospisinde spektroskobik yöntemle yapılmış ve atık katalizörün %9.6 nikel içerdiği saptanmıştır. Atık katalizörün nem, yağ, ve kül miktarı analizlenmiş sırasıyla %0.9, %52.1, ve %47.0 bulunmuştur. Asitle çözünmeyen kül miktarı %27.7 olarak saptanmıştır. Katalizörde nikel dışında bulunan diğer metaller ise %10.6 Si, %1.1 Al, %0.3 Mg, %0.4 Fe şeklindedir. Atık katalizör çamurundaki nikel özütlemeye etki eden faktörlerden (NH4)2SO4 derişimi 2M, NH3 derişimi 5M, özütleme süresi 8 saat, özütleme sıcaklığı 50°C ve pH=10-10.5 olarak optimze edilmiştir. Atık katalizör çamurundaki nikel, özütleme koşullarına bağlı olarak %55-60 verimle çözeltiye geçmiştir. Katalizördeki yağı CCLj çözgeni ile uzaklaştırıldıktan sonra yapılan özütleme işleminde %70.4 verimle nikel geri kazanılmıştır.Özütleme işleminde gübre olarak kullanılan (NHOaSC^ ucuz ve kolay bulunabildiği gibi çevreye zarar vermektedir. Nikel NH// NH3 tampon ortamında [Ni(NH3)6]2+ kompleksine dönüştürülmüştür. Ortamda nikel ile yarışacak başka kompleks veren madde olmadığından sadece nikel özütlenmiştir. Özütlenen nikel elektroliz yöntemiyle katoda metalik halde toplanmıştır. Anahtar kelimeler: Nikelin geri kazanılması, atık katalizör, hidrojenasyon katalizörü.
Waste nickel catalyst from the hydrogenation of liquid oils is an important secondary source of nickel. This study reports the recovery of nickel from waste nickel catalyst. The quantitative analysis of nickel in the waste catalyst was carried out by gravimetric and atomic absorption spectroscopic methods of the catalyst was analysed yt was found to be 9.6%. The moisture, fat and ash contents which were found to be 0.9%, 52. 1% and 47.0% respectively. The acid insoluble fraction of the ash was found 27.7%. The metalic composition of spent catalyst other than nickel were found to be 10.6% Si, 1.1% Al, 0.3% Mg, and 0.4 % Fe. Nickel in the waste catalyst has been leached out by using aqueous (NH4)2S04 and NH3 mixture for the effect of the concentration of (NHO2SO4 and NH3, extraction time, temperature, and the pH of the medium were investigated. The optimum conditions were found to be 2 M (NH4)2S04, 5 M NH3, 8 Hours, 50°C pH=10-10.5 respectively. The recovery of nickel from spent catalyst was in the range of 55-60 % depending on the extraction conditions. If the oil is removed by CCI4 extraction, high recovery of nickel such as 70 % was obtained in shorter extraction time. The advantage of the method proposed is that the compound (NH4)2S04 can be found commercially as fertiliser. It is therefore readily available, cheapVI and non hazardous to the environment. Nickel ions were converted to the Ni(NH3)62+ complex in the NH//NH3 buffer medium. Because of the absence of other agents to compete with nickel only nickel was extracted in our process. Subsequently by electrolysis of nickel ions in the solution, nickel was regained in the pure metallic state Key words Nickel recovery, spent catalyst, hydrogenation catalyst.
Waste nickel catalyst from the hydrogenation of liquid oils is an important secondary source of nickel. This study reports the recovery of nickel from waste nickel catalyst. The quantitative analysis of nickel in the waste catalyst was carried out by gravimetric and atomic absorption spectroscopic methods of the catalyst was analysed yt was found to be 9.6%. The moisture, fat and ash contents which were found to be 0.9%, 52. 1% and 47.0% respectively. The acid insoluble fraction of the ash was found 27.7%. The metalic composition of spent catalyst other than nickel were found to be 10.6% Si, 1.1% Al, 0.3% Mg, and 0.4 % Fe. Nickel in the waste catalyst has been leached out by using aqueous (NH4)2S04 and NH3 mixture for the effect of the concentration of (NHO2SO4 and NH3, extraction time, temperature, and the pH of the medium were investigated. The optimum conditions were found to be 2 M (NH4)2S04, 5 M NH3, 8 Hours, 50°C pH=10-10.5 respectively. The recovery of nickel from spent catalyst was in the range of 55-60 % depending on the extraction conditions. If the oil is removed by CCI4 extraction, high recovery of nickel such as 70 % was obtained in shorter extraction time. The advantage of the method proposed is that the compound (NH4)2S04 can be found commercially as fertiliser. It is therefore readily available, cheapVI and non hazardous to the environment. Nickel ions were converted to the Ni(NH3)62+ complex in the NH//NH3 buffer medium. Because of the absence of other agents to compete with nickel only nickel was extracted in our process. Subsequently by electrolysis of nickel ions in the solution, nickel was regained in the pure metallic state Key words Nickel recovery, spent catalyst, hydrogenation catalyst.
Açıklama
Anahtar Kelimeler
Kimya, Chemistry, Atıklar, Wastes, Nikel, Nickel, Yeniden kazanma, Recycling
