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Titre : Chromium recovery or reuse Type de document : texte imprimé Auteurs : Karl Flowers, Auteur Année de publication : 2019 Article en page(s) : p. 52-56 Langues : Anglais (eng) Catégories : Chrome -- Recyclage
Récupération (Déchets, etc.)
Tannage au chromeIndex. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Chromium tanning is a highly inefficient chemical process if allowed. For the last 130 years, tanners have learnt progressively how to make this process more efficient. There are a few significant methods that allow the process to go from a low yield process into a more efficient method :
- Effective chromium and collagen masking allowing deeper penetration.
- Lower float use, increases the concentration of chromium and this drives penetration.
- pH at the higher end of basifying range.
- Temperature at the end of basifying.
- Masking agents that help with chromium binding (chrome savers).
- Chase pickle type tannages.
Many of these have driven the process towards efficiencies that are in the 80-90% range. Some tannages have even claimed 95-99% efficiencies. For those levels of efficiencies, the residual levels of chromium may be too insignificant to financially motivate for the reuse or recycling of the chromium salts.
For a tannery that has a 65% uptake of the chromium salts, the amount of remaining chromium salts will be in the order of 35% (350 g/L) chromium that could be used in the next iteration of the process. A tannery having 5% (50 g/L) chromium could use the liquor remaining from the tannage (after pH correction) and could directly apply it into the pickle, the sait and residual chromium (and water of course) would mean significant reductions in chemicals and water used at this processing step.Note de contenu : - Waste hierarchy
- Chromium efficiency
- Recycling/reuse
- Recovery
- Circularity
- Fig. 1 : The waste hierarchy
- Fig. 2 : The chromium recycle system
- Fig. 3 : The chromium recovery systemEn ligne : https://drive.google.com/file/d/1QCSUQSP7K8PMiZbsw8Deh4eDFqHdspoC/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33141
in INTERNATIONAL LEATHER MAKER (ILM) > N° 38 (11-12/2019) . - p. 52-56[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 21284 - Périodique Bibliothèque principale Documentaires Disponible Factors influencing chromium recovery from chromium sulphate tanned leather scrap ashes / S. Carneiro in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 87, N° 1 (01-02/2003)
[article]
Titre : Factors influencing chromium recovery from chromium sulphate tanned leather scrap ashes Type de document : texte imprimé Auteurs : S. Carneiro, Auteur ; M. F. Almeida, Auteur ; M. F. Ferreira, Auteur Année de publication : 2003 Article en page(s) : p. 1-10 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cendres -- Teneur en chrome
Chrome -- Recyclage
Cuirs et peaux
Déchets industriels -- Recyclage
Incinération
Tannage -- DéchetsIndex. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Basic chromium salt is the main tanning reagent used all over the world and it represents one of the most important applications of chromium salts. When leather scrap tanned with chromium sulphate is burned, the respective ashes contain meaningful amounts of chromium, some of it in the hexavalent form.
This paper presents some efforts aimed at using the ashes from a fixed grate incinerator (FGI) as a source of chromium for various applications. Two types of ashes were characterised. Several tests with mixtures of alkaline and alkaline earth fluxes followed by hot washing the product were carried out to recover chromium from the ashes. The factors influencing chromium recovery were screened through an experimental design approach and hypothesis testing. Using ashes as pigment for ceramic glazes was also evaluated.Note de contenu : - CHARACTERISATION OF ASHES AND EXPERIMETNAL PROCEDURES : Principles of the experimental process
- RESULTS AND DISCUSSION : First set of experiments - Second set of experiments - Third set of experiments - Fourth set of experiments
- Table 1 : Experiments carried out at 750°C with NA2CO3 based mixtures and respective Cr recoveries
- Table 2 : Experiments carried out at 350, 450 and 550°C with mixtures based on NaOH
- Table 3 : Cr recoveries at 350, 450 and 550°C with mixtures based on NaOH
- Table 4 : Experiments carried out at 350, 450 and 550°C with mixtures based on NaOH and NaNO3En ligne : https://drive.google.com/file/d/19Zv2OsYHHMm0WjcPxW4ash70Z_iVjqG8/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39804
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 87, N° 1 (01-02/2003) . - p. 1-10[article]Natural fibers reinforced chrome shaving composites for sound absorption applications / D. Hemalatha in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIII, N° 11 (11/2018)
[article]
Titre : Natural fibers reinforced chrome shaving composites for sound absorption applications Type de document : texte imprimé Auteurs : D. Hemalatha, Auteur ; S. Kowsalya, Auteur ; N. Nishad Fathima ; S. Sowmya ; Jonnalagadda Raghava Rao Année de publication : 2018 Article en page(s) : p. 352-357 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Chrome -- Recyclage
Composites à fibres -- Moulage par compression
Composites à fibres végétales -- Propriétés mécaniques
Cuirs et peaux -- Déchets -- Recyclage
Isolation acoustique
Matériaux -- Propriétés acoustiques
Polypropylène
Résistance à la tractionIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : Chrome shavings, the solid wastes from tanneries, show disposal difficulties due to the presence of the heavy metal chromium. In this present study, we have prepared sound absorbing materials from chrome shavings by blending with suitable synthetic and natural polymers via compression molding technique. Polypropylene (PP), was chosen as a synthetic polymer to improve the blending and natural fibers such as cotton, jute and kapok have been chosen for their porous nature. The composites were prepared, and their morphology was examined using scanning electron microscopy. The sound absorption of the prepared composites has been measured using Impedance tube method. The results suggest that composites blended with polypropylene exhibit more than 90% sound absorption in the mid frequency range. This study shows that chrome shavings in combination with natural fibers can be used as good sound absorption materials. Thus, the proposed approach paves the way for utilization of a leather waste to reduce noise pollution. Note de contenu : - MATERIALS AND METHODS : Materials - Methods. Preparation of chrome shavings - polypropylene composites - Preparation of composites from chrome shavings polypropylene and natural fibers - Sound absorption measurements - Characterizations of sound absorbing materials
- RESULTS AND DISCUSSIONS : Chrome shavings- polypropylene composites - Natural fibers- chrome shavings- polypropylene composites - Tensile strength of the composites - Sound absorption results of the chrome shavings and natural fibers reinforced chrome shavingsEn ligne : https://drive.google.com/file/d/1i3rWh4PzeBQ8UqRsFZIhCeqlhGJ99vNd/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31201
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIII, N° 11 (11/2018) . - p. 352-357[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 20339 - Périodique Bibliothèque principale Documentaires Disponible A practical chrome recovery system using magnesium oxide / Anthony D. Covington in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 67 (Année 1983)
[article]
Titre : A practical chrome recovery system using magnesium oxide Type de document : texte imprimé Auteurs : Anthony D. Covington, Auteur ; John R. Barlow, Auteur ; E. T. White, Auteur Année de publication : 1983 Article en page(s) : p. 5-12 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Chrome -- Recyclage
Eaux usées -- Epuration
Liqueurs de tannage
Oxyde de magnésiumL'oxyde de magnésium, communément appelé magnésie, a pour formule MgO et se présente sous la forme de poudre blanche très fortement basique absorbant l'eau et le dioxyde de carbone présents dans l'atmosphère.
STRUCTURE : L'oxyde de magnésium est un cristal ionique. L'oxyde de magnésium a une structure comparable à celle du chlorure de sodium7. Cela se traduit par
Un réseau d'anion oxygène formant une structure de type cubique à faces centrées
Un réseau de cation magnésium occupant l'ensemble des sites octaèdriques.
L'oxyde de magnésium est un matériau modèle des cristaux ioniques car la faible électronégativité du magnésium, et la forte électronégativité de l’oxygène font que la structure de l’oxyde de magnésium peut s’expliquer quasi uniquement grâce à des interactions entre des particules ponctuelles chargées 10.
La surface de l'oxyde de magnésium la plus stable dans le vide est obtenue en réalisant une coupe selon le plan cristallographique (100). Les particules d'oxyde de magnésium produites par combustion du magnésium métallique présentent d'ailleurs une forme cubique révélatrice de la présence de ces plans. Néanmoins, en présence d'eau, la surface de l'oxyde de magnésium est couverte d'ions hydroxyles qui stabilisent les plans (111)
PRODUCTION : La majeure partie de l'oxyde de magnésium est actuellement obtenue soit à partir de carbonate de magnésium MgCO3 qui constitue certains minéraux tels que la magnésite, soit à partir de chlorure de magnésium que l'on extrait de l'eau de mer ou de saumures souterraines.
Récupération (Déchets, etc.)
Solubilisation
Sulfurique, Acide
Tannage -- DéchetsIndex. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : A practical method of recovering chrome from tannery waste liquors for re-use has been developed. Spent chrome bearing liquor is collected, treated with magnesium oxide and allowed to settle. After discarding the supernatant solution the chrome precipitate is solubilised with sulphuric acid. The recovered chrome can be recycled to tannage ; a prolonged trial showed that no deleterious effect accumulated in the leather produced. The system minimises both capital and labour costs ; model calculatons indicate a payback period (at 1981 prices) of 14-22 months, with considerable savings thereafter. Note de contenu : - Table 1 : Laboratory studies of the reaction between magnesia (Lycal 93/12) and commercial spent chrome tan liquor
- Table 2 : Analytical results of wet blue leather tanned with recovered chrome (metal contents are based on oven-dried weigth)
- Table 3 : Tannage parameters for the third trial
- Table 4 : Metal contents of oven-dried, sammed wet blue butt leathers from the third trial
- Table 5 : Analysis of control and final pack trial leathers (metal contetns are based on oven-dried weight)
- Table 6 : Mechanical properties of control and final pack trial dyed, crust leathers
- Table 7 : Comparison of standard chrome tan powder with recovered liquors for the fourth trial
- Table 8 : Tannage parameters and results of the fourth trial
- Table 9 : Estimated costs (mid-1981) of chrome recovery processing 100 tonnes limed hide per week
- Fig. 1 : The effect of accumulating precipitated chrome on the volume of the precipitate (results from tannery A)
- Fig. 2 : Flow diagram from chrome recovery in the third trial
- Fig. 3 : Schedule for chrome recovery in the third trial
- Fig. 4 : CIELAB 1976 colour values for wet blue and dyed, crust leatehrs from normal production and the final pack of the third trial
- Fig. 5 : Plant requirements for chrome recovery from process liquor from 20 tonnes limed hide per dayEn ligne : https://drive.google.com/file/d/1yMWM5HvApAzHE3Hhpobxi6bPwL1VK7m1/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34168
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 67 (Année 1983) . - p. 5-12[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 007130 - Périodique Bibliothèque principale Documentaires Disponible Production of high carbon ferrochromium alloy from footwear leather waste ash through a carbothermic reduction in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CVII, N° 11 (11/2012)
[article]
Titre : Production of high carbon ferrochromium alloy from footwear leather waste ash through a carbothermic reduction Type de document : texte imprimé Année de publication : 2012 Article en page(s) : p. 375-383 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Alliage fer-chrome
Carbone
Chrome -- Recyclage
Combustion
Cuirs et peaux -- Déchets -- Recyclage
Energie
Incinération
Oxydes de chrome
ThermodynamiqueIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : The majority of hazardous solid waste generated in “Rio Grande do Sul” State, Brazil, is produced from footwear leather industry. Thermal treatment leather waste is considered as a good alternative to deal with this problem, by generating energy. It is also possible to recover chromium from the ash generated during incineration. The aim of this work is to evaluate high carbon ferrochromium alloy production from leather waste ash, through computational and laboratory analysis. Computational thermodynamics was used to simulate ash Cr2O3 carbothermic reduction and to determine composition of the laboratory alloys. Several runs were done using a laboratory furnace at 1600oC to get ferrochromium alloys from the ashes. Different kinds of analyses were done to determine alloys and slags compositions. It was demonstrated that it is possible to use the chromium from leather waste ash for a production of high carbon ferrochromium alloy through carbothermic reduction at 1600oC. The results obtained showed a new opportunity for hazardous solid waste management of the leather industry, in the context of energy generation from combustion of leather waste. The computational thermodynamics simulations presented good agreement with experimental results. Note de contenu : - METHODOLOGY : Materials - Experimental procedure and apparatus - Thermodynamic simulations
- RESULTS AND DISCUSSION : Equipment reproducibility - Chromium - Phosphorus - Sulphur - Silica - Carbon - Other elements - ConversionEn ligne : https://drive.google.com/file/d/1KUS1CjDnYl6rTS_ZbsygJpyL71JCQYd_/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=16521
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CVII, N° 11 (11/2012) . - p. 375-383[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 14323 - Périodique Bibliothèque principale Documentaires Disponible PermalinkSome properties of wet-blue leathers produced from recycled chrome tanning liquors / John R. Barlow in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 61, N° 2 (03-04/1977)
PermalinkSome properties of wet-blue leathers produced from recycled chrome tanning liquors / John R. Barlow in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 61 et 62 (Années 1977 et 1978)
PermalinkPermalinkThe three pot solution for chromium, tannins and solid waste : Recovery and reuse technique for spent semi-chrome liquor and chrome shavings / Subramanian Saravanabhavan in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 88, N° 5 (09-10/2004)
PermalinkUse of solid leather wastes to producte value-added material / M. A. Habib in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 107, N° 6 (11-12/2023)
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