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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]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 87, N° 1 (01-02/2003) . - p. 1-10 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 -- Déchets Index. 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 NaNO3 En ligne : https://drive.google.com/file/d/19Zv2OsYHHMm0WjcPxW4ash70Z_iVjqG8/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39804 [article]

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So, what is wrong with experimental design / S. T. Orszulik in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 87, N° 1 (01-02/2003)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 87, N° 1 (01-02/2003) . - p. 11-14 Titre : So, what is wrong with experimental design Type de document : texte imprimé Auteurs : S. T. Orszulik, Auteur Année de publication : 2003 Article en page(s) : p. 11-14 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Plan d'expérience Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Imagine this : your boss comes to you and tells you to find out everything you can about a particular chemical process — to pull it apart. What do you do? Probably the best answer is to carry out a full factorial experimental design on the variables that are regarded as the most important. Note de contenu : - The problem : A full factorial design - Interaction - Analysis of factorial design - A new method - The answer ? - Fig. 1 : A full factorial design examining the effects of temperature, time, and pH on the yield of a chemical process - Fig. 2 : Two-factor design showing a strong interaction - Fig. 3 : Three-factor design showing a strong interaction - Fig. 4 : Example showing the same interaction - Fig. 5 : Three-factor design showing two strong three-factor interactions - Fig. 6 : Analysis of results in figure 4 using mono-directional interactions - Fig. 7 : Mono-directional effects of the data in figure 1 En ligne : https://drive.google.com/file/d/1KtqrnLBKEsqWVj9TBy1Xoc57O69Uj0ec/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39805 [article]

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Countercurrent-driven continuous tanning of natural leather / D. M. Turtoi in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 87, N° 1 (01-02/2003)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 87, N° 1 (01-02/2003) . - p. 15-19 Titre : Countercurrent-driven continuous tanning of natural leather Type de document : texte imprimé Auteurs : D. M. Turtoi, Auteur ; N. P. Slemcu, Auteur ; M. S. Belcu, Auteur ; E. I. Tudorache, Auteur ; I. Untea, Auteur ; D. Brasoveanu, Auteur Année de publication : 2003 Article en page(s) : p. 15-19 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux Solutions (chimie) Tannage au chrome Transfert de masse Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The present study was aimed to increase the mass transfer rate inside leather, thus allowing the use of concentrated solutions and consequently a reduction in pollutant quantities. Alaboratory installation for wet processing and tanning leather was conceived and put into operation. It is based on the almost instantaneous absorption of the processing solutions by the compressed leather after the compression is removed. The possibility of applying the countercurrent process for pickling and chromium fixing inside the leather was studied. The process parameters taken into consideration were: the concentration and the basicity of the basic chromium sulphate solutions, the intermediate basification of the solution, the intensity, frequency and number of pressing operations, the insertion of rest periods between the pressing operations, the partial removal of pickling solutions before the treatment with chromium solutions. The treated leather was analysed for total, soluble and fixed chromium, stratigraphic distribution, shrinkage index and moisture content were determined. Some correlations between the process parameters and the final leather characteristics were determined. Note de contenu : - Fig. 1 : Laboratory installation for continuous countercurrent-driven wet tanning ; 1 - upper compression tambour ; 2 - processed skin ; 3 - lower tambour ; 4 - tank ; 5 - lead disks; 6 - toothed wheel ; 7 - toothed belt ; 8 - driving toothed wheel ; 9 - tanning solution - Fig. 2 : Section of the pilot installation with unequal tambours for continuous, countercurrent-driven tanning ; 1 - upper compression tambour ; 2 - upper guide ; 3 - processed skin ; 4 - lower tambour ; 5 - lower guide ; 6 - liquid level - Fig. 3 : Section of the pilot installation with equal tambours for continuous, countercurrent-driven tanning ; 1 - upper compression tambour ; 2 - processed skin ; 3 - driving, lower tambour ; 4 - guides ; (P1 < P2 < P3) - Table 1 : Data on the chromium take-up for samples subject to multiple compressions - Table 2 : Compression conditions and stratigraphic distributions En ligne : https://drive.google.com/file/d/1v47g-eI9iM1fIquIQlkjBkjEYkiMO9Px/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39806 [article]

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Is 48 hours conditioning prior to testing necessary / A. J. Long in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 87, N° 1 (01-02/2003)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 87, N° 1 (01-02/2003) Titre : Is 48 hours conditioning prior to testing necessary Type de document : texte imprimé Auteurs : A. J. Long, Auteur ; C. B. Wood, Auteur ; D. A. Langridge, Auteur Année de publication : 2003 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Conditionnement Cuir Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The aim of this work is to determine whether it is feasible to reduce the time required to condition leather prior to physical testing, whilst still ensuring accurate and reliable results. The method SLP 3 / IUP 31 describing the conditioning of leather was first published as an official method in the Journal of the Society of Leather Technologists and Chemists in 1958.2 (It was previously published for comment in 19493). There has been little change since this date. The latest version does acknowledge that in some cases there is the need for rapid conditioning, although this is not widely used in industry due to the possibility of arbitration which still requires the full 48 hour process (suggesting that the rapid method may not be producing the same results as the standard conditions). The aim therefore is to reduce the time required to carry out some key tests, but not necessarily to remove the requirement for the official standard. It is hoped that alternative options will be devised for those tanneries and test houses where 48 hours effective dead time prior to testing is a significant problem. A separate issue that is under discussion is the use of the different conditions 23oC, 50%RH. Whilst it is acknowledged that there are issues of importance in this area, these have not been considered in this research. The work published here uses the UK standard of 20oC, 65% RH. Note de contenu : - Aims of this work - Experimental Work and Results : Determination of the significance of conditioning - Evaluation of the optimum duration for conditioning - Evaluation of the moisture xontent of leather - Investigation of accelerated conditioning - Table 1 : The Effect of conditioning on the tear strength of leather - Table 2 : Effect of conditioning on water vapour absorption of leather - Table 3 : Effect of pre-drying on leather conditioning En ligne : https://drive.google.com/file/d/1ojBnyo0_WPpfRkUXrY-2ixO3stTAxXDO/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39807 [article]

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Measurement of colour difference in the leather dyeing process with natural dyes in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 87, N° 1 (01-02/2003)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 87, N° 1 (01-02/2003) . - p. 25-29 Titre : Measurement of colour difference in the leather dyeing process with natural dyes Type de document : texte imprimé Année de publication : 2003 Article en page(s) : p. 25-29 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Aluminium L'aluminium est un élément chimique, de symbole Al et de numéro atomique 13. C’est un métal pauvre, malléable, de couleur argent, qui est remarquable pour sa résistance à l’oxydation13 et sa faible densité. C'est le métal le plus abondant de l'écorce terrestre et le troisième élément le plus abondant après l'oxygène et le silicium ; il représente en moyenne 8 % de la masse des matériaux de la surface solide de notre planète. L'aluminium est trop réactif pour exister à l'état natif dans le milieu naturel : on le trouve au contraire sous forme combinée dans plus de 270 minéraux différents, son minerai principal étant la bauxite, où il est présent sous forme d’oxyde hydraté dont on extrait l’alumine. Il peut aussi être extrait de la néphéline, de la leucite, de la sillimanite, de l'andalousite et de la muscovite. L'aluminium métallique est très oxydable, mais est immédiatement passivé par une fine couche d'alumine Al2O3 imperméable de quelques micromètres d'épaisseur qui protège la masse métallique de la corrosion. On parle de protection cinétique, par opposition à une protection thermodynamique, car l’aluminium reste en tout état de cause très sensible à l'oxydation. Cette résistance à la corrosion et sa remarquable légèreté en ont fait un matériau très utilisé industriellement. L'aluminium est un produit industriel important, sous forme pure ou alliée, notamment dans l'aéronautique, les transports et la construction. Sa nature réactive en fait également un catalyseur et un additif dans l'industrie chimique ; il est ainsi utilisé pour accroître la puissance explosive du nitrate d'ammonium. Caractérisation Chrome Colorants naturels Cuirs et peaux -- Teinture Eaux usées -- Epuration Formulation (Génie chimique) Solidité de la couleur Tannage minéral Tannage dans lequel interviennent différents minéraux. Le plus répandu est le tannage aux sels de chrome, mais aussi à l’aluminium Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : This paper looks into a tanning and dyeing process offering clean technology, which is in the limelight these days as an advanced leather making technology of the future sought by leather industries both at home and abroad. First of all, chrome-tanned leather is treated with two types of tanning agents (Al and Cr) to manufacture wet-blue and wet-white leather. After the tanning process, various colouring matters and the powder-type natural dye were applied to the leather and, on the basis of the Munsell value function, the chromaticity diagram of the colour system and characteristics such as hue, value and chroma were measured. The colour deepened markedly according to the amount of natural dye used, and multiple colours were obtained depending on the mordant in use. The quality of leather was outstanding, test results gave grade 4 or 5 in such categories as colour fastness to rub, wash, heat and light. In addition, the colour was brighter and cleaner on the wet-white non-chrome tanned leather than on the wet-blue. Note de contenu : - Materials and equipment - Characterisation of leather samples - Fig. 1 : Application of tanning agents and natural dyes - Fig. 2 : Manufacturing diagram for natural dyes - Fig. 3 : Colour difference of natural dyes depending on tanning conditions - Table 1 : Characteristics of natural dyes - Table 2 : Formulation of the tanning and dyeing process - Table 3 : Classification of colouring matter of monogenetic colours and polygenetic colours - Table 4 : Hue differences in the CIELAB system of wet-blue and wet-white with natural dyes - Table 5 : Colour fastness of leather dyed by natural dyes - Table 6 : Average treatment level of effluents from natural dye and synthetic dye effluents En ligne : https://drive.google.com/file/d/1dJVtGjDvKh6CKJQMYLCt8YYWYRnmkEIz/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39808 [article]

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