References of "Gaydardzhiev, Stoyan"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailCharacteristics of EoL Printed Wiring Boards processed by ElectroDynamic Fragmentation
Martino, Rémi ULg; Iseli, Cedric; Gaydardzhiev, Stoyan ULg et al

in Chemie Ingenieur Technik (2017), 89(1-2), 1-10

The ElectroDynamic Fragmentation (EDF) is an innovative technique which enables selective fragmentation of material. Its inherent selective breakage principles enable liberation while avoiding fine ... [more ▼]

The ElectroDynamic Fragmentation (EDF) is an innovative technique which enables selective fragmentation of material. Its inherent selective breakage principles enable liberation while avoiding fine grinding. In this study, the specific effects of the EDF on End-of-Life Printed Wiring Boards have been assessed. A novel methodology for their EDF processing has been developed and compared with hammer mill shredding. Various energy inputs and treatment stages have resulted in fragmentation degrees ranging from removal of components to structure delamination and subsequent size reduction. [less ▲]

Detailed reference viewed: 18 (4 ULg)
Full Text
See detailElektrodynamische Fragmentierung von Elektroschrott
Iseli, Cédric; Streicher-Porte, Martin; Martino, Rémi ULg et al

Poster (2016, November 11)

Untersuchungen dazu werden in diesem Bericht am Beispiel von WEEE und speziell an Leiter-platten aufgezeigt. Die Versuche zeigen, dass EDF für verschiedenste Arten von Elektroschrott eingesetzt werden ... [more ▼]

Untersuchungen dazu werden in diesem Bericht am Beispiel von WEEE und speziell an Leiter-platten aufgezeigt. Die Versuche zeigen, dass EDF für verschiedenste Arten von Elektroschrott eingesetzt werden kann. Verschweisste Kompaktgeräte können zum Beispiel so weit geöffnet werden, dass die ge-wünschte Komponente freigelegt und entfernt werden kann. Leiterplatten haben die Eigenschaft, dass bei kontinuierlich steigendem Energieeintrag zuerst die aufgebrachten Komponenten abgetrennt werden, bevor die Cu-Bahnen freigelegt werden. Bei noch höherem Energieeintrag wird die Leiterplatte schlussendlich zerkleinert und vollständig zer-stört. Durch diese Entfrachtung der Leiterplatte kann ein metallreiches Konzentrat hergestellt werden. [less ▲]

Detailed reference viewed: 47 (7 ULg)
Full Text
Peer Reviewed
See detailMalachite and heterogenite behavior during the locked-cycle recycling of process water in flotation of copper-cobalt oxide ores
Shengo, Michel; Gaydardzhiev, Stoyan ULg; Kalenga, Pierre

in International Journal of Mineral Processing (2016), 157

The behavior of malachite and heterogenite was investigated during the process water recycling in flotation of copper-cobalt oxide ores from the deposit of Luiswishi located in Haut-Katanga province (DRC ... [more ▼]

The behavior of malachite and heterogenite was investigated during the process water recycling in flotation of copper-cobalt oxide ores from the deposit of Luiswishi located in Haut-Katanga province (DRC). A synthetic mill wastewater (SMWW) was utilized as feed water alone and in mixture with water recovered from the flotation tails in view to achieve at the laboratory scale the locked-cycle recycling of the industrial mill wastewater (IMWW). To simulate the chemical species presence in the pulp and their effects on the flotation of malachite and heterogenite, calcium, magnesium and bicarbonate ions were added to the feed water and the recoveries of copper and cobalt followed during the roughing flotation stage. The concentrate XRD and SEM analysis together with the floated minerals microanalyses by EDX spectroscopy, leaching tests of mono-minerals followed by the Pourbaix diagrams construction and DRIFT spectroscopy analyses, have enabled identifying changes in the surface properties of malachite and heterogenite interfering on the recovery of copper (40 %) and cobalt (58 %) with a significant drop in their concentrate grades (7.3 % Cu and 2.7 % Co). The deterioration of the concentrate characteristics results also from the gangue minerals entrainment. A better description of the valuable minerals behaviour in the SMWW presence could enable designing strategies in view enhancing their floatability during the locked-cycle recycling of water. [less ▲]

Detailed reference viewed: 25 (6 ULg)
Full Text
Peer Reviewed
See detailThe role of bacteria and the addition of pyrite during leaching of Co(III) from heterogenite
Zeka, Leon; Gaydardzhiev, Stoyan ULg; Frenay, Jean ULg et al

in Proceedings of the XXVIII International Mineral Processing Congress (IMPC 2016) (2016, September 11)

Reductive leaching of cobalt (III) from a heterogenite bearing ore has been performed. Pyrite was added to the system and simultaneously bioleached in order to provide ferrous iron as reducing agent ... [more ▼]

Reductive leaching of cobalt (III) from a heterogenite bearing ore has been performed. Pyrite was added to the system and simultaneously bioleached in order to provide ferrous iron as reducing agent. Within such arrangement the iron ions are continuously re-circulated inside a Fe3+/ Fe2+ loop. As a result Co(III) is solubilized in the presence of Fe2+ ions in concentrations well below the stoichiometric requirement. The ore has been initially subjected to acid pre-leaching in order to guarantee that the available Co (II) has been entirely removed. Two technological parameters have been studied to show influence on the degree of cobalt leaching: concentration of ferric iron in the inoculum and the presence of bacteria. The bacterial role could be mainly viewed in supplying ferric ions in the system which chemically react with the pyrite to generate ferrous ions used as Co(III) reducing agent. Co(III) dissolution has been less efficient when the concentration of total iron in the system was low, but also when microorganisms were absent. SEM observations on leached heterogenite have evidenced bacterial attack on the mineral; however the precise role of bacterial presence on cobalt (III) leaching is still to be elucidated. [less ▲]

Detailed reference viewed: 36 (3 ULg)
Peer Reviewed
See detailGeometallurgical Modelling of Low-Grade Itabirite Iron Ores from the Iron Quadrangle, Brazil
Martino, Rémi ULg; Correa de Araujo, Armando; Gotelip Barbosa, Marcela et al

in Proceedings of the XXVIII International Mineral Processing Congress (IMPC 2016) (2016, September 11)

The Iron Quadrangle district is a world-class iron ore mining district in the region of Belo Horizonte, capital of Minas Gerais state, in Brazil. Many mining companies have been mining high-grade hematite ... [more ▼]

The Iron Quadrangle district is a world-class iron ore mining district in the region of Belo Horizonte, capital of Minas Gerais state, in Brazil. Many mining companies have been mining high-grade hematite ores for decades throughout the region. The mines reserves often include itabirite ores which are available in high volumes, but have lower iron grades than hematite ores and require elaborated mineral processing to meet the requirements of downstream steelmaking. Itabirite ores have acquired importance, with the depletion of high-grade hematite reserves due to their intensive mining. The objective of this paper is to propose a geometallurgical model for the processing of itabirite ores from an Iron Quadrangle deposit, which will allow predicting the behaviour of ores throughout the deposit, according to their local variations. An initial step consists in characterizing representative samples of the different ores to acquire mineralogical and textural data. Then, itabirite ores of known characteristics are processed with different techniques, in order to extract the trends and key parameters upon which the geometallurgical model is developed. At first, the model takes into account the particle size distribution and its shift during mining and screening, as well as the chemistry and mineralogy of the material. Then, using the previously identified key parameters such as iron recovery, the model predicts the composition of the processing products. Finally, this data is used to model the mineralogy and mass recovery of the products. The geometallurgical model is of great importance, as it is able to model the processing of any sampled ore throughout the deposit. The incorporation of the results in a mining block model will assist mine planning and opens new opportunities for an optimized mining schedule. [less ▲]

Detailed reference viewed: 36 (11 ULg)
Full Text
Peer Reviewed
See detailProcess oriented characterisation of oolitic iron concentrate during dephosphorisation by roasting and leaching
Ionkov, Krassimir; Gomes, Otavio; Neumann, Reiner et al

in Proceedings of the XXVIII International Mineral Processing Congress (IMPC 2016) (2016, September)

Phosphorus in iron ores is considered as a deleterious component to iron making reflecting in cold shortness of the produced steel. The present study investigates the phosphorus migration pattern ... [more ▼]

Phosphorus in iron ores is considered as a deleterious component to iron making reflecting in cold shortness of the produced steel. The present study investigates the phosphorus migration pattern resulting from thermal treatment of an oolitic-type iron concentrate with and without additives. To this end focused mineralogical and microscopic observations were performed. The results have shown that roasting with alkaline additive drives phosphorus outside the hematite hosting mineral, however it remains evenly distributed inside the volume of the oolites. It penetrates inside the newly formed cementing phases of Al-Na-Si-Fe-type and also fills the interstices between the crystals. Other than phosphorus, aluminum, calcium and iron tend also to migrate towards the amorphous-type cementing phase. Finally, the possibilities for P removal by means of magnetic separation and acid leaching of the roasted concentrate were evaluated. The obtained final product presents a standard iron concentrate suitable for steelmaking with its phosphorous being dropped from 0.71% to 0.05% and iron grade of a nearly 66% being reached. [less ▲]

Detailed reference viewed: 18 (1 ULg)
See detailERA-NET ECO-INNOVERA - Fragmentation électrodynamique des matériaux composites à haute valeur ajoutée contenant des substances récupérables - EDF-HVC: Rapport scientifique & technique annuel
Martino, Rémi ULg; Gaydardzhiev, Stoyan ULg

Report (2016)

The EDF-HVC project aims in evaluating the feasibility of electrodynamic fragmentation application to process end-of-life devices such as waste electrical and electronic equipments and secondary resources ... [more ▼]

The EDF-HVC project aims in evaluating the feasibility of electrodynamic fragmentation application to process end-of-life devices such as waste electrical and electronic equipments and secondary resources such as MSW incineration slags, EoL high-end composites, etc. Different target materials will be processed under varying operating parameters and characterized respectively, before and after a selective fragmentation in order to optimize the method and evaluate its economical and environmental perspectives. [less ▲]

Detailed reference viewed: 17 (1 ULg)
See detailIntegration of Composites for Greener Engine - Rapport scientifique & technique
Aatach, Mohamed ULg; Gaydardzhiev, Stoyan ULg

Report (2016)

The project's objective is to achieve a greater integration of composite materials in the low-pressure compressor, major product of Techspace Aero. The recycling of composite materials is one of the main ... [more ▼]

The project's objective is to achieve a greater integration of composite materials in the low-pressure compressor, major product of Techspace Aero. The recycling of composite materials is one of the main parts of this project. The focus is on the review of technologies, reuse and resulting properties on the recycling of fibre reinforced polymers and the development of new processes for end-of-life aerospace grade advanced carbon fiber reinforced composite materials (electrodynamic and conventional fragmentation, physicochemical characterization, environmental impact assessment, etc.) [less ▲]

Detailed reference viewed: 34 (1 ULg)
See detailIntegration of Composites for Greener Engine - Rapport scientifique & technique
Aatach, Mohamed ULg; Gaydardzhiev, Stoyan ULg

Report (2016)

The project's objective is to achieve a greater integration of composite materials in the low-pressure compressor, major product of Techspace Aero. The recycling of composite materials is one of the main ... [more ▼]

The project's objective is to achieve a greater integration of composite materials in the low-pressure compressor, major product of Techspace Aero. The recycling of composite materials is one of the main parts of this project. The focus is on the review of technologies, reuse and resulting properties on the recycling of fibre reinforced polymers and the development of new processes for end-of-life aerospace grade advanced carbon fiber reinforced composite materials (electrodynamic and conventional fragmentation, physicochemical characterization, environmental impact assessment, etc.) [less ▲]

Detailed reference viewed: 29 (14 ULg)
See detailIntegration of Composites for Greener Engine - Rapport scientifique & technique
Aatach, Mohamed ULg; Gaydardzhiev, Stoyan ULg

Report (2015)

The project's objective is to achieve a greater integration of composite materials in the low-pressure compressor, major product of Techspace Aero. The recycling of composite materials is one of the main ... [more ▼]

The project's objective is to achieve a greater integration of composite materials in the low-pressure compressor, major product of Techspace Aero. The recycling of composite materials is one of the main parts of this project. The focus is on the review of technologies, reuse and resulting properties on the recycling of fibre reinforced polymers and the development of new processes for end-of-life aerospace grade advanced carbon fiber reinforced composite materials (electrodynamic and conventional fragmentation, physicochemical characterization, environmental impact assessment, etc.) [less ▲]

Detailed reference viewed: 14 (5 ULg)
See detailERA-NET ECO-INNOVERA - Fragmentation électrodynamique des matériaux composites à haute valeur ajoutée contenant des substances récupérables - EDF-HVC: Rapport scientifique & technique annuel
Martino, Rémi ULg; Gaydardzhiev, Stoyan ULg

Report (2015)

The EDF-HVC project aims in evaluating the feasibility of electrodynamic fragmentation application to process end-of-life devices such as waste electrical and electronic equipments and secondary resources ... [more ▼]

The EDF-HVC project aims in evaluating the feasibility of electrodynamic fragmentation application to process end-of-life devices such as waste electrical and electronic equipments and secondary resources such as MSW incineration slags, EoL high-end composites, etc. Different target materials will be processed under varying operating parameters and characterized respectively, before and after a selective fragmentation in order to optimize the method and evaluate its economical and environmental perspectives. [less ▲]

Detailed reference viewed: 47 (16 ULg)
Full Text
Peer Reviewed
See detailEffects of process water recycling during flotation of copper and cobalt oxidised ores from Luiswishi deposit in the Democratic Republic of Congo
Shengo, Michel; Gaydardzhiev, Stoyan ULg; Kalenga, Pierre

in Desalination and Water Treatment (2015), 55(7), 117

Laboratory flotation tests with copper–cobalt oxidized ore from the Luiswishi deposit in the Katanga province were done using process water being recycled to different degrees. Grade and recovery of ... [more ▼]

Laboratory flotation tests with copper–cobalt oxidized ore from the Luiswishi deposit in the Katanga province were done using process water being recycled to different degrees. Grade and recovery of copper and cobalt were followed by 10, 20 and 80% process to fresh water addition with the results from these conditions being compared to those without water recycling. When process water was recycled at 10%, 83.7% copper and 84.1% cobalt were recovered at the rougher stage bringing the cleaner stage to a concentrate with recovery of 53 and 60% for copper and cobalt, respectively. However, recycling process water, up to 20 and 80%, has reduced the recovery of copper in the final concentrate to 23 and 6%, respectively, and of cobalt to 46 and 27%, respectively. Monitoring of dissolved oxygen content, pulp pH and Es potential during flotation, coupled with thermodynamic estimation of the predominant chemical compounds in the system, has enabled to evaluate the effects on flotation from the undesirable compounds’ formation during process water recycling. DRIFT spectroscopy was used to identify the nature of the chemical compounds formed on malachite and heterogenite surface during their sulphidisation in the presence of thiosulphate ions. Thiosulphate ions depending on their concentration could promote or hinder malachite and heterogenite flotation by inducing changes in pulp physicochemical parameters or by altering mineral surface properties. [less ▲]

Detailed reference viewed: 57 (8 ULg)
Full Text
Peer Reviewed
See detailCopper extraction from coarsely ground printed circuit boards using moderate thermophilic bacteria in a rotating-drum reactor
Rodrigues, Michael; Leão, Versiane; Gomes, Otavio et al

in Waste Management (2015), 41

The current work reports on a new approach for copper bioleaching from Printed Circuit Board (PCB) by moderate thermophiles in a rotating-drum reactor. Initially leaching of PCB was carried out in shake ... [more ▼]

The current work reports on a new approach for copper bioleaching from Printed Circuit Board (PCB) by moderate thermophiles in a rotating-drum reactor. Initially leaching of PCB was carried out in shake flasks to assess the effects of particle size ( 208 lm + 147 lm), ferrous iron concentration (1.25–10.0 g/L) and pH (1.5–2.5) on copper leaching using mesophile and moderate thermophile microorganisms. Only at a relatively low solid content (10.0 g/L) complete copper extraction was achieved from the particle size investigated. Conversely, high copper extractions were possible from coarse-ground PCB (20 mm-long) working with increased solids concentration (up to 25.0 g/L). Because there was as the faster leaching kinetics at 50 C Sulfobacillus thermosulfidooxidans was selected for experiments in a rotating-drum reactor with the coarser-sized PCB sheets. Under optimal conditions, copper extraction reached 85%, in 8 days and microscopic observations by SEM–EDS of the on nonleached and leached material suggested that metal dissolution from the internal layers was restricted by the fact that metal surface was not entirely available and accessible for the solution in the case of the 20 mm-size sheets. [less ▲]

Detailed reference viewed: 86 (28 ULg)
Full Text
Peer Reviewed
See detailCOPPER LEACHING FROM WASTE ELECTRIC CABLES BY BIOHYDROMETALLURGY
Lambert, Fanny ULg; Bastin, David ULg; Gaydardzhiev, Stoyan ULg et al

in Minerals Engineering (2015)

This study examines the leaching of copper from waste electric cables by chemical leaching and leaching catalysed by Acidithiobacillus ferrooxidans in terms of leaching kinetics and reagents consumption ... [more ▼]

This study examines the leaching of copper from waste electric cables by chemical leaching and leaching catalysed by Acidithiobacillus ferrooxidans in terms of leaching kinetics and reagents consumption. Operational parameters such as the nature of the oxidant (Fe3+, O2), the initial ferric iron concentration (0-10 g/L) and the temperature (21-50°C) were identified to have an important influence on the degree of copper solubilisation. At optimal process conditions, copper extraction above 90% was achieved in both leaching systems, with a leaching duration of 1 day. The bacterial leaching system slightly outperformed the chemical one but the positive effect of regeneration of Fe3+ was limited. It appears that the Fe2+ bio-oxidation is not sufficiently optimised. Best results in terms of copper solubilisation kinetics were obtained for the abiotic test at 50°C and for the biotic test at 35°C. Moreover, the study showed that in same operating conditions, a lower acid consumption was recorded for the biotic test than for the abiotic test. [less ▲]

Detailed reference viewed: 125 (42 ULg)
See detailIntegration of Composites for Greener Engine - Rapport scientifique & technique
Aatach, Mohamed ULg; Gaydardzhiev, Stoyan ULg

Report (2015)

The project's objective is to achieve a greater integration of composite materials in the low-pressure compressor, major product of Techspace Aero. The recycling of composite materials is one of the main ... [more ▼]

The project's objective is to achieve a greater integration of composite materials in the low-pressure compressor, major product of Techspace Aero. The recycling of composite materials is one of the main parts of this project. The focus is on the review of technologies, reuse and resulting properties on the recycling of fibre reinforced polymers and the development of new processes for end-of-life aerospace grade advanced carbon fiber reinforced composite materials (electrodynamic and conventional fragmentation, physicochemical characterization, environmental impact assessment, etc.) [less ▲]

Detailed reference viewed: 19 (5 ULg)
Full Text
Peer Reviewed
See detailSEM and EDS observations of carrollite bioleaching with a mixed culture of acidophilic bacteria
Nkulu, Guy; Gaydardzhiev, Stoyan ULg; Mwema, Edouard et al

in Minerals Engineering (2015), doi:10.1016/j.mineng.2014.12.005

Bioleaching of high purity carrollite minerals with mesophilic bacteria was carried out and monitored by observations in scanning electron microscopy (SEM) and elemental X-ray microanalysis (EDS) to ... [more ▼]

Bioleaching of high purity carrollite minerals with mesophilic bacteria was carried out and monitored by observations in scanning electron microscopy (SEM) and elemental X-ray microanalysis (EDS) to provide evidence of the interaction pattern between carrollite and microorganisms. A bacterial consortium involving three different acidophilic chemolithotrophs was adopted. The evolution of the surface topography, inside alteration effects and elemental composition of the mineral with leaching time was followed. It could be postulated that bacterial adhesion takes place on the mineral surface, resulting in the formation of dissolution pits of various shapes and continues by boring elongated channels deep inside the mineral grains. Enhanced concentration of ferric iron and sulphur could be assumed in vicinity of the zones where mineralized polymer substances are precipitated. It could be inferred that carrollite dissolution is governed by cooperative bioleaching involving oxidation induced by bacteria attached to the surface and ferric iron re-oxidized by planktonic bacteria in suspension. [less ▲]

Detailed reference viewed: 76 (23 ULg)
Full Text
Peer Reviewed
See detailPossibilities for Co(III) dissolution from an oxidized ore through simultaneous bioleaching of pyrite
Zeka, Leon; Lambert, Fanny ULg; Frenay, Jean ULg et al

in Minerals Engineering (2015)

Solubilisation of Co(III) from a heterogenite met in copper cobaltiferous oxide ore has been realized through reductive leaching using ferrous iron generated via bio-oxidation of pyrite. Biotic and ... [more ▼]

Solubilisation of Co(III) from a heterogenite met in copper cobaltiferous oxide ore has been realized through reductive leaching using ferrous iron generated via bio-oxidation of pyrite. Biotic and abiotic experiments at various pulp densities and redox potentials have been performed and results compared. Cobalt leaching at elevated redox potential is possible, offering cost reduction benefits due to reduced consumption of ferrous iron. At elevated potential of 625 mV, however, the initial rate of cobalt leaching has been found as 115 mg/(g ore)⋅(24 h), lower than the rate of 865 mg/(g ore)⋅(24 h) registered at 505 mV. Less stochiometric amount of ferrous iron was required when cobalt leaching was coupled to pyrite bioleaching, with 75% of cobalt recovered for 12 h at the optimally found conditions. It could be inferred that the Fe3+–Fe2+ cycle exists and is efficiently maintained through bacterial presence in the studied system. [less ▲]

Detailed reference viewed: 77 (9 ULg)
Full Text
Peer Reviewed
See detailPhysicochemical observations during process water reuse in flotation of oxide copper-cobalt ore
Shengo, Michel; Gaydardzhiev, Stoyan ULg; Kalenga, Pierre

in Yianatos, Juan (Ed.) Proceedings of the XXVII International Mineral Processing Congress (2014, October 20)

Lab-scale flotation of copper and cobalt oxidized ore from the Luiswishi deposit in the Katanga province (DRC) has been done focusing on the influence of the degree of process water recycling on metals ... [more ▼]

Lab-scale flotation of copper and cobalt oxidized ore from the Luiswishi deposit in the Katanga province (DRC) has been done focusing on the influence of the degree of process water recycling on metals recovery. Results have shown that at 20 % recycling rate, the recovery of copper and cobalt in the cleaner stage have been respectively reduced to 23 % and 45 % in comparison to 53 % Cu and 63 % Co if process water has not been recycled. At 10 % recycling rate however, the system could still tolerate the effect from recycling, since Cu and Co recovery has remained respectively at acceptable levels of 52 % and 60 %. In order to explain the reasons for the observed worsening of flotation results if process water was recycled at rate higher than 20 %, electrochemical investigation of the pulp has been performed. It has been established that the chemical compounds formed in the pulp when process water was recycled, do influence the sulfidization of malachite and heterogenite and impact further collector adsorption. To confirm these assumptions, the effect from thiosulphate ions presence during the sulfidization of high purity malachite has been studied. It has been found, that thiosulphate ions depending on their concentration in water induce variations in pulp properties such as DO content, pH, Es and contribute to formation of undesirable chemical compounds on mineral surface as identified by DRIFT spectroscopy. [less ▲]

Detailed reference viewed: 81 (10 ULg)
Full Text
Peer Reviewed
See detailInsights upon the adsorption mechanism of KAX on malachite
Kanda, Jean-Marie; Kongolo, Mukendi; Gaydardzhiev, Stoyan ULg et al

in Yianatos, Juan (Ed.) Proceedings of the XXVII International Mineral Processing Congress (2014, October 20)

The adsorption patterns of potassium amylxanthate on the surface of high purity malachite subjected to prior sulfidization with NaSH have been followed and elucidated. DRIFTS spectroscopy has been used to ... [more ▼]

The adsorption patterns of potassium amylxanthate on the surface of high purity malachite subjected to prior sulfidization with NaSH have been followed and elucidated. DRIFTS spectroscopy has been used to trace the associated physicochemical alterations as well as the chemical species present on the mineral surface. Varying the collector concentration from 5.10-4 to 1.10-2 mol/L has led to different degree of surface coverage of the alkyl groups in combination with formation of organometallic hydrophobic complexes of CuX and CuX – X2 type. The results reveal that the CuX complex formed on the malachite surface without sulfidizing agent is more unstable and prone to dissolution-precipitation phenomena. Based upon the constructed adsorption isotherms and upon the degree of statistical coverage, different zones of mineral-reagent interactions could be distinguished. They correspond respectively to the monolayer, bi-layer and tridimensional condensation domains. In each of the identified zones mono or double layer adsorption patterns of the collector are proposed leading respectively to formation of surface compounds with different degree of hydrophobicity. [less ▲]

Detailed reference viewed: 54 (9 ULg)