[ Caractérisation chimique des scories et boues des fonderies qui recyclent la mitraille à Kinshasa-RDC: Qualité et quantité relatives des polluants du substratum remblayé par ces matériaux ]
Volume 33, Issue 4, September 2021, Pages 637–649
Joseph M. Kakundika1, Dieudonné E. Musibono2, Virima Mudogo3, and Ndongala Lufimpadio4
1 Université de Kinshasa, RD Congo
2 Professeur ordinaire & Directeur du groupe ERGS, Département de l'Environnement, Faculté des sciences, Université de Kinshasa (UNIKIN), RD Congo
3 Département de Chimie, Faculté des Sciences, Université de Kinshasa, RD Congo
4 Département de Chimie-physique, Faculté des Sciences, Université Pédagogique Nationale, RD Congo
Original language: French
Copyright © 2021 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
For nearly a decade and a half, some foundries that recycle scrap metal have been established in Kinshasa, the capital of the Democratic Republic of Congo. These foundries produce annually, as do other foundries, thousands of tons of solid waste, the mismanagement of which was demonstrated in our previous article in the same press. The waste from the foundries being counted among the dangerous waste, it immediately seemed useful to us to determine their chemical composition.After chemical analyses by X-ray fluorescence spectrophotometry (XRF) on 15 samples of slag and 15 samples of sludge from three of the said foundries, the following results were obtained (i) qualitatively, the sludge of the foundries is composed of Na2O, CaO, Cr2O3, MnO, Fe2O3, NiO, CuO, La2O3, Eu2O3, Yb2O3, OsO4, Br, SiO2, K2O, TiO2, V2O5 and ZnO while the slag contains in addition to these last components Ti2O3, Sc2O3, SrO, ZrO2, Nb2O5, RuO2, BaO, Re2O7, Al2O3, Au, MgO, Rb2O and HgO, (ii) On the semi-quantitative level, the chemical analyses indicate that Fe2O3 is the most preponderant component in the sludge with an average mass concentration evaluated at more than 85%, followed by Na2O [6.33%], SiO2 [5.3%], MnO [1.5%]. Eu2O3, Cr2O3 and CuO have concentrations in the order of the tenth (10-1), while the majority of the remaining components have concentrations in the order of the hundredth (10-2), except Re2O7, ZrO2, SrO and V2O5 whose concentrations are small in the order of the thousandth (10-3). On the other hand, the main component of the slag is SiO2 concentrated at 36% of the average total weight, followed by Fe2O3 [23%], MnO [15.5%], Al2O3 [10%], Cr2O3 [1.5%], Na2O [1.1%] which are the major components. TiO2, BaO, ZnO, MgO, SrO, K2O, V2O5, RuO2 have concentrations on the order of tenths ranging from 0.8 ≥ x ≥ 0.112, ZrO2, Eu2O3, Nb2O5, Re2O7 have concentrations on the order of hundredths ranging from 0, 047 ≥ x ≥ 0.02 and NiO, Au, Sc2O3, Ti2O3 and Br have relative concentrations on the order of thousandths ranging from 0.00333% ≥ x ≥ 0.001%.The comparison of the different compositions of the sludge and slag indicates that the slag from the FAMECO smelter, not only has several components related to the other two smelters, but also has higher or lower relative concentrations than the other two. Finally, the pooling or mixing of sludge and slag at the time of disposal indicates that the contribution of pollutants from the slag is far more abundant (78%) than from the sludge (22%).
Author Keywords: Sludge, slag, foundries, scrap metal, pollutants, bedrock, fills.
Volume 33, Issue 4, September 2021, Pages 637–649
Joseph M. Kakundika1, Dieudonné E. Musibono2, Virima Mudogo3, and Ndongala Lufimpadio4
1 Université de Kinshasa, RD Congo
2 Professeur ordinaire & Directeur du groupe ERGS, Département de l'Environnement, Faculté des sciences, Université de Kinshasa (UNIKIN), RD Congo
3 Département de Chimie, Faculté des Sciences, Université de Kinshasa, RD Congo
4 Département de Chimie-physique, Faculté des Sciences, Université Pédagogique Nationale, RD Congo
Original language: French
Copyright © 2021 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
For nearly a decade and a half, some foundries that recycle scrap metal have been established in Kinshasa, the capital of the Democratic Republic of Congo. These foundries produce annually, as do other foundries, thousands of tons of solid waste, the mismanagement of which was demonstrated in our previous article in the same press. The waste from the foundries being counted among the dangerous waste, it immediately seemed useful to us to determine their chemical composition.After chemical analyses by X-ray fluorescence spectrophotometry (XRF) on 15 samples of slag and 15 samples of sludge from three of the said foundries, the following results were obtained (i) qualitatively, the sludge of the foundries is composed of Na2O, CaO, Cr2O3, MnO, Fe2O3, NiO, CuO, La2O3, Eu2O3, Yb2O3, OsO4, Br, SiO2, K2O, TiO2, V2O5 and ZnO while the slag contains in addition to these last components Ti2O3, Sc2O3, SrO, ZrO2, Nb2O5, RuO2, BaO, Re2O7, Al2O3, Au, MgO, Rb2O and HgO, (ii) On the semi-quantitative level, the chemical analyses indicate that Fe2O3 is the most preponderant component in the sludge with an average mass concentration evaluated at more than 85%, followed by Na2O [6.33%], SiO2 [5.3%], MnO [1.5%]. Eu2O3, Cr2O3 and CuO have concentrations in the order of the tenth (10-1), while the majority of the remaining components have concentrations in the order of the hundredth (10-2), except Re2O7, ZrO2, SrO and V2O5 whose concentrations are small in the order of the thousandth (10-3). On the other hand, the main component of the slag is SiO2 concentrated at 36% of the average total weight, followed by Fe2O3 [23%], MnO [15.5%], Al2O3 [10%], Cr2O3 [1.5%], Na2O [1.1%] which are the major components. TiO2, BaO, ZnO, MgO, SrO, K2O, V2O5, RuO2 have concentrations on the order of tenths ranging from 0.8 ≥ x ≥ 0.112, ZrO2, Eu2O3, Nb2O5, Re2O7 have concentrations on the order of hundredths ranging from 0, 047 ≥ x ≥ 0.02 and NiO, Au, Sc2O3, Ti2O3 and Br have relative concentrations on the order of thousandths ranging from 0.00333% ≥ x ≥ 0.001%.The comparison of the different compositions of the sludge and slag indicates that the slag from the FAMECO smelter, not only has several components related to the other two smelters, but also has higher or lower relative concentrations than the other two. Finally, the pooling or mixing of sludge and slag at the time of disposal indicates that the contribution of pollutants from the slag is far more abundant (78%) than from the sludge (22%).
Author Keywords: Sludge, slag, foundries, scrap metal, pollutants, bedrock, fills.
Abstract: (french)
Depuis près d’une décennie et demie, des fonderies qui recyclent la mitraille/ferraille se sont installées à Kinshasa, capitale de la République Démocratique du Congo. Celles-ci produisent annuellement, à l’instar d’autres fonderies, des milliers de tonnes de déchets solides dont la mauvaise gestion a été démontrée dans notre article intitulé « Repérage, géolocalisation et caractérisation des sites de rejets des scories et boues des fonderies (SBF) qui recyclent la mitraille à Kinshasa: RDC » (sous même presse). Les déchets des fonderies étant comptés parmi les déchets dangereux, il nous a aussitôt semblé utile de déterminer leurs compositions chimiques.Au bout d’analyses chimiques par spectrophotométrie à fluorescence X (XRF) réalisées sur 15 échantillons des scories et 15 des boues des trois desdites fonderies, il en est ressorti les résultats ci-après: (i) sur le plan qualitatif, les boues des fonderies sont composées de Na2O, CaO, Cr2O3, MnO, Fe2O3, NiO, CuO, La2O3, Eu2O3, Yb2O3, OsO4, Br, SiO2, K2O, TiO2, V2O5 et ZnO tandis que les scories renferment en plus de ces derniers composants Ti2O3, Sc2O3, SrO, ZrO2, Nb2O5, RuO2, BaO, Re2O7, Al2O3, Au, MgO, Rb2O et HgO, (ii) Sur le plan semi-quantitatif, les analyses chimiques indiquent que Fe2O3 est le composant le plus prépondérant dans les boues avec une concentration massique moyenne évaluée à plus de 85 %, suivi des Na2O [6,33%], SiO2 [5,3 %], MnO [1,5 %]. Eu2O3, Cr2O3 et CuO ont des concentrations de l’ordre du dixième (10-1), tandis que la majorité de composants restants ont des concentrations de l’ordre du centième (10-2), hormis Re2O7, ZrO2, SrO et V2O5 dont les concentrations sont petites de l’ordre du millième (10-3). En contrepartie, le composant principal des scories est SiO2 concentré à 36 % du poids total moyen, suivi de Fe2O3 [23 %], MnO [15,5 %], Al2O3 [10 %], Cr2O3 [1,5 %], Na2O [1,1 %] qui en sont les composants majeurs. TiO2, BaO, ZnO, MgO, SrO, K2O, V2O5, RuO2 ont des concentrations de l’ordre du dixième variant entre 0,8 ≥ x ≥ 0,112, ZrO2, Eu2O3, Nb2O5, Re2O7 ont des concentrations de l’ordre de centième variant entre 0,047 ≥ x ≥ 0,02 et NiO, Au, Sc2O3, Ti2O3 et Br ont des concentrations relatives de l’ordre de millième variant entre 0,00333% ≥ x ≥ 0,001%.La comparaison des différentes compositions des boues et scories indique que les scories de la fonderie FAMECO, non seulement comportent plusieurs composants en rapport avec les deux autres fonderies, mais aussi disposent des concentrations relatives plus ou moins élevées que ne le sont celles des deux autres. Enfin, la mise en commun ou le mélange des boues et scories lors de leurs mise en décharge indique que l’apport en polluants des scories est de loin beaucoup plus abondant (78%) que celui des boues (22%).
Author Keywords: Boues, scories, fonderies, mitraille, polluants, substratum, remblais.
How to Cite this Article
Joseph M. Kakundika, Dieudonné E. Musibono, Virima Mudogo, and Ndongala Lufimpadio, “Chemical characterization of slag and sludge from foundries that recycle scrap metal in Kinshasa-DRC: Relative quality and quantity of pollutants from the substratum backfilled with these materials,” International Journal of Innovation and Applied Studies, vol. 33, no. 4, pp. 637–649, September 2021.
