Thesis--Wisconsin. / Vita. Includes bibliographical references (leaves 123-124).

<p>The aim of the project was to study the manufacturing of synthetic soda ash (sodium carbonate, Na2CO3) on an industrial scale. Currently all Soda ash that is used in South Africa for manufacturing glass is imported at a high cost, and the company Nampak Wiegand Glass (South Africa) is investigating the possibility to locally manufacture synthetic soda ash. About 75% of soda ash is synthetically produced from either the Leblanc process, Solvay process, Modified Solvay (Dual) process or dry lime process. This study concentrated on the Solvay process on a laboratory scale for eventual input into a larger pilot plant. The produced material was analyzed using analytical techniques such as FTIR (Fourier Transform Infrared spectroscopy), Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma Atomic Emission spectroscopy (ICP-AES). There are certain standard requirements for impurities in the soda ash, and this needed to be measured and determined what changes to the process will bring the impurities to the required minimum standard. Environmental issues around the manufacturing process were also studied. After completing of the laboratory experiments and the extraction of required data from the results, Nampak will use the information to decide on a followup to the building of a small pilot plant to further test and develop the engineering and economical aspects of a full plant. If successful a full scale manufacturing plant can be developed in South Africa for producing soda ash.&nbsp / This study thus will not only help Nampak Wiegand Glass in finalizing the decision to go ahead, but its result will also benefit other companies that use the soda ash in oil refining, water treatment, pulp and paper, chemical industry etc. Some parts of the work done will be proprietary to Nampak and subject to confidentiality agreement.</p>

<p>The aim of the project was to study the manufacturing of synthetic soda ash (sodium carbonate, Na2CO3) on an industrial scale. Currently all Soda ash that is used in South Africa for manufacturing glass is imported at a high cost, and the company Nampak Wiegand Glass (South Africa) is investigating the possibility to locally manufacture synthetic soda ash. About 75% of soda ash is synthetically produced from either the Leblanc process, Solvay process, Modified Solvay (Dual) process or dry lime process. This study concentrated on the Solvay process on a laboratory scale for eventual input into a larger pilot plant. The produced material was analyzed using analytical techniques such as FTIR (Fourier Transform Infrared spectroscopy), Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma Atomic Emission spectroscopy (ICP-AES). There are certain standard requirements for impurities in the soda ash, and this needed to be measured and determined what changes to the process will bring the impurities to the required minimum standard. Environmental issues around the manufacturing process were also studied. After completing of the laboratory experiments and the extraction of required data from the results, Nampak will use the information to decide on a followup to the building of a small pilot plant to further test and develop the engineering and economical aspects of a full plant. If successful a full scale manufacturing plant can be developed in South Africa for producing soda ash.&nbsp / This study thus will not only help Nampak Wiegand Glass in finalizing the decision to go ahead, but its result will also benefit other companies that use the soda ash in oil refining, water treatment, pulp and paper, chemical industry etc. Some parts of the work done will be proprietary to Nampak and subject to confidentiality agreement.</p>

Magister Scientiae - MSc / The aim of the project was to study the manufacturing of synthetic soda ash (sodium carbonate, Na2CO3) on an industrial scale. Currently all Soda ash that is used in South Africa for manufacturing glass is imported at a high cost, and the company Nampak Wiegand Glass (South Africa) is investigating the possibility to locally manufacture synthetic soda ash. About 75% of soda ash is synthetically produced from either the Leblanc process, Solvay process, Modified Solvay (Dual) process or dry lime process. This study concentrated on the Solvay process on a laboratory scale for eventual input into a larger pilot plant. The produced material was analyzed using analytical techniques such as FTIR (Fourier Transform Infrared spectroscopy), Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma Atomic Emission spectroscopy (ICP-AES). There are certain standard requirements for impurities in the soda ash, and this needed to be measured and determined what changes to the process will bring the impurities to the required minimum standard. Environmental issues around the manufacturing process were also studied. After completing of the laboratory experiments and the extraction of required data from the results, Nampak will use the information to decide on a followup to the building of a small pilot plant to further test and develop the engineering and economical aspects of a full plant. If successful a full scale manufacturing plant can be developed in South Africa for producing soda ash. This study thus will not only help Nampak Wiegand Glass in finalizing the decision to go ahead, but its result will also benefit other companies that use the soda ash in oil refining, water treatment, pulp and paper, chemical industry etc. Some parts of the work done will be proprietary to Nampak and subject to confidentiality agreement. / South Africa

Le procédé Solvay génère d’énormes quantités de saumures résiduaires au pH alcalin contenant portlandite, brucite et silicates de calcium hydratés. La carbonatation conduit à un abaissement du pH, ce qui favorise la formation de deux phases majoritaires : la calcite et le gypse. L’objectif de la thèse est de valoriser les saumures résiduaires carbonatées par séparation des phases en colonne de flottation. L’étude de la carbonatation en réacteur batch, puis en colonne de carbonatation pilote montre qu’il est préférable de ne pas carbonater les saumures résiduaires jusqu’à l’équilibre thermodynamique. En effet, la mise en solution de métaux lourds intervient à partir d’un pH de l’ordre de 7,5, ce qui limiterait les rejets des saumures dans l’environnement. En outre, une carbonatation brusque et incomplète est souhaitable pour une meilleure séparation des phases par flottation. Les essais de flottation réalisés sur une colonne de 7,6 cm de diamètre et de 3 m de haut ont montré une faisabilité de la séparation des deux minéraux calciques avec l’oléate de sodium comme collecteur malgré une abondante littérature incitant à la prudence. La différence entre la taille des particules de carbonates et celle des particules de sulfates et leurs hydratations de surfaces, ainsi qu’une force ionique élevée du milieu permettent une bonne séparation des phases. Une étude des saumures synthétiques permet de mettre en évidence le rôle des cations métalliques (nature, rayon, charge…) sur la coalescence des bulles dans les conditions dynamiques et dans un milieu à forte force ionique. Une étude des paramètre de fonctionnement effectué sur une colonne de 30,5 cm de diamètre et de 10 m de haut ont permis la modélisation du procédé de flottation en colonne dans le but de proposer une procédure de dimensionnement du procédé industriel. La confrontation des résultats de simulation aux résultats réels permet la détermination des intensités des microprocessus de flottation (attachement/détachement), et conduit à la proposition d’une installation industrielle avec deux colonnes de flottation en série / Solvay process generates huge amounts of waste brines at alkaline pH containing portlandite, brucite and calcium silicate hydrates. Carbonation leads to lowering of pH which favors formation of two predominant phases: calcite and gypsum. The aim of this thesis is to develop carbonated waste brines valorization by phase separation in flotation column Study of carbonation in a batch reactor and in a carbonation pilot column shows it is preferable not to carbonate waste brines until thermodynamic equilibrium. Indeed dissolution of heavy metals occurs from a pH of about 7.5 thereby limiting discharge of brines in the environment. In addition, a sudden and incomplete carbonation is appropriate for phase separation by flotation. Flotation tests carried out in a 7.6 cm diameter and 3 m high column showed feasibility of the separation of the two calcium minerals using sodium oleate as a collector despite abundant literature for caution. The differences between the particle size of carbonates and sulfates and their surface hydration, as well as the high ionic strength of the medium allow an efficient separation of phases. Study of synthetic brines highlights the role of metal cations (nature, radius, charge…) on bubble coalescence in dynamic conditions in an environment with high ionic strength. Study of operation parameter performed on a 30.5 cm diameter and 10 m high column enabled the modeling of the column flotation process in order to provide a scale-up procedure of industrial process. Comparison of simulation results with actual results allows the determination of intensities of flotation subprocesses (attachment/detachment), and led to the proposal of an industrial plant with two flotation columns in series