International Science and Technology Journal of Namibia

Impact of ion concentration on Alamine 336 degradation in uranium solvent extraction processes

2026-02-25T11:02:46+02:00

The degradation of Alamine 336, a critical extractant in uranium solvent extraction (SX) processes, is a significant challenge at the Rossing Uranium Limited (RUL) processing plant. This study investigates the impact of ion concentrations—specifically chloride, nitrate, ferrous, and manganese ions—on the degradation of Alamine 336 in the SX circuit. Through a 2^k-pfractional factorial design, the study evaluates the interactions of these ions, aiming to identify key contributors to solvent degradation. The findings reveal that nitrate and chloride ions are significant predictors of Alamine 336 degradation, with higher concentrations leading to increased solvent breakdown. Manganese and ferrous ions also play a role, with manganese exhibiting an oxidizing effect that exacerbates degradation. The study further identifies nitrosamine formation as a primary degradation product, supporting previous research. By employing regression analysis, the study develops a model to predict Alamine concentration based on ion concentrations, offering a valuable tool for optimizing uranium extraction efficiency and mitigating solvent degradation. These results underscore the importance of maintaining controlled ion concentrations, particularly keeping redox potential below 500 mV, to preserve solvent integrity and enhance the overall sustainability of uranium extraction operations.

The The chemical composition and in vitro dry matter digestibility of herbaceous forage legumes adapted to arid Namibia

2025-07-23T10:37:36+02:00

The nutritional quality of herbaceous forage legumes adapted to the arid environment of Namibia has not been characterised. These legumes are important protein feed resources for animals. The study was conducted to determine the chemical composition and in vitro digestibility of four herbaceous legumes, namely Tylosema esculentum, Vigna unguiculata, Lablab purpureus, and Mucuna pruriens. The legumes were harvested at the vegetative growth stage and separated into leaves, stems, and whole plant fractions. The Tylosema had the lowest DM content in the leaf, stem, and whole plant fractions compared to other legumes, which also differed significantly. The ash content of the Vigna leaf and whole plant fractions was higher, 16.93% and 26.32%, respectively, while Lablab had a high ash content in the stem fraction, 10.40%. Tylosema had the lowest ash content among legumes in all fractions, ranging from 4.81% to 7.87%. Tylosema had the highest OM values, ranging from 92.13% to 94.20%. Lablab had the highest CP in all plant fractions, ranging from 12.95% to 30.05%. The legumes had similar hemicellulose content in leaf and whole plant fractions, while the stem fraction of Vigna had the highest hemicellulose content. The legumes had significantly different in vitro DM digestibility. Vigna recorded the highest DM digestibility in the leaf (88.83%) and stem (74.93%) fractions, while Lablab recorded the highest digestibility in the whole fraction (84.53%). In conclusion, forage legumes differed in chemical composition and in vitro DM digestibility, but all had adequate protein above the minimum requirement of 7% for ruminant livestock diets.

A review of antimicrobial resistance in Sub-Saharan Africa

2025-07-10T13:57:45+02:00

Antimicrobial resistance (AMR) poses a global issue, affecting individuals across all age groups and influencing countries across all income brackets and regions. Modern medicine has been revolutionized by antimicrobials, significantly reducing morbidity, mortality, and disability. Nevertheless, their widespread use has been paralleled by the rapid emergence of AMR. Although AMR poses a global health challenge, its impact is disproportionately severe in low – and middle – income (LMICs) countries, especially in sub – Saharan Africa, where populations face a high burden of bacterial AMR. This is exacerbated by inadequate sanitation and a weak health infrastructure, that heightens dependence on antimicrobial treatment. This narrative review highlights the AMR state on the African continent, and strategies to combat antimicrobial resistance.