Search

Background: Maternal complications contribute to maternal deaths in developing countries. Bangladesh still has a high prevalence of maternal mortality, which is often preventable. There are some geographically challenging and hard to reach rural districts in Bangladesh and it is difficult to get information about maternal complications in these areas. In this study, we examined the community lay knowledge of possible pregnancy complications. We also examined the common practices associated with complications and we discuss the challenges for the community. Methods: The study was conducted in Moulvibazar of north east Bangladesh, a geographically challenged, difficult to reach district. Qualitative methods were used to collect the information. Pregnant women, mothers who had recently delivered, their guardians and traditional birth attendants participated in focus group discussions. Additionally, in-depth interviews were conducted with the family members. Thematic analyses were performed. Results: The study revealed that there is a lack of knowledge of maternal complications. In the majority of cases, the mothers did not receive proper treatment for maternal complications. There are significant challenges that these rural societies need to address: problems of ignorance, traditional myths and family restrictions on seeking better treatment. Moreover, traditional birth attendants and village doctors also have an important role in assuring appropriate, effective and timely treatment. Conclusions: The rural community lacks adequate knowledge on maternal complications. Reduction of the societal barriers including barriers within the family can improve overall practices. Moreover, dissemination of adequate information to the traditional birth attendant and village doctors may improve the overall situation, which would eventually help to reduce maternal deaths.

A new process developed for the production of base metals Ni, Co and Fe, based on chloride hydrometallurgy, is applicable to both high- and low-iron laterite ores. The process comprises atmospheric leaching in mixed HCl-MgCl2 media to bring Fe, Ni, Co and Mg into solution, solvent-extraction steps to generate high-purity pregnant stripping solutions of Fe, Ni and Co individually, precipitation of high-purity Ni and Co products by addition of MgO generated from pyrohydrolysis, production of Fe2O3 and regeneration of HCl by pyrohydrolysis of the iron chloride-rich pregnant stripping solution, production of MgO and regeneration of HCl by pyrohydrolysis of bleed stream from the MgCl2-containing raffinate from the nickel sovent-extraction stage, and recycling of the HCl generated by pyrohydrolysis. A comparison of this process with commercial laterite processes - Caron process, high-pressure acid-leach process and pyrometallurgical process - is additionally presented., A new process developed for the production of base metals Ni, Co and Fe, based on chloride hydrometallurgy, is applicable to both high- and low-iron laterite ores. The process comprises atmospheric leaching in mixed HCl-MgCl2 media to bring Fe, Ni, Co and Mg into solution, solvent-extraction steps to generate high-purity pregnant stripping solutions of Fe, Ni and Co individually, precipitation of high-purity Ni and Co products by addition of MgO generated from pyrohydrolysis, production of Fe2O3 and regeneration of HCl by pyrohydrolysis of the iron chloride-rich pregnant stripping solution, production of MgO and regeneration of HCl by pyrohydrolysis of bleed stream from the MgCl2-containing raffinate from the nickel sovent-extraction stage, and recycling of the HCl generated by pyrohydrolysis. A comparison of this process with commercial laterite processes - Caron process, high-pressure acid-leach process and pyrometallurgical process - is additionally presented.

A process is described which has been developed by Process Research Ortech, Ontario, Canada, which involves the atmospheric leaching of ilmenite ore to bring Fe, Ti and V into solution. After solid/liquid separation the pregnant liquor is subjected to stage 1 solvent extraction to remove Fe. Pregnant strip solution from stage one solvent extraction can be subjected to pyrolysis for the production of Fe oxide and the regeneration of acid for recycling. The raffinate undergoes stage 2 solvent extraction to recover Ti and the pregnant strip is subjected to thermal hydrolysis for TiO2 precipitation and the raffinate undergoes stage 3 solvent extraction to recover V. Tests were carried out on an ilmenite ore containing 22.8 wt% Ti, 38 wt% Fe, 0.13 wt% Cr2O3, 4.69 wt% SiO2 and 2.82 wt% MgO using a solution of HCl and MgCl2 under atmospheric pressure at 70-73 degrees C for 4 h. With increasing MgCl2 concentrations Ti extraction reached maximum levels of 79% and 96.9%, respectively, at HCl levels 1.2 and 1.4 times the stoichiometric amount required to extract Ti and Fe. The mixed chloride lixiviant provides high recovery, allows recycling of HCl and MgCl2 and enables a reduction in HCl concentration which allows azeotropic distillation by the pyrolysis of recycle solutions without the addition of substantial amounts of concentrated HCl. Aliquat 336, Cyanex 923, D2EHPA and LIX 622 were evaluated for the extraction of Ti from the Fe solvent extraction raffinate and Aliquat 336 and Cyanex 923 for the recovery of V from the Ti solvent extraction raffinate., A process is described which has been developed by Process Research Ortech, Ontario, Canada, which involves the atmospheric leaching of ilmenite ore to bring Fe, Ti and V into solution. After solid/liquid separation the pregnant liquor is subjected to stage 1 solvent extraction to remove Fe. Pregnant strip solution from stage one solvent extraction can be subjected to pyrolysis for the production of Fe oxide and the regeneration of acid for recycling. The raffinate undergoes stage 2 solvent extraction to recover Ti and the pregnant strip is subjected to thermal hydrolysis for TiO2 precipitation and the raffinate undergoes stage 3 solvent extraction to recover V. Tests were carried out on an ilmenite ore containing 22.8 wt% Ti, 38 wt% Fe, 0.13 wt% Cr2O3, 4.69 wt% SiO2 and 2.82 wt% MgO using a solution of HCl and MgCl2 under atmospheric pressure at 70-73 degrees C for 4 h. With increasing MgCl2 concentrations Ti extraction reached maximum levels of 79% and 96.9%, respectively, at HCl levels 1.2 and 1.4 times the stoichiometric amount required to extract Ti and Fe. The mixed chloride lixiviant provides high recovery, allows recycling of HCl and MgCl2 and enables a reduction in HCl concentration which allows azeotropic distillation by the pyrolysis of recycle solutions without the addition of substantial amounts of concentrated HCl. Aliquat 336, Cyanex 923, D2EHPA and LIX 622 were evaluated for the extraction of Ti from the Fe solvent extraction raffinate and Aliquat 336 and Cyanex 923 for the recovery of V from the Ti solvent extraction raffinate.

A unique atmospheric mixed chloride leaching process has been developed for the recovery of copper and nickel from sulphide concentrates. The process also produces by-products of high purity cobalt and iron oxide, and recycles chloride lixiviant to the leaching stage. Studies have been carried out of the leaching of sulphide concentrates with a lixiviant containing hydrochloric acid and magnesium chloride at atmospheric pressure at 90-95 degrees C. After solid-liquid separation, the pregnant leach solution was used in solvent extraction steps prior to selective separation of Fe followed by Cu, Co, and Ni. It was found that the addition of MgCl2 to HCl increased the activity of the hydrogen ion in the lixiviant, allowing a rapid leaching rate at modest temperatures and pressures with a lower concentration of HCl. The use of MgCl2 and LIX 63 in the lixiviant gave separation of Ni2+ at a lower pH (0.5-2.5). Other advantages included a reduction in reagent cost by regenerating and recycling HCl and minimising waste production by recycling the chloride lixiviant to the leaching stage. It is concluded the process could be a potential alternative to conventional hydrometallurgical and smelting processes by meeting more stringent environmental requirements and reducing capital and operating costs., A unique atmospheric mixed chloride leaching process has been developed for the recovery of copper and nickel from sulphide concentrates. The process also produces by-products of high purity cobalt and iron oxide, and recycles chloride lixiviant to the leaching stage. Studies have been carried out of the leaching of sulphide concentrates with a lixiviant containing hydrochloric acid and magnesium chloride at atmospheric pressure at 90-95 degrees C. After solid-liquid separation, the pregnant leach solution was used in solvent extraction steps prior to selective separation of Fe followed by Cu, Co, and Ni. It was found that the addition of MgCl2 to HCl increased the activity of the hydrogen ion in the lixiviant, allowing a rapid leaching rate at modest temperatures and pressures with a lower concentration of HCl. The use of MgCl2 and LIX 63 in the lixiviant gave separation of Ni2+ at a lower pH (0.5-2.5). Other advantages included a reduction in reagent cost by regenerating and recycling HCl and minimising waste production by recycling the chloride lixiviant to the leaching stage. It is concluded the process could be a potential alternative to conventional hydrometallurgical and smelting processes by meeting more stringent environmental requirements and reducing capital and operating costs.

Demand of nickel, titanium, aluminum and gold is consistently increasing in the world while the extractable ores of these metals are gradually depleting. Chloride-based processes have several advantages over the conventional hydrometallurgical and smelting processes including higher leachability of complex ores, stability of chloro-complexes and regeneration of leaching reagents. Considering these advantages of the chloride chemistry, innovative mixed-chloride process flowsheets have been developed for the recovery of these metals from low grade laterite, ilmenite, bauxite and refractory complex ores and concentrates. These processes also produce value added byproducts such as cobalt, vanadium and iron oxide. Advantages of addition of magnesium chloride to hydrochloric acid, leaching and separation reaction mechanisms, and developed flowsheets are also discussed. (Authors.), Demand of nickel, titanium, aluminum and gold is consistently increasing in the world while the extractable ores of these metals are gradually depleting. Chloride-based processes have several advantages over the conventional hydrometallurgical and smelting processes including higher leachability of complex ores, stability of chloro-complexes and regeneration of leaching reagents. Considering these advantages of the chloride chemistry, innovative mixed-chloride process flowsheets have been developed for the recovery of these metals from low grade laterite, ilmenite, bauxite and refractory complex ores and concentrates. These processes also produce value added byproducts such as cobalt, vanadium and iron oxide. Advantages of addition of magnesium chloride to hydrochloric acid, leaching and separation reaction mechanisms, and developed flowsheets are also discussed. (Authors.)