Extraction of Al and Na from red mud by magnesium oxide sodium carbonate sinter process

The sintering of Bayer’s process waste residue: Red mud along with magnesium oxide and sodium carbonate is adopted for recovery of aluminum and sodium followed by leaching. This is facilitated by the high temperature reaction of magnesium oxide sodium carbonate and DSP in the red mud to produce an insoluble dimagnesium silicate, magnesium ferrite, magnesium titanate and a soluble sodium aluminate. A variation of the red mud magnesium oxide sodium carbonate sinter process using half the magnesium oxide of existing methods has been investigated. The magnesium to silicon ratio was reduced from 2 to 1 producing a sodium magnesium silicate (Na2Mg2SiO4) rather than the dimagnesium silicate (Mg2SiO4) insoluble phase produced in the existing above sinter method. Synthetic red mud magnesium oxide sodium carbonate sinter products were investigated to understand the phases produced during sintering at varying temperatures and the chemistry of extraction. The target phases and morphological behaviors were seen in XRD and SEM and the highest extractions were produced from a sinter temperature of 900°C for 4 h. A two-stage (105°C / 60 min, 105°C / 240 min) water or caustic leaching process was found to be most effective for extraction. Sodium and aluminum extractions were 99 and 98.7% respectively. The experimental method devised was then used to treat red mud and the target phases were produced. An extraction of sodium and aluminum respectively was achieved. Silicon extractions were below 2%.Key word: Red mud, sinter, leaching, extraction

Analysis of Antibody and Cytokine Markers for Leprosy Nerve Damage and Reactions in the INFIR Cohort in India

Leprosy is one of the oldest known diseases. In spite of the established fact that it is least infectious and a completely curable disease, the social stigma associated with it still lingers in many countries and remains a major obstacle to self reporting and early treatment. The nerve damage that occurs in leprosy is the most serious aspect of this disease as nerve damage leads to progressive impairment and disability. It is important to identify markers of nerve damage so that preventive measures can be taken. This prospective cohort study was designed to look at the potential association of some serological markers with reactions and nerve function impairment. Three hundred and three newly diagnosed patients from north India were recruited for this study. The study attempts to reflect a model of nerve damage initiated by mycobacterial antigens and maintained by ongoing inflammation through cytokines such as Tumour Necrosis Factor alpha and perhaps extended by antibodies against nerve components

Bauxite residue sinter leach process – phases formation, reaction pathways and kinetics

Reactive silica in bauxite is a key challenge for the alumina industry due to the associated losses of sodium hydroxide and alumina associated with processing this impurity. The bauxite residue sinter leach process (BRSLP) is a potential method of recovering sodium hydroxide and alumina from bauxite residue. In this research, bauxite residue lime sinters were characterised using a combination of quantitative X-ray diffraction in conjunction with scanning electron microscopy as well as for leaching performance. It is shown that sintering reactions proceed at a significantly faster rate than previously reported which has a positive implication for industrial application. A new set of reactions and reaction pathways are proposed which describe bauxite residue lime sintering in greater detail than previously possible