The theoretical energy requirement (TER) for the fusion of batch samples of flat and container glasses was determined by using the drop-mixing method. The TER values obtained from this study have been compared to values derived from other models; a deviation of up to 8% was observed. This comparison suggested no significant difference between the experimental results and those derived from the different models. A new procedure for the TER determination was developed. The TER value obtained from this procedure showed deviations of <2%.

In this study a novel process for extraction of titanium valuables from its minerals is presented. The process entails roasting of titanium ore with alkaline metal salt, hydrolysing fused cake and dissolution in acid. Optimum conditions were found to be 1 hr fusion at 850 °C, using 2:1 mole ratio, NaOH:FeTiO 4 , irrespective of the particle size interval used in this work. It was found that under these conditions » 80% of titanium was recovered. Na 0.75 Fe 0.75 Ti 0.25 O 2 , NaFeTiO 4 and Na 2 Fe 2 Ti 3 O 10 were the dominant phases at this temperature. The presence of these phases is viewed as beneficial to the economics of the process, it consumes less NaOH. Fusions conducted at 550 °C or below produced chiefly binary phases, Na 2 TiO 3 and NaFeO 4 , reducing process economy. Optimum leaching conditions were S/L= 0.26, leaching at 75 ºC, for 15 min. 85% of NaOH were recovered, under these conditions. Leaching obeys shrinking core mechanism model. IntroductionTitania (TiO 2 ) is a white pigment used in paints, paper, plastics, cosmetics and coatings. Its wide application is due to its higher opacity and covering power. There are two commercial methods of TiO 2 production, the chloride and the sulphate process. In the chloride process titanium mineral is converted into TiCl 4 which is subsequently oxidized at high temperatures.In the sulphate process the ore is converted into sulphate solution and then thermally hydrolysed to hydrous titanium. The later is calcined to produce the pigment (Braun et al, 1992;Nielsen and Chang, 1996;Xue et al, 2009).According to Pong et al (1995) a commercially viable process has to be environmentally benign, to generate a minimum waste, be able to use all grades of ores and be economically favourable. The above processes are, either environmentally unfriendly, costly, generate high levels of waste or recycle, are unable to process low grade ores, as well as, ores such as anatase, sphene, and perovskite (Bulatovic, 1999;Cole, 2001;Nielsen and Chang, 1996;Van Dyk et al, 2004;Yuan et al, 2005).Generally low grade titanoferrous ores are submitted to slagging process. The slagging process however faces uncertain future due to its higher energy consumption and green house gases emission. Additionally slagging is unable to treat radioactive ores, since the radionuclides remain in the solid solution during slagging process. With increasingly restringent environmental policies on radionuclides content, further treatment has to be conducted to reduce it. This will result in additional production costs (Nielsen and Chang, 1996; Habashi, 1997;Doan, 2003; Jha et al, 2005;Lahiri et al, 2006;Lahiri and Jha, 2007

Poly(ε-caprolactone) MgAl -layered double hydroxides (MgAl-LDH) nanocomposites were prepared by melt intercalation. Two organically modified MgAl-LDH, stearic acid (stearate) and sodium dodecyl sulphate (SDS), were used. Nanocomposites morphology was studied by XRD and TEM. Thermal properties were analysed by TG and DSC. Although both systems showed presence of a mixed morphology, exfoliated and intercalated, MgAl-LDH stearate nanocomposites showed a better dispersion of inorganic platelets. TEM images showed the presence of individual platelets in the PCL matrix. MgAl-LDH SDS nanocomposites 1.

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Limestone has been used as a partial substitute for cement, due to its beneficial effect on mechanical properties of mortars and concretes. In the present research, we studied the effect of the mineralogical composition in mortars produced from limestone samples collected in different areas of Mozambique, using two cement types (Portland cement 32.5N and 42.5N). Additions of 10 to 25% limestone gave, in general and for the 32.5N cement, good results of the compressive strength for all limestone samples, while for the 42.5N only the Massinga samples performed well. Effect of the limestone additions on the flexural strength showed a beneficial effect for all samples and at all compositions studied, when using the 42.5N cement, while for the 32.5N cement only additions of 10% limestone gave values of the flexural strength higher than the reference material, with the exception of the Magude samples.