Explore the vast range of titles available.

The leaching kinetics of sodium zirconate in hydrochloric acid has been studied. Sodium zirconate was the result of melting zircon sand after separation from sodium silicate. The variables studied were temperature, contact time and the mole ratio of solvent to feed (R). These study aims are to determine the optimum conditions, the reaction rate controller and the reaction rate constant (k) and activation energy (Ea) for the leaching process of sodium zirconate (Na2ZrO3).This experiment performed by leaching the sodium zirconate in hydrochloric acid with various temperatures of 50 °C, 70 °C and 90 °C, the mole ratio of solvent to feed of 5, 7 and 9, and various contact time of 10 minutes to 50 minutes. The experimental data were analyzed according to the kinetic models for heterogeneous reaction processes by using shrinking core models. It was found that the leaching of sodium zirconate in hydrochloric acid solution is controlled by chemical reaction with the activation energy was-62.974 kJ/mol. The optimum conditions for the performed experiment in the leaching step were achieved at a temperature of 50 °C, the mol ratio of solvent to feed of 5 and contact time of 50 minutes with the conversion of sodium zirconate was 43.43% and the value of reaction rate constant was 0.0027 min−1.

Solvent extraction was performed on Nd (III) concentrate by using synegistic solvents D2EHPA, TOPO and TBP. The aim of this research is to know the effect of synergistic solvent on the extraction result. The extraction process of the Nd (III) concentrate was carried out at the feed pH of 1.0. The first extraction was carried out using a mixture of D2EHPA and TOPO extractants while the second extraction used a mixture of D2EHPA and TBP at various concentrations (10: 0, 8: 2, 6: 4, 4: 6, 2: 8 and 0:10) and variation of feed and solvent volume ratio (0.5: 1.0; 0.75: 1.0; 1.0: 1.0; 1.0: 0.5; 1.0: 0.75) at constant stirring speed of 250 rpm and extraction time of 30 minute. The results showed that the concentration and volume of synergistic solvents greatly influenced the distribution coefficient (Kd), extraction efficiency (E) and separation factor (α). From all parameters studied the highest separation factor was obtained using the synergistic % ratio of D2EHPA-TOPO 4: 6 solvent and the volume ratio of feed and solvent 1: 0,5 ie α Nd-Pr = 2.55 and α Nd-Sm = 1.47 but the distribution coefficient and efficiency of the three elements are low so they are not selected. The recommended condition is to use a 4% -6% D2EHPA-TOPO synergistic solvent and a 0.5: 1.0 solvent and solvent ratio. In this condition obtained Kd Nd = 0.46 Kd Pr = 0.27 Kd Sm = 0.72, E Nd = 31.5% E Pr = 21.3% E Sm = 41.8 with the separationfactor α Nd-Pr = 1.7and αNd-Sm = 0.84.

Sintering process is the final stage of fuel kernel manufacturing prior to the coating process. This stage is very important part of the whole process, because it will determine the feasibility of UO2 kernel to comply with the specifications of HTR reactor fuel. The objective of this research was to obtain UO2 kernel with the density of ≥ 95% TD. The results showed that the highest density reached 92.56% TD or about 10.1441 g/cm3. This condition of sintering was gained at the temperature of 1400 °C with sintering time of 2 hours. The sintering product diameter gained was around 919 μm the specific surface area 4.4213 m2/g, and a total pore volume 4,751 x 10−3 cm3/g. The density of UO2 kernel produced from this research is the best compared to previous finding because of its density already approaches the HTR fuel specification requirements.

The extraction of neodymium concentrates of monazite sand processed product has been done. The objective of this investigation was to determine the best solvent to separate Nd from Nd concentrate. As an aqueous phase was Nd(OH)3 concentrated in HNO3 and as solvent or the organic phase was trioctylamine (TOA). tryibuthyl phosphate (TBP). trioctylphosphine oxyde (TOPO) and di-ethyl hexyl phosphoric acid (D2EHPA) in kerosene. The investigated variables were HNO3 concentration. feed concentration. solvent concentration or solvent in kerosene. time and stirring speeds. From the investigation on the selection of solvent for the extraction of Nd(OH)3 concentrate with various solvents. it was concluded that the extraction of Nd could be carried out by using TBP or TOA. Extraction of Nd using TOA at the optimum HNO3 concentration of 2M. feed concentration of 5 gram/10 mL. TOA in kerosene concentration of 6 %. stirring time of 15 minutes. stirring speed of 200 rpm was chosen if the Y concentration in Nd concentrate is small. In these condition DNd obtained was 0.65; extraction efficiency of Nd (ENd)=37.10%. the concentrations of Nd2(C2O4)3 = 67.14%. Ce2(C2O4)3 = 1.79%. La2(C2O4)3 = 1.37% and Y2(C2O4)3 = 24.70%. Extraction of Nd using TBP at the optimum HNO3 concentration of 1M. feed concentration of 5 gram/10 m. the TBP concentration in kerosene of 15%. stirring time of 15 minutes and stirring speed of 200 rpm was chosen if the Ce concentration in Nd concentrate is small. In these condition DNd obtained was 0.20. extraction efficiency of Nd (ENd)=17%. concentration of Nd2(C2O4)3 = 70.84%. Ce2(C2O4)3=15.53%. La2(C2O4)3 = 0.00% and Y2(C2O4)3 = 8.63%.