[en] The influence of dilution on the fluorescence of Ce, La and Nd by x-raywith Am-241 as excitation source was done. X-ray fluorescence has countedboth single standard and mixed standard of Ce, La and Nd. Energy of Ce in3472/3428 keV, La 3303/3304 keV, Nd 3684/3736 keV. Given concentration of Ce,La and Nd oxides were dissolved in 200 mesh alumina, added by 1 gram starch,dilution alumina until 6 grams total volume. Then homogeneous powder haveshake in 6 minutes, then excitation by XRF in 5 minutes until three times.Product of Ce curve mixed had been eliminated with fluorescence correction,by proportional factor (Fp) 0.48 - 0.82, and correction factor ± 3.58 %.Fp for La 0.42 - 0.64, with correction factor ± 2.36 %, and Fp for Nd 0.48- 0.82 with correction factor 2.69 %. (author)

[en] The chelation of metals ion (Cu²⁺, Cd²⁺ and Cr³⁺) with processyields of humic acid from peat soil has been done. The chelatizationcalculation was carried out using a mathematical model of the metals ionneutralization to the humic acid functional group. The model has superioritydue to the introduction of the humic acid concentration conditional and theloading capacity. Chelation is expected to obtain the constant experimentthat agrees with environmental conditional were the chelatization to takeplaces. By the tree neck flask of bath reactor, 250 ml volume at thetemperature of 25 ^oC chelation have been done and the AAS was used toanalyzes the yield. By mathematical calculate was obviously proved that thechelation constants was not influenced by pH, ionic strength and origin peatsoils. As log β, chelation constants of Cu²⁺, Cd²⁺ and Cr³⁺ were4.67 (± 0.02); 5.98 (± 0.02) and 6.09 (± 0.01) for humic acid fromSumatra I (Silaut III) and 4.68 (± 0.01); 5.97 (± 0.02) and 6.09 (±0.02) for Sumatra II (Silaut IV). While chelation constant Cu²⁺, Cd²⁺ andCr³⁺ from Kalimantan were 4.66 (± 0.03); 5.99 (± 0.01); 6.08 (±0.02). (author)

[en] The interface of computer based process control for uranium separationhas been designed and constructed. The system function is for controlling thetemperature, stirring velocity and pump flow of extraction process. Theinterface card consist of temperature transducer, voltage amplifier, 12 bitADC system, address decode, peripheral Parallel Interface D8255C-2, currentamplifier and motor stepper. The testing on water temperature measurementwith flow rate of 10 ml/sec at the process temperature of 72 ^oC and 80 ^oCare 72.89 ^oC and 81.25 ^oC respectively. The testing made to the ADC andamplifier systems shows good performance of the expected values, withlinearity is 0.999. At the stirring velocity of 400 rpm the efficiency ofcontinuous extraction system is 66.89 %. By the control system theperformance of uranium extraction process by continuous liquid emulsionmembrane can be enhanced. (author)

[en] The separation of humic substances by polysulfone has been done. Thisinvestigation aims at separating the humic substances contained in theestuary environment. Because of without sample pre-treatment, cheap and easythis method has been to choice. At preliminary study proved that byincreasing the pressure until 50 psia, the yield of flux was 13.5 l/m².jamand the reject coefficient was 90.98%, so that polysulfone membrane isappropriate to be applied. More over the pressure could be increased morethan 50 psia. The feed concentration should be lower than 150 ppm, though thevolume should be greater. The pH condition should be alkaline (pH> 7), sinceat this condition the filtration process is easily conducted and the rejectcoefficient could reach 95.09%. (author)