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Abstrak :
CaCO, scale formation on pipe walls and heat exchange equipments in industrial or domestic water processes is a serious problem. A great number of experimental researches on the prevention ofthe CaCO3 precipitation process by magnetic field have been carried out. The efforts to understand the effect of the magnetic field on the CaCO, precipitation are still being developed In this research, Na2CO, solution was magnetized by 5200 gauss permanent magnet before mired with CaCl2 in quescient condition (static fluid system). Magnetization time was variated to examine its influences to magnetization process. CaCO; content at solution and on deposit was measured by titration method of EDTA complexometry. Conductivity test was conducted to find out hydrate ion bonding. SEM (Scanning Electron Microscope) and XRD (X-Ray diffraction) rest were conducted to see the morphology of CaC O3 crystal deposit. The results showed that magnitization decreases CaCO; precipitation rate at initial precipitation (nucleation period and optimum process reaches for 30 minutes magnetization. The magnetic field depreses precipitation rate but has no eject on the equilibrium of the reaction. Magnetic field increases the conductivities of Na;C.`O_, and CaCl; solution hence reducing its ion hydrate diameter and reinforcing ion hydrate banding. SEM and XRD test results shows that CaCO, crystal formed was predominated by calcite type and magnetization depressed the number of CaCO, crystals and enlarge the crystal size. These results show that magnetization is efective in controlling the CaCO, deposit by supressing CaCO3 precipitation on deposit and in solution.

Abstrak :
Anti scale magnetic treatment is a hard water treatment method using magnetic field to prevent (CaCO3) scale formation. This method has along and controversial history due to its unclear result of its mechanism and effectiveness. The results of researches, hypothesis, or explanations given by researchers were still partial and didn't satistfy yet in answering the magnetic phenomenon. There were three mechanisms which were suggested: ion mechanism. particle mechanism and Lorentz force eject. Hard water contain Ca2+ cations , CO3 anions, and CaCO3, particles. Magnetic field eject on CO3 (ion mechanism) modified hydration of ions which suppressed CaC03 precipitation, whereas magnetization CaCO; particle (particle mechanism) supported particles to attract to each other and increased nucleation rate. Both ion and particle mechanism are clearly showed by using static magnetization system, system where water were static to magnetic field Lorentz force caused ion shift in solution and known as by the magnetohydroidinamic phenomenon that forced nucleation of CaCO3. Lorentz force acts on every ions in hard water when it 's moving through applied magnetic field therefore dynamic magnetization system was needed to investigate this phenomenon. Particle mechanism and Lorentz force effect could increase CaCO, particle formation so that reduced concentration of Ca" ions in bulk solution, in the other hand ion mechanisms with its memory effect on CO3 could suppress CaCO, formation. Magnetization followed by deposition and filtration could increase effectiveness of AMT process.

Abstrak :
Penelitian ini membahas perilaku presipitasi CaCO3 dalam air sadah dibawah pengaruh medan elektromagnetik beserta aplikasinya dalam pengolahan air sadah dan pencegahan kerak. Hasil penelitian membuktikan bahwa medan elektromagnetik mempengaruhi interaksi hidrat ion dan interaksi ion serta presipitasi CaCO3 pada pola aliran fluida dinamik. Elektromagnetisasi larutan NaHCO3 dan CaCl2 dapat meningkatkan presipitasi CaCO3 dengan sifat deposit yang lebih mudah lepas dari dinding. Peningkatan presipitasi secara signifikan terjadi pada konsentrasi, lama sirkulasi dan laju alir tertentu. Hasil tersebut dapat menjadi alasan bagi pengembangan sistem pengolahan air sadah dengan proses elektromagnetisasi yang efektif dalam menurunkan kesadahan dan pencegahan kerak pada air sadah. ......The purpose of this study is to investigate CaCO3 precipitation in hard water with electromagnetic-field effects and its application in hardwater treatment and scale prevention. The observation results showed that electromagnetic-field influence hydrat interaction, ionic interaction and CaCO3 precipitation in dynamic fluid. Electromagnetic treatment on NaHCO3 and CaCl2 solutions can increase CaCO3 precipitation being kind of deposits that easily removed from the wall. The precipitation's improvement found in certain concentration, circulating time and flow rate. This result can be the reason to develop hard water treatment with electromagnetic field that can be effective to decrease water hardness and prevent scale.