Atom economy of the process of rare earth separation by using fluoride was discussed in this paper.We compared the atomic economic characters between the processes of vitriolic composite salt and fluoride,then stated ...Atom economy of the process of rare earth separation by using fluoride was discussed in this paper.We compared the atomic economic characters between the processes of vitriolic composite salt and fluoride,then stated that changing present rare earth producing process by green chemistry and technology transformation was the best way to make our rare earth manufacture prosperous.展开更多
It is found through experiments that metallic chromium coating with fine grained and compact crystal structure and high lustre degree can be obtained at near room temperatures by addition of 1.2g.L-1 Ce4+ ion in a cli...It is found through experiments that metallic chromium coating with fine grained and compact crystal structure and high lustre degree can be obtained at near room temperatures by addition of 1.2g.L-1 Ce4+ ion in a clirondum plating bath containing 200g.L-1 CrO3 and 2g.L-1 H2SO4. As compared with the traditional chromium plating technology, the new technology can decrease the CrO3 concentration in the plating bath by one-fifth, and decrease the operating temperature by about 30 degrees. The results of X-ray diffeaction experiments reveal that the electrocrystallization of metallic chromium in the coating is orientated along the (200) crystal plane. Hence, the coating eAnbits high degree of lustre. The results of cathodic polarization curve and differential capactiance curve mesearements show that Ce4+ ion can be adsorbed specifically on the cathode surface. This increases the cathodic polarization value and thus malles the rate of nucleation much faster than that of crystal growth, leading to the formation of fine grained chromium coating. Consequently, the lustre degree of the chromium coating is increased.展开更多
文摘Atom economy of the process of rare earth separation by using fluoride was discussed in this paper.We compared the atomic economic characters between the processes of vitriolic composite salt and fluoride,then stated that changing present rare earth producing process by green chemistry and technology transformation was the best way to make our rare earth manufacture prosperous.
文摘It is found through experiments that metallic chromium coating with fine grained and compact crystal structure and high lustre degree can be obtained at near room temperatures by addition of 1.2g.L-1 Ce4+ ion in a clirondum plating bath containing 200g.L-1 CrO3 and 2g.L-1 H2SO4. As compared with the traditional chromium plating technology, the new technology can decrease the CrO3 concentration in the plating bath by one-fifth, and decrease the operating temperature by about 30 degrees. The results of X-ray diffeaction experiments reveal that the electrocrystallization of metallic chromium in the coating is orientated along the (200) crystal plane. Hence, the coating eAnbits high degree of lustre. The results of cathodic polarization curve and differential capactiance curve mesearements show that Ce4+ ion can be adsorbed specifically on the cathode surface. This increases the cathodic polarization value and thus malles the rate of nucleation much faster than that of crystal growth, leading to the formation of fine grained chromium coating. Consequently, the lustre degree of the chromium coating is increased.
