Electrostatic Separation of Fine Particles in Vibrated Fluidized Beds
Very fine particles which cannot be fluidized by means of a flowing gas alone because of entrainment may be effectively individualized and retained in the bed through a combination of gas at low rate flow and mechanical vibrations of selected frequency and amplitude. A mixture of very fine particles may be fluidized and successfully separated and/or concentrated by means of electrostatic fields. Results are presented of a factorial experiment in which the conditions of temperature, humidity, and voltage were investigated for the separation of a (50-50 by weight) synthetic mixture of iron and glass powder of particle size ranging from 15-45¿m. A new and highly efficient particle collection mechanism is introduced, and mathematical models of the process are presented as part of the optimization work.
Electrostatic separation for recycling waste printed circuit board: a study on external factor and a robust design for optimization.
Electrostatic separation is an effective and environmentally friendly method for recycling waste printed circuit board (PCB) by several kinds of electrostatic separators. However, some notable problems have been detected in its applications and cannot be efficiently resolved by optimizing the separation process. Instead of the separator itself, these problems are mainly caused by some external factors such as the nonconductive powder (NP) and the superficial moisture of feeding granule mixture. These problems finally lead to an inefficient separation. In the present research, the impacts of these external factors were investigated and a robust design was built to optimize the process and to weaken the adverse impact. A most robust parameter setting (25 kv, 80 rpm) was concluded from the experimental design. In addition, some theoretical methods, including cyclone separation, were presented to eliminate these problems substantially. This will contribute to efficient electrostatic separation of waste PCB and make remarkable progress for industrial applications.
First diamino Daphniphyllum alkaloid, daphnipaxinin, with an unprecedented heterohexacyclic skeleton from Daphniphyllum paxianum.
[structure: see text] The first diamino Daphniphyllum alkaloid, daphnipaxinin (1), with an unprecedented hexacyclic fused skeleton, along with a known alkaloid, daphnicyclidin A (2), was isolated from the stem of Daphniphyllum paxianum Rosenth. The structure and absolute stereochemistry of 1 were established by spectral methods, especially two-dimensional NMR techniques and CD analysis.