Recovery of Silicon Carbide Waste liquor

Silicon carbide waster liquor, is polyethylene glycol waste liquor from photovoltaic semiconductor industry. The main components are polyethylene glycol, polycrystalline silicon, silicon carbide, metal ions of copper, iron and zinc, and also macromolecule pigment, which changes after repeated use, can not be reused any more.
Polycrystalline silicon, silicon carbide, polyethylene glycol are by-product of high economic value, it is not only a pollution to the environment but also a heavy economic losses if they are disposed as waste. So it is meanful to recover and reuse plycrystalline silicon, silicon carbide, polyethylene glycol.

Technical principle
Membrane separating technology is composed of microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmois (RO). And the ultrafiltration has been popularized and applied in various industrial areas.
After centrifugal separation, the particles contained in silicon carbide waste liquior are tiny, 20-200 nanometers in diameter generally. So we select the ultrafilter as the main device.
Ultrafitration membrane is made from inorganic material or macromolecule organic materials, the membrane supporting layer, transition layer and membrane layer are distributed dissymmetrically. Ultrafiltration is a separation process of cross flow filtration: the feed material is flowing at a high speed inside the membrane layer, the clean penetrants flow outwards thourgh the membrane in tangential direction or dissymmetric with membrane, and the concentrate containing macromolecules are hold back by the membrane.
Compared with traditional separation process, the ultrafiltration has advantages as follows:
1. pollution-free, residual-free, kind of green and eviromental protection technology.
2. high separation accuracy and clear and transparent penetrants, reducing technical load of following refining process greatly and improving effective contents of products.
3. filtration takes the pressure as the driving force of the membrane separation, simple separation device, easy to operate and to control.
4. simplify the process, shorten process flow and production cycle.
5. no phase change happened, no need of addtions, energy saving and lower running cost.

Process Unit

In consideration of the features of silicon carbide waste liquor, demands of photovoltaic semiconductor plant and product quality index, we select membrane ultrafilter as the key equipment, and complete with film evaporator, has advantages of high quality, low energy consumption, high efficiency and low cost.