Separate dust particles by colour by light

Question

I have a stream of dust with coloured particles. I want to sort those particles by color. We are wondering if it is possible to let it flow by an intens light in a specific color and then extract the loaded particles by electrostaticity. I cannot really find if it is a feasable solution or that the only way to find out is through building a test machine (which I want to prevent)

What we did find is that the materials themselves can be separated because (e.g.) plastic has a different charge than rubber. That way we can seperate them with electrostaticity. Would it be possible to expand that method to sorting by color?

Answer 1

Well, there is a simple answer to it actually. If you are willing to just "see" the particles differently you can definitely. And then, you might oft for Handpicking. (Only if I could consider Handpicking for dust, which is absolutely a big 'NO').

But at present, we don't have a mechanism, which can separate particles just by colour, simply because there is nothing much unique in the colour, except that it reflects a particular wavelength of light. Observations can be made, however, a method of separation is still unknown.

Note:- I considered it colour in the normal sense of the word and not colour charge.

Answer 2

Recycling center sort glass this way. Glass is crushed into small chips. A stream of chips is dropped. they fall past a light and sensor. A computer measures the color of each chip. Little air jets are used to blow the chip into a bin for that color.

Answer 3

I think that electrostatic interactions would not work since the only way you can charge dust is with light at very high frequencies (photoelectric effect) by ionizating the matter. But the ionization frequency is often above ultraviolet colors. Also ionization frequencies are not necessary different for different color particles.

The best you can achieve with an intense light in a specific color is "push" certain color dust particles with the light pressure, but I'm pretty sure that the Brownian motion will dominate the motion of this particles so the mechanism would not be effective.

Investigate about Optic Tweezers, maybe this machines can help you.