[echoangle]

I think the third point (vibrating a container to mix different dry particles) is actually the worst way to do it. If the particles have different sizes (or densities technically, I think), they will separate when vibrated, not mix together. If you ever tried to mix Cereals by shaking, you know what I mean. The proper technique is turning over the container continuously to mix the different layers, like in a cement mixer.

[WJW]

I was thinking more about "tossing a salad" type vibrations that get high enough to completely get all the particles airborne, possibly with some sort of mechanical structure above the mixture interfering with the mixing. If you just vibrate everything in-place then all the smaller particles will obviously just fall to the bottom.

I got curious and found https://making.com/equipment/high-frequency-vibratory-mixer, but that is for liquids and not for solids.