The various forms of silica sand can have differing melting temps
for the component items making it up. Some will melt and stick to
the things in the kiln. Including the heating elements. Possibly
causing problems in the future heating cycles of the kiln, causing a
burn out at that site of clumping or sticking and melting.
The reactivity may not be of a chemical nature that you might be
thinking of. But a physical one.
After 33 years in the public education field and being called to the
art rooms to remove/repair or save the brick work, heating elements
in their kilns. I have seen a lot of stuff that was added to the mix
in the name of art. Whether it was trying for a texture on the
outside or using it inside to prevent the afore mentioned slumping.
Some people are art teachers and some are just teachers in the art
dept. You can run a search for silicosis on the archive during the
last year it has come up a number of times in regards tosand or
media blasting. Or on the net, silicosis, sand box cough,miners cough
They really don’t have a perfect answer as to the amount or duration
of exposure to the silica dust that causes harm. Almost every study
wants to be boss. So keeping all exposure to a minimum would be
best. Most of the play sand isn’t pure silica sand any longer.
Blasting sand is pure silica and when used outside people in the
work area are using positive displacement masks.
On the subject of masks of the disposalable type. If you are using
them for a hazardous material. When you get done, throw the mask
out. Taking the mask off and hanging it up or placing it on the
bench will only transfer the material inside the mask closest to
your face for the next time.
Hope this covers some of the possible answers to your question