How is Silicon Carbide disposed of or recycled?
It is not toxic. It doesn't disolve, not even in acids. It doesn't burn. It does not need any special disposal - it can be treated just like sand. The only real issue is that it is a very hard abrasive substance - you might know it by its common name "Carborundum". SiC dust may irritate skin due to its abrasivness and eye protection and maybe a dust mask is advisable when handling it in powder/granular form in case fine dust becomes airborne. Thats all there is to it as far as disposal is concerned.
Can sand paper be recycled?
In answer to your multipart question: Not really, Not easily, Not effectively and yes it will ruin the blender in short order. Sand paper is a card backing which is a thin coat of glue and then sprinkled with standard sized grit which was sorted through a sieve. If you re-pulped it the grit would be embedded in the sheet and not at the uniform height to be an effective sander. Plus in time you would commingle grit sizes which if used to sand a finish would produce scratches. It would be more effective to collect emory or corrundum sands and sort it through a $800-$1200 standard laboratory sieve stack and make it a new. That is only if you can't find sand paper at a hardware store.
On television, guns in crimes can be identified by the marks left on bullets from leaving the barrel. Why do criminals not have some sort of scraper that they can put in their gun that changes the marks on the next bullet fired?
“On television, guns in crimes can be identified by the marks left on bullets from leaving the barrel. Why do criminals not have some sort of scraper that they can put in their gun that changes the marks on the next bullet fired?”You could, very easily, run some silicon carbide sandpaper down the barrel and create a few new scratches. Unlikely that would remove the old ones. You wouldn’t much be able to change the marks inside the rifling (grooves), but you could change the marks left on the lands. Glocks and several other pistols don’t use cut rifling, but use polygonal barrels to change the bullet into a vague pentagon or hexagon. A little extra-fine sandpaper there would go a long ways. It’s really hard for a CSI to match bullets out of polygonal barrels anyway. Unless the entire barrel is affected by the sandpaper, there will likely be some area that still matches.As others have mentioned, easier to swap out a barrel than try to alter the machine marks made when the gun was built.Over time those marks change through use. So a bullet from a well used gun fired 20 years ago may not match up anymore even though the barrel was never altered. Every bit of dust and grit that may get stuck on a bullet will add its mark.The reality is that criminals won’t hold onto the gun after a crime. They’ll sell it to someone else, or toss it. That next guy, if he’s caught with the crime gun, is the one in the interrogation room!
Is there such thing as a spray-on treatment for making glass into translucent frosted privacy glass? Is there any such option besides adhesive plastic sheets, for dressing already existing windows in homes?
Yep, there is a product designed specifically for that.Frosted Glass - | KrylonIt is also much safer than etching the glass with hydrofluoric acid. It can also be removed with lacquer thinner, unlike etching or sanding the glass.