White silica is considered a 'soft' abrasive by abrasive standards. There are many out there all with intended purposes. Some are much softer, like walnut shell and aluminum oxide where there are others made from metal slag. Hard and agressive.
The pressure, psi, at which you blast also has an affect on how well, or poor, an abrasive works.
If you're just removing paint the white silica will probably suffice. Anything around 100psi should work for you but do a little research and see the health and safety considerations when using any sand blasting media and equipment. Typically you'll want to use a respirator and do the blasting outdoors in good ventilation.
Tom