Calcium silicate is an absorptive food additive used as an anti-caking agent in powdered foods such as powdered sweeteners and meal replacement mixes and salt. It is also used as a sealant on egg shells, to extend shelf life.
An acceptable daily intake level has not been established, however there have been no health effects attributed to calcium silicate consumption reported. Calcium silicate is also used as an antacid.
Silicon has not yet been established as an essential human nutrient, though it is not toxic at the levels expected through typical diets. Silicon in calcium silicate contributes a very small amount to daily silicon intake.
Powdered sugar, powdered sweeteners, eggs, dried whey products, table salt, baking powder
U.S. Food and Drug Administration
Calcium orthosilicate, E552