Food grade carbon dioxide is produced from oxyfuel fired glassmaking furnace waste gas by a series of steps including quenching the waste gas with aqueous quench liquid, dry-filtering sulfur salt from the gas, scrubbing the filtered gas with aqueous carbonate to convert the remaining sulfur dioxide to an aqueous sulfite suspension and using the suspension as part or all of the above-mentioned aqueous quench liquid, contacting the sulfur dioxide-free waste gas with ammonia in the presence of a catalyst that selectively converts nitrogen oxides to nitrogen, thereby removing substantially all nitrogen oxides from the waste gas, and distilling the resulting waste gas stream thereby producing high purity liquid carbon dioxide and producing an off-gas, which is recycled to the furnace as fuel.