Process for the removal of particulate matter from an aqueous stream

A process for the removal of particulate matter from an aqueous stream containing a concentrated acid, wherein the average particle size of said particulate matter is in the range 0.05-10 μm, and the concentration of the sulfuric acid in said aqueous stream is above 60% wt., said process comprising mechanical filtration by passing said aqueous stream through a filter unit, and said filter unit comprising a metallic, ceramic or polymeric filter, or a filter comprising a filter aid on a septum, wherein the aqueous stream is the exit stream of a sulfuric acid condenser, optionally the exit stream of a sulfuric acid concentrator arranged downstream the sulfuric acid condenser, of a process plant for producing sulfuric acid from a process gas stream, said process gas stream containing sulfur and said particulate matter, said process plant including:

• converting the sulfur in the form of SO2 of said process gas stream into a SO3-rich gas stream in a SO2-conversion unit, said SO2-conversion unit comprising a catalyst bed and passing said process gas through said catalyst bed;
• converting the SO3-rich gas stream into said exit stream of said sulfuric acid condenser, optionally said exit stream of said sulfuric acid concentrator;
• and optionally providing an acid cooling step for reducing the temperature of said exit stream.