Concn. of dil. sulphuric acid - using silicon-contg. cast iron film evaporator, to obtain conc. acid for reuse in chemical processes

摘要

The dil. acid(a) contains 60-80% H2SO4; and is fed down a film evaporator, made of cast iron contg. 14-17% silicon, and heated by radiation from burners. The pref. reactor consists of a film evaporator located in a furnace heated by radiation from burners. Dil. H2SO4 is obtd. as a by-prod. in many processes, and must be concd. before it can be reused. The invention provides an efficient method of obtaining acid contg. 90% H2SO4 while avoiding the disadvantages involved with the known method using an indirectly heated cascade.