Assertion: hydrogen fluoride's fluorine | /r/MadeOf | hydrogen fluoride
Facets:
value: essentially
type: DEGREE
Source sentences:
text: A process of removing hydrogen fluoride from aluminum reduction cell gas which contains combined fluorine that consists essentially of hydrogen fluoride, and which also contains sulfur dioxide in significant amount, comprising scrubbing the aforesaid gas with aqueous liquid which is subjected to recirculation for succeeding scrubbing operations, said liquid being a dilute acidic solution having a pH in the range of 1.0 to about 5.5 in which the acidic component consists essentially of dissolved hydrogen fluoride and in which an alkaline neutralizing agent has been introduced, introducing successive quantities of alkaline neutralizing agent into said liquid in the course of recirculation to maintain said liquid at a pH within the aforesaid range during the scrubbing operations, said introductions of neutralizing agent into the liquid and said operations of scrubbing the aforesaid cell gas with the liquid being performed to convert hydrogen fluoride from said gas into the form of fluoride salt in said liquid, said fluoride salt being a reaction product of said neutralizing agent and hydrogen fluoride, and treating successive quantities of the liquid to recover fluoride therefrom, for removal of fluoride salt from the course of recirculation, said process including sutficiently limiting the introductions of neutralizing agent and maintaining sufficient concentration of dissolved hydrogen fluoride by absorption from the gas, to keep the pH of the liquid substantially no higher than the aforesaid range, for inhibiting absorption of sulfur dioxide in the liquid.