Abstract: Encrusted filter surfaces that have been used for filtering wet process phosphoric acid slurries are effectively cleaned, e.g., of crystalline deposits, by washing same with a solution of fluosilic acid.

Abstract: Gas/liquid heat exchanger with condensation.It is presented in the form of blocks juxtaposed (1) within an enclosure (2) and in which two series of channels (3,4) are pierced, these blocks (1) being disposed within an enclosure (2), the space between the enclosure (2) and the central column which the blocks form being separated into two chambers (6,7), connected respectively to the gaseous phase supply circuit (10) and the other to the circuit (14) for the evacuation of the condensates formed.

Abstract: An apparatus for distributing a substance over a surface includes a feed compartment which is provided with substance feed means and which is defined by a bottom, a rear wall, two side walls and a front wall forming an overflow. A distribution compartment has a rear wall defined by the overflow, two side walls, a front wall, a bottom and an opening for the substance to flow out. The feed compartment is provided with baffle members to ensure distribution of the substance therein.

Abstract: Phosphoric acid is produced, with concomitant recovery of solids comprising compounds of fluorine and silica, by (i) acidulating a first amount of phosphate ore with a strong acid to produce a first phosphoric acid slurry, (ii) filtering said first slurry to separate the liquid phosphoric acid content therefrom, (iii) concentrating a fraction of the phosphoric acid thus separated, (iv) recovering same, and (v) condensing the evolved vapors of concentration with a liquid absorbent to produce a solution of fluosilicic acid, (vi) acidulating a second amount of phosphate ore with said solution of fluosilicic acid together with a fraction of said first slurry, or together with a fraction of the phosphoric acid separated in the step (ii), to produce a second phosphoric acid slurry, (vii) filtering said second slurry to separate both the liquid phosphoric acid content and a solids fraction therefrom, said solids fraction comprising fluorine and silica compounds, (viiia) recycling the phosphoric acid thus separated f

Abstract: A slurry is discharged from an attack tank and degassed. At the top of the tank there is an overflow for discharging a first slurry portion. A container communicates with a pump. A receptacle is disposed between the overflow discharge and the container and comprises a downwardly inclined connecting surface for conducting the first slurry portion to the container. A conduit leads from the bottom of the tank and opens into the receptacle to combine a second slurry portion with the first slurry portion.

Abstract: Crude wet process phosphoric acid is pretreated, to ensure against impurity precipitation and objectionable coloration during the downstream processing, e.g., liquid-liquid extraction thereof, by first homogeneously admixing same with an impurity adsorbent, next mixing the liquid dispersion which results with a liquid suspension of a flocculating agent, maintaining the resulting admixture under nonshearing agitation until same separates into a flocculated phase and a liquid solution phase, and then separating therefrom the flocculated phase and a purified, product acid liquid solution phase.