Abstract: A method for separating boric acid from a liquid, especially liquid waste obtained from a nuclear power plant. In the method, the waste solution containing the boric acid is contacted with steam in a reactor so that the boric acid evaporates from the liquid and passes into the steam vapor phase. Consequently, the radioactive wastes which are not evaporated with the steam remain in the waste water while the boric acid is removed from the waste water when it passes into the vapor or steam phase. The boric acid can then be separated and recovered from the steam by means of a distillation and fractionating column or a wash column. By removing the boric acid from the liquid waste, it is possible to obtain concentrated radioactive waste having a reduced volume due to the absence of boric acid in the waste.

Abstract: A high solids black liquor which has solids content of at least 65% by weight of liquor is mixed with a viscosity reducing additive prior to firing in a chemical recovery furnace. The additive is an admixed compound consisting of monoethylene glycol, diethylene glycol and triethylene glycol.

Abstract: A process and installation for vaporizing liquids and in particular radioactive liquids. A two-step flash vaporization is carried out. The vapor exiting from a first vaporizing stage is condensed by means of liquid taken from a second vaporizing stage, the latter liquid being injected into a condenser into which the vapor steam from the first vaporizing stage is being conducted. The thus formed mixture is conducted into the second vaporizing stage.

Abstract: Process and apparatus for recovering clean water from aqueous wastes by evaporation while avoiding scaling and fouling as well as corrosion of the evaporator tubes. Addition of an oil, preferably a volatile oil, to the aqueous waste feed results in the formation of a coating of said oil on the surfaces of the tubes, thereby preventing corrosion and fouling and build-up of scale deposits. Volatile oil that distills over is separated from the aqueous distillate by conventional means and may be recirculated.

Abstract: An improved arrangement is described for self-controlling the evaporation rate in the first stage of a two-stage expansion type evaporation installation for radio-active liquid purification, as described e.g. in the U.S. patent application Ser. No. 328065 filed on Jan. 30, 1973, in case of failure of the main circulating pump of the second stage. Such failure causes a pressure drop at the mixing condenser between first and second stage and normally, thus, a pressure drop in the first stage too. Such pressure drop leads to unwanted evaporation in the first stage and transfer to the second stage of excessive and insufficiently purified fluid from the first stage. A flow throttle element such as a diaphragm or a necked-down section of steam conduit is interposed between the vapor exit of the first stage and the mixing condenser in which the vapor is condensed by contact with a portion of the liquid from the second stage circulated therethrough by the pump.

Abstract: Process and apparatus for recovering clean water from aqueous wastes by evaporation while avoiding scaling and fouling as well as corrosion of the evaporator tubes. Addition of an oil, preferably a volatile oil, to the aqueous waste feed results in the formation of a coating of said oil on the surfaces of the tubes, thereby preventing corrosion and fouling and build-up of scale deposits. Volatile oil that distills over is separated from the aqueous distillate by conventional means and may be recirculated.