Abstract: The invention concerns the recovery of heavy metals from concentrated solutions.The process comprises complexing the metals with an organophosphorous complexing agent and recovering the metallic complex by sedimentation, filtration, flotation and the like.The process can be used to recover uranium and rare earths from phosphoric acid solutions.

Abstract: The present invention relates to an enrichment process, by flotation, of sedimentary ores containing phosphate, and comprising a gangue of the carbonated type and in some cases a gangue of the siliceous type, wherein an amphoteric product of formula ##STR1## is at least used as collecting agent, in which formula: R is of form R.sub.1 or R.sub.1 O--, R.sub.1 being a saturated or unsaturated alkyl radical, either linear or branched, and comprising between 5 and 19 carbon atoms.R' and R" are H or --Aq--Z, bearing in mind that for R", when n is greater than 1, there can be in the molecule simultaneously radicals H and radicals --Aq--Z.Ap and Aq are polymethylene chains containing between 1 and 4 carbon atoms,n is a number equal to O or an integer between 1 and 5,Z is a radical selected from the carboxylic, the sulphonic and the phosphonic radicals, and in obtaining the flotation of the carbonated gangue by a reverse flotation in "basic medium .

Abstract: The method for the inhibition of corrosion of ferrous metals in an aqueous medium consists in adding to the aqueous medium 10 to 2000 ppm of a mixture constituted by a water-soluble complex salt of a metal of groups II to VIII of the periodic table and of a hydroxycarboxylic acid and by a phosphoric ester of alkanolamine.

Abstract: The invention relates to bituminous binder compositions containing in the proportion of 0.5 to 2% by weight of the bitumen used, a mixture of polynitrogenous compounds such as those obtained by reacting polyalkylene polyamines having the general structure: R -- NH (CH.sub.2 -- CH.sub.2 -- CH.sub.2 -- NH).sub.n -- H with formic acid while removing the reaction water. The main component consists of a tetrahydropyrimidine substituted on nitrogen by means of a long linear chain comprising one or a plurality of amine groups having the general structure: ##STR1## wherein R is a saturated or unsaturated linear hydrocarbon comprising 8 to 22 carbon atoms, n is an integer from 2 to 5 and p another integer equal to (n - 1), that is from 1 to 4.