Improved methods for the removal of heavy metals, in particular cadmium, from an aqueous phosphoric acid containing composition, wherein an organothiophosphorous heavy metal precipitating agent and an ionic polymeric surfactant, particularly a cationic polyacrylamide copolymer surfactant, are both added to a phosphoric acid containing composition, particularly under vigorous mixing conditions, such as between 500 and 700 rpm. The ionic polymeric surfactant promotes the precipitation of the heavy metals. More in particular, the phosphoric acid containing composition is obtained by the acid digestion of phosphate rock, preferably by nitric acid, sulfuric acid, or a combination thereof.

Improved methods for the removal of heavy metals, in particular cadmium, from an aqueous phosphoric acid containing composition, wherein an organothiophosphorous heavy metal precipitating agent and an ionic polymeric surfactant, particularly a cationic polyacrylamide copolymer surfactant, are both added to a phosphoric acid containing composition, particularly under vigorous mixing conditions, such as between 500 and 700 rpm. The ionic polymeric surfactant promotes the precipitation of the heavy metals. More in particular, the phosphoric acid containing composition is obtained by the acid digestion of phosphate rock, preferably by nitric acid, sulfuric acid, or a combination thereof.

The present invention concerns a method for recovering phosphorus by thermochemical reaction of a phosphorus-containing material such as an alternative fuel, for example, in the presence of calcium-containing particles in a moving bed reactor and subsequent separation of fines enriched with phosphorus from the moving bed reactor. Furthermore, the present invention concerns the use of a recyclable material obtained by the method as a fertilizer or fertilizer additive.

The present invention concerns a method for recovering phosphorus by thermochemical reaction of a phosphorus-containing material such as an alternative fuel, for example, in the presence of calcium-containing particles in a moving bed reactor and subsequent separation of fines enriched with phosphorus from the moving bed reactor. Furthermore, the present invention concerns the use of a recyclable material obtained by the method as a fertilizer or fertilizer additive.

A new integrated method based on upgrading low-grade calcareous phosphate ore with low CO.sub.2 emissions and low phosphogypsum waste production is disclosed. The method is an alternative integrated method that increases P.sub.2O.sub.5 recovery, reduces costs, minimizes the environmental impact of product phosphogypsum and CO.sub.2, and overcomes limitations due to different impurities that have negatively affected the yield of traditional processes to a wide range of natural phosphate sources.

A new integrated method based on upgrading low-grade calcareous phosphate ore with low CO.sub.2 emissions and low phosphogypsum waste production is disclosed. The method is an alternative integrated method that increases P.sub.2O.sub.5 recovery, reduces costs, minimizes the environmental impact of product phosphogypsum and CO.sub.2, and overcomes limitations due to different impurities that have negatively affected the yield of traditional processes to a wide range of natural phosphate sources.

The present application relates to a process for the reduction of NOx from a gaseous effluent generated in the production of fertilizer comprising the acid digestion of phosphate ore in the presence of urea, wherein said gaseous effluent generated has a NOx composition of 70 to 100 mole % NO.sub.2 and 0 to 30 mole % NO, comprising the steps of: a) contacting said gaseous effluent for 0.5 to 15 seconds with ozone, thereby providing a resultant gas mixture wherein NO and NO.sub.2 present in the NOx are oxidized to higher nitrogen oxides; and; b) removing higher nitrogen oxides from said resultant gas mixture; wherein urea is present during said acid digestion of phosphate ore in an amount of 0.25 wt % or less based on the weight of said phosphate ore; and; ozone is added to said gaseous effluent in an ozone/NOx ratio ranging between 0.5 and 1.4.

The present application relates to a process for the reduction of NOx from a gaseous effluent generated in the production of fertilizer comprising the acid digestion of phosphate ore in the presence of urea, wherein said gaseous effluent generated has a NOx composition of 70 to 100 mole % NO.sub.2 and 0 to 30 mole % NO, comprising the steps of: a) contacting said gaseous effluent for 0.5 to 15 seconds with ozone, thereby providing a resultant gas mixture wherein NO and NO.sub.2 present in the NOx are oxidized to higher nitrogen oxides; and; b) removing higher nitrogen oxides from said resultant gas mixture; wherein urea is present during said acid digestion of phosphate ore in an amount of 0.25 wt % or less based on the weight of said phosphate ore; and; ozone is added to said gaseous effluent in an ozone/NOx ratio ranging between 0.5 and 1.4.

Provided herein are systems and methods for producing nitrophosphates and mineralized carbon. Advantageously, the systems and methods are capable of sequestering carbon from the atmosphere. The systems generally include a first reactor for producing nitric acid; a mixer for mixing the nitric acid produced in the first reactor with a phosphate source, thereby producing nitro-phosphoric acid; and a second reactor for producing a solution comprising nitrophosphates and mineralized carbon, wherein the second reactor is operable to receive: the nitro-phosphoric acid from the mixer, ammonia, water, and carbon dioxide.

The invention concerns a method of treating phosphate-containing waste, in particular phosphate-containing ash from waste-incineration plants, by wet-chemical digestion in order to obtain compounds of aluminum, calcium, phosphorus and nitrogen.