Methods for removing heavy metals from a phosphoric acid solution produced in a wet process for manufacturing phosphoric acid, comprising treating the wet-process phosphoric acid solution with a small amount of a solid adsorbing material and a complex reagent to form a heavy metal complex-contaminated solid adsorbing material, and removing the contaminated solid adsorbing material to yield a treated phosphoric acid solution having a low heavy metal content.

Methods for removing heavy metals from a phosphoric acid solution produced in a wet process for manufacturing phosphoric acid, comprising treating the wet-process phosphoric acid solution with a small amount of a solid adsorbing material and a complex reagent to form a heavy metal complex-contaminated solid adsorbing material, and removing the contaminated solid adsorbing material to yield a treated phosphoric acid solution having a low heavy metal content.

In particular, in alternative embodiments, the invention provides for a method to recover silicofluoride and phosphate species from wastewaters, or barometric condenser waters, that are typically utilized in wet-process phosphoric acid facilities. The species are recovered via a continuous ion exchange approach that allows for economic recovery of the materials and especially with the silicofluoride component allows for the production of valuable industrial materials such as hydrofluoric acid and other fluoride salts as well as industrial-grade precipitated silica materials. Return of the treated waste water to the phos-acid plant allows for optimization of reagent usage.

In particular, in alternative embodiments, the invention provides for a method to recover silicofluoride and phosphate species from wastewaters, or barometric condenser waters, that are typically utilized in wet-process phosphoric acid facilities. The species are recovered via a continuous ion exchange approach that allows for economic recovery of the materials and especially with the silicofluoride component allows for the production of valuable industrial materials such as hydrofluoric acid and other fluoride salts as well as industrial-grade precipitated silica materials. Return of the treated waste water to the phos-acid plant allows for optimization of reagent usage.

Processes for enhancing filtration rate and/or clarification of phosphoric acid produced by the wet process and containing suspended insoluble particulates by adding to one or more stage of the wet process phosphoric acid production stream an effective amount of a reagent including polymeric microparticles characterized as being anionic or amphoteric and having a weight average molecular weight of greater than 60 Million daltons are provided herein.

Processes for enhancing filtration rate and/or clarification of phosphoric acid produced by the wet process and containing suspended insoluble particulates by adding to one or more stage of the wet process phosphoric acid production stream an effective amount of a reagent including polymeric microparticles characterized as being anionic or amphoteric and having a weight average molecular weight of greater than 60 Million daltons are provided herein.

The present invention refers to an improved process for recovering phosphoric acid from sewage sludge ash, said process comprising a leaching step; a transforming step for converting phosphate metallic salts into phosphoric acid; a solvent extraction of the phosphoric acid from the leached solution with an organic solvent; a washing step for removing sulfuric acid; and stripping of phosphoric acid to obtain an aqueous solution containing phosphoric acid.

A method can include coupling sulfur dioxide depolarized electrolysis (e.g., electrochemical oxidation of sulfur dioxide to sulfuric acid with electrochemical reduction of water to hydrogen) with the contact process to facilitate formation of high concentration sulfuric acid with concurrent hydrogen production. The sulfuric acid and hydrogen can optionally be used cooperatively for downstream processes (e.g., metal extraction from ore, fertilizer production, hydrocarbon processing, etc.).

A method can include coupling sulfur dioxide depolarized electrolysis (e.g., electrochemical oxidation of sulfur dioxide to sulfuric acid with electrochemical reduction of water to hydrogen) with the contact process to facilitate formation of high concentration sulfuric acid with concurrent hydrogen production. The sulfuric acid and hydrogen can optionally be used cooperatively for downstream processes (e.g., metal extraction from ore, fertilizer production, hydrocarbon processing, etc.).

The present application provides a method for separating and purifying phosphoric acid and phosphogypsum from a wet-process phosphoric acid slurry, and phosphoric acid and phosphogypsum prepared thereby. The method is beneficial for the dissociation, precipitation and separation of colloidal silicon and carbon impurities, such that the aim of in-situ removal and rapid separation of colloidal impurities to obtain the ore slurry, from which impurities have been removed, during a reaction process for outputting phosphogypsum is realized, and a low-impurity phosphoric acid product and phosphogypsum product can be obtained after the ore slurry, from which impurities have been removed, has been further treated.