The flotation reagents from acidic olive oil are made by transesterification of acidic olive oil. Acidic olive oil is olive oil having an acid value high enough to render it unsuitable for consumption, typically greater than 3.3% and/or between 3.3-7%. Transesterification of the olive oil with methanol converts fatty acids in the olive oil to an ester fraction and a glycerol fraction. The ester fraction may be sulfonated and used as the collector in a reverse flotation process, selectively removing the carbonate gangue from phosphate-carbonate rock in the froth, leaving phosphates in the sink. The glycerol fraction may be used without modification as the collector in the reverse flotation process. Both fractions are highly selective for carbonates, substantially reducing loss of phosphates in the froth.

The flotation reagents from acidic olive oil are made by transesterification of acidic olive oil. Acidic olive oil is olive oil having an acid value high enough to render it unsuitable for consumption, typically greater than 3.3% and/or between 3.3-7%. Transesterification of the olive oil with methanol converts fatty acids in the olive oil to an ester fraction and a glycerol fraction. The ester fraction may be sulfonated and used as the collector in a reverse flotation process, selectively removing the carbonate gangue from phosphate-carbonate rock in the froth, leaving phosphates in the sink. The glycerol fraction may be used without modification as the collector in the reverse flotation process. Both fractions are highly selective for carbonates, substantially reducing loss of phosphates in the froth.

A process for recovering phosphorus from sewage sludge in which sewage sludge undergoes a tumbling process in a rotary kiln and the expelled phosphor is collected in the form of a gaseous phosphorus pentoxide.

A process for recovering phosphorus from sewage sludge in which sewage sludge undergoes a tumbling process in a rotary kiln and the expelled phosphor is collected in the form of a gaseous phosphorus pentoxide.

A phosphorous pentoxide producing method includes forming pre-feed agglomerates containing phosphate ore particles, carbonaceous material particles, and silica particles and heating the pre-feed agglomerates in a reducing or inert atmosphere to an induration temperature from above 900 C to less than 1180 C and maintaining the induration temperature for 15 minutes or more. The method includes forming feed agglomerates and increasing a compression strength of the feed agglomerates to above 25 lb.sub.f using the heating, the feed agglomerates exhibiting a calcium-to-silica mole ratio less than 1 and a silica-to-(calcium+magnesium) mole ratio greater than 2. A reducing kiln bed is formed using the feed agglomerates, kiln off-gas is generated, and phosphorous pentoxide is collected from the kiln off gas.

A phosphorous pentoxide producing method includes forming pre-feed agglomerates containing phosphate ore particles, carbonaceous material particles, and silica particles and heating the pre-feed agglomerates in a reducing or inert atmosphere to an induration temperature from above 900 C to less than 1180 C and maintaining the induration temperature for 15 minutes or more. The method includes forming feed agglomerates and increasing a compression strength of the feed agglomerates to above 25 lb.sub.f using the heating, the feed agglomerates exhibiting a calcium-to-silica mole ratio less than 1 and a silica-to-(calcium+magnesium) mole ratio greater than 2. A reducing kiln bed is formed using the feed agglomerates, kiln off-gas is generated, and phosphorous pentoxide is collected from the kiln off gas.

Disclosed herein are methods of making acidic short-chain potassium polyphosphate compositions with reduced levels of water-insoluble materials. Also disclosed herein are acidic short-chain potassium polyphosphate compositions.

A method of producing lithium difluorophosphate, the method including: a step of obtaining a first raw material mixture by mixing lithium hexafluorophosphate, at least one selected from the group consisting of an oxide of phosphorus (A) and a lithium salt of a phosphoric acid (B), and a hydrocarbon solvent having from 6 to 12 carbon atoms; a step of obtaining a second raw material mixture by removing at least a part of the hydrocarbon solvent contained in the obtained first raw material mixture; and a step of producing a crude product containing lithium difluorophosphate by reacting the second raw material mixture.

A method of producing lithium difluorophosphate, the method including: a step of obtaining a first raw material mixture by mixing lithium hexafluorophosphate, at least one selected from the group consisting of an oxide of phosphorus (A) and a lithium salt of a phosphoric acid (B), and a hydrocarbon solvent having from 6 to 12 carbon atoms; a step of obtaining a second raw material mixture by removing at least a part of the hydrocarbon solvent contained in the obtained first raw material mixture; and a step of producing a crude product containing lithium difluorophosphate by reacting the second raw material mixture.

The present invention is generally directed to improved processes for the preparation of various phosphorus oxides and phosphoric acid. Phosphorus oxides prepared in accordance with the present invention include phosphorus (III) oxides (e.g., tetraphosphorus hexaoxide (P.sub.4O.sub.6)). Phosphorus (III) oxides such as P.sub.4O.sub.6 are useful products and are also useful as precursors in preparation of other products, including phosphorous acid (H.sub.3PO.sub.3) and other phosphorus-containing chemicals. Certain aspects of this invention are also directed to using various byproducts formed during P.sub.4O.sub.6 production as precursors for the formation of phosphoric acid (H.sub.3PO.sub.4) and P.sub.2O.sub.5. In particular, the present invention is directed to improved processes for the preparation of phosphorus (III) oxides (e.g., P.sub.4O.sub.6) suitable for use in the preparation of phospho-herbicides such N-(phosphonomethyl)glycine (glyphosate) and precursors thereof (e.g., N-(phosphonomethyl)iminodiacetic acid (PMIDA)). The present invention is thus further directed to preparation of these compounds.