The present invention relates to a process to produce high purity strontium sulfate and strontium carbonate from subterranean brines. The present disclosure also relates to chemical precipitations of subterranean brines to isolate strontium from divalent cations, such as calcium and barium. Such precipitations include the use of sulfate and subsequent solids separations and washing of the precipitate. In a latter step in the strontium carbonate process, a metathesis reaction with a carbonate is performed upon the strontium sulfate to produce strontium carbonate while allowing optional recycling of the sulfate. An additional rinse with acid or water of the strontium sulfate may be performed prior to metathesis to increase the purity of the resulting strontium carbonate.

A composition for use in surfactant polymer flooding processes in a carbonate reservoir, the composition comprising a surfactant, the surfactant operable to reduce interfacial tension, a polymer, the polymer operable to increase the viscosity of the composition, and a tailored water, the tailored water operable to alter a wettability of the in-situ rock, where the tailored water has a total dissolved solids of between 5,000 wt ppm and 7,000 wt ppm, where the total dissolved solids comprises a salt, where the composition has a viscosity between 3 cP and 100 cP.

A composition for use in surfactant polymer flooding processes in a carbonate reservoir, the composition comprising a surfactant, the surfactant operable to reduce interfacial tension, a polymer, the polymer operable to increase the viscosity of the composition, and a tailored water, the tailored water operable to alter a wettability of the in-situ rock, where the tailored water has a total dissolved solids of between 5,000 wt ppm and 7,000 wt ppm, where the total dissolved solids comprises a salt, where the composition has a viscosity between 3 cP and 100 cP.

A method for the production of potassium sulphate comprising contacting an aqueous potassium- and sulphate-containing composition with magnesium chloride (MgCl.sub.2), thereby obtaining a composition comprising kainite; optionally concentrating the kainite from the composition; reacting the kainite with magnesium sulphate (MgSO.sub.4) and potassium sulphate (K.sub.2SO.sub.4) so as to convert the kainite into leonite (K.sub.2SO.sub.4.MgSO.sub.4.4H.sub.2O); optionally contacting the leonite with water to remove excess MgSO.sub.4; and contacting the leonite with water so as to leach the MgSO.sub.4, contained in the leonite, and to at least substantially selectively precipitate potassium sulphate (K.sub.2SO.sub.4). The method can be operated at higher temperatures, in particular, at temperatures above 35 C., and does not require a cooling step at 20 to 25 C. The method produces potassium sulphate with a low amount of chloride.

A method for the production of potassium sulphate comprising contacting an aqueous potassium- and sulphate-containing composition with magnesium chloride (MgCl.sub.2), thereby obtaining a composition comprising kainite; optionally concentrating the kainite from the composition; reacting the kainite with magnesium sulphate (MgSO.sub.4) and potassium sulphate (K.sub.2SO.sub.4) so as to convert the kainite into leonite (K.sub.2SO.sub.4.MgSO.sub.4.4H.sub.2O); optionally contacting the leonite with water to remove excess MgSO.sub.4; and contacting the leonite with water so as to leach the MgSO.sub.4, contained in the leonite, and to at least substantially selectively precipitate potassium sulphate (K.sub.2SO.sub.4). The method can be operated at higher temperatures, in particular, at temperatures above 35 C., and does not require a cooling step at 20 to 25 C. The method produces potassium sulphate with a low amount of chloride.

There are provided methods for the production of potassium sulphate. The methods comprise contacting an aqueous potassium- and sulphate-containing composition with magnesium chloride (MgCl.sub.2), thereby obtaining a composition comprising kainite; optionally concentrating the kainite from the composition and reducing or removing halite therefrom; reacting the kainite with magnesium sulphate (MgSO.sub.4) and potassium sulphate (K.sub.2SO.sub.4) so as to convert the kainite into leonite (K.sub.2SO.sub.4.MgSO.sub.4.4H.sub.2O); optionally contacting the leonite with water to remove excess MgSO.sub.4; and contacting the leonite with water so as to leach the MgSO.sub.4, contained in the leonite, and to at least substantially selectively precipitate potassium sulphate (K.sub.2SO.sub.4), further involving a process brine sulphate control step, based on bloedite precipitation, to control the overall level of sulphate in the method and further comprising a step for the substantially complete reduction or removal of halite from the flotation concentrate, accompanied by an additional precipitation of kainite, thus also increasing the overall recovery of kainite in the process. The method according to the invention can be operated at higher temperatures, in particular at temperatures above 35 C. and does not require a cooling step at 20 to 25 C. The method produces potassium sulphate with a low amount of chloride.

A composition for use in surfactant polymer flooding processes in a carbonate reservoir, the composition comprising a surfactant, the surfactant operable to reduce interfacial tension, a polymer, the polymer operable to increase the viscosity of the composition, and a tailored water, the tailored water operable to alter a wettability of the in-situ rock, where the tailored water has a total dissolved solids of between 5,000 wt ppm and 7,000 wt ppm, where the total dissolved solids comprises a salt, where the composition has a viscosity between 3 cP and 100 cP.

A composition for use in surfactant polymer flooding processes in a carbonate reservoir, the composition comprising a surfactant, the surfactant operable to reduce interfacial tension, a polymer, the polymer operable to increase the viscosity of the composition, and a tailored water, the tailored water operable to alter a wettability of the in-situ rock, where the tailored water has a total dissolved solids of between 5,000 wt ppm and 7,000 wt ppm, where the total dissolved solids comprises a salt, where the composition has a viscosity between 3 cP and 100 cP.

There are provided methods for the production of potassium sulphate. The methods comprise contacting an aqueous potassium- and sulphate-containing composition with magnesium chloride (MgCl.sub.2), thereby obtaining a composition comprising kainite; optionally concentrating the kainite from the composition; reacting the kainite with magnesium sulphate (MgSO.sub.4) and potassium sulphate (K.sub.2SO.sub.4) so as to convert the kainite into leonite (K.sub.2SO.sub.4.MgSO.sub.4.4H.sub.2O); optionally contacting the leonite with water to remove excess MgSO.sub.4 and contacting the leonite with water so as to leach the MgSO.sub.4, contained in the leonite, and to at least substantially selectively precipitate potassium sulphate (K.sub.2SO.sub.4), and further involving a process brine sulphate control step, based on bloedite precipitation, to control the overall level of sulphate in the method. The method according to the invention can be operated at higher temperatures, in particular at temperatures above 35 C. and does not require a cooling step at 20 to 25 C. The method produces potassium sulphate with a low amount of chloride.

There are provided methods for the production of potassium sulphate. The methods comprise contacting an aqueous potassium- and sulphate-containing composition with magnesium chloride (MgCl.sub.2), thereby obtaining a composition comprising kainite; optionally concentrating the kainite from the composition; reacting the kainite with magnesium sulphate (MgSO.sub.4) and potassium sulphate (K.sub.2SO.sub.4) so as to convert the kainite into leonite (K.sub.2SO.sub.4.MgSO.sub.4.4H.sub.2O); optionally contacting the leonite with water to remove excess MgSO.sub.4 and contacting the leonite with water so as to leach the MgSO.sub.4, contained in the leonite, and to at least substantially selectively precipitate potassium sulphate (K.sub.2SO.sub.4), and further involving a process brine sulphate control step, based on bloedite precipitation, to control the overall level of sulphate in the method. The method according to the invention can be operated at higher temperatures, in particular at temperatures above 35 C. and does not require a cooling step at 20 to 25 C. The method produces potassium sulphate with a low amount of chloride.