Provided is a method of manufacturing high-purity, high-quality manganese sulfate which can be immediately used for manufacturing a lithium ion secondary battery from manganese sulfate waste liquid of a wasted battery. Since impurities are removed from the manganese sulfate waste liquid by using sulfides causing no secondary contamination in the manganese sulfate waste liquid and the manganese sulfate is manufactured by performing evaporation concentration through heating, the manufacturing method is very environment-friendly and economical. Since the manganese recovering process improving the manufacturing yield of the manganese sulfate and the waste water treatment process capable of recycling the source materials and discharging waste water are integrated, the manufacturing method is very efficient and environment-friendly. The manufacturing method is applied to the recycling industry, and thus, it is possible to obtain effects of preventing environmental pollution and facilitating recycling the resources.

A method of treating a wastewater is provided and can be used, for example, to treat a gas well production wastewater to form a wastewater brine. The method can involve crystallizing sodium chloride by evaporation of the wastewater brine with concurrent production of a liquor comprising calcium chloride solution. Bromine and lithium can also be recovered from the liquor in accordance with the teachings of the present invention. Various metal sulfates, such as barium sulfate and strontium sulfate, can be removed from the wastewater in the production of the wastewater brine. Sources of wastewater can include gas well production wastewater and hydrofracture flowback wastewater.

A method is provided for recovering barium sulfate from a contaminated water source comprising barium cation. The method involves combining the contaminated water source with a source of sulfate ion, thereby forming a modified contaminated water source. The method includes forming precipitated barium sulfate within the modified contaminated water source; isolating precipitated barium sulfate from the modified contaminated water source, thereby forming isolated precipitated barium sulfate; dewatering the isolated precipitated barium sulfate, thereby forming a low-moisture precipitated barium sulfate; combining the low-moisture precipitated barium sulfate with clean water to form a slurry comprising precipitated barium sulfate; subjecting the slurry to density separation to form a refined barium sulfate; and subjecting the refined barium sulfate to particle size reduction and/or particle size classification to yield a recovered barium sulfate.

A method for carbon dioxide (CO.sub.2) storage includes injecting a brine solution into a subterranean anhydrite-rich formation, then injecting carbon dioxide into the subterranean anhydrite-rich formation and reacting the carbon dioxide with the subterranean anhydrite-rich formation to form one or more minerals thereby sequestering the carbon dioxide in the subterranean anhydrite-rich formation. The temperature in the subterranean anhydrite-rich formation is from 300 Kelvin (K) to 365 K and the pressure in the subterranean anhydrite-rich formation is from 90 bar to 120 bar.

Disclosed herein is a process for recycling carbon and a hardly soluble alkaline earth sulfate from a leaching residue, including the steps of contacting in an alkaline earth metal contacting step a lithium battery material with an alkaline earth metal including material in a solvent yielding an alkaline earth metal contacted lithium battery material: leaching in a leaching step the alkaline earth metal contacted lithium battery material in sulfuric acid yielding a leaching solution and the leaching residue; separating in a solid-liquid separation step the leaching residue from the leaching solution; suspending in a suspension step the leaching residue in a solvent yielding a suspended leaching residue: contacting in a carrier contacting step the suspended leaching residue with a plurality of at least one type of a carrier body; and separating in a solid-solid separation step at least a part of the carrier-body agglomerates from the suspension.