A system for asbestos neutralization, that includes a neutralization unit having a module configured for sorting of asbestos waste, an asbestos waste grinder; a concentrated sulfuric acid tank, a vat containing a hot diluted acid solution, for which temperature is between 70° C. and 100° C., in which grinded asbestos waste containing asbestos is dipped, the solution is configured for neutralizing asbestos contained in the grinded asbestos waste, a filtration unit to separate, at the end of the neutralization reaction, a solid inert waste from a liquid phase of the diluted acid solution, a regeneration unit for the diluted acid solution, which adjusts the hydrogen potential of the extracted liquid phase by adding concentrated sulfuric acid from the tank, and means for transferring the regenerated solution into the vat.

A system and method for generating base water and precipitate, including combining produced water with seawater to precipitate barium sulfate from barium in the produced water and from sulfate in the seawater, and separating the precipitate to give the base water and the precipitate. The base water may have less than a specified amount of sulfate and be utilized for hydraulic fracturing fluid. The precipitate may give a weighting agent for drilling.

A method of concentrating lithium containing solutions includes inputting a feed brine solution to an initial separation stage, the feed brine solution including lithium sulfate and one or more of sodium sulfate, potassium sulfate, calcium sulfate, and sodium chloride dissolved in water. In the initial separation stage, the feed brine solution is introduced to a pre-treatment membrane at a pressure that is less than the osmotic pressure of the feed brine solution. An initial permeate that passes through the pre-treatment membrane becomes the feed to a final separation stage, and an initial retentate that does not pass through the pre-treatment membrane includes a precipitate of at least one of the salts other than lithium sulfate. In the final separation stage, the initial permeate is introduced to a nanofiltration membrane at a pressure that is less than the osmotic pressure of the initial permeate. A final retentate that does not pass through the nanofiltration membrane is combined with the initial retentate to obtain a product solution having a higher concentration of dissolved lithium sulfate than the feed brine solution.

The present invention provides an exhaust gas purification catalyst including an alkaline earth metal supported in a highly dispersed state on a porous carrier. A catalyst layer of the exhaust gas purification catalyst provided by the invention has an alkaline earth metal-supporting region including a porous carrier, a catalyst metal belonging to the platinum group, and a sulfate of at least one type of alkali earth metal supported on the porous carrier. In a cross-section of this region, a Pearson correlation coefficient R.sub.Ae/M is at least 0.5 as calculated using α and β for each pixel obtained by carrying out area analysis by FE-EPMA under conditions of pixel size of 0.34 μm×0.34 μm, and measured pixel number 256×256, and by measuring the characteristic X-ray intensity (α:cps) of the alkaline earth metal element (Ae) and the characteristic X-ray intensity (β:cps) of the main constituent element of the inorganic compound constituting the porous carrier for each pixel.

A method of treating a waste liquid includes: an aluminum dissolution step of dissolving aluminum in an acidic waste liquid and performing separation into a first treated water and a reduced heavy metal precipitate; a gypsum recovery step of adding a calcium compound to the first treated water at a liquid property of a pH of 4 or less, and performing separation into a second treated water and gypsum; an aluminum and fluorine removal step of adding an alkali to the second treated water and performing separation into a third treated water and a precipitate containing aluminum and fluorine; and a neutralization step of adding an alkali to the third treated water and performing separation into an alkali neutralization treated water and a neutralized precipitate of a heavy metal hydroxide.

A method of treating a waste liquid includes: an aluminum dissolution step of dissolving aluminum in an acidic waste liquid and performing separation into a first treated water and a reduced heavy metal precipitate; a gypsum recovery step of adding a calcium compound to the first treated water at a liquid property of a pH of 4 or less, and performing separation into a second treated water and gypsum; an aluminum and fluorine removal step of adding an alkali to the second treated water and performing separation into a third treated water and a precipitate containing aluminum and fluorine; and a neutralization step of adding an alkali to the third treated water and performing separation into an alkali neutralization treated water and a neutralized precipitate of a heavy metal hydroxide.

A method for recycling lead from spent lead-acid battery paste, relating to the technical field of hydrometallurgy. In the method, firstly a reducing agent, and a lead paste are added into a zinc chloride solution for leaching in a stirring mill to cause lead in the lead paste to enter the solution, a lead cementation is performed by using zinc in the leached solution, after the lead cementation, the electrolytic zinc is produced by controlling an electrodeposition on the zinc chloride solution for a short time, the reducing agent is zinc, lead or hydrogen peroxide, a part of the electrolytic zinc is returned as the reducing agent for leaching, the step of returning the electrolytic zinc as the reducing agent can be omitted when the lead or the hydrogen peroxide is used as the reducing agent.

Disclosed herein are systems and methods from processing flue gas desulfurization (FGD) gypsum feedstock and ash feedstocks, either separately or together. FGD gypsum conversion comprises reacting FGD gypsum (calcium sulfate) feedstock or phosphogypsum, in either batch or continuous mode, with ammonium carbonate reagent to produce commercial products comprising ammonium sulfate and calcium carbonate. A process to separate the impurities and convert the calcium carbonate to a pure precipitated calcium carbonate is disclosed. These impurities include a concentrate of valuable Rare Earth Elements, and radioactive thorium and uranium. A process to convert calcium sulfite to calcium sulfate using oxygen and a catalyst is also disclosed. Ash conversion comprises a leach process followed by a sequential precipitation process to selectively precipitate products at predetermined pHs resulting in metal hydroxides which may be converted to oxides or carbonates. The processes may be controlled by use of one or more processors.

A system for producing a magnesium chloride aqueous solution includes a crystallization unit configured to generate reaction slurry in which particles of magnesium hydroxide are dispersed by adding a sodium hydroxide aqueous solution to water to be treated, a precipitation unit configured to store reaction slurry, precipitate particles and separate the reaction slurry into recovered slurry and a separated liquid, a removal unit configured to remove divalent cations from the water to be treated or the separated liquid to generate a reaction liquid, an acid-alkali generation unit configured to generate a sodium hydroxide aqueous solution and hydrochloric acid from the reaction liquid, and a reaction unit configured to generate a magnesium chloride aqueous solution by adding hydrochloric acid to the recovered slurry. The acid-alkali generation unit has a main body section configured to generate a sodium hydroxide aqueous solution and hydrochloric acid from the reaction liquid.

The present disclosure relates to a method for producing, high-purity lithium hydroxide from a lithium-containing waste liquid of a spent lithium secondary battery.