A process for treating wastewater or waste brines that include sodium and chloride ions. The waste brine is concentrated and thereafter directed to a Mirabilite crystallizer that produces hydrated sulfate salt crystals and a first solution. The hydrated crystals are melted to form an aqueous sulfate solution that is directed to a sodium sulfate crystallizer which produces sodium sulfate salt crystals. The first solution produced by the Mirabilite crystallizer is directed to a nanofiltration device which produces a permeate stream and a reject stream containing sulfate removed by the nanofiltration device. The permeate stream is directed to a sodium chloride crystallizer that produces sodium chloride salt crystals. The reject stream is recycled to the Mirabilite crystallizer.

A system and method for cleaning of a forced-circulation evaporative crystallizer. The crystallizer is used to produce salt solids and includes a circulation pump, a heat exchanger, a separator, and a vapor processor. Solids deposits accumulate during salt solids production within at least one of the circulation pump, heat exchanger, and separator. A solids deposits metric representative of an amount of the accumulated solids deposits is measured. The solids deposits metric is determined to deviate from a baseline by at least a cleaning threshold. Certain determinations are made based on the solids deposits metric: determining a cleaning mode and at least one of a type of cleaning solution and a duration for which at least one of the circulation pump, heat exchanger, and separator is to be cleaned. At least one of the circulation pump, heat exchanger, and separator is then cleaned in accordance with those determinations.

A Reflux Rinsing apparatus for purifying crystals using solvent vapor through dynamic equilibrium recrystallization. A pressure vessel contains a liquefied gas solvent, impure crystalline starting material initially, and a purified crystalline mass at the conclusion of the purifying process. A mechanism is provided for providing pressure to contents of the pressure vessel and for heating the lower portion thereof. A timer is also connected to the mechanism, the timer being set to heat the pressure vessel to drive vapors and reflux rinsing to remove impurities at the surface of an impure crystalline mass, to reclaim the solvent, leaving purified crystals and impurities in the pressure vessel, and to open the pressure vessel to remove the purified crystals from the vessel walls and bottom surface and to remove the impurities from the vessel. The angle of a crystal bed in the apparatus can be adjusted.

Methods and systems for producing lithium hydroxide and lithium carbonate are described. One or more embodiments involve reacting potassium hydroxide with lithium chloride or lithium nitrate to create a reciprocal salt system, and precipitation to form lithium hydroxide and potassium chloride crystals, potassium nitrate crystals, or any combination thereof. In certain embodiments, lithium chloride feedstock, nitrate feedstock, or mixture thereof, is obtained by reacting lithium sulfate with calcium chloride, calcium nitrate, or combination thereof. Additional embodiments include producing lithium carbonate, including, but not limited to, by reacting lithium hydroxide with carbon dioxide.

The present disclosure relates to the technical field of wastewater treatment, and provides a wastewater treatment method and apparatus based on hydrate-based water vapor adsorption. The apparatus includes a wastewater evaporation zone, a hydrate formation zone, a hydrate decomposition zone, and a data acquisition and control system. Rising water vapor and condensed water formed during evaporation of wastewater at normal temperature react with a hydrate former on a cooling wall surface to form a hydrate, continuous evaporation of the wastewater is promoted, the hydrate is scraped off to a collecting zone below by a scraper after being formed, and the hydrate is decomposed into fresh water, thereby realizing wastewater treatment. The present disclosure provides a method for treating complex wastewater containing a plurality of pollutants, where water vapor is consumed to form the hydrate to promote wastewater evaporation, and water obtained from the decomposition does not contain pollutants theoretically.

A method for preparing a purified styrene composition is provided. The method includes providing a crude composition and subjecting the crude composition to at least one crystallization step. The crude composition contains 70% by weight or more styrene based on the total weight of the crude composition. The at least one crystallization step comprises at least one of a static crystallization stage and a dynamic crystallization stage. The crude composition contains at least one impurity selected from the group consisting of: color inducing species, oxygenates, sulfur species, alpha-methylstyrene, and mixtures thereof.

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 device and method for increasing solid holdup in a reaction crystallizer are disclosed. The device includes a discharge pipe, a clear liquid pipe, a clear liquid tank and a gas collecting pipe. A lower end of the discharge pipe is inserted into the crystallizer below the liquid level, while that of the clear liquid pipe is inserted into the clear liquid tank below the liquid level. By using the gas collecting pipe, the reaction crystallizer and the clear liquid tank are communicated all the time. When feeding, a liquid-solid mixture in the crystallizer automatically enters the discharge pipe and flows upward slowly therein, during which solid particles gradually settle down and automatically fall back into the crystallizer while the clear liquid keeps on flowing upward, enters the clear liquid pipe and thereby flows into the clear liquid tank. The clear liquid tank maintains a constant liquid level via overflowing.

A hybrid process and system for separating water from an inlet brine solution is disclosed. The hybrid process couples at least two different separation processes/systems. The inlet brine solution is fed into a first separation process, which produces a water distillate and a brine concentrate. The brine concentrate from the first separation process is then fed into the second separation process to further recover additional water. The excess heat from the second separation process is supplied to the first separation process.

A method for preparing a purified styrene composition with a styrene yield of at least 80%. The method comprises providing a crude composition containing styrene, and subjecting the crude composition to at least one crystallization step. The at least one crystallization step comprises at least one static crystallization stage and at least one dynamic crystallization stage.