A method of concentrating and/or producing lithium hydroxide in an evaporator entails feeding a stream comprising lithium, hydroxide and carbonate to the evaporator. In the evaporator, the feed is concentrated to form lithium hydroxide and lithium carbonate crystals. Further, the method entails reducing the tendency of lithium carbonate to scale the evaporator by increasing the concentration of lithium carbonate crystals in the evaporator by: (1) clarifying at least a portion of the concentrate in the evaporator to form a clarified solution; and (2) discharging the clarified solution as a clarified solution stream from the evaporator.

The present invention relates to a method for fractionating a crude mixture comprising at least one oil and at least one wax, which comprises the following method steps: (a) carrying out a pre-fractionation stage as a layer crystallization (i) with a crude mixture comprising at least one oil and at least one wax or (ii) with a crude solvent mixture obtained by adding prior to the pre-fractionation stage at most 100% by weight of solvent relative to the weight of the crude mixture, to prepare a first fraction containing low waxy oil and a second fraction containing low oily wax, (b) carrying out a first crystallization stage including (b1) a first suspension crystallization sub-stage with the first fraction containing low waxy oil to prepare a third fraction containing dewaxed oil and a fourth fraction and (b2) after the first suspension crystallization sub-stage, a second suspension crystallization sub-stage with a mixture of the fourth fraction obtained in method step (b1) and the second fraction containing low oily wax obtained in the pre-fractionation stage of method step (a) to prepare a fifth fraction containing slack wax and a sixth fraction.

There is disclosed a process for the separation of long chain amino acid and long chain dibasic acid, comprising: (1) cooling the hydrolysis solution to crystallize and separate alkali salt of long chain dibasic acid to provide an aqueous solvent solution; (2) distilling the aqueous solvent solution of step (1) to recover the solvent and to recover alkylamine; (3) cooling the residual solution of step (2) to precipitate and separate alkali salt of long chain amino acid to provide a mother liquor; (4) adding an acid to the mother liquor of step (3) to yield alkanoic acid; (5) adding an acid to an aqueous solution of the alkali salt of long chain dibasic acid of step (1) to obtain long chain dibasic acid; and (6) neutralizing the alkali salt of long chain amino acid of step (3) with an acid to obtain long chain amino acid.

There is disclosed a process for the separation of long chain dibasic acid and fatty acid, comprising: (1) reacting a mixture of long chain dibasic acid and fatty acid with ammonium hydroxide to form an insoluble ammonium salt of fatty acid and a soluble ammonium salt of long chain dibasic acid; (2) recovering the insoluble ammonium salt of fatty acid; and (3) adding an acid to the mother liquor of step (2) to obtain the long chain dibasic acid.

There is disclosed a process for the separation of long chain amino acid and long chain dibasic acid, comprising: (1) recovering alkylamine from an aqueous solution of an alkali hydroxide hydrolysis of the mixed amide derivatives by distilling or by extracting with an extractant solvent; (2) cooling the aqueous solution of step (1) to precipitate a mixed alkali salts of long chain amino acid and dibasic acid; (3) recovering the mixed alkali salts of long chain amino acid and dibasic acid to provide a mother liquor; (4) separating long chain amino acid and dibasic acid by acidification-extraction of long chain dibasic acid with an extractant solvent or by selective dissolution of alkali salt of long chain amino acid in an aqueous solvent; and (4) adding an acid to the mother liquor of step (3) to obtain alkanoic acid.

A wastewater purification system is provided. The wastewater purification system comprises a chamber. One or more wastewater nozzles are positioned near the top of the chamber. An intake duct is further provided to supply chilled air into the chamber, and one or more exhaust ducts are provided to remove the chilled air from the chamber. One or more perforated receptacles positioned near the bottom of the chamber to collect solid byproducts, and a watertight receptacle at the bottom of the chamber to collect a liquid product. The wastewater enters the chamber as wastewater droplets via the one or more wastewater nozzles, wherein the wastewater undergoes freeze separation due to heat exchange with a high mass flow of the chilled air between the intake duct and the one or more exhaust ducts.

Embodiments relate to systems and methods directed towards arrangements of a preheater, a heat exchanger, a plasma recovery system, and at least one processing stage configured to use steam output of a calciner for heating incoming wastewater that is being processed.

The invention discloses a purification method, system and a detection method of N-methylmorpholine N-oxide (NMMO), and a N-methylmorpholine N-oxide obtained thereof. The NMMO is derived from a NMMO crude product prepared by the reaction of N-methylmorpholine with hydrogen peroxide. The mass concentration of NMMO in the NMMO crude product is 50% to 60%. The purification method includes: performing cooling crystallization to the NMMO crude product between ?20? C. and 78? C. to obtain crystalline NMMO. The NMMO purification method has a low cost, a high purity of the obtained NMMO product, and almost no generation of exhaust gas, waste water, and solid waste. Different from current NMMO purification process, the purification method of the invention does not require ion-exchange resin, thus completely solved problems of significant amount of wastewater with high concentration of salt and COD and spent ion-exchange resin caused by the regeneration of ion-exchange resin.

Disclosed is a preparation system and a preparation method for high-quality xylitol crystals. The preparation system comprises a blending tank, a heat exchanger, a decolorization tank, an ion exchange system, a microporous filter, a first evaporator, a first crystallization kettle, a first centrifuge, a fluidization drying bed, a xylitol dissolution tank, a second evaporator, a second crystallization kettle, a second centrifuge, a hot air drying tank, and a cold air fluidization bed sequentially connected through pipelines. Liquid outlet of the first centrifuge is connected with first inlet of the blending tank. Liquid outlet of the second centrifuge is connected with first inlet of the xylitol dissolution tank. The blending tank is provided with second inlet for receiving xylitol hydrogenation solution. The xylitol dissolution tank is provided with water inlet for pure water. The material output from a product outlet of the cold air fluidization bed is xylitol crystal product. First prepared xylitol crystals are redissolved and recrystallized to prepare xylitol crystals with higher pH and better flavor.

A method of removing one or more of solutes from an aqueous solution comprises introducing, into a first fractional crystallization chamber, dimethyl ether and a salt containing solution comprising one or more dissolved salts to form an aqueous solution, and precipitating a first solid from the aqueous solution. Related systems and additional methods are also described.