The present invention provides a continuous process for producing ammonium sulfate crystals, wherein said process comprises: i) feeding to a series of crystallization sections, which crystallization sections are heat integrated in series, a solution of ammonium sulfate; ii) crystallizing ammonium sulfate crystals from said solution of ammonium sulfate; iii) purging a fraction of the solution of ammonium sulfate from each of said crystallization sections; and iv) discharging ammonium sulfate crystals from each crystallization section, characterized in that: a fraction of said solution of ammonium sulfate is purged from at least one crystallization section to at least one other crystallization section; and an apparatus suitable for producing ammonium sulfate crystals.

A diaryl carbonate containing a compound of the following formula (I) in an amount of less than 1,000 ppm by mass, and a method for producing the same:

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wherein R.sup.1 represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, or an aryloxy group.

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.

A method for the extraction and isolation of the terpene and isoprenoid compounds from plant material, followed by a centrifugal force induced selective crystallization of isoprenoids resulting in a separation of terpene and isoprenoid fractions. This this method is suitable for the extraction of cannabinoids from Cannabis and the enrichment tetrahydrocannabinolic acid and reduction of tetrahydrocannabinol in an extract. The purity of tetrahydrocannabinolic acid resulting from centrifugal crystallization is such that dissolution and selective recrystallization of tetrahydrocannabinolic acid is possible resulting in >99.9% pure tetrahydrocannabinolic acid, w/w.

Provided are an inositol nicotinate crystalline form A and a preparation method therefor. The X-ray powder diffraction analysis, obtained by using Cu-K ray measurement, of the inositol nicotinate crystalline form A has obvious characteristic diffraction peaks at least at 2 values, expressed in degrees, of 7.05, 7.41, 9.74, 17.80, 19.86, 23.57, 25.48 and 26.20 with an error range of +/0.2. The preparation method is one of or a mixed crystallization method of two or more of an evaporation crystallization method, a cooling crystallization method or an anti-solvent crystallization method. The process thereof is simple and easy to operate, and has more selectivity; the inositol nicotinate crystalline form A can be prepared by various methods, and the prepared product has a good crystallization degree and high chemical stability; and the inositol nicotinate crystalline form A prepared by the present method does not have the problem that a residual solvent is out-of-limit.

A method for producing manganese(II) sulfate monohydrate includes a pulverization and washing step of pulverizing and washing a manganese-containing by-product, a leaching step of leaching the pulverized manganese-containing by-product after the pulverization and washing step to produce a leachate, a neutralization step of neutralizing the leachate produced in the leaching step, an impurity removal step of removing impurities from the leachate neutralized in the neutralization step, a solvent extraction step of recovering manganese in the form of an aqueous solution of manganese sulfate from a process liquid subjected to the impurity removal step by using a solvent extraction method, and a crystallization step of producing manganese(II) sulfate monohydrate by evaporating and concentrating the aqueous solution of manganese sulfate produced in the solvent extraction step.

A wastewater treatment equipment and a treatment method of a wastewater are provided. The wastewater treatment equipment includes: a microfiltration unit, configured to receive and filter a wastewater to obtain a solution; a membrane salt separation unit, configured to receive the solution and separate monovalent ions and multivalent ions from the solution to obtain a first solution including the monovalent ions and a second solution including the multivalent ions; a first evaporative crystallization unit, configured to crystallize the first solution to form a monovalent salt; and a second evaporative crystallization unit, configured to crystallize the second solution to form a mixed salt; the microfiltration unit is connected to the membrane salt separation unit, and the first evaporative crystallization unit and the second evaporative crystallization unit are both directly connected to the membrane salt separation unit, the wastewater treatment equipment can achieve the standard discharge of wastewater.

The invention relates to a process for purification of a stream containing a cyclic ester of an alpha-hydroxycarboxylic acid of formula (I), wherein each R independently represents hydrogen or an aliphatic hydrocarbon having 1 to 6 carbon atoms comprising the steps of: (a) separating the cyclic ester-containing stream into one or more cyclic ester-containing vapor fractions and one or more cyclic ester-containing liquid fractions; (b) condensing a cyclic ester-containing vaporized fraction as obtained in step (a) to obtain a cyclic ester-containing condensate; (c) subjecting at least part of the cyclic ester-containing condensate as obtained in step (b) to melt crystallization to obtain a purified cyclic ester-containing stream and a residue stream; and (d) recovering the purified cyclic ester-containing stream as obtained in step (c). The invention further relates to an apparatus suitable for carrying out the present process.

A process for preparing solid sodium carbonate monohydrate from a solution of sodium carbonate is described.

The present disclosure is directed to methods for treating an organic material, including the steps of transporting the organic material into a first vessel; heating the organic material in the first vessel and applying a negative pressure to the organic material in the first vessel to a boiling point of the organic material, wherein the heat and negative pressure separates a portion of an ammonia from the organic material; removing the portion of the ammonia from the first vessel; transporting the removed portion of the ammonia from the first vessel to an acid solution in a second vessel; and separating a portion of the ammonia from the acid solution.