A method for crystallizing calcium nitrate from an aqueous calcium nitrate composition including from 6 to 12 weight % nitric acid, from 11 to 17 weight % phosphoric acid, and from 36 to 49 weight % dissolved calcium nitrate, which aqueous composition is optionally directly obtainable from digesting phosphate rock in nitric acid. The method includes filling at least one vertical crystallizing tank through an inlet with the aqueous calcium nitrate composition. The crystallizing tank includes a vertical cylindrical section, a first inlet, a first outlet, a second inlet, three concentric banks of cooling coils, an agitator, and a temperature measurement device. The method includes circulating through the banks of cooling coils a cooling fluid, having an initial temperature ranging from 40 C. to 5 C., and rotating the agitator such that a minimum average heat transfer of 400 W/m.sup.2.Math.K is achieved on the cooling coil the most distant from the agitator.

Disclosed is a method to prepare a polylactic acid comprising the steps of performing a ring opening polymerization using a catalyst and either a catalyst killer compound or an endcapping additive to obtain a raw polylactic acid of MW greater than 10,000 g/mol, purifying the raw polylactic acid by removing and separating low boiling compounds comprising lactide and impurities from the raw polylactic acid by devolatization of the low boiling compounds as a gas phase stream, and purifying the lactide from the devolatization and removing the impurities from the gas phase stream of evaporated low boiling compounds by means of crystallization by desublimation from the gas phase, wherein the lactide is purified and the removed impurities include a catalyst residue and a compound containing at least one hydroxyl group such that the purified lactide is then polymerized by feeding it back into the ring opening polymerization. The invention further relates to an apparatus for carrying out the method comprising a polymerization reactor for performing a ring opening polymerization to obtain a raw polylactic acid, a devolatization apparatus for separating low boiling compounds comprising lactide and impurities from a raw polylactic acid, and a crystallization apparatus for purifying a lactide and removing impurities by means of a desublimation and a crystallization in the same crystallization apparatus.

A process to purify a compound comprising a suspension crystallization step and additionally comprises a layer crystallization step and a storage step of an intermediate product obtained from the layer crystallization step before to its further purification in the suspension crystallization step.

The present disclosure relates to methods of removing brominated contaminants from polystyrene waste and recovering the brominated contaminants. The present disclosure further relates to methods of recycling polystyrene waste, wherein the recycling comprises retention of brominated contaminants or removal of contaminants. The present disclosure also relates to use of monocyclic aromatic benzenic solvents in the removal and/or recovery of brominated contaminants from polystyrene waste and in the recycling of polystyrene waste. Moreover, the present disclosure relates to use of the recovered brominated contaminants in the manufacture of polystyrene products such as insulation.

A process for the production of lithium carbonate from an aqueous salt solution at least containing lithium ions, chloride ions and calcium ions; the aqueous salt solution with a lithium content of at least 0.005% by weight and a maximum 0.2% by weight is condensed in a first evaporation step at a temperature between 40 C. and 160 C. until a concentrate I with a water content of 70% by weight and >60% by weight is formed. In a second evaporation step, the concentrate I is evaporated at a temperature between 60 C. and 180 C. until a concentrate II with a water content of 60% by weight is formed. In a Li concentration step, the lithium content is raised to at least 0.14% by heating the concentrate II to a temperature of at least 60 C. and thus a lithium-rich concentrate III and a residue III are formed.

The present disclosure relates to methods of removing brominated contaminants from polystyrene waste and recovering the brominated contaminants. The present disclosure further relates to methods of recycling polystyrene waste, wherein the recycling comprises retention of brominated contaminants or removal of contaminants. The present disclosure also relates to use of monocyclic aromatic benzenic solvents in the removal and/or recovery of brominated contaminants from polystyrene waste and in the recycling of polystyrene waste. Moreover, the present disclosure relates to use of the recovered brominated contaminants in the manufacture of polystyrene products such as insulation.

Disclosed is a process for the purification of LNnT (lacto-N-neotetraose) from a fermentation broth, the process comprises subjecting a fermentation broth to a first step of membrane filtration, thereby providing a filtrated solution, such filtrated solution is subjecting to a second step of simulated moving bed chromatography, obtaining a purified solution thereof, then subjecting this purified solution to a third step of crystallization, obtaining crystals containing the LNnT of interest, and subjecting the crystals to a fourth and final step of drying, thereby providing a highly purified powder of LNnT.

The pharmaceutical industry is highly regulated to ensure the safety, efficacy, and quality of medicines and drug discolouration is one of the leading causes for drug recall. An object of the present invention is to provide an improved method of manufacturing cannabinoids for use in pharmaceuticals that is both stable and substantially pure. Such use of stable and substantially pure cannabinoids in pharmaceuticals will improve patient compliance to medication. The main steps of the method are decarboxylation, extraction, winterization and crystallisation.

A production system, production method and application of general-purpose high-purity chemicals are disclosed. The production system includes a raw material tank, and an adsorption system, a crystallizer, a first light-impurity removal tower, a first heavy-impurity removal tower, a second light-impurity removal tower, a motorized tower, a second heavy-impurity removal tower, a vapor permeation device, a membrane separation system and a filling system connected with the raw material tank in sequence. The high-purity chemicals produced by the above system have high purity and excellent quality. Compared with the prior art, the system and method designed by the present disclosure have more pertinence, integrity, progressiveness, energy-saving, precision, high safety coefficient and great industrial promotion value. And the products produced are of excellent quality, which can meet the standards applied to the manufacturing of integrated circuit electronic components and meet the high-end needs of the semiconductor industry market.

The present invention provides a method capable of sufficiently reducing impurities with excellent separation efficiency even from a crystal-containing slurry that contains a low-purity mother liquor and has poor solid-liquid separation properties. The present invention relates to a method for producing a compound, the method including: a step of feeding a slurry containing crystals of the compound to a hydraulic wash column; a step of melting crystals in a crystal-containing circulation slurry discharged from the hydraulic wash column; and a step of returning a portion of a circulation liquid containing a melt obtained in the melting step to the hydraulic wash column, wherein the circulation liquid returned in the returning step in an amount of more than 30% by mass relative to 100% by mass of the melt serves as a washing liquid for crystals.