Abstract: A method for the purification or recovery of lactide rich streams by the combination of a suspension-based melt crystallization process with a subsequent separation of the pure lactide crystals in a wash column is disclosed.

Abstract: The invention relates to a method for the purification or recovery of orthophosphoric acid rich streams by suspension-based melt crystallization. The orthophosphoric acid is crystallized as the hemi-hydrate form and subsequent separation of such crystals in a wash-column produce a high purity acid/water solution that has been depleted of most of the metals and impurities other than water, thereby separating an orthophosphoric acid rich feed liquor into an ultra-pure orthophosphoric acid hemi-hydrate and a mother liquor containing almost all impurities originally present in the feed. The orthophosphoric acid rich feed liquor typically contains no more than 15 wt % water and 1 wt % other impurities. Individual metal ion composition in the purified orthophosphoric acid product is in the range of 100 to 1000 ppb (parts per billion= 1/1000 ppm) of each metal ion. The metal ion composition of the resulting purified product is thus typically below the detection limit of typical analysis equipment.

Abstract: A method for the purification or recovery of lactide rich streams by the combination of a suspension-based melt crystallization process with a subsequent separation of the pure lactide crystals in a wash column is disclosed.

Abstract: The invention relates to a method for the purification or recovery of orthophosphoric acid rich streams by suspension-based melt crystallization. The orthophosphoric acid is crystallized as the hemi-hydrate form and subsequent separation of such crystals in a wash-column produce a high purity acid/water solution that has been depleted of most of the metals and impurities other than water, thereby separating an orthophosphoric acid rich feed liquor into an ultra-pure orthophosphoric acid hemi-hydrate and a mother liquor containing almost all impurities originally present in the feed. The orthophosphoric acid rich feed liquor typically contains no more than 15 wt % water and 1 wt % other impurities. Individual metal ion composition in the purified orthophosphoric acid product is in the range of 100 to 1000 ppb (parts per billion= 1/1000 ppm) of each metal ion. The metal ion composition of the resulting purified product is thus typically below the detection limit of typical analysis equipment.

Abstract: The invention relates to an apparatus for the purification of a substance from a solution, a suspension or a mixture of liquids by crystallization, preferably in a continuous manner. The apparatus comprises a first crystallizer (1c) comprising an input (1) for receiving a liquid comprising the substance and an output (4) for discharging a slurry of liquid and crystals. The apparatus comprises also a first separator (1s) connected to the output 4 of the first crystallizer (1c) having a product output (2), and being with a residue output (5) connected to an input of a second crystallizer (2c), and a second separator (2s) being with an input connected to an output (6) of the second crystallizer (2c), a crystal output (7) of the second separator (2s) being connected to an input of the first crystallizer (1c).

Abstract: An apparatus for separating solids from a suspension includes a hollow cylindrical column having a central axis therethrough. The column has an interior with a cross-section, perpendicular to said axis, that is constant along said axis, and that extends from a first end to a second end of the column; one central tube axially disposed in said column and extending from said one end toward said opposite end, said central tube having an outer wall of constant diameter, said cylindrical column and said central tube defining an annular zone between them, extending axially from said first end of the column to at least near said second end of the column; at least one filter in said outer wall of the said central tube, forming the only direct communication between the said annular zone and the interior of the tube and at least one filter in the outer wall.

Abstract: An apparatus for separating solids from a suspension includes a hollow cylindrical column having a central axis therethrough.

Abstract: An installation for crystallizing a liquid from a solution, for example for freeze-concentrating effluent, having a nucleation zone, a ripening zone and a separator where the nucleation zone is constructed as a vacuum crystalline, such that the installation is of relatively simple and inexpensive construction, can easily be scaled up and is suitable for concentrating liquids containing undissolved particles, such as, for example, precipitated salts.

Abstract: The invention relates to a crystallization apparatus and to a method for crystallizing a liquid from a solution, a mixture of liquids or a suspension. The apparatus comprises a growth zone in a vertically positioned tank, which growth zone is positioned below a nucleation zone. Via a delivery line the seed crystals are fed from the nucleation zone to the bottom end of the growth zone. In the growth zone the ice slurry slowly moves in a vertical direction at such a low velocity that heavier particles are able to precipitate and to be discharged at the bottom end. Preferentially, the nucleation zone comprises a vacuum apparatus for effecting a reduction in pressure in the nucleation zone to between 10−4 and 7·10−3 bar. Using the apparatus according to the present invention it is possible for waste water and effluent to be concentrated in a simple manner, clogging of, for example, filters owing to the settling of solid particles being prevented.

Abstract: The present invention relates to a method and installation for the crystallisation of a liquid from a solution, a suspension or a mixture of liquids using a crystalliser 2 which, for example, is provided on its wall with a heat exchanger 4 and comprises a single chamber for both nucleation and growth. Depleted mother liquor is withdrawn from the crysiallisation vessel via a filter 10 located in the crystalliser, so that the crystal content in the vessel can be accurately adjusted for the purpose of optimum separation of the crystals, preferably using a packed-bed wash column. The crystalliser preferably contains a stirrer with the filter on the stirrer 5 shaft. The filter rotates past a scraper 12, which is arranged in a fixed position, as a result of which the filter cake can be reintroduced into the suspension without damage to the crystals.

Abstract: An installation for separating and purifying solids from a suspension and/or for leaching out solid particles has a cylinder and a piston movable therein. A sealing part of the piston is in contact with the interior wall of the cylinder. A filter is positioned some distance away from the sealing part of the piston. A discharge chamber is located between the filter and the sealing part of the piston. A pump chamber is formed below the sealing part of the piston and a washing column chamber containing a packed bed of solid particles is formed above the filter. During a downward pump stroke of the piston, suspension is forced, via at least one connecting channel between the pump chamber and the washing column chamber, to the washing column chamber. During a compression stroke, liquid is brought via the filter to the discharge chamber and discharged via a discharge line. Solid particles, such as crystals, remain behind on the filter and are compressed against the packed bed.

Abstract: An apparatus for purifying waste streams having water, dissolved noxious substances and volatile organic compounds, comprising a distillation unit having distillate and bottoms products, a freeze-concentration unit and a processing unit. The distillate product is processed in the processing unit and the bottoms product is processed in the freeze-concentration unit, where purified water is extracted.