A treatment system for removing hardness, silicon, and turbidity from wastewater having a high salt concentration, comprising an integrated reaction apparatus comprising a reaction box and a chemical drug adding device, and a membrane separation apparatus comprising a membrane pool and a membrane component. The wastewater having the high salt concentration enters the reaction box; a required chemical drug is added to the wastewater by means of the chemical drug adding device; the chemical drug and the wastewater are fully mixed and reacted to produce different kinds of sludge particles; a sludge particle mixed liquid directly enters the membrane pool; under the action of an aeration device, the sludge particle mixed liquid is in a suspension state and uniform in concentration, and is screened and filtered by the membrane component; and produced water is discharged from the membrane pool, and intercepted sludge particles are discharged from the membrane pool.

Provided are: an economically superior protein crystallization method capable of efficiently finding conditions for crystallization by using a small amount of protein; and a crystallization device used for the method. According to the present invention, a transparent sealed container 1 is filled with a solution of protein, a part of the transparent sealed container 1 being formed of a semipermeable membrane 2 with a molecular weight cut-off that inhibits passage of the protein while allowing passage of a precipitant, and then, a precipitant solution with changed concentration and/or pH of the precipitant is continuously supplied to the semipermeable membrane 2, to crystallize the protein with the precipitant that infiltrates from the semipermeable membrane 2 into the sealed container 1.

Disclosed are methods of treating wastewater using a membrane bioreactor and achieving a target phosphorus concentration for the membrane permeate stream. These methods include the steps of dosing a wastewater stream with a rare earth clarifying agent and passing the dosed wastewater stream through the membrane to obtain a membrane permeate stream with a permeate concentration that is less than the phosphorus concentration of the influent stream. This permeate concentration also can be equal to or less than a target phosphorus concentration. In the methods as disclosed herein, the rare earth clarifying agent can be chloride salts of one or more rare earth elements and in certain embodiments, the rare earth clarifying agent can be CeCl.sub.3 and LaCl.sub.3.

A membrane separation process is described. The process comprises pumping of a fluid stream through a membrane module to produce a permeate during a plurality of membrane operating cycles. Each membrane operating cycle comprises a filtration cycle and a relaxation cycle. Concentration polarisation is controlled during the process by controlling duration of filtration cycles and relaxation cycles to relatively short duration to maintain the degree of concentration polarisation below a target.

A membrane separation process is described. The process comprises pumping of a fluid stream through a membrane module to produce a permeate during a plurality of membrane operating cycles. Each membrane operating cycle comprises a filtration cycle and a relaxation cycle. Concentration polarisation is controlled during the process by controlling duration of filtration cycles and relaxation cycles to relatively short duration to maintain the degree of concentration polarisation below a target.

Disclosed by the invention is a method for preparing lithium carbonate from lithium ore, comprising the steps of: preparing lithium sulfate leachate from lithium ore concentrate, removing Fe.sup.2+ and Al.sup.3+ from the lithium sulfate leachate by adding alkali, removing Ca.sup.2+ and Mg.sup.2+ from the lithium sulfate leachate by an ion exchange method, adding a saturated solution of soda ash into the obtained concentrated solution of lithium sulfate leachate, precipitating lithium carbonate, filtering and separating the lithium carbonate precipitate, washing with hot water and drying to obtain a finished lithium carbonate product. The invention saves the production cost, and obviously improves the purity of lithium carbonate as a final product. In addition, disclosed by the invention is also a system for realizing the method for preparing lithium carbonate from lithium ore.

Disclosed by the invention is a method for preparing lithium carbonate from lithium ore, comprising the steps of: preparing lithium sulfate leachate from lithium ore concentrate, removing Fe.sup.2+ and Al.sup.3+ from the lithium sulfate leachate by adding alkali, removing Ca.sup.2+ and Mg.sup.2+ from the lithium sulfate leachate by an ion exchange method, adding a saturated solution of soda ash into the obtained concentrated solution of lithium sulfate leachate, precipitating lithium carbonate, filtering and separating the lithium carbonate precipitate, washing with hot water and drying to obtain a finished lithium carbonate product. The invention saves the production cost, and obviously improves the purity of lithium carbonate as a final product. In addition, disclosed by the invention is also a system for realizing the method for preparing lithium carbonate from lithium ore.

A method for highly concentrating aqueous solutions containing thermally sensitive organic constituents and with or without mineral constituents, wherein firstly, a major portion of the water is extracted by membrane filtration from the solution for pre-concentration and is discharged from the process and the solution which is pre-concentrated is then subjected to a freeze concentration procedure, in which, in the form of separated ice crystallisate, further water is extracted from the solution. To promote results, that concentration may be effected in the freeze concentration procedure until a viscosity of the mother solution of at least 0.0002 m.sup.2/s is achieved, and in that the separated ice crystallisate from the freeze concentration with the mother solution adhering thereto as a suspension is returned to the membrane filtration upstream of the membrane filtration or after melting of the ice crystallisate.

A method for highly concentrating aqueous solutions containing thermally sensitive organic constituents and with or without mineral constituents, wherein firstly, a major portion of the water is extracted by membrane filtration from the solution for pre-concentration and is discharged from the process and the solution which is pre-concentrated is then subjected to a freeze concentration procedure, in which, in the form of separated ice crystallisate, further water is extracted from the solution. To promote results, that concentration may be effected in the freeze concentration procedure until a viscosity of the mother solution of at least 0.0002 m.sup.2/s is achieved, and in that the separated ice crystallisate from the freeze concentration with the mother solution adhering thereto as a suspension is returned to the membrane filtration upstream of the membrane filtration or after melting of the ice crystallisate.

Disclosed is an apparatus for water treatment, including a membrane separator for solid-liquid separation; and a particle fractionator which has at least two exits of a fractionated solid-liquid mixture produced therein, wherein a liquor containing particles of different sizes including submicron particles is fed to the particle fractionator before a membrane separation by the membrane separator, and wherein a first fraction of the fractionated solid-liquid mixture is returned to the membrane separator from one exit of the at least two exits of the particle fractionator, the first fraction being less than the liquor in terms of content of the submicron particles. This apparatus enables a rapid achievement of suppression of membrane fouling.