A method of determining the remaining water volume (RLV) which can still be softened prior to the exhaustion of an ion exchange resin contained in a filter device. A water softening system, a computer program and a computer readable medium having stored thereon the computer program.

A method of determining the remaining water volume (RLV) which can still be softened prior to the exhaustion of an ion exchange resin contained in a filter device. A water softening system, a computer program and a computer readable medium having stored thereon the computer program.

Provided are an apparatus and a method for ion-exchange extraction of lithium from natural or technological brine by using a lithium-selective inorganic sorbent operating on a principle of an ion sieve. The apparatus contains a plurality of ion-exchange columns arranged and interconnected in sequence. Flows of the brine, flush water, acidic desorption solution, and outputs, of the processed products are controlled via switchable shut-off valves. The method can be carried out by operating the apparatus in a parallel or a serial mode of column operations. In the parallel mode, all columns work simultaneously in the same manner. In the serial mode of operation, the columns work individually with a shift of the sorption-flushing-desorption-flushing cycles sequentially and with a transfer of the processed brined sequentially from the first column to the last column and from the last column to the first one thus providing continuity of the lithium-extraction process.

Provided are an apparatus and a method for ion-exchange extraction of lithium from natural or technological brine by using a lithium-selective inorganic sorbent operating on a principle of an ion sieve. The apparatus contains a plurality of ion-exchange columns arranged and interconnected in sequence. Flows of the brine, flush water, acidic desorption solution, and outputs, of the processed products are controlled via switchable shut-off valves. The method can be carried out by operating the apparatus in a parallel or a serial mode of column operations. In the parallel mode, all columns work simultaneously in the same manner. In the serial mode of operation, the columns work individually with a shift of the sorption-flushing-desorption-flushing cycles sequentially and with a transfer of the processed brined sequentially from the first column to the last column and from the last column to the first one thus providing continuity of the lithium-extraction process.