Abstract: Process for treating phosphoric acid for removing heavy metal cations, in particular cadmium, and sludges contained in the acid, characterized in that concentrated phosphoric acid having a low solids content is used and in that the calcium sulfate supersaturation of the phosphoric acid is controlled to form a compound of the formula I:(SO.sub.4).sub.1-x (PO.sub.4).sub.x (H).sub.y Ca.sub.1-67 M;where x is between 0.5.times.10.sup.-2 and 1.times.10.sup.-1 ; y is between 0 and x+.delta.; .delta. indicates the chemical substitution of calcium by other metal cations; and M represents one or more metal cations contained in the initial phosphoric acid, whose total charge is approximately equal to 2.delta.+x-y.The following "Brief Description of Drawings" has been inserted between lines 19 and 20 on page 4 of the specification to comply with 37 CRF 1.74 and MPEP 608.01(f).The sole FIGURE of the Drawings is a flow diagram illustrating one embodiment of the process according to the present invention.

Abstract: A telephone set is provided enabling seizure for originating and terminating calls of a telephone line connected thereto to be performed as well as release thereof, as the result both of a first command produced by a first switching entity actuated from the handset of the telephone set as well as via a second command produced by a second switching entity that is able to be actuated independently of the handset, switching entities producing the commands via individual communication establishment elements which are inserted in parallel in a loop which links, via the controlled power feeding arrangement, the output terminals of a first diode bridge, the input terminals of which are connected to the two line wires via a protection circuit, together with a second diode rectifying bridge, performing actual rectification, linked via capacitors to the output of the protection device, in parallel with the first diode bridge, and adapted to power a microprocessor and relevant circuits of telephone set circuitry, via a