Silver recovery apparatus

Claim 2

A silver recovery apparatus, in which silver bearing source material is digested by nitric acid to form a reaction mixture for which silver(I) cyanide is thereafter precipitated by addition of cyanide solution, comprising in combination: a digestion vessel; a precipitation vessel; first communication means for selectively motivating filtered fluid flow from the digestion vessel to the precipitation vessel; a waste reservoir; second communication means for selectively motivating fluid flow from the precipitation vessel to the waste reservoir; a filter assembly disposed in the interior of the precipitation vessel at the terminus of the second communication means; a cyanide solution reservoir; third communication means for selectively motivating fluid flow from the cyanide solution reservoir to the precipitation vessel; a source of inert pressurized gas; and fourth communication means for selectively motivating flow of inert pressurized gas into the precipitation vessel.

Claim 3

The apparatus of claim 1 in which the filter assembly disposed in the interior of the precipitation vessel comprises: a header connected to the second communication means; an internal pipe connected to header, with the internal pipe carrying a plurality of perforations; a filter sleeve disposed coaxially over the internal pipe so as to overlay the perforations in the internal pipe; and sealing means establishing a fluid-tight seal between the ends of the filter sleeve and the exterior surface of the internal pipe.

Claim 4

The apparatus of claim 2 in which the first, third and fourth communication means terminate in a single, shared conduit within the interior of the precipitation vessel.

Claim 5

The apparatus of claim 3 in which the first communication means and second communication means further comprise: a pumping means having a suction port and a compression port; a first conduit connecting the suction port of the pumping means and the lower interior portion of the digestion vessel; a first valve interposed in the first conduit; a second conduit having a first end connected to the pressure port of the pumping means, and a second end; a filter means interposed in the second conduit a third conduit having a first end connected to the second end of the second conduit, and a second end; a second valve interposed in the third conduit; a fourth conduit having a first end connected to the second end of the third conduit, and a second end; a third valve disposed in the fourth conduit; a feeder nipple having a first end connected to the second end of the fourth conduit and a second end connected to the filter assembly; a fifth conduit having a first end connected to the junction of the third and fourth conduits, and a second end connected to to the junction of the second and third conduits, and a second end disposed in the waste reservoir; a fourth valve interposed in the fifth conduit; and a sixth conduit having a first end connected to the junction of the second and third conduits, and a second end disposed in the waste reservoir; and a fifth valve disposed in the sixth conduit.

Claim 6

The apparatus of claim 4 in which the digestion vessel is sealed by a cover having a ventilation outlet, with the ventilation outlet connected by conduit means to a gas disposal area.

Claim 7

The apparatus of claim 4 in which the precipitation vessel is sealed by a cover having a ventilation outlet, with the ventilation outlet connected by conduit means to a gas disposal area.

Claim 8

The apparatus of claim 4 in which the digestion vessel is sealed by a substantially transparent cover.

Claim 9

The apparatus of claim 4 in which the precipitation vessel is sealed by a substantially transparent cover.

Claim 10

The apparatus of claim 3 in which the third communication means comprise: a seventh conduit establishing fluid communication between the cyanide solution reservoir and the precipitation vessel; a sixth valve interposed in the seventh conduit; and elevating means holding the cyanide solution reservoir at an altitude substantially higher than that of the precipitation vessel.

Claim 11

The apparatus of claim 3 in which the fourth communication means comprise: an eighth conduit establishing fluid communication between the source of inert pressurized gas and the precipitation vessel; and a seventh valve interposed in the eighth conduit.

Claim 12

The apparatus of claim 3 additionally comprising: a water source; a ninth conduit connecting the water reservoir and the precipitation vessel; and an eighth valve interposed in the ninth conduit.