1992-04-02_REVISION - M1988112 - Laserfiche WebLink

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..: i ~- 1 ' Pape 15 TABLE 12 CYANIDE DECAY IN ENTRAINED LIOUOR FLOLLOWING CYANIDE RECOVERY t't 1 1 1 Parameter nRl 1 Week .-;;2 Weeks 4 Weeks ' _ 8 Weeks 2~ ,Weeks pH 102 9.7 ~ ~ '' 9.1 9.8 9.8 9.3 SO4 2525 2525 2580 2530 2370 2390 Ca - 858 858 858 858 808 805 Total hardness 2140 2140 '2140 2140 2013 2008 (as CaCO,) Total CN 29.4 29.4 3i.3 25.5 27 26 WAD CN 6.8 6.6 5.5 3.8 2.1 1.51 Cd 0.1 <0.01 <0.01 <0.01 <0.01 <D.Ot CO 0.33 0.25 0.2 ---- -- -- Cu 6 4.3 2.9 2.1 0.63 D.16 Fe 8.7 8.9 9 9.3 9.3 B.5 Zn 0.01 0.03 0.01 <0.01 0.01 0.01 Pb <0.1 <0.1 <0.1 <0.1 - -- Mn 0.02 0.02 <0.01 0.01 0.02 0.02 Ag 0.04 0.01 0.01 0.02 0.02 0.02 Cr 0.02 ---- ---- <0.02 --- --- Hg 0.0002 <0.0001 <0.0001 <0.0001 -- --- CYANIDE DECAY IN TAILINGS DECANT FOLLOWING CYANIDE RECOVERY t't Exposure 71me BFI T tai tr WAD Pf Initial 10.2 29.4 6.8 1 day B.0 29.4 ---- 3 days 8.2 30.0 ---- 7 days 8.3 30.0 ---- 14 days 8.0 31.9 ---- 28 days 7.3 32.0 0.33 t'~ All values In mg/I, unless otherv+ise stated. The results of the laboratory end pilot plant Investigations have proven the vtabilRy of the Cyanltsorb Process for recovery of cyanide }rpm slurries. In addRion to the recovery of cyanide, there were further environmental advantages retating to the disposal of fallings and the potenC~al (or groundwater contamination. The next section of the paper examines the economic aspects of cyanide recovery from solutions and slurries. ECONOMICS OF CYANIDE RECOVERY PROCESSES In apptlcations where treatment of tailings prior to disposal Is warranted, there are sevetal economic advantages to cyanide recovery systems. First, the operating costs associated with chemical treatment are eliminated, while second, a useful and expens(ve reagent (i.e. cyanide) Is recovered. The cost recovery more than offsets the cost of the cyanide recovery system. Third, the cyanide recovery systenns are simple in design and operation, thereby minimizing operator requirements end the degree of automated contrd.