Laserfiche WebLink
:O:SJ <br />9a_8 <br />C\'Qlli(1C Chrntisn•v mrd Trrnlmeal <br />C I V' <br />• Sulphite which wins access ro the absorption solution may cause positive <br />or negative interference with colourimetric procedures at vcAy low <br />concentrations. <br />• Thibgan:uc is a major interference to the total cyanide distillation rhethod. <br />usually rtsultine in high cyanide v;t0.ics: however, decomposition is not <br />predictable :md the mechanism ix uncertain. <br />• Bisulphate appear to he a primary ncativc intcrferenre with the pbtcntial <br />for some degree of cyanide desvucuon. Residual bisulphate is an <br />interterence. <br />• Sulphur species interference may he minimized by the following trea)ments: <br />- sulphide precipitation from the sample <br />- distillation of smallest possible sample <br />• sulphide precipitation from the absorption solution <br />- increased levels of chloratninc-T in ttte colourimetric procedure <br />2.5 CALCULATIUi+i OF A MASS BALA\Cl: <br />It is possible to check the validity of a series of cyanide analyses by complt_tin~ a <br />mass balance. comparing the various cyanide and metals levels obtained From the <br />analysis of else :;tme solution. <br />006.001 <br />be notes <br />associates <br />cyanide !c <br />The di;'I'er <br />cyanide .:.: <br />is that ci <br />corresoe:t: <br />(i.e. 0.30 <br />AsSumin'_ <br />complexc <br />nickel cc: <br />metais' :~ <br />result. it _ <br />are relia~. <br />are come <br />2.6 REF: <br />ASCI/Sn <br />Remove! <br />Dakota. ~. <br />ASTM. <br />I The mass calculations an. prepared assumins• that iron is bowed to six cyanide <br />molecules (i.e. FutCNh), copper is bound to thrcc ~y:midc molecules (i.e. CuICN),). <br />nickel ix bound to four cyanide molecules (i.c. Ni(CN),). and zinc cyanide is <br />completely dissociated as free cyanide anti the arcs metal. Thexe are the four main <br />metals in cymtidation solutions, althnu_,h nthur mct:ds could be addtd to thu <br />calculations l i.e. Iced. silver or mercury) if present in elevated concentrations. Based <br />upon the number ofcyanide molecules bound nr rtrh instal. the weight ratio pl each <br />metal to cyanide is as follows: <br />r • Iron (1.?6 me Fehm_ CN <br />~ ,. • Copper 0.82 nn, Cu/me CN' <br />• Nickel 0.5b m, Vi/nr~ CM <br />As an ex:unple ,usunte a total, wad ;utd li~uc c•:anitle :utalv+is of the same solution <br />~i , protiuccd conccntr;uion. of 300 mJl. 171 ot_~/I ,uul 121 mg/I. respcctivuly. It ~hnuld <br />:~ <br />.Snrirlr unrl .tluddrr ~~ <br />~.:'~ <br />' I <br />i <br />Banon.:= <br />wascw;: <br />1978. <br />Brickell, <br />Minir.e <br />Geordie: <br />Conn. ;~. <br />Induatn <br />Csik::t. <br />Thiocv.n <br />