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<br />FMC Corporation <br />-- Research and Dsvslvpsisnt <br />_ s+rittoeton,~ Nsr Jaraay <br /> <br />CAG/s-93-012 <br />Biqa` 4 <br />1. TO elmulata additictt o! $~0~ to the actual tailings pehd, the pond <br />solution ras only stirsad !or ao segonds attar the addition or <br />bydrogan peroxide. <br />t. 2n another s.t of arissnts, the slusry vas a33owad to ssttls <br />and lI30a vas added xitkeut stis~ritfq tv the tap o! tt~a aaparaLad <br />slurry. l-ftar the 8ZO= rsaoted, ~ as widanoad by 3;)( Quant Tabs, <br />msasuramanta !or iaaDB CN' rata taxatt and the trutad • attics Mara <br />stirred to Mtarmina hot nuoh additional cyanide roul bs raised <br />troy the slurry bottoms. <br />3. In a third sat or experiments, stirring was continuac~ throughout <br />the addition of hydrogen peroxide to the slurry to simt~lats adding <br />tlyiirigas peroxide to the tailings sump prior to dirchh~rgs to the <br />nq pond. <br />The reanits are sammarlsad in liqurs i and Table 1. <br />eetaesri att and 49.9 = wens CN' dastruotion was achiavsd in stirred <br />alurrlas rith a H2O2/CN- rt ratio o! 1/1, 3.5/1 and S/1 r~apsotiwly <br />(Figure 1 and Table i). Ths rt. ratio ras oaloulatsd on the aesusptian <br />that ail the cyanide (initial oono 760 ppm) ras concentra ad in the <br />equaeua pardon of the slurry. Thane results should oor late with <br />adding H2o3 directly into the tailings ling on tt-s my to a pond. <br />since the pond rater lays over a bottom layer of tailings i the pond, <br />it i^ rsalistio to examin. the results o! the H3o3 trsatn~tst of the <br />unstirred tailings slurries it 830 injection into the po rater is <br />to bs mech. Steaults tnsa about as ettective as tr•atmsnt o the sleet <br />pond rater containing no slurry at the bottom. 1-ttar st~.rrinq the <br />prwiously tteatsd unstirred slurris^ horevsr, W11DS CH' val s roan as <br />anticipated but leveled o!! aL a substantial ~Ot to {8• lea than the <br />starting iU-DS CA7' oonaantratlon (ligare l and Table 1). <br />Treatment of clanr pond rater rith i.s/1 and 4/1 wt ratios of <br />8203/C!Q'(100t basis) resulted in !Et to 47i reductions i NADS C!i- <br />conaantrations rsspeotively (Figure i and Tabl• 1). ~n actual <br />ppr~notice, soma migration of cyanide trom the tailings at the bottom of <br />the pond bAOk into the pond rater is likely to ooour init~ally. Tha <br />sxtant of the migration rouid depend on the degree of diatiprbanca of <br />the bottom slurry layer during and altar the time Hy03 is added. <br />Treatment o! the pond water could be achieved rith a recirculating <br />