INDUSTRY ti33
possibly bc niisscd in nu ordinary nnnlysis to dctcrminc the purity of n snmplc of IICI. It was detected and cstirnated nftcr its prcscncc ivns suriiiiscd I J ~ osidizing n litrc of tlic ncid nnd cviipornting to sninll bulk with p r c IT,SO, to cliniin;itc chlorides nnd eetimnting tho LI,l'OI by the Pemberton phosphomolybtlntc nicthotl, which is pcculinrly siiitcd to tlie estimat,ion of slnnll nmounts of phosphntcs. A quantity of phosphoru~ equnl to 0.0001 9% of tlie original " purc " acid taken for annlysis w i s found. Hence, the use of hypophosphitc seciiictl to be undeairablc as hcing n possible source of pollution with phosphorus rompounh.
Activated carbon \Tiis tlicrcforc trictl in tlic liopc that i t would prcfiwntiiilly adsorb thc AsCI, from the stream of IICI pis-rcnsoiiing tlint volntilc arficnic compounds nrc strongly iitlsorbetl by the cntnlyst in thc contact proccss, iind would, thcreforc, probnbly be strongly ndsorbcd hy activated cnrhon. Wood chnrconl w i s nctiwtcd 197 the mcthod recoinmcndcd by ITolnics, " 1,nl)oriit ory JIitnt1ii1 of Colloid Chemistry," nntl chnrgcd into n sinnll spcciirlly-mndc lead towcr construct cd roiintl nn eidiciiwnrc p i p .
This small towcr \ w s found to I)c cntircly euccessful in rcmoring AsCI, from I-ICI gas, the find product showing no tritcc of iirscnic by citlirr t,hc Cutzcit or Nm-di tests.
To rcniovc SO,, I<irInOJ is first atlded to the large \'oulf's bottle contiiining t,he ncitl, which rcsults in t h osidnt,ion of SO, to 1 I,SO, iintl t Iic production of rnucli frcc clilorinc. JIost of this is then IJlO\Vil out with compressed iiir and thc rciniiintlcr is got rid of hy adding FeCI, soltition, hcing thereby oxidized to FcCI,.