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Determination of magnesium and aluminium in zinc-base die-casting alloys
SHORT
404
COMMUNICATION
i.e. 96,500 C/o.5 mole of water) amounts to 17.9 PA for each mg of water present per the water content in p.p,m, (v/v), cubic meter gas at 760 mm and 20”. Expressing this factor becomes 13.4 ,uA. The range of the cell is from 5-2000 mg of water per cubic meter.Xoth t.hg,_absorption and the electrolysis proceed with IOO~/~efficiency, hence no additional calibration 63a/o-response is The standard deviation is about SOL,. The so-called is necessary. achicvccl within x.5 min. It is interesting to note that phosphoric acid spattering on the inner wall of the cylindrical glass mantle does not noticeably disturb the measurement. Several instruments of this type have been satisfactorily used for four years.
Addendum Determination of magnesium and aluminium zinc-base die-casting alloysl
in
In the above paper, brief mention was made of the possibility oi applying the mcthocl describccl for cletcrmination of magnesium in aluminium alloys. We have since found that silica interferes in this method by causing coprccipitation of magnesium with l;c, Mn and Al. ‘I’hc method given (2nd pnrngrapll, 1~. 339) should thcreforc be modified as follows. The main constituent (aluminium) was removed by clissolving the alloy in sodium hydroxiclc. The insoluble residue was filtered off on paper and the residue and paper were digestccl with nitric and sulphuric acicls, nitric acid being removed by fuming. More nitric acid was added as required to ensure complete rcmovnl of organic matter. Under these conditions, silica is insoluble. After cligcstion and dilution, silica was ‘The PC, Mn and Al remaining were then climfilterccl off along with lcacl sulphatc. inated with ammonia and ammonium pcrsulphate, before the magnesium was dctcrminccl as clcscribccl originally. The aclclition of potassium cyanide before titration with ISDTA masks any zinc which may coprccipitate with MgNHlrl’0,1*6 HzO. H. J. vcm dev Rijlt,N .V. Research L&oratory, Nmrdeu (‘l’h Netherlands) 1
L.
l3LOCI-1,
Received
nmd.
June
Ciritrr.
28th,
Ada,
1g61
“3 (1gGo) ,233.
L.
HLOCH
404
COMMUNICATION
i.e. 96,500 C/o.5 mole of water) amounts to 17.9 PA for each mg of water present per the water content in p.p,m, (v/v), cubic meter gas at 760 mm and 20”. Expressing this factor becomes 13.4 ,uA. The range of the cell is from 5-2000 mg of water per cubic meter.Xoth t.hg,_absorption and the electrolysis proceed with IOO~/~efficiency, hence no additional calibration 63a/o-response is The standard deviation is about SOL,. The so-called is necessary. achicvccl within x.5 min. It is interesting to note that phosphoric acid spattering on the inner wall of the cylindrical glass mantle does not noticeably disturb the measurement. Several instruments of this type have been satisfactorily used for four years.
Addendum Determination of magnesium and aluminium zinc-base die-casting alloysl
in
In the above paper, brief mention was made of the possibility oi applying the mcthocl describccl for cletcrmination of magnesium in aluminium alloys. We have since found that silica interferes in this method by causing coprccipitation of magnesium with l;c, Mn and Al. ‘I’hc method given (2nd pnrngrapll, 1~. 339) should thcreforc be modified as follows. The main constituent (aluminium) was removed by clissolving the alloy in sodium hydroxiclc. The insoluble residue was filtered off on paper and the residue and paper were digestccl with nitric and sulphuric acicls, nitric acid being removed by fuming. More nitric acid was added as required to ensure complete rcmovnl of organic matter. Under these conditions, silica is insoluble. After cligcstion and dilution, silica was ‘The PC, Mn and Al remaining were then climfilterccl off along with lcacl sulphatc. inated with ammonia and ammonium pcrsulphate, before the magnesium was dctcrminccl as clcscribccl originally. The aclclition of potassium cyanide before titration with ISDTA masks any zinc which may coprccipitate with MgNHlrl’0,1*6 HzO. H. J. vcm dev Rijlt,N .V. Research L&oratory, Nmrdeu (‘l’h Netherlands) 1
L.
l3LOCI-1,
Received
nmd.
June
Ciritrr.
28th,
Ada,
1g61
“3 (1gGo) ,233.
L.
HLOCH