Hidrotalsiet, vervaardig uit magnesieterts, as niegiftige hittestabiliseerder vir polivinielchloried : research and review article

The production of hydrotalcite from magnesite ore as non-toxic heat stabiliser for polyvinyl chloride In recent years polyvinyl chloride (PVC) processors had to submit to worldwide pressure to convert to environmentally friendly stabilisers such as hydrotalcite (HT), since most of the heat stabilisers currently in use contain heavy metals such as lead, cadmium or barium - these being highly toxic. The presently used HT production process is, however, very expensive as it involves the recovering of magnesium from seawater magnesia. The purpose of this study was to prove that it is indeed possible to produce cost effective and non-toxic HT from an alternative source. During this study the costing and heat stabilising ability of the hydrotalcite produced from magnesite was compared to that of commercially available heat stabilisers. The effect of the pre-mixing process, as well as the influence of particle size distribution was also investigated. A cost comparative and stabilising efficiency study indicated the cost effectiveness of HT produced from magnesite ore, in comparison with other commercially available stabilisers. The use of HT as produced from magnesite ore would indeed assist in the worldwide changeover to environmentally friendly stabilisers. Gedurende die afgelope paar jaar het die druk op polivinielchloried (PVC) -verwerkers aansienlik toegeneem om na omgewingsvriendelike stabiliseerders soos hidrotalsiet (HT) oor te skakel, aangesien die meeste hittestabiliseerders wat tans in gebruik is, giftige swaarmetale soos lood, kadmium, of barium bevat. Die vervaardigingsproses van HT is tans baie duur, aangesien dit die herwinning van magnesium uit seewatersoute behels. Hierdie studie is daarop gemik om te bewys dat dit wel moontlik is om meer bekostigbare en niegiftige HT uit magnesieterts te vervaardig. Tydens die studie is die doeltreffendheid en koste-implikasies van HT vervaardig uit magnesieterts, vergelyk met kommersieel beskikbare stabiliseerders asook HT-stabiliseerders soos vervaardig uit seewatersoute. Die effek van voorafvermengingsprosesse van die stabiliseerders en smeermiddels, asook partikelgrootteverspreiding op die finale stabiliseringsvermoë, is ook ondersoek. 'n Kostevergelykende studie het aangetoon dat PVC-verwerkers wel koste kan besnoei deur na hierdie plaaslik vervaardigde stabiliseerder oor te skakel. HT kan dus inderdaad as kostedoeltreffende en niegiftige stabiliseerder vir geplastiseerde PVC aangewend word. Die wêreldwye o