Studies On The Determination Methods Of Three Typical Tin Contained Samples

In this thesis,a determination method of tin content by potassium iodate titration has been developed for three typical tin contained samples of silver tin oxide alloy,regenerated tin sample and organotin stabilizer.In particular,silver tin oxide alloy is a main electrical contact material which is widely used in electronical switches,contactors,load switches,circuit breakers,household appliances,automotive electric appliances and other switchgear.The recycled tin comes from the waste and waste residue produced in the process of manufacturing industry or smelting enterprise.Moreover,organotin stabilizer is a kind of organic tin contained compounds,which are widely used in the process of plastic processing.The contents of this paper are summarized as follows:1.The potassium iodate titrimetric method is used to determine the tin content of silver tin oxide alloy,where the alloy samples were first dissolved in nitric acid and then silver was isolated by ammonia separation with mixed flux melting.Finally,the tin content is determined in the range of 3%-13% with a recovery rate between 97.30% and 99.60%.The relative standard deviation was obtained as 0.51%-1.93%.2.The potassium iodate titrimetric method is also successfully applied for the determination of tin content in tin recycled materials.In particular,samples were initially treated with nitric acid dissolution and ammonia separation to remove copper,silver and other impurities,and then with sodium hydroxide for alkaline fusion and iron replacement reduction to separate the impurities such as arsenic,bismuth,antimony,silver and tellurium from the sample.The determination was ranging from 5% to 50% and the recovery rate was between 98.55% and 100.10% with the relative standard deviation of 0.23%-1.69%.3.The potassium iodate titration is also available for the determination of the tin component in organic tin stabilizers.The samples were decomposed by the mixture of nitric acid and sulfuric acid,and then the produced tin was reduced by aluminum.The determination range was obtained as 15%-20%.The recovery was 98.55%-99.70% and the relative standard deviation was 0.57%-0.66%.