Research On Stability Of Insoluble Sulfur By Using Low Temperature Method

The technologies for insoluble sulfur (IS) production and related stabilizers at home and abroad were summarized in the paper. Low temperature method was used to produce IS with commercial sulfur as feedstock. Common sulfur and IS were analyzed by XRD and SEM, The results show as following:Their characteristic peaks are different, clarity of the characteristic peaks of IS are better than common sulfur, intensity of the characteristic peaks of IS are greater than common sulfur. The greater the characteristic peak in XRD is, the higher the content of IS is. The particle structure of IS affects significantly its thermal stability. Effect of stabilizers on IS thermal stability in the extraction and oil-treating processes were studied, the results show that the suitable stabilizer for extraction is ester III (by 2.0 m%),as a result, the thermal stability of IS at 120℃ is 45.89%(wt/%), the ideal for oil-treatment is ester III (by 2.0 m%) and at 120℃ is 49.03%(wt/%), and effect of the mixed stabilizer on increasing the thermal stability of IS is invisible. Effect of the addition of stabilizer in oil-treating process on increasing the thermal stability of IS is better that in extraction process. The thermal stability of IS can be improved further if the stabilizers are simultaneously added in the extraction and oil-treating processes. The addition of stabilizer ester III (by 2.0 m%) in both extraction and oil-treating process gets the best result and the thermal stability of IS produced by using low temperature method is 52.31%(wt/%) at 120℃, the result have reached the leading domestic level in the same process. Acidity, dash content and heating reduction of oil-treatment IS can meet the requirement of IS standard. Rubber accelerators with alkalinity have negative effect on the thermal stability of IS.