Research On The Properties Of Basalt Fabric/PPS Needle Punched Filter

Air pollutions were mainly caused by exhaust gases, which included dusts, hydrochloride, O₂, CO, SO₂, NO_x, H₂O and emitted from coal-fired power plant, cement plants, steel works, incinerating plants at the temperature of 160²40℃. People paid more attention to environmental protection and improvement of the clean level of emitted gases. Thus, the study of high temperature filtration became an important work.The aim of the study was to investigate the mechanical properties of PPS fibers in high temperature, acids and alkali, the mechanical and chemical resistant properties of basalt fabric, the effect of needle-punched on the properties of basalt fabric/PPS filter and the effect of finishing on the properties of basalt fabric/PPS filtration.The results showed that HCl and HNO3 had obviously detrimental effect on the properties of PPS fibers relative to NaOH and H₂SO₄. Many cracks and holes appeared on the surface of PPS fibers after HCl or HNO₃ exposure. The breaking strength and breaking elongation of PPS fibers were decreased as the increasing of concentrations and extension of time. Their melting heat was mostly affected by HNO3 among those acids and alkali. HCl accelerated the degradation of HNO3 on PPS fibers. When the treatment temperature was over 230℃, there were more and more small particles appeared on the surface of the PPS fibers as the increase of the treatment temperature.Tensile strength of basalt twill fabric was greater than that of plain fabric. Basalt fabric is not alkali resistance, good performance in HNO3 resistance, general performance in H2SO4 resistance, poor performance in HCl resistance. The color of basalt fabrics changed from the golden yellow to Silver and the breaking strength dropped significantly after HCl treatment.The breaking strength and breaking elongation rate of basalt fabric and the basalt based/ PPS filter decreased as increasing of the needling density. The breaking strength of basalt twill fabric and basalt twill fabric based / PPS filter than that of the plain fabric and plain fabric based PPS filter punched by the same needling density.Filter became smoother and denser after the singeing and calendering treatment, which also decreased the thickness, reduced gas transmission to be nearly half of the untreated filter, decreased the average pore size and enhanced the filtration efficient. Single-side gelatinizing treatment increased the breaking strength of the filter, reduced gas transmission to be half of the pre-coating filter and increased the filtration efficient. Single-side tectorial membrane treatment decreased the media pore size and enhanced filtration efficient of the filter. The filtration efficient against the particle size bigger than 0.3μm was over 94%, and the filtration efficient increased to 100% when the particle size was greater than 3μm.