The Preparation Of Floating Materials Used In Floating Island Type Artificial Wetland

Artificial floating island is an ecology landscape started in recent years. It has asignificant role in purification and remediation of polluted water. Silicate glass havemany superior performances such as high chemical resistance, tailored porosities,high strength, no secondary pollution. It is the preferred material used in artificialfloating island. In this paper, Borosilicate foam glasses were prepared by sinteringpowder. We find out the basic formula and the best firing system through theinvestigation of the kind of foaming agent, the amount of foaming agent and foamstabilizer. The effects of additives(Sb2O3,CaSO4,Ba(NO3)2) on borosilicate foam glasshave also been investigated. X-ray diffraction (XRD) were used to analyze thecrystalline phase and scanning electron microscope (SEM) were used to characterizepore structure. The bulk density， porosity, compressive strength and thermalexpansion coefficient were also tested.Results indicated that: when the additive amount of foaming agent carbon was1%, the pore size was more homogeneous and the shape was spherical. Under thisadditive amount, the bulk density, porosity and the compressive strength was0.346g/cm3,83.53%, and3.24MPa. When the graphite was foaming agent, the bulkdensity was larger than that made of carbon. What’s more, the foam glass was difficultto machine. When the additive amount of foam stabilizer was4wt.%, the borosilicatefoam glasses presented uniform pores structure and the average pore size was0.5mm.The best firing temperature was775℃after adding foam stabilizer and the bulkdensity was0.434g/cm3, compressive strength was3.18MPa and the porosity was79.33%.When added Sb2O3in the batch, the shape of pores had a little variation lookinglike ellipse. The bulk density decreased firstly and then increased. The change rule ofthermal expansion coefficient was as same as that of bulk density. The compressivestrength increased with the addition of Sb2O3. When the additive amount of Sb2O3was0.9wt.%, the bulk density reached the minimum0.408g/cm3, the compressivestrength was4.39MPa, the average thermal expansion coefficient was10.16×10-6/℃ between room temperature to300℃. The XRD analysis showed that the crystallinephase was cristobalite and sodium aluminium phosphate without the crystalline phaseof Sb.When added CaSO4in the batch, the bulk and compressive strength decreased.When the additive amount of CaSO4was4wt.%, the bulk density was0.24g/cm3,compressive strength was2.31MPa and the porosity was87.17%. The averagethermal expansion coefficient was8.78×10-6/℃between room temperature to300℃.When added Ba(NO3)2, the bulk density firstly increased and then decreased, thevariation of compressive strength was contrary to that of density. When the additiveamount was3wt.%, the color of foam glass changed from black to white.