A Study on White Porcelain of Beijing Longquanwu Kiln in Liao and Jin Dynasties

The white porcelain samples are two types of body:fine and coarss.The composition characteristics of fine body are high in Al 2O 3(37 4%～39 0%)、Na 2O(2 7%～4 3%)and TiO 2(1 2%～1 7%)contents and low of SiO 2(52 4%～54 9%)content.The compositions of fine body are different from those of northern famous ancient white porcelain body.And their Fe 2O 3 content(0 2%～0 3%) is very low,the quartz grains in the bodies are very fine(about 25μm),their porosities(0 08%～0 79%)are low.It is illustrated that the firing quality of fine white Porcelain samples is nearly the same as that of Ding white porcelain.But the porosities of coarse body samples is high,the most of these samples were underfired.The chemical compositions of the glaze samples are different.The Ca glaze was used in the early period of Liao Dynasty.To the middle of Liao,the Ca alk glaze had been used.In the later of Liao to Jin Dynasties,the alk Ca glaze had been used.In the period,it was new discorvery that the composition of a glaze sample is low in CaO(0 8%)and MgO(0 5%)contents,its RO molecular is only 0.19 .This kind of alk glaze was not seen in the chinese ancient porcelain glaze.The firing temperature of the white porcelain samples is about 1240～1270℃.