This paper briefly introduces the experimental research and industrial application of high-concentration arsenic industrial wastewater by chemical precipitation in recent years, discusses the key processes in the arsenic removal process by chemical precipitation, and points out that the composition of arsenic-containing precipitate is complex (arsenic, Iron and calcium ions, etc.) and stability are not ideal. In order to meet the stringent requirements of the current environmental protection as well as waste treatment resources that arsenic and heavy metals for the high concentration of large-scale waste water, study the comprehensive management of the recovery process should pay attention to. PN40 Flange is a rating of nominal pressure, full nominal pressure of PN have PN6 PN10 PN16 PN25 PN40 for Hyupshin Flange Supplying. Norms of DIN EN1092-1 BS4504 GOST33259-2015 and NFE29203 are have nominal pressure rating, PN40 flanges are high pressure rating and used in high pressure piping, PN40 flange thickness is bigger than PN6 PN10 PN16 PN25. PN40 Flange pn16 steel flanges manufacturer, DIN 2527 2635 PN40 flanges, EN1092-1 PN40 flanges, BS4504 PN40 Flanges, gost33259 pn40 flanges Jinan Hyupshin Flanges Co., Ltd , https://www.iflange.com