Weigh 0.2g sample Calcium, accurate to 0. O001g, sodium sulfate, manufacturers, after adding 50mL dissolved in distilled water, was dropped by a pipette 0.05mol / L EDTA standard solution of about 250mL (close to the titration end point is appropriate, the use of sodium sulfate, and then l0mLl0% NaoH solution, 1 % calcium red indicator 0.1g, continue with EDTA standard solution titration until the solution just becomes a pure blue from red to end the recording volume consumed EDTA standard solution, calculated as calcium formate content measurement results are shown in Table 2 From Table 2, high-precision measurement method, sodium sulphate, mean deviation and coefficient of variation were less than 0.2%; and easy to operate, the end color keen as a water softener, boiler detergents, metal rust. agent, the physical properties of a juice purification agents, colorless to white crystal or crystalline powder, anhydrous or containing from 1 to 12 molecules of crystal water, odorless. dodecahydrates melting point 73.4 ° C. Soluble in water , pH 0.1% insoluble in aqueous ethanol is 11.5 to 12.1. Chemical Properties 1 ,. In dry air easily deliquescence weathering agents sodium sulfate, sodium dihydrogen phosphate, and sodium bicarbonate to generate almost completely decomposed in water disodium hydrogen phosphate and sodium hydroxide. was heated to 55 ~ 65 ° C into ten water was heated to 60 ~ 100 ° C into hexahydrate was heated to above 100 ° C into a water was heated to 212 ° C above become anhydrous solution pH .1% of the value of 11.5 to 12.1. Groundhog oral LD50> 2g / kg, ADl0 ~ 70mg / kg (FAO / WHO, 1994). Three sodium sulfate vendors, sulfuric acid trisodium Zhengzhou Longda Chemical (Views) provided by the Zhengzhou Longda Chemical Products Co., road Zhiyuan, temper forward. Zhengzhou Longda Chemical Products Co., Ltd. (www.longdahuagong.com/) aims to become and you win, symbiosis, together strategic partnership forward, more determined to become the most influential of inorganic acid companies, and you leap together to success!