Determination of magnesium oxide neutralization titration step

　　Precision weighing magnesium oxide sample 0.5g, precision sulfate titration solution (0.5mol / l) 30ml dissolved, add 1 drop of methyl orange indicator solution, titration with sodium hydroxide titration solution (1mol / l), according to the amount of sulfuric acid consumed minus the amount of sulfuric acid mixed with calcium oxide should be consumed to obtain the amount of sulfuric acid consumed by magnesium oxide in the test amount. Read out the amount of sodium hydroxide titration solution used, calculating that each 1 ml sulfuric acid titration solution (0.5 mol/l) is equivalent to 20.15 mg of magnesium oxide or 28.04 mg of calcium oxide.

　　Note 1: "Precision weighing" means that the weight should be accurate to one thousandth of the weight weighed, and "precision weighing" means that the accuracy of the volume should meet the accuracy requirements of the volume pipette in the national standard.

　　Note 2: "Moisture determination" with drying method, take the sample 2 ~ 5g, flattened in a flat weighing bottle dried to constant weight, the thickness does not exceed 5mm, the loose sample does not exceed 10mm, precision weighing, open the bottle cap at 100 ~ 105 ° C drying for 5 hours, the bottle cap is covered, transferred to the dryer, cooled for 30 minutes, precision weighing, and then dried at the above temperature for 1 hour, cooling, weighing, until the difference between the two consecutive weighing does not exceed 5mg. Based on the weight lost, the moisture content (%) in the test product is calculated.