Determination of boron in silica refractory by acid-base titration

An acid-base titration of boron in silica refractory was established.After being dissolved with water and filtrated,the sample solution was adjusted to pH 7.0and added with mannitol as reinforcer.Phenothalin was used as titration indicator of the end point,and sodium hydroxide was used as titrant to turn the solution to red.The effect of dissolution methods,temperature,sample particle size and mannitol dosage was tested.It showed when the sample was ground to 80μm,the titration effect was optimal with 6g of mannitol in water-dissolved sample at room temperature.The proposed method was applied to determine two silica refractory samples,whose results were consistent with those of inductively coupled plasma atomic emission spectrometry.The relative standard deviation(RSD,n=6)was 0.016%-0.017%.