Determination of SiO₂, Total Fe, Al₂O₃, MnO, CaO and MgO in Basic Slag.

Study on chemical analysis of basic slag-I

Abstract

This investigation was undertaken to find rapid and accurate chemical methods for the analysis of basic slag. In the report (I), a continuous titration method with EDTA is described for determination of total Fe, Al₂O₃, MnO, CaO and MgO which are contained in basic slag.
Determination of SiO₂: Weigh a sample of 0.5 grams. Add HCl and HClO₄ and evaporate to fume. Cool, and dissolve the residue with hot water, and filter in to a 250ml. volumetric flask, wash the precipitate with hot water, and then SiO₂ is determined by conventional gravimetric method.
Determination of total Fe: Make the filterate up to 250ml. with water. Pipet 50ml. of fiilterate. Adjust to pH 2.0 with ammonium acetate, and titrate with FDTA using salicylic acid as an indicator.
Determination of Al₂O₃: In the same solution, adjust to pH 3.0 with ammonium acetate, Add excess EDTA and back-titrate the excess with CuSO₄ using a-pyridyl-β-azonaphthol (PAN) as an indicator.
Determination of MnO: In the same solution, adjust to pH 4.5 with ammonium acetate. and titration is carried as above for determination of Al₂O₃.
Determination of CaO plus MgO: The solution is divided into two portions. In one portion, adjust to pH 10 with NH₄OH. Add excess EDTA and back-titrate the excess with CuSO₄ using PAN as an indicator. Determination of MgO : After separating Ca²⁺ as CaC₂O₄ in the other portion, adjust to pH 10 with NH₄OH. Titration is carried as above for determination of CaO, plus MgO. The difference in values between CaO, plus MgO, and MgO, gave the amount of CaO.