Rare earth elements are excellent deoxidizers and desulfurizers in ductile iron. They can weaken many harmful impurities in steel and are important additives in casting ductile iron; Magnesium element is a reactive metal element and a necessary spheroidizing agent for ductile iron. However, magnesium element is difficult to dissolve in the cast iron matrix and exists in the form of compounds. Only when the residual amount of magnesium element is above 0.04% can ductile iron be formed.

The sample is dissolved in a mixed acid at low temperature to prepare a mother liquor.

The total amount of rare earths is determined by masking interfering elements with oxalic acid and directly coloring with chlorophosphonazo III. According to the national standard method: GB/T223.49-1994 Analysis methods of steel and alloy Extraction separation chlorophosphonazo mA photometric method for determination of total rare earth content

Triethanolamine, ortho phenanthroline, and EGTA-Pb combined masking agents are used to eliminate the interference of iron, nickel, and oxygen ions in the determination of magnesium elements. In a medium with pH=10, divalent magnesium ions form a purple red complex with chlorophosphonazo I, and its absorbance is measured. According to the national standard method: GB/T223.46-1995 Methods for analysis of steel and alloys - Determination of magnesium content - Chlorophosphonazo I photometric method.

The metal element analyzers applicable to this method are:

XY-FB microcomputer high-speed analyzer XY-FC microcomputer high-speed analyzer XY-FD computer multi-element analyzer

XY-3A Intelligent Element Analyzer XY-3B Intelligent Element Analyzer XY-1A Intelligent Element Analyzer