Method for measuring calcium ions after dissolution of dolomite

Abstract

The invention relates to a method for measuring calcium ions after dissolution of dolomite, which comprises the following steps: crushing a dolomite sample to below 200 meshes, dissolving in water or a weak acid solution, centrifuging, taking clear liquid, and diluting to obtain a dissolved solution; sequentially adding an acidic chrome blue K solution and an ammonia-ammonium chloride buffer agent into the dissolving solution, and then adding deionized water to a constant volume; pouring the solution into a cuvette, putting the cuvette into an ultraviolet-visible spectrophotometer for measurement at the measurement wavelength of 492 cm <-1>, and recording absorbance; respectively substituting into a magnesium and calcium ion total concentration standard curve and a magnesium and calcium ion concentration ratio standard curve, and calculating a magnesium and calcium ion total concentration A and a magnesium and calcium ion concentration ratio B, namely, the calcium ion concentration in the dissolving solution is equal to A / (B+1). An ultraviolet-visible spectrophotometer is adopted for determination, and the method has the advantages of simple process, convenience in operation, small medicament dosage, small influence of interference ions on calcium ion determination, small environmental pollution and the like.

Description

technical field [0001] The invention relates to the field of mineral processing, in particular to a method for determining calcium ions after dolomite is dissolved. Background technique [0002] Dolomite (Ca Mg(CO 3 ) 2 ) is a carbonate of magnesium and calcium, which has solubility properties in water. After dolomite dissolves, its own buoyancy may change, and the dissolution has a significant impact on the buoyancy of dolomite. Under the condition of cationic collectors, slight dissolution is beneficial to the floating of dolomite. Dissolution of dolomite produces Mg 2+ and Ca 2+ and other metal ions. Metal ion Mg 2+ and Ca 2+ The impact of such on mineral flotation behavior cannot be ignored. Therefore, the measurement of calcium ion concentration of dolomite under different dissolution conditions is a key link in the optimization of dolomite flotation and its process conditions. At present, atomic absorption spectrophotometry or EDTA complexometric titration is ...

AI Technical Summary

Problems solved by technology

At present, atomic absorption spectrophotometry or EDTA complexometric titration is generally used to measure calcium ion concentration for calcium ion concentration measurement, and the existing problems are: 1) atomic absorption spectrophotometry or EDTA complexometric titration method for measuring calcium ion concentration process is more complicated , the requirements for the operation process are relatively high; 2) there are many kinds of medicines needed, and atomic absorption spectrophotometry needs nitric acid, perchloric acid, acetylene, lanthanum solution and calcium standard solution, etc.; EDTA complexometric titration needs nitric acid, hydrofluoric acid, Perchloric acid, hydrochloric acid, ammonia water, potassium hydroxide, ammonia buffer solution, calcium indicator, chrome black T indicator, EDTA standard solution, etc.; Acids, especially hydrofluoric acid and perchloric acid with strong corrosiveness and irritation, have certain dangers in the process of configuration; 4) atomic absorption spectrophotometry or EDTA complexometric titration method needs to be interfered shielding or interference separation

The atomic absorption method requires the use of lanthanum solution to shield aluminum, sulfate, phosphate, and silicate from interference; the EDTA complexometric titration method requires the use of potassium hydroxide solution combined with ammonia water to adjust the acidity of the solution until the Congo red test paper turns red, and then add copper reagent Interference separation of iron, copper, lead, zinc, manganese and other metal ions, which will affect the accuracy of measurement

[0003] EDTA complexometric titration is suitable for the determination of higher concentrations, but not for the determination of low concentration samples; the determination process of EDTA complexometric titration and atomic absorption spectrophotometry requires a variety of reagents, the preparation of a variety of liquids, high cost and waste water; A large amount of acid is used in the determination process, especially hydrofluoric acid and perchloric acid, which are highly corrosive and irritating, are dangerous in the configuration process; atomic absorption spectrophotometry or EDTA complexometric titration method requires interference shielding or interference separation

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