Method for determination of calcium sulfite and calcium carbonate content of flue gas desulfurization gypsum

Abstract

The invention discloses a method for determination of calcium sulfite and calcium carbonate content of flue gas desulfurization gypsum and belongs to the method for determination of calcium sulfite and calcium carbonate content. The method comprises respectively dissolving flue gas desulfurization gypsum subjected to full oxidation treatment and unoxidized flue gas desulfurization gypsum by a diluted hydrochloric acid solution, determining mass losses of the flue gas desulfurization gypsum and the unoxidized flue gas desulfurization gypsum by an analytical balance in dissolution, calculating calcium carbonate content of the flue gas desulfurization gypsum according to the mass loss of the flue gas desulfurization gypsum subjected to full oxidation treatment, and calculating total content of calcium sulfite and calcium carbonate of the flue gas desulfurization gypsum according to the mass loss of the unoxidized flue gas desulfurization gypsum, wherein the difference of the calcium carbonate content and the total content of calcium sulfite and calcium carbonate is the total content of calcium sulfite of the flue gas desulfurization gypsum. Calcium sulfite of the flue gas desulfurization gypsum produces large influence on portland cement setting time and strength, and through determination of calcium sulfite and calcium carbonate content, flue gas desulfurization gypsum slow setting effects on portland cement can be determined. The method promotes large scale use of flue gas desulfurization gypsum as industrial waste residue. The method has the advantages of simple determination method, accurate result and low determination cost.

Description

technical field [0001] The invention relates to a method for determining the content of calcium sulfite and calcium carbonate, in particular to a method for determining the content of calcium sulfite and calcium carbonate in desulfurized gypsum. Background technique [0002] my country's cement industry needs more than 35 million tons of natural dihydrate gypsum every year. This is because most cement enterprises in my country still use traditional production methods and use natural dihydrate gypsum as a cement retarder. Desulfurization gypsum is a by-product of limestone (lime)-gypsum wet desulfurization in coal-fired power plants, which produces more than 10 million tons per year, and the output is still growing. The main component of desulfurization gypsum is dihydrate gypsum, and it also contains some impurities, such as calcium sulfite that has not been fully oxidized in the desulfurization process and calcium carbonate that has not completely reacted in the desulfuriza...

AI Technical Summary

Problems solved by technology

But the analysis method of VGB calcium sulfite mainly has the following two shortcomings: 1) when the content of calcium sulfite in the desulfurized gypsum is low, the VGB analysis method cannot accurately measure the content of calcium sulfite, and the error is often large; 2) due to the VGB method Concentrated sulfuric acid with strong oxidizing and corrosive properties is used in the determination reaction, which poses a great threat to the safe operation and safety management of thermal power plants.

Therefore, the determination of calcium sulfite and calcium carbonate in desulfurized gypsum is extremely important to evaluate the performance of desulfurized gypsum as a cement retarder, but there is no fast, accurate and low-cost method for determining calcium sulfite and calcium carbonate in desulfurized gypsum Methods