Continuous determination method of sodium nitrite-potassium nitrate mixed salt in salt bath

Abstract

The invention relates to a continuous determination method of sodium nitrite-potassium nitrate mixed salt in a salt bath, which is mainly technically characterized by firstly heating sample solution of the sodium nitrite-potassium nitrate mixed salt to a certain temperature, using potassium permanganate standard solution for titration under appropriate acidity, and utilizing the quantitative reaction of sodium nitrite and the potassium permanganate standard solution to calculate the content of the sodium nitrite in the sample solution; further acidifying the sample solution, adding excess ferrous ammonium sulphate standard solution, heating till boiling, keeping for 2-4 minutes, cooing to normal temperature, then sequentially adding water, phosphoric acid solution and sodium diphenylamine sulfonate indicator solution, using the potassium permanganate standard solution for titration, obtaining the volume of the potassium permanganate standard solution consumed by the sample solution, simultaneously carrying out a blank test, obtaining the volume of the potassium permanganate standard solution consume in the blank test, and further calculating the content of potassium nitrate in the sample solution. The method can detect the change situation of components in the salt bath and prevent the components in the salt bath from aging, and has the characteristics of simple method, rapidness, low cost, high accuracy and the like.

Description

technical field [0001] The invention relates to a continuous determination method of sodium nitrite and potassium nitrate mixed salt in a salt bath, which belongs to the field of chemical analysis methods, and is especially suitable for the determination of nitrate salt bath components during isothermal cooling, graded cooling and tempering heating of steel parts . Background technique [0002] Heat treatment salt bath heating is to use the liquid medium formed after salt melting to heat the workpiece. It has a fast heating speed and a wide working temperature range, which can realize non-oxidative corrosion and non-decarburization heating of the workpiece. When using the mixed salt of sodium nitrite and potassium nitrate for salt bath, the composition of the salt bath will change after working for a period of time, resulting in "aging" phenomenon and affecting the heat treatment quality of the product, which requires detection of the composition of the salt bath and Make t...

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Problems solved by technology

In the background technology, there is no publicly published detection method of sodium nitrite and potassium nitrate mixed salt in China at present. In order to detect and analyze the main component changes of the quenching liquid in time, ensure the heat treatment quality of the product and promote the improvement of product performance, the salt bath sodium nitrite , Potassium nitrate mixed salt continuous determination method was studied

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