Acid-Base Titration Determines Tungsten Trioxide Content

For a long time, the determination of high levels of tungsten ore and tungsten trioxide content is generally used in the gravimetric method. Such method has a certain degree of accuracy, but it is also affected by a number of interfering elements. What is more, the process of it is slow, and the need to use expensive platinum dish. The method of acid-base titration assay is simple, rapid compared with a net separating interfering element, eliminating the difficult separation of molybdenum, niobium, tantalum, etc.; it can be applied to high levels of scheelite and analysis of wolfram ore.

Acid-base titration method is based on water to proton transfer reaction; it is also a method of utilizing the capacity analysis. Taking acid as titrant base can measure alkali, and measuring acid by taking alkali as titrant base, this is an extremely versatile method of analysis. The most commonly used standard solution is hydrochloric acid, nitric acid and sulfuric acid is also sometimes used. Acid-base titration is very important in industrial and agricultural production and medical and health.

In the determination of the content of the tungsten trioxide, firstly, reacting grease with an ethanol solution of potassium hydroxide, and then dropping back to an excess of potassium hydroxide with hydrochloric acid. We take tungsten trioxide content as a base amount basis in order to calculate the consumption of 1 g of tungsten trioxide milligrams of potassium hydroxide. We determine the content of the mixture of tungsten trioxide with hydrochloric acid, taking phenolphthalein as an indicator, titration with hydrochloric acid, and then adding methyl orange indicator, the consumption of the difference between the volumes of hydrochloric acid is the content of tungsten trioxide.

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