ADAPTATION OF THE STANDARD NORM UNE-EN 993.3 FOR CONTROL OF THE GRANULOMETRIES OF THE ALUMINAS OF THE MARKET.

Our technical department has developed a technique to control the different types of alumina on the market, with the aim of improving the quality control of these products.

The development of this technique is done by an adaptation of the standard UNE-EN 993.3 (Methods of testing cement, part 1 and part 3), requiring probe Tetmajer penetration trial for evaluating both the normal consistency of the mixture and rheology.

The methodology consists in mixing a particular time a certain amount of Alumina with water and measure the penetrability, i.e. the normal consistency of this mixture.

Using this technique, it is possible to advised that all the aluminas in the market are maintaining a common pattern according to their nature. It has been observed also that there are some aluminas who advocate the same size of particle, according to their technical sheets, and the reality has been that the required additions of water for a same normal consistency are different, contradicting their same behavior despite having equal size…

This new system to detect and quantify the granulometry of the alumina, has been very helpul for the detection of small differences between very similar products.

Below are various relations found, for each group of alumina, which include AC-1 and AC-2 AC-6 designations refer to groups of alumina, where value expressed refers to its value d50, expressed in the technical sheets of the distribution companies.

Fig. 1 Representation ratio of wáter against d50.

Our technical team has kept these results as valid patterns to accept or reject some types of alumina, allowing by this way, to use different alumina, ensuring an equal rheology in any case.

Vicat’s needle is shown here below and in this case, using the probe Tetmajer also, it is possible to measure the normal consistency of our blend water- alumina.