Sodium aluminate – the chemical compound having formula NaAlO2. It is widely used for sewage treatment (industrial and municipal), thanks to the high efficiency and rather small cost. Also it is applied in the cosmetic, paper, tanning industry, by production of molecular sit, titanic dyes and some polymers. How it is possible to receive sodium aluminate?
It is required to you
- - rector from stainless steel with the mixer and "a steam shirt";
- - sodium hydroxide solution;
- - aluminum hydroxide;
- - reception capacity;
- - filters.
Instruction
1. The main industrial method of receiving substance - sodium aluminate – reaction of just formed hydroxide of Al (OH) 3 aluminum with hot solution of a caustic natr of NaOH.
2. For this purpose load necessary amount of solution of caustic sodium into the reactor, then when hashing begin to add an aluminum hydroxide, do it slowly. At the same time, passing steam through so-called "shirt" of the reactor, bring temperature of a reactionary zone to the size close to temperature of boiling of a caustic natr.
3. After the end of reaction, carefully cool the formed mix and filter. If necessary repeat filtration several times, do it until pure, transparent liquid is received. It is also sodium aluminate solution. The received product needs to be stored at a temperature, it is not lower than twenty degrees (otherwise the aluminum hydroxide which is dropping out in the form of a deposit begins to be formed).
4. Simply the course of reaction can be presented in the following form: Al(OH)3 + NaOH = NaAlO2 + 2H2O.
5. It is necessary to remember that water solution of aluminate of sodium is steady only in the alkaline environment therefore the amount of sodium hydroxide always should be taken with some surplus.
6. At such way the liquid product turns out. But happens that it is necessary to receive sodium aluminate in a firm look. For example, if it is used in construction, at addition in concrete, that is for acceleration of its hardening. Then it is necessary to use other methods. For example, you can receive this product by Al2O3 aluminum oxide alloyage with Na2O sodium oxide at the increased temperature. Reaction proceeds according to the following scheme: Al2O3 + Na2O = 2NaAlO2.