Home – Home – Jornals – Chemistry for Sustainable Development 2016 number 1

The effect of preliminary mechanochemical treatment of the mixtures of metal bismuth and the compounds of different composition on bismuth oxidation by atmospheric oxygen was studied by means of X-ray phase analysis and thermogravimetry. It was established that the oxidation of metal bismuth occurs at the stage of dispersion. It is shown that mechanochemical treatment of a mixture of metal bismuth with 10-30 % its oxide leads to a decrease in the temperature of the start of bismuth oxidation from 350 to 200 °C. It was established that complete transformation of bismuth into its oxide may be carried out by means of annealing of mechanochemically treated mixture of metal bismuth and its oxide (20 %) at 300 °C for 12 h, while at annealing temperature 400 °C - for 1 h. In the case of mechanochemical activation of the mixture of metal bismuth and sodium carbonate, followed by washing with water, the product is mainly bismuth oxide and oxo(hydroxo)carbonate and can be used at the stage of obtaining solutions of bismuth salts. It was shown that mechanochemical activation of a mixture of metal bismuth and sodium chloride followed by washing with water leads to the formation of a mixture of bismuth oxide and oxochloride. This mixture can be used at the stage of obtaining bismuth-containing hydrochloric solutions. It was established that bismuth oxide may be obtained by preliminary mechanochemical activation of metal bismuth with sodium or ammonium nitrate, as well as with stearic acid. The specific surface of bismuth oxide obtained as a result of mechanochemical activation of metal bismuth with different compounds was determined; it varies within the range 0.29-5.87 m²/g.