PROCESSING OF BOROSILICATE RAW MATERIALS WITH AMMONIUM HYDRODIFLUORIDE
Rubrics: 2. CHEMICAL TECHNOLOGY
Authors:
1.
Dushanbe, Tajikistan
2.
Dushanbe, Tajikistan
3.
Dushanbe, Tajikistan
4.
Dushanbe, Tajikistan
5.
Tajik national University
(Inorganic chemistry, Nauchnyy sotrudnik)
Dushanbe, Tajikistan
Dushanbe, Tajikistan
Type:
Article
Pages:
from 81
to 86
Status:
In work
Language:
Russian
Keywords:
BOROSILICATE ORE, LEACHING, AMMONIUM HYDRODIFLUORIDE, HEATING, FLUORINATING AGENT, AMMONIUM TETRAFLUOROBORATE
Abstract (English):
The article presents the results of studies on the decomposition of borosilicate ore with ammonium hydrodifluoride. Opening of borosilicate ores is carried out by solid-phase fluorination with ammonium hydrodifluoride at a mass ratio of boron raw materials to ammonium hydrodifluoride of 1:2.5 and a temperature of 250-300°C. The phase transformation of a charge consisting of borosilicate ore and ammonium hydrodifluoride upon heating was studied using the method of differential analysis. The derivatogram curves show three deep endo-effects at temperatures of 130, 240 and 280°C. Obviously, these endothermic effects are associated with the removal of physical as well as hydrate moisture from the charge composition and the decomposition of borosilicate raw materials with the formation of ammonium hexafluorosilicate, ammonium tetrafluoroborate, ammonium hesafluoroferrate and calcium fluoride. The above transformation was confirmed by X-ray phase analysis. The experimental results show that when heated, a mixture of borosilicate raw materials and ammonium hydrodifluoride is divided into two fractions, which X-ray phase analysis revealed that the first fraction belongs mainly to ammonium hesafluorosilicate and ammonium tetrafluoroborate, and the second fraction to calcium fluoride. To obtain boric acid, the first fraction was treated with freshly prepared lime milk for an hour. The result is a pulp containing calcium fluoride, boric acid and ammonia. The pulp is filtered, separating calcium fluoride, and ammonia is distilled off from the solution, and then boric acid is separated from the solution by crystallization. The main factors influencing the process of decomposition of borosilicate raw materials with ammonium bifluoride are the mass ratio of raw materials to fluorinating agent and the duration of the heating process. It has been established that, with a mass ratio of raw materials to fluorinating agent of 1:2.5 and a heating process duration of up to 2.5 hours, the degree of boron oxide extraction is achieved more than 87%.
The article presents the results of studies on the decomposition of borosilicate ore with ammonium hydrodifluoride. Opening of borosilicate ores is carried out by solid-phase fluorination with ammonium hydrodifluoride at a mass ratio of boron raw materials to ammonium hydrodifluoride of 1:2.5 and a temperature of 250-300°C. The phase transformation of a charge consisting of borosilicate ore and ammonium hydrodifluoride upon heating was studied using the method of differential analysis. The derivatogram curves show three deep endo-effects at temperatures of 130, 240 and 280°C. Obviously, these endothermic effects are associated with the removal of physical as well as hydrate moisture from the charge composition and the decomposition of borosilicate raw materials with the formation of ammonium hexafluorosilicate, ammonium tetrafluoroborate, ammonium hesafluoroferrate and calcium fluoride. The above transformation was confirmed by X-ray phase analysis. The experimental results show that when heated, a mixture of borosilicate raw materials and ammonium hydrodifluoride is divided into two fractions, which X-ray phase analysis revealed that the first fraction belongs mainly to ammonium hesafluorosilicate and ammonium tetrafluoroborate, and the second fraction to calcium fluoride. To obtain boric acid, the first fraction was treated with freshly prepared lime milk for an hour. The result is a pulp containing calcium fluoride, boric acid and ammonia. The pulp is filtered, separating calcium fluoride, and ammonia is distilled off from the solution, and then boric acid is separated from the solution by crystallization. The main factors influencing the process of decomposition of borosilicate raw materials with ammonium bifluoride are the mass ratio of raw materials to fluorinating agent and the duration of the heating process. It has been established that, with a mass ratio of raw materials to fluorinating agent of 1:2.5 and a heating process duration of up to 2.5 hours, the degree of boron oxide extraction is achieved more than 87%.
Keywords:
BOROSILICATE ORE, LEACHING, AMMONIUM HYDRODIFLUORIDE, HEATING, FLUORINATING AGENT, AMMONIUM TETRAFLUOROBORATE
BOROSILICATE ORE, LEACHING, AMMONIUM HYDRODIFLUORIDE, HEATING, FLUORINATING AGENT, AMMONIUM TETRAFLUOROBORATE
