Українська   Русский
DonNTU   Masters' portal

Abstract

Содержание

Introduction

Alumina is the main raw material for aluminum production. In addition, it is used in other areas of the national economy: for the production of special types of sintered ceramics and electrocorundum, high-alumina dense and lightweight refractory ceramics. Alumina is also used for coating to protect metals from oxidation, the action of corrosive media and erosive wear. Alumina is also added to the glass batch when cooking different types of glass: for the production of cathode-ray television rectangular tubes and for glasses resistant to radioactive radiation and neutrons, for optical glasses, for the production of heat-resistant dishes and glass fibers, etc.

Aluminum is one of the most important strategic metals. The development of aviation, shipbuilding, artillery, tank building requires the use of a large amount of aluminum and its alloys. Aluminum replaces a lot of non-ferrous metals, especially copper on power lines and in the manufacture of various equipment. As a lead substitute, it is used in the manufacture of protective sheaths of cables, tubes, etc. Aluminum is widely used in the construction of civil structures. The cost of aluminum for construction is, for example, in Canada, about 30% of total consumption, in the US - over 20%, in Japan, 14%. A significant amount of aluminum is spent for the production of household items, as well as packaging and manufacturing containers.

The low density of aluminum, high electrical conductivity, plasticity and resistance to corrosion allow it to be used in its pure form and in alloys with other metals in a wide variety of industries.

The most important areas of application of aluminum alloys are mechanical engineering, electrical, automotive, chemical and metallurgical industries, water and rail transport, the production of consumer goods, housing.

The following minerals and ores are used as raw materials for alumina production: alunite, kaolin, nepheline and bauxite.

Alumina is obtained from ores in three main ways: electrolytic, acidic and alkaline. The most common method of producing alumina is the Bayer alkaline method, during which alumina is extracted from high grade bauxite.

However, a certain disadvantage is the difficulty of disposing of red mud that accumulates in sludge dumps.

The relevance of this work lies in the fact that in the industrialized Donetsk region there is a need for the disposal of geotechnogenic waste. On the one hand, they contain alumina, and, on the other hand, they represent an environmental burden on the environment.

Among the possible schemes for the production of alumina, a method of sintering with limestone or chalk is promising. So, in the case of using alkali-free raw materials, self-disintegrating specs are obtained, which are further processed by alkaline methods, including the steps of leaching alumina, desilication, carbonization and calcination.

1. Relevance of the work

The implementation of the method requires the use of such an expensive component as soda, which is not economically feasible when processing millions of tons of waste.

To isolate Al(OH)3, it is advisable to use carbonation, since, along with aluminum hydroxide, a solution of soda is obtained, which is used as a working solution.

A new scheme of the carbonization process of aluminate solutions, including the formation of sodium hydroaluminocarbonate as the primary product and its subsequent transformation into aluminum hydroxide in the reaction with sodium aluminate, is considered.

2. Goals and objectives of the study

The main goal is the technological separation of aluminate solution in time and space. The process of obtaining pure aluminum hydroxide can be carried out so that the carbonization process takes place with the formation of GAKN and obtaining from it Al(OH)3.

The task is to obtain experimental data that will confirm the new scheme of the process of carbonization of aluminate solutions.

Conclusion

The main cause of contamination of aluminum hydroxide and alumina obtained from it during carbonization of aluminate solutions is the production of sodium hydroaluminocarbonate in the first stage of the process. Experience shows that, in order to improve the quality of Al(OH)3, it is necessary to separate the process into the stage of formation of sodium hydroalumino carbonate, followed by the stage of processing it into aluminum hydroxide using an aluminate solution.

References

  1. Клименко, А.А. О возможности получения глинозема из отходов угле- и горнодобывающей промышленности методом спекания бесщелочного сырья с известняком / А.А.Клименко, В.Н.Вечерко, Л.И. Кукоба, В.В.Шаповалов, В.И. Ванин // Научные труды ДонНТУ. Серия: Химия и химическая технология. – 2012. – №19 (199). – С. 151-157.
  2. Ханамирова, А. А. Глинозем и пути уменьшения содержания в нем примесей / Ханамирова А. А., отв. ред. И.З. Певзнер. – Ереван: Изд-во АН АрмССР, 1983. – 243 с
  3. Клименко, А.А. К вопросу о механизме выделения гидроксида алюминия из растворов алюмината натрия / А.А.Клименко, В.В.Шаповалов, Т.В.Колесник, Т.В.Шаповалова, А.А.Осовская // Научные труды ДонНТУ. Серия: Химия и химическая технология. – 2013. – №1 (20). – С. 158-166.
  4. Колесник, И.В. Инфракрасная спектроскопия / И.В. Колесник, Н.А. Саполетова ? М.: МГУ, 2011.? 88 с.
  5. Лайнер, А. И. Производство глинозема / А. И. Лайнер, Н. И. Еремин, Ю. А. Лайнер. М.: Металлургия, 1978. 420 с.
  6. Мазель, В. А. Производство глинозема / В.А. Мазель. - М.: Металлургиздат, 1955. - 430 с.
  7. Клименко А.А. О возможности получения глинозема из отходов угле- и горнодобывающей промышленности методом спекания бесщелочного сырья с известняком / В.Н. Вечерко, Л.И. Кукоба, В.В. Шаповалов, В.И. Ванин // Наукові праці ДонНТУ. Серія: Хімія і хімічна технологія. 2012. Вип. 19(199). С. 151-157.
  8. Томилов Н.П. Об условиях образования гидроалюмокарбонатов при взаимодействии алюминия с растворами карбонатов щелочных металлов / Н.П. Томилов, А.С. Бергер, А.И. Бойкова // Ж. нерган. химии. - 1969. Т. 14, № 3. С. 674-680.
  9. Абрамов, В. Я. Физико-химические основы комплексной переработки алюминиевого сырья / В.Я. Абрамов, И.В. Николаев, Г.Д. Стельмакова. - М.: Металлургия, 1985. - 288 с.