1 General provisions
1.0.1 This code is developed in order to unify technical requirements for alumina process design, propel technological advance, improve design quality, and make design technologically advanced, economically reasonable, safe and reliable and be in line with national conditions.
1.0.2 This code is applicable to process design of newly constructed, extended and renovated large and medium-sized alumina refinery that produces metallurgical-grade alumina using diasporic bauxite as raw material.
1.0.3 Process design of alumina refinery shall be achieved by actively and prudently applying and promoting advanced technologies at home and abroad, pushing to enhance the level of mechanization and automation upon the actual situation, protecting the environment, and effectively using resources, saving energy, land, water and materials, controlling cost and shortening construction duration to improve labor productivity and civilized production level.
1.0.4 For alumina refinery constructed in phases, a comprehensive plan shall be established, and phased construction scale and scheme shall be defined reasonably to create conditions for long-term construction.
1.0.5 Design for renovation and extension of alumina refinery shall make full use of existing production facilities, utilities and amenities, and shall avoid or reduce the impact on production during construction.
1.0.6 This code specifies the basic requirements for process design of alumina refinery. When it is in contradiction with the provisions of national laws and administrative regulations, the latter shall prevail.
1.0.7 Process design of alumina refinery shall comply with the relevant current national standards, in addition to this code.
2 Terms
2.0.1
alumina
an aluminum oxide, with molecular formula Al2O3, that has many different crystal forms and is the main raw material for aluminum smelting
2.0.2
sandy alumina
alumina that has large and uniform particle size, large specific surface area, small angle of repose, high strength and good fluidity, and is the optimum raw material for flue gas purification by dry process and for large central-feeding pre-baked anode cell
2.0.3
bauxite
a generic term for ores mainly composed of gibbsite, boehmite or diaspore, which, in addition to alumina, mainly contains impurities such as silicon oxide, iron oxide, titanium oxide, and compounds of minor or trace elements, and is the most important ore resource in alumina production at present
2.0.4
gibbsite
an aluminum hydroxide, with molecular formula Al(OH)3, that is monoclinic, and has a density of 2.35 g/cm3 to 2.42 g/cm3 and a Mohs hardness of 2.5 to 3.5
2.0.5
diaspore
an aluminum oxyhydroxide, with molecular formula AlOOH, that is orthorhomibc, and has a density of 3.3 g/cm3 to 3.5 g/cm3 and a Mohs hardness of 6.5 to 7
2.0.6
Bayer process
a process of producing alumina, that is, the alumina in bauxite is directly extracted using caustic solution, to obtain sodium aluminate solution
2.0.7
sintering process
a process of producing alumina, that is, aluminum-containing material is sintered using burdening, making the alumina therein convert into aluminate
2.0.8
combination process
a generic term for process of producing alumina according to Bayer process and sintering process which are combined in different ways
2.0.9
serial combination process
a process of producing alumina, that is, red mud, which is obtained by processing bauxite according to Bayer process, is processed according to sintering process to recycle the alumina and alkaline therein
2.0.10
mixed combination process
a process of producing alumina, that is, red mud, which is obtained by processing bauxite according to Bayer process, is blended with an appropriate amount of bauxite and processed according to sintering process
Foreword ii
1 General provisions
2 Terms
3 General requirements
4 Raw materials and fuels
4.1 Raw materials
4.2 Fuels
5 Storage and handling of raw materials and fuels, bauxite crushing
5.1 Unloading facilities of raw materials and fuels
5.2 Material stockyard
5.3 Bauxite crushing
5.4 Storage and delivery of caustic soda
5.5 Storage silo of soda
6 Lime burning and lime milk slaking
6.1 Lime burning
6.2 Lime milk slaking
7 Bauxite dressing
7.1 Grinding and classification
7.2 Flotation
7.3 Storage, preparation and addition of agent
7.4 Dewatering
7.5 Maintenance facilities
7.6 Automatic control, measuring and weighing
8 Slurry preparation
8.1 Bauxite grinding
8.2 Bauxite slurry preparation of dressing-Bayer process
8.3 Raw mix slurry adjustment of sintering process
9 Autoclave digestion
9.1 Pre-desilication of bauxite
9.2 Feeding pump to autoclave digester
9.3 Autoclave digestion
10 Sintering and sinter crushing
10.1 Preparation of coal powder
10.2 Sintering
10.3 Sinter crushing
11 Sinter leaching
12 Red mud settling, washing and control filtration
12.1 Red mud settling and washing
12.2 Control filtration
13 Desilication in sintering process
13.1 Desilication
13.2 Separation of desilication product
14 Decomposition of sodium aluminate solution
14.1 Seed precipitation
14.2 Carbonization
15 Hydrate separation, washing and storage
15.1 Hydrate separation and washing
15.2 Hydrate storage
16 Spent liquor evaporation, causticization and recycled spent liquor proportioning
16.1 Spent liquor evaporation
16.2 Separation of soda crystal
16.3 Causticization of soda crystal
16.4 Caustic solution proportioning
17 Hydrate calcination, product packing and stacking
17.1 Hydrate calcination
17.2 Alumina storage
17.3 Product packing and stacking
Explanation of wording in this code
List of quoted standards
