Type of alumina production process outlined

Alumina is a different production methods is extracted from bauxite a white powder. Alumina is typical of large and complex industrial processes of the world more than 90% of alumina is used in direct economic Bayer production process, and our aluminum business due to mineral is different, they each use different production processes.
Sintering method: suitable for high ore grade silicon, insoluble, a middle-grade resources diaspore, long process, complex process. Most of the old aluminum companies to use more of this approach alumina smelting. Shandong Aluminum Plant, Zhongzhou Aluminum stage Ⅰ, Shanxi Aluminum Plant Phase Ⅰ
Alumina sintering production process including clinker, clinker dissolution, semen preparation, decomposition and evaporation and other major production processes.
From raw material grinding raw slurry through the rotary kiln firing into easily dissolved sodium aluminate clinker, and then the carbon of liquor and one lotion after soaking the dissolution; thereafter through the separation of red mud washing off the crude liquid silicon, silicon slag separation processes generated semen was sent to carbon points and kinds of processes for the decomposition reaction, precipitated aluminum hydroxide; kinds of species formed by evaporation of the mother liquor distilled liquor after mixing lye Bayer sent to the original pulp ingredients; carbon distilled liquor then return to the raw mill ingredients. The precipitated aluminum hydroxide is calcined to send firing step.
Compared with Bayer, sintering clinker and carbon mainly in the control section of decomposition of the two processes are completely different
Bayer: Bayer is Karl Joseph Bayer invented in 1887, he discovered that adding a fine kind of sodium aluminate solution can be decomposed AL (OH) 3, after evaporation of the mother liquor can be decomposed at high temperature and pressure leaching bauxite The AL (OH) 3. This finding was later confirmed in experiments and applied to industrial practice, is the most widely used foreign alumina production process. Suitable for producing soluble gibbsite and boehmite a deal with medium grade bauxite alkali consumption is high, consumption of large mine is a conventional Bayer process alumina production shortcomings. Guizhou Aluminum stage Ⅰ, Pingguo Aluminum
Bayer alumina production process includes pre-desilication, the dissolution process, red mud washing, filtration process, kind of decomposition process and aluminum hydroxide filtration, roasting and other major production processes.
Bayer processing: can be A / S of 4 or more of bauxite by flotation into A / S of 11.2 slurry, single-tube can improve the dissolution rate of dissolution systems, process piping and the tank is not easy to stutter. Zhongzhou Aluminum Phase Ⅱ
Tandem method: Processing bauxite low crystalline bits Suitable methods. Bayer first with relatively simple treatment of ore to maximize the extraction of ore alumina sintering method and then use Bayer red mud recycling Al2O3 and Na2O, can reduce the overall energy consumption of the production of alumina, Al2O3 total high recovery, alkali consumption reduced product costs can be significantly reduced. Without increasing construction investment and equipment in existing plant hybrid method application. Guizhou Aluminum Plant, Luneng Jinbei (Planning)
Parallel method: by Bayer France, composed of parallel alumina sintering production process. Zhongzhou Aluminum, aluminum mooring former Soviet Dnepr
Hybrid method: by Bayer France, sintering, whose production process is characterized by: complex process, strong continuity, parameter detection difficulties associated with strong production management is difficult, in the chemical and metallurgical industry has a strong representation for process automation demanding. Is a complex metallurgical and chemical processes, with wet and dry metallurgical common characteristics, particularly suitable for processing in a country dominated diaspore bauxite, it has a high crystallinity, insoluble ore characteristics, required at high temperature (250 ℃ above), pressure (5.5MPa), high concentration of alkali (NaOH 20% or more) under the conditions of dissolution; need for lower grade ore sintering a more complex process; Ore high silicon, in the production process and the surface of the device easy to scale, but also seriously affect the collection of monitoring data. Shanxi Aluminum Plant Phase Ⅰ, Ⅱ, Guizhou Aluminum Plant, Zhengzhou Aluminum
A domestic manufacturer of hybrid alumina alumina production line process flow diagram, covering domestic and international law and the typical Bayer typical sintered alumina production process. Chart has three material exchanges: the Bayer process red mud and accompanying fluid delivery sintering system ingredients; Bayer seeds liquor evaporation precipitated crystal base and attach the liquid delivery sintering system prepared raw slurry; sintering kinds of liquor by evaporation Bayer evacuation systems do fill base used. Bayer and sintering two systems are interrelated, mutual restraint, mutual influence between processes, production organization difficult.
Lime Bayer: Bayer process compared with conventional, in addition to appropriate to increase the separation of lime burning and red mud washing process production capacity outside the other identical. By adding an excess of lime dissolution process, in addition to meeting with TiO2 addition amount of lime required for the reaction, the need to partially meet with bauxite as much as possible in the SiO2 CaO reacts with hydrated alumina calcium, so that the dissolution process in part by the removal of silicon product type sodalite becomes hydrated aluminum silicate hydrate hydrated alumina garnet-type calcium, thus greatly reducing the red mud of the N / S. Compared with the hybrid method processes, eliminating heat consumption of clinker sintering process and its corresponding wet production systems, less investment, low energy consumption, but consumption is relatively large bauxite and limestone.