The sludge is generated as a byproduct during the production of alumina from some bauxite ores by the Bayer process. ... all at temperatures around 85°C. Based on the experimental work, a schematic flow chart for the recovery of vanadium oxide from the vanadium bearing Bayer sludge has been presented. Recommended articles. References (8) ...
This Chapter provides an introduction to the Bayer process and how the mineral composition of bauxites affects the process variants and the principal parameters to be selected.
The raw material for the Bayer process is most commonly mined bauxite, a rock containing aluminium, which as we already know also contains many other substances (admixtures) in addition to aluminium oxide hydrates, such as iron, titanium and silicon oxides in particular. The main task of the process is to remove these admixtures.
The Bayer process is not easily explained in brief. This method of obtaining alumina from bauxite ore is complex and involves a lengthy succession of chemical reactions, with the process varying slightly depending on the makeup of the unique source of bauxite ore. Crushed and washed bauxite ore must first go through a process to remove any ...
Bauxite inputs into the Bayer process at a Jamaican refinery were found to contain approximately % inorganic carbon (or % CaCO3) and % organic carbon. Thermal treatment or heating of 10 g ...
Of all Bayer process impurities, few attract more attention than the simplest dicarboxylate. While some oxalate enters the Bayer process with bauxite as oxalic acid adsorbed on various minerals, the majority is created by the oxidation and pyrolysis of bauxite organics under Bayer digestion conditions. The rate of its formation in digestion is ...
1. The Bayer Process Aluminium manufacture is accomplished in two phases: the Bayer process of refining bauxite ore to obtain aluminium oxide (which is carried out at AAL), and the HallHeroult process of smelting the aluminium oxide to release pure aluminium (the smelting process is not carried out at AAL).
The actual Bayer process is an alkaline circulation process and in chemical terms it is a wet digestion. In chemistry, digestion is generally understood to be a process in which an insoluble compound is converted into a soluble one.
Alumina Extraction Problem. In the standard Bayer Process for refining bauxite to produce alumina, the dissolution of the alumina in the ore to form sodium aluminate is accomplished in autoclaves under high pressures varying from 70 to 200 pounds per square inch. However, some lateritic bauxite ores are readily soluble in caustic, making it ...
1 Citations Part of the Springer Series in Materials Science book series (SSMATERIALS,volume 320) Abstract This chapter aims to illustrate and discuss the inputs and outputs for both water and energy in the context of the Bayer process, highlighting throughout the sections their interconnectedness.
Summary This chapter contains sections titled: Introduction Evaluation of Bauxite Extraction Silica Residue Separation Decomposition Causticization of Sodium Aluminate Liquors Flow of Fluids Heat T...
Bauxite ores which originated from separate mines are different in chemical compositions, mineralogical properties and other characteristics, each bauxite ore has its own individual specifications. Jajarm bauxite is of the diasporechamosite type and its alumina to silica mass ratio is lower than other diaspore ores.
Aluminum Production. Alton T. Tabereaux, Ray D. Peterson, in Treatise on Process Metallurgy: Industrial Processes, 2014 Impact of Different Bauxites on the Bayer Process. The Bayer process is basically used for the extraction of aluminum hydrate from the bauxite ores with the mass ratio of alumina to silica (A/S) above 9. The sinter process is widely used to process the poorgrade ...
![A schematic flow chart of the primary aluminium production [35].](/wlzyj9a/264.jpg)
Aluminium production from bauxite is a costly process, which is carried out in several clearly defined process steps, first transforming the bauxite into alumina, the Bayer process, and ...
The Bayer process flow diagram. Bauxite ore is a mixture of hydrated aluminium oxides and compounds of other elements such as iron.
In October, 1943, Alcan was incorporated under the name Jamaica Bauxites Limited as a Jamaican company to investigate the commercial potential of Jamaican bauxite. In the same year, 2500 tonnes of ore was shipped to the USA for process investigation and it was realised that the bauxite was suitable for processing using Bayer technology.
Bayer's process reactionsConcentration of Al
Baeyer's process is used to leach Red Bauxite, which has Fe2O3 as the chief impurity. Serpeck's process, on the other hand, is used to leach White Bauxite, which has Silica as main impurity. Both are efficient for their respective ores. But Baeyer's process is more frequently used, as Bauxite, more often than not, is also a source of Gallium ...
Bayer Process for Alumina Extraction. The Bayer method is used to treat lowsilica bauxite. The process is simple, the operation is convenient, and the product quality is high. Over 90% of the aluminum oxide and aluminum hydroxide produced in the world are produced by the Bayer method. The Bayer method includes two main processes: At normal ...
Mining and Refining Process. The Bayer Process was invented and patented in 1887 by Austrian scientist Karl Josef Bayer. Two to three tonnes of bauxite are required to produce one tonne of alumina. 90% of the global alumina supply of around 90 million tonnes is used in aluminium production. Alumina refineries tend to be located close to ...
Simplified flow sheet of the Bayer process indicating the sampled materials. The following production units are depicted in Figure 1 above: I — digestion, settling, washing; II —...
The basic flow chart of the Bayer process is shown in Fig. 1, mainly involving the bauxite digestion, solidliquid separation, gibbsite precipitation and calcination (Hind et al., 1999; Power and ...
Steps in Bayer process : (1) Ore Preparation : It is important to do ore preparation to reduce total precentage of silica in boxite. Using crushing and grinding, the silica content reduced from 10% to % as bauxite tends to get concentrated in the finer fractions (, 100 mesh). Another importance of using finer bauxite is to increase ...
The Hall and Heroult process is used to obtain aluminium by electrolysis of a mixture of purified alumina and cryolite. This aluminium extraction process has three stages: The concentration of bauxite . Extraction of metals from concentrated ore . Refining of metals. Bayer Process. The Bayer process extracts pure alumina from bauxite ore.
Bauxite via the Bayer process. This process will be briefly introduced in the following, as well as the reduction to aluminium, the anodes production and further steps of primary production. Alumina Production (Bayer Process) The aluminium production starts with the production of alumina from bauxite according to the socalled Bayer process.
Mostly aluminum is produced in two ways. 1. Primarily Production Process. 1. By refining aluminum from grinding and extracting from bauxite ore Bayer process. 2. By using reduction process for crystalline alumina HallHéroult process. 2. Secondary Production Process.
the dissolved metal as the "back" end. This is the essence of the continuous Bayer Process used by the industry today. Caustic liquor (a strong caustic soda solution) is the medium moving around the circuit. When bauxite is added, the aluminium dissolves and a "green" (or pregnant) liquor richer in aluminium is formed.
The Bayer Process. The Bayer Process, which is used by about 80 active plants worldwide, is the primary method of producing aluminum from bauxite. Bauxite ore is dissolved in sodium hydroxide, or lye, at a high temperature and pressure. Then, the alumina and bauxite ores are separated by washing out the waste (red muds or sands) from the alumina.
Refineries around the world use the Bayer chemical process to extract alumina from bauxite. Karl Bayer, invented the process in 1888. The alumina refining process consists of four main stages, as shown below: Dr. Hussin Ahmed, hussien135 Dissolve alumina in a hot solution of caustic soda Digestion Remove of residues from the liquor ...
The Bayer process was invented 130 years ago and remains the global method of choice for converting bauxite to alumina for aluminum and industrial alumina production. In general, the three largest problems in the Bayer process are as follows: (a) The removal of silica (a problem with high silica bauxite). (b)
HALL HEROULT PROCESS • In the HallHéroult process, aluminum metal is obtained by electrolytic reduction of alumina. • Pure alumina melts at over 2000°C. • To produce an electrolyte at lower temperature, alumina is dissolved in molten cryolite at 1000°C. • The electrolyte is placed in an iron vat lined with graphite.
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