Alumina Solutions

Alumina Solutions Outotec offers leading technology and life-cycle solutions for the production of high-quality alumina from bauxite and non-bauxite raw materials. Our integrated refinery concept features state-of-the-art process technology and proprietary equipment and is designed to minimize energy

WhatsApp: +86 18221755073

An Innovative Approach to Smelter-Grade Alumina Calcination …

The Specific Surface Area (SSA) reduced from 128 m 2 /g at 900 °C to 69 m 2 /g when the wall temperature was increased to 1120 °C. A similar trend in LOI was observed in the moisture-bound aluminum hydroxide raw material. The SSA decreased from 185 m 2 /g at 750 °C to 84 m 2 /g at 1050 °C. Alumina conversion to SGA quality standards (at least 99%) was …

WhatsApp: +86 18221755073

(PDF) Rice grain quality parameters and determination tools: a …

The determination of rice grain quality (RGQ) parameters is important because it is the benchmark of rice breeding success to meet up the consumers' demand.

WhatsApp: +86 18221755073

(PDF) Aluminium Determination in Foodstuffs by ICP-MS: …

Aluminium (Al) is the third most common element in the Earth's crust and occurs naturally in drinking water and agricultural products, and humans are consequently exposed to the element from ...

WhatsApp: +86 18221755073

Intelligent operational control method integrating human expertise …

The alumina digestion process (ALDP) is a key component of the Bayer alumina refinery, where recycled alkali solution reacts with aluminum hydroxides in bauxite slurry under high …

WhatsApp: +86 18221755073

Alumina Solutions

All are designed to improve aluminum extraction in the digestion plant by maximizing the performance of heat-transfer equipment and reducing erosion rates in piping. We also ofer …

WhatsApp: +86 18221755073

Smelter Grade Alumina Properties

In alumina refineries there are two different categories of quality parameters: Chemical impurities and physical properties. The main chemical impurities/properties are iron (Fe 2 O 3 ), silica …

WhatsApp: +86 18221755073

Alumina recovery from bauxite residue: A concise review

Desilication reaction is the most complex step in the Bayer digestion process which increases the loss of alumina and soda while reducing the quality of alumina product (Pan et al., 2020). That is because co-dissolution of silica in the NaAlO 2 solution decreases the final alumina product quality and thus necessitates a desilication stage ...

WhatsApp: +86 18221755073

ALUMINA YIELD IN THE BAYER PROCESS PAST, PRESENT AND PROSPECTS

The Bayer process is universally applied for the production of alumina from bauxites. The process has three main steps: Digestion, where bauxite is digested with caustic soda at elevated temperature and pressure to produce aluminate liquor; precipitation, where the aluminate liquor is hydrolysed at 55-60°C to produce crystalline alumina trihydrate, (gibbsite, Ah03.3H20) and …

WhatsApp: +86 18221755073

Advanced Process Control and Optimization of Alumina …

four main stages in the Bayer Process: digestion, clarification, precipitation and digestion [1]. Calcination is the last stage of Bayer Process, where the aluminium trihydroxide (Al(OH) 3), formed and separated in the preceding process stages, has its hydroxides removed, forming the aluminum oxide (Al 2 O 3) and water.

WhatsApp: +86 18221755073

Digestion mechanism and crystal simulation of roasted low-grade …

The desulfurization ratio, Al2O3 digestion ratio, and dynamics of alumina digestion were investigated. Moreover, the mechanism of the effect of roasting on alumina digestion was studied by DFT simulations. 2 Experimental 2.1 Materials A LGHS bauxite sample was obtained from Guizhou Province, China, and its composition is given in Table 1.

WhatsApp: +86 18221755073

DOUBLE DIGESTION PROCESS: AN ENERGY EFFICIENT …

With depleting gibbsitic or tri-hydrate bauxite reserves and the recent step increase in energy costs, alumina plant operators are looking for ways to process boehmitic or mono-hydrate …

WhatsApp: +86 18221755073

Effective Desulfurization and Alumina Digestion of High …

Processes 2021, 9, 390 3 of 15 2.2. Thermal Infrared Spectroscopy Analysis The test parameters of the thermal analyzer (NETZSCH 409PC STA, Selbu, Germany) and infrared spectrometer (Bruker FTIR-7600, Karlsruhe, Germany) were 90% N2 + 10% O2 atmosphere; a flow rate of 75 mL/min; heating rates of 5, 10, 15, and 20 C/min; and a sample mass of 5.0 0.5 mg.

WhatsApp: +86 18221755073

Toward sustainable green alumina production: A critical review on

Most of the silicon fractions were separated by the solution, enriching the red mud iron grade to 50%. The alumina digestion rate of bauxite could reach 85% by this method. ... the equipment requirements have a high cost because the Na 2 O concentration used in this method is very high. Most of the silicon oxide also enters the solution during ...

WhatsApp: +86 18221755073

Effective Desulfurization and Alumina Digestion of High …

Processes 2021, 9, 390 2 of 15 process is extremely difficult [13–16]. Roasting desulfurization is considered an ideal desulfurization method, as the pyrite in high-sulfur bauxite can be ...

WhatsApp: +86 18221755073

Aluminum Analysis

Alumina (Al 2 O 3) is an intermediate raw material generated during the production of aluminum from bauxite ore.Processing parameters such as particle size, Al2O3 polymorphs, or impurities have a direct impact on the use of energy and chemicals during refining and smelting and therefore affect both the efficiency and profitability of the process.

WhatsApp: +86 18221755073

DOUBLE DIGESTION PROCESS: AN ENERGY EFFICIENT …

44 Proceedings of the 8th International Alumina Quality Workshop • 2008 DOUBLE DIGESTION PROCESS: AN ENERGY EFFICIENT ... flowsheets and their possible application to different bauxite feed and plant equipment layout scenarios. 1. ... in caustic have resulted in three formats of alumina digestion processes i.e. low to medium temperature (105 ...

WhatsApp: +86 18221755073

Development and Utilization of Detailed Process and Technology …

The content of impurity K 2O in Bauxite is only several thouhs, but it can accumulate in the process and over 10g/l (sometimes ∼55g/l), which brings serious negative effect on precipitation ...

WhatsApp: +86 18221755073

Modelling and optimization of digestion efficiency of bauxite …

The operating parameters affecting the digestion of bauxite in Iran Alumina Plant is shown in Table 4. In this research work, the four factors residence time, temperature, Na2O concentrationt and lime content in three levels were used to investigate their relationship with the digestion efficiency, A/S, and N/S using RSM in the

WhatsApp: +86 18221755073

Evolution of Tube Digestion Technology for Alumina Refining …

Alumina refineries use primarily the "Bayer" process to extract alumina from Gibbsitic, Boehmitic or Diasporic bauxites. The Bayer process utilises a recirculating stream of caustic soda to extract the valuable alumina from the bauxite in four main processing steps.

WhatsApp: +86 18221755073

Multi-objective optimization based optimal setting control for

The operation variables, including feed rate of ore slurry, caustic solution and live steams in the double-stream alumina digestion process, determine the product quality, process costs and the environment pollution. Previously, they were set by the technical workers according to the offline analysis results and an empirical formula, which leads to unstable process indices …

WhatsApp: +86 18221755073

Dynamic Simulation and Control of the Bayer Process. A Review

In the Bayer process, used for the production of alumina from the bauxite ores, there are frequent disturbances and a large number of interacting processes which incorporate considerable dead time.

WhatsApp: +86 18221755073

Alumina Tube Digestion

The use of innovative high-capacity, single-stream tube digestion technology reduces refinery complexity and improves energy efficiency. Tube digestion replaces the conventional shell-and …

WhatsApp: +86 18221755073

APPLICATIONS OF THREE-PHASE FLASHING FLOW IN …

the example below. A typical three-phase flow data set for an alumina digestion flash train is given in Table 2. Table 2: Typical Process Data for Alumina Digestion Slurry. Process criteria Flash Tank 1 to Flash Tank 2 Upstream temperature (oC) 160 Flow rate (m3/h) 2500 Upstream vapour pressure (kPa abs) 450 Downstream vapour pressure (kPa ...

WhatsApp: +86 18221755073

A new prediction model based on the leaching rate kinetics in the

A prediction model for leaching rate of alumina based on mechanistic analysis of the digestion process and the leaching kinetics of diaspore was proposed and scaled to an industrial operation. The constant parameters of the model were identified from the industrial process data using the state transition algorithm method.

WhatsApp: +86 18221755073

ALUMINA YIELD IN THE BAYER PROCESS PAST, PRESENT AND PROSPECTS

Table I. Theoretical maximum yield and process conditions Digestion Precipitation Yield 675 160 g/l A/C feed 0.190 0.800 A/C discharge 0.800 0.190 C feed flow 1110 265 g/l T > 150 30 C DIGESTION Alumina dissolution in digestion is, from a thermodynamic point of view, primarily controlled by the following parameters: The alumina mineral phase ...

WhatsApp: +86 18221755073

Intelligent operational control method integrating human expertise …

An intelligent control method is proposed for the alumina digestion process. A BiGRU-based dual-network approach predicts the caustic ratio in real-time. A fuzzy system with closed-loop …

WhatsApp: +86 18221755073

Aluminium Determination in Foodstuffs by ICP-MS: Influence …

Four parameters were assessed for the digestion: (1) test portion size, (2) maximum digestion temperature, (3) digestion reagents and (4) digestion duration. These param-eters were decided based on the answers provided by PT participants (Table S1) in order to be representative of the practices in the participating NRLs. The detailed assess-

WhatsApp: +86 18221755073

Energy Consumption Optimization in Alumina Production

digestion and evaporation areas. The ETI alumina refinery in Seydişehir has been examining ways to reduce energy consumption and improve the overall energy efficiency of the refinery. This has included evaluating process design parameters, equipment efficiency, and …

WhatsApp: +86 18221755073

Advances in Processing Alumina Refinery Bauxite Residue Waste

Bauxite residue is an insoluble solid waste by-product generated after the digestion of gibbsitic bauxite ore with sodium hydroxide at elevated temperature and pressure in the Bayer process for the extraction of alumina. During the digestion process, aluminum minerals react with caustic soda process liquor to form soluble sodium aluminate ...

WhatsApp: +86 18221755073