Bauxite Beneficiation Electrostatic

The most widely used chemical process of refining bauxite into alumina, o proceso de Bayer, involves dissolving the Al2O3 out of the bauxite rock with caustic soda (NaOH) at elevated temperature and pressure. The Al2O3 fraction of the bauxite is dissolved into solution, to later be precipitated out as alumina. con todo, a high-grade bauxite contains up to 60% Al2O3, and many operating bauxite deposits are well below this, en ocasións, tan baixo como 30-40% Al2O3. Because the desired product is a high purity Al2O3, os óxidos remanentes na bauxita (Fe2O3, SiO2, TiO2, Organic material) are separated from the Al2O3 and rejected as alumina refinery resides (ARR) or red mud. En xeral, a calidade inferior da bauxita (ie lower Al2O3 content) the more red mud is generated per ton of alumina product. Ademáis, even some Al2O3 bearing minerals, nomeadamente caulinita, produce un-desirable side reactions during the refining process and lead to an increase in red mud generation, así como unha perda de caro química sosa cáustica, un gran custo variable no proceso de refino de bauxita.

barro ou ARR vermello representa unha grande e permanente desafío para a industria de aluminio. A Lama vermella contén cáustica residual resto química significativa do proceso de refino, e é altamente alcalino, moitas veces con un pH 10 - 13. It is generated in large volumes worldwide – according to the USGS, estimou a produción mundial de alúmina foi 121 millóns de toneladas en 2016. This likely resulted in more than 150 millóns de toneladas de lodo vermello xerada durante o mesmo período. Aínda investigación en curso, lama vermella ten actualmente uns camiños comercialmente viables para re-utilización benéfica. Estímase que moi pouco de barro vermello é beneficiosa reutilizados en todo o mundo. Instead the red mud is pumped from the alumina refinery into storage impoundments or landfills, onde se garda e monitor polo gran custo.

A perda de caro sosa cáustica (NaOH) and the generation of red mud are both related to the quality of the bauxite used in the refining process. En xeral, the lower the Al2O3 content of the bauxite, canto maior sexa o volume de lama vermella que será xerado, as the non-Al2O3 phases are rejected as red mud. Ademáis, the higher the kaolinite or reactive silica content of the bauxite, a lama máis vermello xerarase. The reactive silica content not only increases the volume of red mud, but also consumes caustic soda reagent and reduces the yield of Al2O3 recovered from the bauxite. polo tanto, there is both an economic and environmental argument to be made for improving the quality of bauxite prior to refining.

As ofertas de proceso STET seco separación bauxita produtores ou refinados de bauxita unha oportunidade para realizar a actualización de pre-Bayer proceso de mineral de bauxita para mellorar a calidade. Esta visión ten moitos beneficios:

• Redución no custo de funcionamento de refinaría debido ao menor consumo de sosa cáustica, reducindo a entrada de sílice reactivo.
• Savings in energy during refining due to lower volume of inert oxides (Fe2O3, TiO2, Non-reactive SiO2) entrando con bauxita. Smaller mass flow of bauxite to refinery results in less energy to heat and pressurize.
• Reduction in red mud generation volume (ie – lama vermella para alúmina proporción) by removing reactive silica and inert oxides.
• Tighter control over input bauxite quality to refinery reduces process upsets and allows refiners to target ideal reactive silica level to maximize impurity rejection.
• Improved quality control over bauxite feed to refinery reduces process upsets, maximizes uptime and productivity.
• Reduction in red mud volume translates into less treatment and disposal costs and better utilization of existing landfills.
• A diferenza de barro vermello, residuos dun proceso electrostático seco non conteñen produtos químicos e non representan un pasivo de almacenamento ambiental a longo prazo.
• A diferenza de barro vermello, dry by-products/tailings from a bauxite processing operation can be utilized in cement manufacture as there is no requirement to remove the sodium, o que é prexudicial para a fabricación de cemento. Centrais – Bauxite is already a common raw material for Portland cement manufacturing.
• Extend operating life of existing bauxite mine by improving quarry utilization and maximizing recovery.
• STET is a low operating cost, high throughput continuous process. No water or chemicals required.