Bauxite Beneficiation Electrostatic

The most widely used chemical process of refining bauxite into alumina, the Bayer process, involves dissolving the Al2O3 out of the bauxite rock with caustic soda (Nao) at elevated temperature and pressure. The Al2O3 fraction of the bauxite is dissolved into solution, to later be precipitated out as alumina. Međutim, a high-grade bauxite contains up to 60% Al2O3, and many operating bauxite deposits are well below this, povremeno nisko kao 30-40% Al2O3. Because the desired product is a high purity Al2O3, preostale oksidde u bauxitu (Fe2O3, SiO2, TiO2, Organic material) are separated from the Al2O3 and rejected as alumina refinery resides (ARR) or red mud. Općenito, "donja kvaliteta" bauxit (ie lower Al2O3 content) the more red mud is generated per ton of alumina product. Osim toga, even some Al2O3 bearing minerals, posebno kaolinite, produce un-desirable side reactions during the refining process and lead to an increase in red mud generation, kao i gubitak skupe uzroke sode, velika varijabilna cijena u procesu rafiniranja bauxita.

Crveno blato ili ARR predstavlja veliki izazov za Aluminijumske industrije.. Crveno blato sadrži značajne ostatke kemijskih ostataka od procesa rafiniranja, i veoma je alkalan., često sa pH 10 – 13. It is generated in large volumes worldwide – according to the USGS, procijenjena je globalna alumina produkcija 121 miliona tona u 2016. This likely resulted in more than 150 milion tona crvenog blata proizvedena u istom periodu. Uprkos tekućim istraživanjima, crveno blato trenutno ima nekoliko komercijalnih puteva za korisnu upotrebu.. Procjenjuje se da se vrlo malo crvenog blata korisnika ponovo koristi širom svijeta.. Instead the red mud is pumped from the alumina refinery into storage impoundments or landfills, Gdje je pohranjen i nadgledani pod velikim troškovima.

Gubitak skupe kastične sode (Nao) and the generation of red mud are both related to the quality of the bauxite used in the refining process. Općenito, the lower the Al2O3 content of the bauxite, veći obim crvenog blata koji će biti generisan, as the non-Al2O3 phases are rejected as red mud. Osim toga, the higher the kaolinite or reactive silica content of the bauxite, više crvenog blata će se generisti. 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. Stoga, there is both an economic and environmental argument to be made for improving the quality of bauxite prior to refining.

Proces razdvojenosti stet-a nudi boksita producentima ili bauxitovim rafinerima priliku da obavljaju pregradnju bauxita rude da poboljša kvalitet. Ovaj pristup ima mnogo prednosti.:

• Smanjenje operativne cijene rafinerije zbog smanjenja potrošnje karstične sode smanjenjem unosa reaktivne šilica.
• Savings in energy during refining due to lower volume of inert oxides (Fe2O3, TiO2, Non-reactive SiO2) Ulazim sa bauxitom. Smaller mass flow of bauxite to refinery results in less energy to heat and pressurize.
• Reduction in red mud generation volume (Ie – crveno blato do alumina odnos) 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.
• Za razliku od crvenog blata, skrozi iz sušnog elektrostatičkog procesa ne sadrže hemikalije i ne predstavljaju dugoročnu odgovornost za okoliš..
• Za razliku od crvenog blata, dry by-products/tailings from a bauxite processing operation can be utilized in cement manufacture as there is no requirement to remove the sodium, što je detrimentalno za proizvodnju cementa. zapravo – 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.