Bauxite Beneficiation Electrostatic

The most widely used chemical process of refining bauxite into alumina, बायर प्रक्रिया, 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. तथापि, a high-grade bauxite contains up to 60% Al2O3, and many operating bauxite deposits are well below this, रूपमा कम रूपमा कहिले काँही 30-40% Al2O3. Because the desired product is a high purity Al2O3, को bauxite बाँकी आक्साइड (Fe2O3, SiO2, TiO2, Organic material) are separated from the Al2O3 and rejected as alumina refinery resides (ARR) or red mud. सामन्यतया, तल्लो गुणवत्ता bauxite (ie lower Al2O3 content) the more red mud is generated per ton of alumina product. साथै, even some Al2O3 bearing minerals, बाहेकलाई kaolinite, produce un-desirable side reactions during the refining process and lead to an increase in red mud generation, राम्रो महंगा कास्टिक सोडा रासायनिक एक हानि रूपमा, को bauxite शोधन प्रक्रिया मा एक ठूलो चल लागत.

रातो माटोको वा ARR देखि एक ठूलो र-जा एल्यूमीनियम उद्योग लागि चुनौती प्रतिनिधित्व. रातो माटोको को शोधन प्रक्रिया देखि महत्वपूर्ण अवशिष्ट कास्टिक रासायनिक बाँकी समावेश, र अत्यधिक alkaline छ, अक्सर एक पीएच संग 10 - 13. It is generated in large volumes worldwide – according to the USGS, अनुमानित वैश्विक अल्युमिना उत्पादन थियो 121 लाख टन मा 2016. This likely resulted in more than 150 एउटै अवधिमा उत्पन्न रातो माटोको को लाख टन. निरन्तर अनुसन्धान बावजुद, रातो माटोको हाल लाभदायक पुन प्रयोग गर्न केही व्यावसायिक कारगर बाटो छ. यो रातो माटोको को धेरै सानो beneficially छ कि अनुमान गरिएको छ पुन प्रयोग विश्वव्यापी. Instead the red mud is pumped from the alumina refinery into storage impoundments or landfills, जहाँ यसलाई भण्डारण र ठूलो लागत अनुगमन गरिएको छ.

महंगा कास्टिक सोडा को हानि (NaOH) and the generation of red mud are both related to the quality of the bauxite used in the refining process. सामन्यतया, the lower the Al2O3 content of the bauxite, उत्पन्न हुनेछ भन्ने ठूलो रातो माटोको को मात्रा, as the non-Al2O3 phases are rejected as red mud. साथै, the higher the kaolinite or reactive silica content of the bauxite, अधिक रातो माटोको उत्पन्न हुनेछ. 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. त्यसैले, there is both an economic and environmental argument to be made for improving the quality of bauxite prior to refining.

को STET ड्राई अलग प्रक्रिया प्रस्ताव उत्पादकहरु वा bauxite refiners गुणस्तर सुधार गर्न bauxite अयस्क को पूर्व-बायर-प्रक्रिया अपग्रेड प्रदर्शन गर्ने मौका bauxite. यो दृष्टिकोण धेरै लाभ छ:

• कारण इनपुट प्रतिक्रियाशील सिलिका कम द्वारा कास्टिक सोडा को कम खपत गर्न रिफाइनरी को सञ्चालन लागत मा कमी.
• Savings in energy during refining due to lower volume of inert oxides (Fe2O3, TiO2, Non-reactive SiO2) bauxite संग प्रवेश. Smaller mass flow of bauxite to refinery results in less energy to heat and pressurize.
• Reduction in red mud generation volume (ie – अल्युमिना अनुपात रातो माटोको) 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.
• रातो माटोको विपरीत, सुक्खा electrostatic प्रक्रिया बाट tailings कुनै रसायन समावेश र दीर्घकालीन पर्यावरणीय भण्डारण दायित्व प्रतिनिधित्व छैन.
• रातो माटोको विपरीत, dry by-products/tailings from a bauxite processing operation can be utilized in cement manufacture as there is no requirement to remove the sodium, जो सिमेन्ट निर्माण गर्न हानिकारक छ. वास्तबमा – 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.