Abstract
Brown corundum fly ash (BCFA), which is the collected ash in brown corundum production, has received lots of environmental concerns due to its ultra-fine particle size and complex composition. Aiming to recycle the major elements including K, Al and Si from BCFA environmentally, this work proposed a simple and non-pollution process to utilize BCFA by water leaching, size screening and solution evaporation. The influences of water leaching conditions including leaching temperature, time and liquid-to-solid ratio was considered to optimize the K2SO4 recovery efficiency. Results show that the potassium sulfate content of the product is 75.7% after water leaching at 60 °C for 15 min with the liquid–solid ratio of 20:1. The wet screening and size separation with a 1 μm sieve can separate and enrich aluminum and silicon significantly. The aluminum-rich product is composed of 54.65% of alumina and 11.04% silica, with the alumina and silica ratio (A/S) of 4.95. The silicon-rich product with a particle size of less than 1 μm has a silica content of 57.57% can be used as high-value micro-sphere silica. The research results revealed in this work offers a potential and environmentally industrial treatment technique for the BCFA.
Highlights
Brown corundum, which is composed of 95–97% Al2 O3, and small amounts of Fe and Si, is widely used in refractories and grinding wheels because of its distinctive self-sharpness and strong grinding force [1]
The solubility of Brown corundum fly ash (BCFA) in the different solvents is shown in Table 2, revealing that only 17.50 wt.% of BCFA was dissolved in DI water, while 40.80 and 63.15 wt.% of BCFA was dissolved in acid and alkali, respectively
Based on the above discussion, potassium sulfate can be separated by water leaching, which be can further recovered by vaporization, and the silica and alumina can be separated by the simple size be further recovered by vaporization, and the silica and alumina can be separated by the simple separation method
Summary
Brown corundum, which is composed of 95–97% Al2 O3 , and small amounts of Fe and Si, is widely used in refractories and grinding wheels because of its distinctive self-sharpness and strong grinding force [1]. Brown corundum is produced from high-quality bauxite and other raw materials in an electric arc furnace at a temperature higher than 2250 ◦ C [2]. In this high-temperature process, dusts are exhausted with flow gas, and the brown corundum fly ashes (BCFA) are collected by a dedusting technique [3,4]. Xue et al [11] studied the casting performance of corundum–silicon nitride using BCFA as an additive agent. The impurities have a remarkable influence on the utilization of BCFA, especially potassium, sodium, etc. Environmental and and non-polluting progress to recover the potassium sulfate, enrich and separate alumina and silica in non-polluting progress to recover the potassium sulfate, enrich and separate alumina and silica in BCFA, and the recovery ratio and effect factors were well-studied
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