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Industrial symbiosis: Boron waste valorization through CO2 utilization
Mehmet Çopur,Turgay Pekdemir,Mehmet Muhtar Kocakerim,Haluk Korucu,Rövşen Guliyev 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.10
Various wastes being generated globally and dumped on land by mineral processing activities pose great ecological and health problems. An example is the boron mineral beneficiation solid wastes. Even greater threat is anthropogenic carbon dioxide (CO2) emissions among key causes of prevalent climate change. By this work, we propose a symbiotic solution to alleviate both environmental threats through recovering valuable boron products from boron wastes (BW), while also utilizing and sequestering CO2 stably and permanently. This article presents the results on the effect of important operation parameters for the performance of such a process within the following ranges determined by preliminary tests: temperature: 20-60 oC, solid-to-liquid ratio: 0.1-0.5 g/ml, reaction time: 15-120 min, stirring speed: 300-700 rpm and particle size: 150-600 m. CO2 gas (99.9%) flow rate was maintained continuously at 1.57 l/min under atmospheric pressure. The important findings are (1) per ton of BW production of commercially valuable either (a) 310 kg sodium penta-borate or (b) 350 kg sodium penta-borate mixed with Na2CO3, depending on the process configuration, (c) 725 kg relatively pure CaCO3, a potential source for precipitated calcium carbonate (PCC) and (d) 72 kg CO2 utilization, (2) effective parameters for CO2 utilization, in decreasing order are temperature, solid-toliquid ratio and time, while stirring speed and particle size are ineffective within the range investigated and (3) the optimum operating conditions as: temperature: 60 oC, solid-to liquid ratio: 0.1 g/ml, time: 90 min, stirring speed: 500 rpm and particle size: <180 m.
Boron removal by means of chemical precipitation with calcium hydroxide and calcium borate formation
Alper Erdem Yilmaz,Recep Boncukcuoglu,Serkan Bayar,Baybars Ali Fil,Mehmet Muhtar Kocakerim 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.10
Boron removal was investigated by chemical precipitation from aqueous solutions containing boron using calcium hydroxide. pH, initial boron concentration, amount of Ca(OH)2, stirring speed and solution temperature were selected as operational parameters in a batch system. The highest boron removal efficiency was reached at pH 1.0. Increasing initial boron concentration and amount of calcium hydroxide raised to boron removal efficiency. Boron removal efficiency was highest at a stirring speed of 150 rpm. The most important parameter affecting boron removal efficiency was solution temperature. Increasing solution temperature increased importantly boron removal. XRD analysis showed that CaB3O3(OH)5·4H2O, which is a borate mineral called inyoite, occurred between Ca(OH)2 and borate ions. As a result of the obtained experimental data, when the optimum operational conditions were selected, over 96% of boron removal efficiency was reached by this method.