Leaching of Lithium and Rubidium Elements from Boron Production Wastes

Journal of ChemicalReyhan Technology Ozbas, and Emek Metallurgy, M. Derun 56, 4, 2021, 845-852

LEACHING OF LITHIUM AND RUBIDIUM ELEMENTS FROM BORON PRODUCTION WASTES

Reyhan Ozbas, Emek M. Derun

Department of Chemical Engineering, Received 14 November 2020 Faculty of Chemical and Metallurgical Engineering Yildiz Technical University, Accepted 08 March 2021 Istanbul, Turkey E-mail: [email protected]

ABSTRACT

In this study it is aimed to recover rare elements and boron with high potential for evaluation from the contents of different boron wastes obtained from Eti Mine Works. For this purpose, raw material analysis and then rare elements and boron recovery by different methods and instrumental devices were performed. Some boron waste sites are remarkable for being rich in rare elements such as lithium and rubidium. For the most efficient utilization of such wastes, samples were obtained from the Eti Mine Kırka Plant for the recovery of both boron and rare elements by using roasting-leaching and acid-leaching methods. The chemical analysis results of borax clay for the main oxides are: 3.3 % boron oxide (B2O3), 0.27 % lithium (Li2O), and 0.0221 % rubidium oxide (Rb2O); in the waste samples the main oxides are 11 % boron oxide (B2O3), 17 % lithium (Li2O), and 0.0264 % rubidium oxide (Rb2O).

The XRD analysis of the samples showed predominantly the presence of dolomite (CaMg(CO3)2) and tincalconite

(Na2B4O7.5H2O) minerals. After roasting-water leaching of these samples, it was determined that the sample of borax clay contained up to 75 ppm lithium and the boron waste sample contained up to 124 ppm lithium. After HNO3 leaching it was observed that the best lithium amount passing from the borax clay sample to the solution was 276,7 ppm. In addition to lithium, the presence of rubidium and cesium as trace elements was noticed. It was observed that the best rubidium amount passing from boron waste to the solution was 3.67 ppm with a mixture of Calcium

Chloride Dihydrate (CaCl2.2H2O) and Borogypsum (CaSO4.2H2O). The best amount of rubidium that passed from borax clay to solution was found to be 3.58 ppm with a mixture of Calcium Chloride Dihydrate (CaCl2.2H2O) and

Borogypsum (CaSO4.2H2O). Keywords: boron clays, boron wastes, lithium, rubidium, roasting-water leaching method, acid leaching.

INTRODUCTION possible, the wastes must be properly disposed of. There have been several attempts to use boron wastes 72 % of the world’s total boron reserves are found and some main strategies were formerly applied [2 - 5]. in the inland areas of the Aegean region of Turkey, The Emet/Kütahya boron-containing clays were used in and borax constitutes the major part of these reserves studies conducted with samples from the region and it [1]. Colemanite is found in the Emet, Bigadiç, and was shown that rubidium metal was dominant. Rubidium Kestelek deposits, which are extracted by the world’s was extracted from picric acid with 18-Crown-6 (0.1 M) boron leader, Eti Mine, and enriched and ground in a in nitrobenzene and separated from the organic phase high-tech concentrator plant. Because boron, the most with 2 M hydraulic acid. The best rubidium extraction important natural resource of Turkey, is a mineral asset obtained was 89.52 % [4]. with increasing production and demand, the amount of Rare elements can be recovered from industrial waste produced as a result of the enrichment processes wastes as well as from electronic wastes [6, 7]. In a study is also increasing every year. Utilization of enrichment conducted on this subject, gold was recovered from the plant wastes is now a prominent technique; if it is not shredder light fraction of an E-waste recycling plant with 845 Journal of Chemical Technology and Metallurgy, 56, 4, 2021 flotation-ammonium thiosulfate leaching [8]. ent processes developed for the extraction of lithium and The presence and distribution of lithium was investi- related metals from both primary and secondary sources. gated within the scope of Turkey’s borates in some non- Acid, alkaline, and chlorination processes and lithium Neogene basins and lakes. When clay samples in Turkish extraction from primary sources such as adsorption, borate deposits, the Soma lignite basin and Beypazarı precipitation, and ions and ores/minerals (spodumene, trona basin, and Acigöl, Salda, Yarişçi, Burdur, Eğirdir, petalite, and lepidolite) from brine received particular Tersakan, Bolluk, Karapınar (Acigöl), and Tuzgölü attention. Issues related to the use of other sources such were analyzed, lithium values of 0.17 % were obtained as bitterns and seawater were highlighted. The hot from the clays of the examined borate deposits. A value water leaching of calcines indicated that increasing the of 0.58 % Li2O was found, and the lake water samples calcination temperature had a considerable effect on contained 0.30 to 325 mg L-1 Li+ [9]. the dissolution of lithium. The leaching of lithium from The compressive and flexural strength, thermal prop- lepidolite was notably higher than that from spodumene erties, and pore structure of mortars modified with boron [17]. As for secondary sources, industrial processes were waste CuO nanoparticles were examined. The addition followed, and more recent developments have aimed at of calcined and non-calcined borogypsum to clinker and recovering lithium from lithium-ion batteries (LiBs). its effects on cement mortar were also studied [10, 11]. In particular, the pretreatment of spent LiBs, filtration The chlorination process is technologically feasible of metals in acids different from cathode materials, and and has the potential for efficient applications. Chlorina- separation of lithium and other metals from leaching tion roasting-water leaching is used to obtain lithium solutions have been discussed [18]. It is known that from lepidolite. The microstructures of lepidolite and lithium in smectite clays is contained in hectorite. In a roasted materials were characterized by X-ray diffraction study carried out in this area, 89 % of lithium in clay (XRD). Various parameters such as chlorination roasting samples was dissolved from the Kırka beds, while 71 temperature, duration, and type and amount of chlorina- % of the lithium in samples from the Bigadiç beds was tion agent have been optimized [12]. Lepidolite is the dissolved [19]. Rubidium is acquired as a by-product in most common source for rare elements such as lithium, the processing of lepidolite and pollucite. It is found in rubidium, cesium, and potassium [13, 14]. several pegmatite regions. Pegmatite deposits are ex- In a study carried out by applying a chlorination plored and operated primarily for their Li contents. Since process for the co-extraction of Li, Rb, Cs, and K, the the chemical structure of rubidium is mostly similar to lepidolite concentrate was roasted at a moderately high adjacent alkali metals, it is extracted only from their temperature with mixed CaCl2 and NaCl chlorinat- deposits, from lepidolite [(K, Rb) Li2AlSi4O10F2] and ing agent, followed by water filtration. Under optimal pollucite (Cs2Al2Si4O12) deposits, and is separated after conditions, the extraction efficiencies of Li, Rb, Cs, the staged chemical processing of cesium and potassium and K reached 92.49 %, 98.04 %, 98.33 %, and 92.90 [20]. Trace element analysis of industrial boron wastes %, respectively [15]. In another study, the recovery of revealed that rubidium was predominant in boron clay. alkali metals and the leaching kinetics of lithium from Although the results are different from each other, it sulfuric acid solution under atmospheric pressure were has been demonstrated that the sulfuric acid leaching investigated from lepidolite in Yichun, Jiangxi Province, method may be an alternative method [21]. In recent China. The results showed that the recoveries of alkali years, the adsorption method is also encountered in metals were achieved under the following leaching con- rubidium extraction [22, 23]. In a study related to this ditions: mass ratio of lepidolite with particle size of less method, the adsorption of rubidium was investigated than 180 µm to sulfuric acid of 1.2, leaching temperature using rubidium(I) potassium cobalt hexacyanoferrate

.[and leaching time (K2[CoFe(CN)6])[23 ,1׃of 411 K, liquid to solid ratio of 2.5 of 10 h. Under the optimal conditions for the leaching In this study, it is aimed to analyze rare elements experiments, the leaching rates of lithium, potassium, and boron in different wastes obtained from Eti Maden rubidium, and cesium were 94.18 %, 93.70 %, 91.81 %, Kırka Enterprises, first by analyzing raw materials with and 89.22 %, respectively [16]. A comprehensive review instrumental devices and then via metal recovery by of lithium extraction summarized the state of the differ- different methods. In this study boron in Turkey for the 846 Reyhan Ozbas, Emek M. Derun

production of lithium carbonate is investigating the use Lithium Recovery experiments with Roasting-Water of waste as raw material. Leaching Method For the limestone-gypsum roasting-water leaching EXPERIMENTAL method, the proportions of the mixtures were prepared as shown in Table 2. In these mixtures clays (I), borax Characteristic of Wastes pentahydrate production solid wastes (II), and calcium

Preparation of Samples carbonate (CaCO3) and borogypsum (CaSO4.2H2O) Clays (I) and borax pentahydrate production solid in the borax zone were used. After the mixtures were wastes (II) in the borax zone were obtained from Kırka ground, the roasting process was carried out in a high- Borax Enterprises. Clays and borax pentahydrate pro- temperature oven for 2 hours at 900°C. In these mixtures, duction solid wastes in the borax zone were taken from the lithium in the borax clay is released and reacted with the plant as samples. Each sample was first dried at the sulfur in the gypsum to form Li2SO4. This Li2SO4 105°C. After drying, the samples were crushed to sizes is dissolved in water and lithium is transferred to the smaller than 1.1 cm in a jaw crusher and then milled to solution. The main reactions during roasting are given below 500 µm in a ball mill. After grinding, samples in reactions (1) and (2) (Büyükburç and Köksal, 2005): were prepared for the experiment.

CaSO4.2H2O + SiO2 → CaSiO3 + SO2 + 1/2 O2 (1)

Mineralogical Composition of Samples Li2Si2O5 + SO2 + 1/2 O2 → Li2SO4 + 2SiO2 (2) In this study, the question of how to evaluate the boron clays and waste landfills of Eti Mine Works is Leaching experiments were performed at differ- emphasized. Therefore, the samples were obtained ent temperatures, times, and solid/liquid ratios. After from the Eti Maden Kırka operations. Borax wastes and leaching was finished, filtration was carried out using a borax clays were analyzed by X-ray diffraction (XRD) vacuum filtration system and the solution was separated. spectrometer. The amount of lithium introduced into the solution was then determined by ICP-MS analysis. Chemical Analysis of Samples First of all, X-ray fluorescence (XRF) analysis was Leaching of Rubidium applied to determine the chemical content of the samples. Experiments with Calcite (CaCO3) and Calcium Chlo-

In the case of borax clays and wastes, solutions of HCl ride Dihydrate (CaCl2.2H2O) and HNO3 acids were made to recover the lithium and Rubidium and other alkaline elements (sodium, the rubidium and cesium trace elements, respectively. lithium, potassium, and cesium) can be separated from Trace element analysis was carried out with an Induc- other elements by the Berzelius and Smith methods. tively coupled plasma mass spectrometry (ICP-MS) The Berzelius method uses HF-HClO4-H2SO4 mixture device after the dissolution process in HCl and HNO3 to separate materials. It then converts alkali sulfates into acids applied to the samples. chlorides for the final precipitation of a suitable rubidium compound (Leddicotte, 1962).

Methods for leaching In these experiments, the amount of CaCO3 was

Leaching of Lithium stabilized and the amount of CaCl2 was changed. In this Acid Leaching Tests way, the effect of the concentration on the amount of Rb Leaching was carried out in a stirred reactor. Sam- transferred to the solution was tried to be determined. ples of 5 g were taken from the reaction vessels, and In addition, the most suitable test parameters were

100 mL of > 65 % HNO3 was added to the samples determined by repeating the experiments at different and leaching was performed at 50°C for 1 hour. In HCl temperatures. The working temperatures were 650°C, leaching, the same process was applied using 30 - 32 % 700°C, and 750°C. After the oven was set to the speci-

HCl. After leaching, the solution was filtered in vacuo. fied temperature, 0.4 g, 1.0 g, and 1.6 g of CaCl2.2H2O The amount of lithium in the filtrate was measured with were weighed and the weighed substances were mixed an ICP-MS instrument. with 2.0 g of CaCO3 and 1.0 g of sample until a homo- 847 Journal of Chemical Technology and Metallurgy, 56, 4, 2021 geneous mixture was obtained. These mixtures were kept in a porcelain crucible at the specified temperatures for 1 hour and then removed from the oven and cooled afterwards. Distilled water was then added and heated and filtered by vacuum filtration followed by analysis by ICP-MS to determine the amount of Rb in the mixture.

Experiments with Calcium Chloride Dihydrate

(CaCl2.2H2O) and Borogypsum (CaSO4.2H2O)

In these experiments, the amount of CaCl2 was kept constant and the amount of borogypsum (CaSO4.2H2O) was changed. The working temperatures were 650°C, 700°C, and 750°C. After setting the oven to the specified temperature, 1.0 g, 2.0 g, and 2.5 g of borogypsum Fig. 1. XRD patterns of borax waste and clay. (CaSO4.2H2O) were weighed and then weighed again with 1.5 g of CaCl2.2H2O and 1.0 g of sample until a homogeneous mixture was obtained. Filtration was performed and the filtrate was analyzed by ICP-MS to determine the amount of Rb in the mixture.

RESULTS AND DISCUSSION

Mineralogical Composition of Samples From the X-ray diffraction (XRD) analyses, borax waste was found to be a mixture of the powders with diffraction file (pdf) number 01-0084-1208 coded “Dolomite (CaMg(CO3)2)” and 00-007-0277 Fig. 2. Lithium values analyzed with acid leaching. pdf coded “Tincalconite (Na2B4O7.5H2O)”. Borax clay contains the powder with 01-0084 pdf coded “Dolomite

(CaMg(CO3)2)”. XRD patterns of borax wastes and Acid Leaching Test Results for Lithium Recovery borax clays are shown in Fig. 1. from Borax Clay Effect of Solid/Liquid Ratio in Acid Leaching Chemical Analysis of the Samples As a result of these studies, the acid leaching method The amounts of major and minor oxides accord- applied to borax clay samples was found to be more ef- ing to XRF analysis results are given in Table 1. The ficient than the roasting-water leaching method. In borax results of ICP-MS analysis are shown in Fig. 2. In light clay, the solid/liquid ratio, leaching temperature, and leach- of these dissolutions, the amount of lithium passing to ing time parameters were examined in HNO3 acid leaching the solution was respectively found for borax clay in where lithium passed to the solution in higher amounts.

HNO3 solution, borax clay in HCl solution, borax waste The amount of lithium passed to the solution in HNO3 in HNO3 solution, and borax waste in HCl solution. was at most 20 % solids-liquid ratio as given in Fig. 3(a).

Table 1. Chemical contents of Kırka borax clays (I) and operational wastes (II). CaO SiO2 MgO B2O3 Na2O SrO Al2O3 F Cl K2O SO3 Fe2O3 Li2O

I (%) 43.500 18.390 22.710 3.300 1.550 2.302 0.540 1.040 0.074 0.559 0.457 0.245 0.270

II (%) 33.300 22.640 20.450 11.000 7.450 2.091 0.830 0.770 - 0.666 0.519 0.296 0.170

848 Reyhan Ozbas, Emek M. Derun

Fig. 3. (a) Solid/liquid ratio effect in HNO3 dissolution; (b) Particle size effect in HNO3 dissolution; (c) Temperature effect in HNO3 dissolution; (d) Leaching time effect in HNO3 dissolution. Effect of Particle Size in Acid Leaching Lithium Leaching Test Results from Roasting-Water For borax clay acid analysis, experiments were car- Leaching Method ried out using samples of different particle sizes and the In the roasting-water leaching method applied for effect of grain size on the amount of lithium passed to the recovery of lithium, the samples were roasted with the solution was examined. The maximum amount of CaCO3 and borogypsum at different mixing ratios and lithium taken into the solution was obtained with 90-µm then leached at room temperature. Lithium values ana- samples as shown in Fig. 3(b). lyzed as a result of roasting and leaching of boron waste are given Table 2. In the borax clay samples, 75 ppm Effect of Leaching Temperature in Acid Leaching lithium was leached in the ratio of 5 : 1.5 sample-borax Another parameter that is changed in acid leaching clay, which is the best mixing ratio. applied to borax clay samples is the temperature. The The best mixing ratio in the roasting-water leaching amount of lithium transferred to the solution at differ- applied to the boron waste sample was likewise taken ent temperatures is shown in Fig. 3(c) and the optimum for lithium solution of 124.3 ppm with a 5 : 1.5 sample- leaching temperature is 50°C. borogypsum mixture as shown in Table 2. To examine the effect of roasting temperature ap- Effect of Leaching Time in Acid Leaching plied to the samples at 900°C, 950°C, and 1000°C, ex- When the leaching time of acid leaching of the periments were carried out for 2 hours. It was observed solution was analyzed, it was found that the optimum that the structure of the boron waste sample above 900°C leaching time was 60 minutes. This effect is also shown was degraded, and for the borax clay samples, the best in Fig. 3(d). result was obtained with the sample roasted at 950°C. Table 2. Lithium values analyzed as a result of roasting and leaching of boron waste.

Amount of CaCO3 - 1.0 2.0 3.0 2.0 4.0 3.0 2.0 (g)

Amount of 1.5 2.0 2.0 3.0 4.0 2.5 2.0 3.0 CaSO4.2H2O (g)

Amount of Li 124.3±6.1 103.3±5.1 103.7±5.1 78.01±3.81 65.75±3.22 62.98±3.08 65.56±3.21 87.86±4.30 (µg/mL)

849 Journal of Chemical Technology and Metallurgy, 56, 4, 2021

Fig. 4. (a) Effect of solid/liquid ratio on lithium dissolution in the waste sample; (b) Effect of leaching temperature on lithium dissolution in the waste sample; (c) Effect of leaching time on lithium dissolution in the waste sample.

Effect of Solid/Liquid Ratio a constant amount of CaCO3 was investigated. When the -1 The effects of the solid/liquid (µg mL ) ratio on dis- effect of the CaCl2.2H2O ratio on samples was examined, solved lithium concentration in boron waste and borax it was seen that the best result was obtained with a ratio of clay samples were examined, and the results are shown 1/0.4/2.0 sample/CaCl2.2H2O/borogypsum mixture and at in Fig. 4(a). As is indicated, when the solid/liquid ratio 750°C as seen in Fig. 5. In boron waste samples, the experi- is 5 %, the resolution is the lowest, and the highest value ments with borogypsum yielded better results. As indicated is 10 %. In this case, as shown in Fig. 4(a), the optimum in Fig. 6, the best result was observed in 1/1.5/2.5 sample/ value for the solid/liquid ratio was determined to be 20 %. CaCl2.2H2O/borogypsum mixtures at 700°C.

Effect of Leaching Temperature The temperature of the aqueous solution to which leaching was applied was tested in order to see the effect on the concentration at room temperature (25°C), 35°C, 55°C, and 75°C. The optimum temperature for the leaching process for the waste sample was determined to be 25°C and the temperature effect is illustrated in Fig. 4(b). The optimum temperature in the leaching process for borax clay samples was found to be 75°C and the effect of the temperature on the amount of dissolved lithium is also given in Fig. 4(b).

Fig 5. Amounts of rubidium dissolved in constant CaCO3 Effect of the Leaching Time (2 g) and variable CaCl2.2H2O at different temperatures. When the effect of leaching time was examined, it was observed that the optimum leaching time was 60 minutes for the amount of lithium passed from the waste sample to the solution, and the optimum leaching time was 30 minutes for the lithium amount from the borax clay sample to the solution. The effect of the leaching time is shown in Fig. 4(c).

Leaching Experiments of Rubidium In the leaching studies of rubidium, the effects of

CaCl2.2H2O and borogypsum with different mixing ratios were investigated. Experiments with borogypsum in the bo- Fig. 6. Amounts of rubidium dissolved in constant amounts rax clay sample gave better results. First of all, in borax clay of CaCl2.2H2O (1.5 g) and variable borogypsum at different temperatures. and boron waste samples, the effect of CaCl2.2H2O ratio on 850 Reyhan Ozbas, Emek M. Derun

CONCLUSIONS 2670-2683. When the roasting-water leaching method and acid 6. S.R. Mueller, P.A. Wäger, R. Widmer, I.D. Williams, leaching method applied to the above-mentioned sam- A geological reconnaissance of electrical and elec- ples were compared, it was seen that HNO3 analysis tronic waste as a source for rare earth metals, Waste for borax clay samples yielded better results than the Management, 45, 2015, 226-234. roasting-water leaching method. For this reason, acid 7. A. Lixandru, P. Venkatesan, C. Jönsson, I. Poenaru, leaching method has been found more suitable as it B. Hall, Y. Yang, A. Walton, K. Güth, R. Gauß, O. provides higher efficiency in the recovery of lithium. For Gutfleisch, Identification and recovery of rare-earth this reason, acid leaching method has been found more permanent magnets from waste electrical and elec- suitable as it provides higher efficiency in the recovery of tronic equipment, Waste Management, 68, 2017, lithium in borax clay. The optimum leaching parameters 482-489. for the amount of lithium transferred from borax clay to 8. S. Jeon, M. Ito, C.B. Tabelin, R. Pongsumrankul, N. solution were found to be 20 % solid/liquid ratio, 50°C Kitajima, I. Park, N. Hiroyoshi, Gold recovery from temperature, and 60 minutes of leaching time. shredder light fraction of E-waste recycling plant When acid treatment and roasting water leaching by flotation-ammonium thiosulfate leaching, Waste method are compared, the acid leaching process requires management, 77, 2018, 195-202. high equipment cost due to the corrosive effect. In addi- 9. C. Helvaci, H. Mordogan, M. Çolak, I. Gündogan, tion, while roasting water leaching method takes place Presence and distribution of lithium in borate de- at room temperature, acid leaching process provides posits and some recent lake waters of west-central an optimum condition at 50oC, thus it brings heating Turkey, International Geology Review, 46, 2, 2004, costs. Although it is possible to recover rare elements at 177-190. high efficiency with acid treatment, the roasting-water 10. M. Yildirim, E.M. Derun, The influence of CuO leaching process is more economical and more environ- nanoparticles and boron wastes on the properties mentally friendly in industrial-scale works. of cement mortar, Materiales de Construcción, 68, 331, 2018, 161. REFERENCES 11. K. Kunt, F. Dur, M. Yildirim, E.M. Derun, Effect of chemical admixtures on borogypsum containing 1. C. Helvacı, M.R. Palmer, Origin and distribution of cement mortar, Main Group Chemistry, 16, 4, 2017, evaporite borates: the primary economic sources 227-239. of boron. Elements, An International Magazine of 12. Q. Yan, X. Li, Z. Wang, X. Wu, J. Wang, H. Guo, Mineralogy, Geochemistry, and Petrology, 13, 4, Q. Hu, W. Peng, Extraction of lithium from le- 2017, 249-254. pidolite by sulfation roasting and water leaching, 2. T. Uslu, A.I. Arol, Use of boron waste as an addi- International Journal of Mineral Processing, 110, tive in red bricks, Waste Management, 24, 2, 2004, 111, 2012, 1-5. 217-220. 13. N. Vieceli, C.A. Nogueira, M.F. Pereira, F.O. Durão, 3. A. Büyükburç, D. Maraşlıoğlu, M.U. Bilicive, G. Kök- C. Guimarães, F. Margarido, Recovery of lithium sal, Extraction of lithium from boron clays by using carbonate by acid digestion and hydrometallurgical natural and waste materials and statistical modelling processing from mechanically activated lepidolite, to achieve cost reduction, Minerals engineering, 19, Hydrometallurgy, 175, 2018, 1-10. 5, 2006, 515-517. 14. N. Setoudeh, A. Nosrati, N.J. Welham, Lithium 4. B. Ertan, Y. Erdoğan, Separation of rubidium from recovery from mechanically activated mixtures of boron containing clay wastes using solvent extrac- lepidolite and sodium sulfate, Mineral Processing tion, Powder Technology, 295, 2016, 254-260. and Extractive Metallurgy, 2019, 1-8. 5. F. Özmal, Y. Erdoğan, Li+ adsorption/desorption 15. X. Zhang, T. Aldahri, X. Tan, W. Liu, L. Zhang, S. properties of lithium ion-sieves in aqueous solution Tang, Efficient co-extraction of lithium, rubidium, and recovery of lithium from borogypsum, Journal cesium and potassium from lepidolite by process of Environmental Chemical Engineering 3, 4, 2015, intensification of chlorination roasting, Chemical 851 Journal of Chemical Technology and Metallurgy, 56, 4, 2021

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