The Calcination Behaviour of Fine-Sized Colemanite and Ulexite

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Research Article Volume 9 Issue No. 7 The Calcination Behaviour of Fine -Sized Colemanite and Ulexite Ore Under Conventional Heat Treatment Hoskan, Samil Graduate Student Department of Mining Engineering Dokuz Eylül University, İzmir, Turkey

Abstract: Because waste material stroges and their enviromental problems are main problem in mining, re-use and evalaution of wastes are reasonable solutions. In this study, fine sized ( -3mm) waste Colemanite and Ulexite ores were exposured to conventional heat treatment in a spesific time (15-60 minute) to determine behaviour of ores under heat range bet ween 450C -600C. İn this study, beside measuring Boron calcination behaviour, it is targeted that seperating calcinated Boron minerals from unwanted minerals such as clay and calcite by screening. In order to make physical and chemical characterization of t he material to be used within the scope of experiments, 50 kg of Colemanite and Ulexite ore were taken and it was determined that 22,8% and 27,53% B2O3 grade respectively in chemical analysis. The sieve analysis of the samples were performed to determine c haracterization of the samples. The materials were dried and divided into 1 kg samples with cross -groove divider. After that, each 1 kg of samples were divided in to 125’gr of representative samples with small size cross -sectioned slicers and packaged for the planned experiments.

Key words: Colemanite, Ulexite, Heat Treatment, Calcination, Boron .

1. INTRODUCTION were chosen on stock area and samples were taken from these locations. Boron combines with oxides and alkali ions in the earth crust to form minerals such as colemanite and ulexite. As it is 2.2 Sample Preparation known, Boron mineral are mostly deposited in Turkey and Because sample preparation is most important part of any almost 72% of total worlds Boron deposit is locoted in experiment in ore processing, considerable attention was paid Turkey’s tetritorial regi on. İn spite of vast source of Boron in this stage. Chosen 50 kg samples taken from stock area was availability, fine sized Colemanite and Ulexite are produced as brought to laboratory. After this stage -250 micron part of the a waste product from ore processing plants located in Turkey. samples was eliminated from the whole part. As we know t hat The waste products are mostly -3 mm fine sized. İn experiment high amount of undesired minerals such as clay is found in - series, Protherm metalurgical o ven was used for calcination. 250 micron part of whole.After the elimination stage, sample Temperature variables and time variables were selected was divided to 125 gr representative units. between 450-600 ⁰C and 15-30-45-60 minute respectively. 2.3 Complete Chemical Analysis : Chemical analysis was performed to determine the compo sition and composition 2. MATERIAL AND METHODS ratios of the samples. Complete chemical analysis show that 2.1 Source of Material samples Colemanite and Ulexite samples contain 22,8% B2O3 Samples were taken from waste stock area whose size reachs and 27,53% B2O3Chemical analysis was performed before the over 2 million tons. İn order to obtain homogenious samples, elimination of -250 micron part of the samples. The follo wing one thing was taken in to account that 6 different locations table shows content of the samples chemical analysis

Table.1.Colemanite Chemical Analysis

B₂O₃ Na ₂O MgO Al ₂O₃ SiO ₂ SO ₃ SO 4 CaO Fe 2O3 As 2O3 AS SrO H2O 22.87 0.33 8.18 2.02 14.86 0.34 0.408 24.72 0.129 113 86 0.84 3.07

Table.2. Ulexite Chemical Analysis

B₂O₃ Na ₂O MgO Al ₂O₃ SiO ₂ SO ₃ SO 4 CaO Fe 2O3 As 2O3 AS SrO H2O

27.99 2.26 3.99 0.08 7.06 0.27 0.32 21.94 0.044 57 43 0.94 0.41

2.4 Sieve analysis Sieve analysis was performed to determine the grain size distribution of the sample and the grade distribution according to t he grain size . Sizes of sieves were used as 2,1,0.5,0.25 and 0.150 mm and the resul ts are given below.

IJESC, July 2019 23221 http://ijesc.org/ Table 3. Colemanite sieve analysis

Table .4. Ulexite sieve analysis

2.5 Conventional Calcination Tests exposed to 450-600 ⁰C in 15-60 minutes. The aim of these Calcination tests were performed in Protherm metalurgical expreriments is to determine relationship between temperature oven in order to determine calcination behaviour under the and time during calcination process. Following table shows temperature between certain time. İn this case, materials were B2O3 grade and recovery by weight

Table.5. -3+0.25 mm Colemanite conventional calcination in terms of grade and recovery

Table .6. -3+0.25 mm Ulexite conventional calcination in terms of grade and recovery

IJESC, July 2019 23222 http://ijesc.org/ 3. CONCLUSIONS

As it is seen from the table 5, highest Colemanite B 2O3 grade %55.25 with %80.82 recovery was obtained in 30 minutes under the 600°C temperature. As temperature and time increase, grade and recoveryrise. Ulexite calcination behaviour is different from Colemanite, As it is seen from the table 6, highest Ulexite B 2O3 grade %53.35 with %35.89 recovery was obtained in 60 minutes under the 600°C temperature. Even though the temperature level which used in Ulexite calcination was chosen at the same level of Colemanite calcination, high recoveries were not detected. The reason of this, Mineral degradation can not be seen for Ulexite. Ulexite crystal structure is the essential factor that cause keep degradation low.

4. REFERENCES

[1].www.etimaden.gov.tr (2019)

[2]. www.boron.gov.tr (2019)

IJESC, July 2019 23223 http://ijesc.org/