Turkey’s borates bounty

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Published: Wednesday, 26 January 2011

Haldun Kurama of Turkey’s Boron Research Center discusses the market applications and production potential for the country’s significant boron reserves


Borates bounty: lumps of colemanite at Eti
Maden’s Bigadic works


Boron is a relatively rare element and does not appear on Earth in elemental form; instead, it is found as a mineral deposit in the crystalline group known as ‘borates’ (oxides of boron). These are distinguished by a structural framework formed of polymerized boron-oxygen-hydroxyl tetrahedral or triangles, which are linked to each other by means of cations.

This group includes boric acid, borax and others. Boron, with an atomic number of 5 and weight of 10.81, is a trivalent metalloid element that has a covalent bond like non-metals but with intermediate properties between metals and non-metals. It occurs abundantly in the evaporative ores borax and ulexite.

Boron’s position in the periodic table would indicate a close relationship to aluminium, gallium, indium, and thallium, but it is actually much more similar to carbon and silicon in its chemical properties. Elemental boron is used as a dopant in the semiconductor industry, while boron compounds play important roles as light structural materials, insecticides and preservatives, and reagents for the chemical synthesis of carbon.


Figure 1: Turkish boron sales and global market share




Figure 2: World boron production, 2009 (3.29m. tonnes)




Boron background

Boron compounds may have been known of for about 6,000 years, starting with the Babylonians. The Egyptians, Chinese, Tibetans and Arabians are reported to have used such materials.

The first European borax source was discovered in 1777 at the hot springs (soffini) near Florence, Italy, and became known as sal sedativum, with mainly medical uses. It was the main European source from 1827 to 1872, at which date US sources replaced it. Boron was not recognized as an element until it was isolated by Sir Humphry Davy and by Joseph Louis Gay-Lussac and Louis Jacques in 1808 through the reaction of boric acid and potassium. Davy called the element boracium. Jšns Jacob Berzelius identified boron as an element in 1824. The first pure boron was arguably produced by the US chemist W Weintraub in 1909.

Although the use of boron or its combined form of borax (Na2B4O7. 10H2O) dates back to early times, it did not become of interest until the twentieth century. Early uses of it were as a mild antiseptic ore cleaner because of its detergent and water-softening properties and as ceramic flux due to its ability to dissolve metal oxides.

Nowadays, the usage of boron varies from insulation or textile fibreglass, heat resistant glass, detergent, soaps, personal care products, ceramics, agriculture micronutrients to aircraft fuel and hydrogen storage due to the following advantages. First, borates are safe. Used for centuries, they pose no risk to people, animals or the environment under normal handling and use. Second, they are versatile. In some applications, there is simply no substitute for borates.

Boron forms several commercially important compounds. The most important boron compound is sodium borate pentahydrate (Na2B4O7•5H2O). Large amounts of this compound are used in the manufacture of fibreglass insulation and sodium perborate bleach. The second most important compound is boric acid (H3BO3), which is used to manufacture textile fibreglass and is also used in cellulose insulation as a flame retardant. Sodium borate decahydrate (Na2B4O7•10H2O), better known as borax, is the third most important boron compound. Borax is used in laundry products and as a mild antiseptic.

Boron could also play an important role in the world’s move away from fossil fuels toward greener energy. Hydrogen can be obtained from the pyrolysis and hydrolysis of some borohydrides. In its usage in fuel cells, boron compounds are considered the most promising candidates among the metal hydrates for the safe storage of hydrogen which is an impediment to the commercial use of hydrogen as fuel in fuel cells. NaBH4 has been found to be a feasible material for a portable and safe hydrogen gas generator.

Commercialisation of NaBH4 has been performed by Millennium Cell as the ‘Hydrogen on Demand’ process. The production of magnesium diboride (MgB2) can be given as another attractive research interest for the usage of boron. MgB2 is a simple metallic compound differing from ordinary metallic superconductors due to such unique properties as a relatively high-critical temperature (Tc) of 39K, and the low cost of the starting materials. This makes MgB2 a promising candidate for practical applications, in comparison with low temperature superconductors (LTS).

In combination B and N have many similarities to carbon. Both carbon and boron nitride (BN) have hexagonal (graphitic) and cubic (diamond) crystal structures. Hexagonal boron nitride is a soft lubricious material while cubic boron nitride is second only to diamond in hardness and is commonly used as an abrasive. The most notable differences between C and BN are color and electrical properties. Graphitic carbon is black and electrically conductive while (h)BN is white and electrically insulating.

These properties and other unique performance characteristics are the reason why BN is valuable in many applications. Ceramics and intermetallic composites incorporate boron nitride in their formulations to enhance performance characteristics. A partial list includes: SiC/BN TiB2/BN, Si3N4/BN AlN/BN, ZrO2/BN Al2O3/BN.


Table 1: Turkish boron reserves

Boron mineral Reserve (m. tonnes) Share (% )
Colemanite 888 74
Ulexite 24 2
Tincal 288 24


Figure 3: Turkey’s domestic boron sales, 2000-2009




Turkish boron market


The most important boron bearings in the world are, respectively, Turkey, the USA, and Russia. Large deposits of boron reserves occur in southern California and in Turkey. Turkey has approximately 67% of the world’s known reserves base, with 1.2bn tonnes. The USA, Russia and Kazakhstan follow Turkey with 7% share rates. The US deposits consist primarily of tincal and kernite, while Turkish deposits are 70% colemanite.

The borate deposits of Turkey occur in western Anatolia, south of the Sea of Marmara, within an area roughly 300km east-west by 150km north-south. The main borate districts are Bigadic, Kestelek, Sultancayõr, Emet and Kõrka (see map). These borate deposits are generally enveloped by, or grade into, limestone or clay stone.


Figure 4: Turkish boron sales by market (2009)





Turkey’s global role


Turkey has the largest and highest quality reserves and is the world’s leading exporter of the mineral. In proportion to its reserve share, Turkey has had a relatively stable position in the boron market in the last five years. In 2009, Turkey possessed 37% of the total world production on the B2O3 basis. This makes Turkey a major world producer of both concentrated and refined boron products. The total sales amounted to 1.1m. tonnes.

The mined boron minerals of Turkey primarily consist of tincal, colemanite and ulexite. The tincal ore is concentrated at Kõrka while colemanite is mined mainly in the Emet and Bigadic regions. In addition, a relatively small amount of ulexite is also mined in the Bigadic and Kestelek regions. The reserves and share rates of these regions are given in Table 1.

Boron mining was started in Turkey in 1861 by foreign companies. Later, mining exploitation rights were transferred to the state sector, Eti Maden Works General Management (Eti Mine). The Eti Mine was established in 1935 under the name of Etibank in order to utilise the natural resources of Turkey.

The annual production capacities of Eti Mine are 2.45m. tonnes concentrated boron and 1.277m. tonnes boron chemicals, respectively. In recent years, the trading strategy of Turkey has shifted from the marketing of boron concentrate to value-added products. In 1998, the share of boron concentrate in total trade was 53%. This rate had decreased to 8% by 2009. Most of the concentrated boron is used for boron chemicals production.

The production of boron concentrate and chemicals is performed by five plants, namely; Emet, Kõrka, Bigadic, Kestelek boron works and the Bandõrma boron and acid plant works. The production levels of these foundations are given in Table 2.

The main mining method at the most important borate deposits throughout the world is the open pit operation. However, at the Bigadi and Kestelek mines some part of the deposits had been operated by underground methods. Today, all are open pit mines. In the industrial application, the upgraded minerals are widely-preferred to refined products because they are cheaper and compatible. Most of the commercially mined deposits have a simple beneficiation plant which consists of crushing, hand sorting, screening, washing and classification circuits.

Following years of strong growth, in 2009 a sharp decrease was observed in demand for borates owing to the effects of economic crises and economy growth rate in 2008. The decrease in the consumption of boron in 2009 was calculated at 51% for Europe and 33% for North America, respectively. It is estimated that the consumption of boron decreased to 2.9m. tonnes (26.3%) compared to the previous year. However, in the second half of the year, the markets for both textile-grade fibreglass and borosilicate glass recovered and demand for borosilicate glass in LCD screens is expected to have grown by 15% in 2010.

The world production of natural and refined borates remained highly concentrated in Turkey and the USA in 2009. The two countries provided total production of around 75% of the world supply. The actual production of boron was estimated at about 3.29m. tonnes. Turkey kept its leading role (41%), and North America (USA 29%), South America (Chile, Argentina, Peru, and Bolivia 18%) and finally Asia (China, Russia, India 12%) followed Turkey in share rates.

Although the state still plays a major role in industry, Turkey has a very energetic, productive private sector. This makes Turkey a rapidly growing country compared to other developing regions.

According to statistical data released by the Eti Mine base on domestic boron sales between 1999 and 2009, the Turkish boron market can be characterised by several highs and lows caused by the general economic condition of the country, overall growth rate per capita, GDP and industrial output.

The domestic boron sales graph given in Figure 3 clearly indicates that the boron consumption in the domestic market developed with an increasing industrial production rate especially due to the driving force of the ceramic and glass sectors from 2001 to 2004, and kept this position up to 2006. But the trend reversed after this relatively stagnant period, and a continued decline in consumption was observed due to economic recession and the results of the global economic crisis on the domestic market. Boron sales reached their lowest value in 2009, corresponding to 40,306 tonnes.

The estimated distribution pattern for boron compounds consumed in Turkey in 2009 is given in Figure 4. The glass industry (glass fibre, glass wool, and borosilicate glass) had the highest consumption share at 41%. This was followed by ceramics at 38%, soaps, detergents, and bleaches at 3%, and agriculture, packaging, textiles and timber preservation with a consumption rate of 19%.


Figure 5: Distribution of Turkish boron research projects by area




Research & investment


The economy of Turkey is largely developed. The country is among the world’s leading producers of agricultural products, textiles, motor vehicles, ships and other transportation equipment, construction materials, consumer electronics and home appliances. Turkey has the world’s seventeenth largest nominal GDP. However, the usage of boron and boron end products in the domestic market is far from the expected level.

Not only to boost the boron market but also to overcome an observed weakness in science and technological policies of Turkey, a new technological roadmap has been implemented since 2003. The road map ‘Vision 2023’ has been implemented to:

  • Overcome a weakness in innovation;
  • Increase the competitive advantage in today’s global market;
  • Connect with global research;
  • Invest in a knowledge based economy.

A released report consists of:

  • Assessment of the current status of Turkey in the field of science and technology;
  • Assessment of the long term scientific and technological developments in the world;
  • Identification of the strategic technologies required for achievement of creative production;
  • Recommendation of policies aimed at development and/or acquisition of designated technologies.

According to Vision 2023, the foundation of a national boron institute (BOREN) and university research centres have been completed in addition to an existing technology development department of Eti Mine. This institute and other research centres, and also researchers from different universities, are focusing the investigation of new application areas for boron and its compounds and are carrying out exploration of new products as well as studies on the improvement of product quality. Since 2003, BOREN has provided financial support for 131 research projects, 64 of which were completed successfully.

The main industrial outputs of these projects were; the production or synthesis of boron additive cement, boron additive ceramics, three-methyl borate, Na-borehydrate, zinc borate, boron nitrate, fire retardants and micro-feeders for agricultural applications. The distribution of the completed projects according to related application areas are given in Figure 5.

The usage of borates in ceramics production, especially as an additive for frit production due to its ability to dissolve metal oxides goes back to historical times. The Chinese have traditionally used boron mainly in the production of ceramics and glassware. However, recent research studies performed by the Boron Research Center, Osmangazi University, Turkey, show that borax could also be used as an additive in the production of ceramic bodies.

The laboratory and plant studies on the production of terracotta and floor tiles show an increased presence of borax compared to the standard mixture of clay, as a co-fluxing material in the body. It considerably accelerates the vitrification process and allows for better technological properties for the firing regime involved with relatively lower energy consumption due to the decreased firing temperature. The increased demand for boric acid from Turkish ceramic producers in recent years could be attributed to the practice of these findings in commercial production.

Eti Mine has also continued its investment and research activities to increase the recovery and plant capacities of boron. The rehabilitation and investment programme started in 2005 has mainly focused on the projects related to increasing capacity. The construction and equipping of the Bandõrma agri boron production plant, with a capacity of 8,000 tpa and borax decahyrate/pentahydrate production plant (80,000 tpa) in Kõrka can be given as examples of completed projects in 2009.


Table 2: The production capacities and main products of Eti Mine at its five sites




Conclusions


A frequently discussed forecast concerning the world’s economic status for the next 20-30 years sees a shift away from the dominant current production centres or economic powers to the fast growing countries, having young and productive populations such as China, Brazil, India, Indonesia, Mexico and Turkey. It has been estimated that approximately 75% of the total world production will be supplied by these emerging economic nations.

Borates are an integral part of the natural world. Plants and even humans are reliant on them; not only as a nutritionally important part of their diet, but also as an essential component of many products in everyday use. The latest developments in materials science have tended to focus on electrical properties. However, mechanical properties are also of major importance and the contribution of boron to improve the material properties in the production of such materials continues to grow.

Turkey holds approximately a 67% share of the total known world deposits. These boron reserves are high in tenor and quality and are estimated as being sufficient to supply world demand for the next 250-500 years. Such facts improve Turkey’s position on the global marketplace as both a raw and processed materials supplier and combine with increased productivity due to implemented new supporters on education and technological innovation.


Principal borate deposits in Turkey




Contributor: Prof. Haldun Kurama, Boron Research Center, Eskisehir Osmangazi University, Turkey. Adapted from a paper presented at the 3rd Liaoning Boron Industry Exposition, 27-28 September 2010, Shenyang.