**1. Introduction**

Turkey has 2.5% of the global industrial mineral reserves, 73% of the global boron mineral reserves, 20% of the global bentonite reserves, and more than half of the global perlite reserves. The mines extracted from these sources are used as raw materials in the industry, with the excess being exported. Around 791 million tons of industrial minerals are produced worldwide, and Turkey accounts for 42.3 million tons of this global production. Turkey ranks 3rd in the world with a share of 5.3% in industrial mineral production. When we consider this production rate in terms of value, it ranks 8th with a 4 percent share. Based on the figures for 2016, the mines extracted most in Turkey's industrial raw material production were calcite, feldspar, gypsum, quartz sand, pumice, and boron. These production data were drawn up based on the production amount figures declared by licensed mine sites to the Turkey General Directorate of Mining and Petroleum Affairs.

Quartz sand deposits are very common in Turkey. There are quartz sand deposits in İstanbul-Şile and Çatalca, Zonguldak-Kilimli, Bartın, Tekirdağ-Safaalan and Sinop-Sarıkum. In Turkey, there are 1.884.208.585 tons of (visible+probable) quartz sand reserves containing over 90% SiO2. A total of 54.820.154 tons of quartz sand were produced in Turkey between the years 2011 and 2016.

Quartz sand is formed as a result of the decomposition of quartz-rich magmatic metamorphic rocks. Quartz sand is divided into two types based on its formation. Magma-origin rocks have decomposed and weathered where they formed by physical forces such as the atmosphere and faults. These deposits have higher SiO2 content. Some other deposits piled up in one area during being moved and formed placer beds. During transportation, heavy minerals also collapsed and turned into deposits when moving with the silica. Quartz sand consists of silica particle of 1/16 and 2 mm size. Its pure one is white in color. On the other hand, depending on the amount of iron minerals (limonite, pyrite, magnetite, hematite, etc.) in it, it can be brown, red, or pink in color. It contains a high amount of silica. Although it can be found pure in nature, it may contain small amounts of clay, feldspar, iron oxides, or carbonates. The beneficiation processes such as gravity, frotation, and leaching are applied in order to bring the requested chemical, physical, or thermal properties depending on the intended use. According to their intended use, quartz sands are generally named core sand, glass sand, golf course sand, hydraulic fracturing sand and blasting sand. In determining the usage area of quartz sand, it is important to know the maximum chemical impurity and minimum SiO2 levels, and the features such as particle size distribution and grain shape. There must be at least 95% SiO2 in quartz sand to be used in the production of casting mold, silica bricks, silicone, ferrosilicon, and building sand, and there are certain limit levels for Al2O3 and Fe2O3 content. Quartz sand is in a general sense used in the glass and casting industry. Apart from these areas of application, it is also used in industries such as construction, aerated concrete, ceramic, iron-steel, dyeing, plastic, and abrasive, which is used for removing rusted surfaces, corroded surfaces, old paint, as well as for shaping marble and glass. The open-pit mining method is applied as the production method from the pit. For quartz sand production to be economical, the ratio of the thickness of the cover layer to the thickness of the quartz sand layer should not exceed the 4 m<sup>3</sup> /ton level [1–4].

In this study, quartz sand in the district of Şile on the Black Sea Coast of İstanbul, Turkey, which is used in the production of traditional ceramic materials, is preferred. Over 4 million tons of quartz sand are produced annually from the Şile Basin and utilized in many fields in Turkey. Şile region quartz sand reserves are estimated to be over 100 million tons. In the traditional ceramics industry, quartz sand containing 90% > SiO2 and Fe2O3 < 0.5% with a particle size of approximately 1 + 0.075 mm is preferred. The quartz sands of the Şile region generally have the characteristics to meet these expected oxide properties. Mining companies sell these quartz sands only after they have been washed and classified. Non-plastic raw materials such as feldspar and quartz sand supplied by traditional ceramic factories are also applied to the grinding process. Generally, an alumina ball is used as the grinding medium in the grinding process to give ceramic materials the desired physical, chemical, thermal and mechanical properties. Ball mills are preferred for intermediate grinding (P80; 0.040 to 0.40 mm) in plants producing traditional ceramic products such as tile, sanitaryware, tableware, and. The non-plastic composition is ground to a particle size finer than 0.075 mm with the grinding process. After the grinding process, the Fe2O3 content in the ceramic sludge is removed with magnetic holders.

#### *The Effects of Mill Conditions on Breakage Parameters of Quartz Sand in the District… DOI: http://dx.doi.org/10.5772/intechopen.102554*

Upon examination of the quartz sand of the Şile region, which was supplied for use in the studies, with a loop, dark-colored ferrous minerals with a grain size of approximately 0.010–0.040 mm were discovered. These minerals, which do not pose a significant problem in the traditional ceramic industry, can be considered as an essential impurity in areas such as glass and casting mold production. If it is necessary to obtain quartz sands with higher SiO2 and lower Fe2O3 content, such as glass and casting mold production, enrichment processes must be applied. In such cases, quartz sands are enriched by gravity method, flotation, or extraction according to their intended use, and the impurities it contains are removed. In the gravity method, first of all, the clay minerals that form slime must be cleaned. Then, minerals with magnetic properties such as hematite, magnetite, or ilmenite must be removed with magnetic separators of 1000–15,000 gauss intensity. Wet magnetic separators are preferred for cleaning magnetic minerals smaller than 0.075 mm. Enrichment by gravity becomes increasingly challenging as the grain size decreases. As in the quartz sand of the Şile region used in this study, some impurities can be liberated in grain sizes below 0.075 mm. In such cases, the quartz sand must first be ground into the liberation size. Afterward, enrichment by flotation is required [3, 5]. Since the grinding process is under a specific particle size, most of the energy used is converted into heat energy. While specific energies of ball mills increase exponentially in these fine particle sizes, the grinding efficiency decreases economically [6–10].

Quartz sand acts as a grinding medium on other non-plastic raw materials that form the ball mill phase in ceramic materials production. Raw materials such as feldspar in the mill show fracture along smooth surfaces because they have cleavage. However, since quartz sand is no cleavage, it does not show the smooth fracture. Fracture occurring along irregularly developed cracks in quartz sand takes place conchoidally (mussel shell) [11]. As a result, when compared to other raw materials in the mill, quartz sand grinding and the energy consumed during this operation are significantly high. It also causes some wear on grinding media such as quartz sand, alumina ball, and flint pebbles. In this study, alloy steel balls were favored as a grinding medium in grinding units above alumina balls and flint pebbles, which are preferred by ceramic producers. Alloy steel balls have approximately twice the specific gravity of alumina balls. The grinding medium's weight applied to the unit volume during the grinding process and the size of the grinding medium are critical elements determining the mills' capacity and efficiency. There are some studies in the literature on the selection of the grinding medium size in the ball mill [6, 12–17]. In addition, there are studies of breakage rate parameters of some raw materials [18–20].

In this study, the effect of different sizes of alloy steel balls on specific rates of breakage (*Si*) was investigated. The quartz sand used in grinding works was supplied by a private mining company, which is located in the district of Şile, Istanbul. The variation of the specific rate of breakage of quartz sand was investigated using 6.35, 7.94, 9.52, 12.70, and 19.05 mm alloy steel balls. For the grinding tests carried out in dry conditions, the powder (*fc* = 0.120) and ball loads (*J* = 0.35) are taken as fixed. For this purpose, the kinetic model, the basis of which was developed by Austin et al. (1984), was applied. In this model, mathematical expressions are defining the breakage distribution and breakage rate of raw material [21]. Studies with kinetic model-based grinding and the values obtained in the laboratory are suitable for simulation in an industrial environment [22].
