Barit konsantreleri ve şlam atıklarının flotasyonla zenginleştirme olanaklarının incelenmesi
Investigation of beneficiation possibilities of barite concentrates and slime tailings by flotation
Yazar: ULAŞ ÇUĞU
Danışman: PROF. DR. ABDULLAH EKREM YÜCE
İstanbul Teknik Üniversitesi / Lisansüstü Eğitim Enstitüsü / Cevher Hazırlama Mühendisliği Ana Bilim Dalı / Cevher Hazırlama Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2021
Konu: Maden Mühendisliği ve Madencilik = Mining Engineering and Mining

Özet:
Barit minerali, petrol ve gaz sondajları, boya, plastik-kauçuk bileşimleri, lastik-balata, cam gibi endüstriler için önemli bir endüstriyel hammaddedir. Halihazırda üretilen baritin %75-80'i petrol sondajları için API kalite olarak sunulmaktadır. Bunun dışında kalan üretimde de diğer endüstriler için miktarca düşük ancak pahada yüksek bir endüstriyel hammadde olarak gösterilebilir. Türkiye barit üretimi konusunda dünyanın %3,0-3,5'u gibi bir payı elinde bulundurmaktadır.
Barit cevherleşmeleri dünyanın farklı yerlerinde farklı mineral toplulukları ile bir arada bulunabilmektedir. Barit-Florit ve Barit-Sfalerit-Galen gibi cevherleşmelerinin aksine bu çalışma kapsamında incelenen cevherleşmede, barit mineralinin yan taşları kalker, kuvars, kil, kalkşist ve demir oksitler olup, değerli mineral ile gang minerali arasında bariz bir özgül ağırlık farkı bulunmaktadır. Bu nedenle de genellikle özgül ağırlık farkına göre zenginleştirme yapılan cihazlar kullanılır ancak 100 mikron altı tane boyutunda klasik gravite ayırıcılarından istenilen verimler alınamamakta ve atıklarda kaçaklar görülmektedir. Bu tez kapsamında da Isparta/Şarkikaraağaç-Konya/Hüyük bölgelerinde yer alan özel işletmelerin düşük yoğunluktaki Barit şlam atıkları ve zenginleştirme tesisinde elde edilen ön konsantrenin flotasyonla zenginleştirme olanakları incelenmiştir.
Nihai baritin satış koşulları ağırlıklı olarak spesifik gravitesi, tane boyutu ve beyazlığı üzerinden değerlendirilir. Spesifik gravite (SG) değeri 3.03-3.09 bandında değişen şlam atıkları ve SG değeri 3.85-3.98 civarında değişen barit ön konsantrelerine yapılan flotasyon deneylerinde esas olarak atık SG değerlerinin 2.80'in altına indirilmesi hedeflenmiş olup, verimli bir flotasyon zenginleştirmesi için uygun reaktif-kollektör seçimi ve miktarı, bastırıcının ve miktarının etkisi, pülpte katı oranı, köpürtücü ve kıvam süreleri incelenmiştir.
Flotasyon deneyleri, Denver tipi Ünal marka laboratuvar ölçekli flotasyon cihazında gerçekleştirilmiş olup, deneylerde 750 gr numune için 2,5 L ölçekli hücreler kullanılmıştır ve 950 devir/dakika karıştırma hızında, sabit 5 L/dk hava miktarında çalışılmıştır. Numunelerin spesifik gravite ölçümleri hem API 13A standardında belirtildiği gibi Le Chatelier balon jojesi kullanılarak ve tekrar SG ölçümleri de helyum gazlı piknometre kullanılarak gerçekleştirilmiştir.
Şlam atığı üzerinde yapılan deneylerde en efektif kollektör olarak sülfonik bazlı anyonik kollektör seçilmiştir. Kollektör miktarı arttıkça atıkta kaçaklar azalmakta ancak konsantre SG değeri de düşmektedir. Bu nedenle en efektif kollektör miktarı 200 gr/ton olarak seçilmiştir. Kollektör miktarının yanı sıra bastırıcı olarak sodyum silikat kullanmanın etkisi incelenmiş ve bastırıcı varlığında atık SG'si 2.74'e kadar düşürülebilmiştir. Şlam atıklarının zenginleştirilmesi ile sondaj ve endüstriyel boya-balata sektörüne uygun SG 4.20-4.26 olan konsantreler üretilebilmiştir.
Barit ön konsantresi üzerine yapılan deneylerde ise, kollektör miktarı arttıkça atık SG değeri azalmış ancak flotasyon konsantresi miktarı artarken, konsantre SG değeri de azalmıştır. Şlam atığının aksine bastırıcı olarak sodyum silikat miktarının artmasının atık SG değerinde kayda değer bir değişiklik yaratmadığı görülmüştür. Deneylerde kondüsyon süresi ve flotasyon PKO'sunun etkisi, kollektör kıvam süresinin etkisi, köpürtücü kullanımı gibi parametreler incelenmiş ayrıca alternatif olarak ters flotasyon deneyleri de yapılarak optimum flotasyon koşulları belirlenmiştir. Flotasyon devresinde kaba + süpürme devreleri ile beslenenin %72,5 oranında satılabilir bir konsantre SG değerine uygun olarak elde edilirken, atık SG değeri de 2.81'e kadar düşürülmüştür.

Abstract:
Barite mineral is an important industrial raw material for oil and gas drilling and industries such as paint & coating, plastic-rubber compounds, brake lining, glass. Currently, 75-80% of the barite produced is used as API grade for oil and gas drilling. Apart from this, the barite production can be shown as an industrial raw material that is low in quantity but high in price for other industries. Turkey has a share of 3.0-3.5% of the world in barite production. The changes in oil prices also influence petroleum explorations and drillings, and therefore also affects the trade of the barite mineral used in this field. When Turkey's foreign trade data of barite mineral is evaluated, it is seen that domestic suppliers meet the demand of the domestic market and export to many countries of the World.  So, our country is not foreign-dependent on the barite mineral and it exports to other countries. Therefore the barite mineral can be considered a strategic mineral for our country.
Barite mineralizations can exist together with different minerals in different parts of the world. Contrary to mineralizations such as Barite-Fluorite and Barite-Sphalerite-Galena, the gangue minerals of the barite mineral are limestone, quartz, clay, calcschist, and iron oxides in the mineralization investigated in this study, and there is an obvious specific gravity difference between the precious mineral and the gangue mineral. For this reason, separation devices that are beneficiated according to the specific gravity difference are generally used, but the desired efficiency cannot be obtained from the gravity separators with a particle size below a hundred microns and precious mineral appears in the tailings. Within the scope of this thesis, the possibilities of beneficiation of barite slurry tailings which as low specific gravity value, and the pre-concentrate obtained by a private enterprise of the same region were investigated by flotation.
Barite's terms of sales are predominantly evaluated on its specific gravity, grain size, and whiteness. As a result of the experimental studies, specific gravity (SG) was taken as the analysis value. The most important reason for this is that SG is mainly based on the sales conditions of barite. According to SG, BaSO4 grade varies from ore to ore, and chemical analysis methods to determine the BaSO4 % value are also open to discussion. According to API 13K standard, crystallographic techniques of X-ray-based XRF-XRD analyzes do not work properly in barite mineral analysis due to the strong X-ray absorption of barium atoms and industrial experiences also show this. Because of its strong X-ray absorption, barite finds use in areas such as nuclear power plants and x-ray rooms. For this reason, the classical wet method is recommended for chemical analysis in API 13K. However, there are 3 different standard-chemical analysis methods related to BaSO4 % analysis in which the wet method is used. In each of these standards, it is stated that it is applied for ores containing more than 90% barite and for its use in the industries specified in the standard. In the determination of ores containing less than 90% barite, clear results cannot be found especially for materials with approximately 15-25 BaSO4 % by a gravimetric wet method such as slurry tailings. In addition, due to the presence of strontium in mineralization, it replaces barium in barite mineral and exists as isomorphic in the crystal system, the radius of strontium and barium elements being compatible with each other, it is not possible to obtain clear results in chemical analysis. In the API 13K standard, it is stated that ICP analysis should be done separately for strontium, while other standards also state that strontium should be neglected and included in the BaSO4 content. For all these reasons, SG results were used as an analysis method in the studies.
In the experimental studies, in the flotation tests performed on slurry tailings with specific gravity (SG) values varying in the 3.03-3.09 and barite pre-concentrates with SG values between 3.85-3.98, it was mainly aimed to reduce the tailing SG values below 2.80, which is suitable for efficient flotation. Reagent-collector selection and amount, the effect of depressant and its amount, the solid ratio in pulp, frother, and conditioning times were examined.
Flotation experiments were carried out with a Denver-type Unal brand laboratory scale flotation device, 2.5 L scaled cells were used for 750 g sample and worked at a constant 5 L/min air rate at 950 rpm stirring speed. Specific gravity measurements of the samples were made using a Le Chatelier flask as specified in the API 13A standard and repeat SG measurements were made using a helium gas pycnometer.
In the experiments on slurry tailings, a sulphonic-based anionic collector was chosen as the most effective collector. In the literature studies, since the products obtained by using Oleate-type collectors cause various problems in the drilling industry, so it has been evaluated that the collector used in the thesis will not pose a problem for use in the drilling industry As the amount of collectors increases, the presence of barite in the tailing decrease, but the SG value of concentrate also decreases. For this reason, the most effective collector amount was chosen as 200 gr/ton. In addition to the amount of collectors, the effect of using sodium silicate as a depressant was observed and as the amount of depressants increased, the SG value of tailing could be reduced to 2.74. By enriching the slime tailings, SG 4.20-4.26 concentrate suitable for drilling and industrial brake lining industry could be produced.
In the experiments on barite pre-concentrate, as the amount of collectors increased, the SG value of tailings decreased, but as the flotation concentrate amount increased, the SG value of concentrate decreased. Contrary to the flotation of slurry tailings, it was observed that the increase in the amount of Sodium Silicate as a depressant did not cause a significant effect on the SG value of tailing. In addition, it was seen that the change in the condition and flotation solid ratio did not have a significant effect, but it was determined that it would be more appropriate to work at a 25-30% solid ratio in terms of the flotation circuit design. It has been determined that more repeated experiments are required in order to clearly determine the effect of the change in the collector conditioning time on the products, when the frother is used, more material is transferred to the frother zone, and the concentrate is contaminated. Since the collector itself has a frothing feature, it is thought that there is no need for a frother. However, it was also stated that new experimental sets should be carried out to determine the effect of different types of frothers and frother amounts on the SG values of concentrate and tailing.
 In the experiments on barite pre-concentrate, it was desired to float the silicates with reverse flotation, but it was seen that reverse flotation was not suitable to obtain the desired SG value in the sinking product. As a result of the studies, the ideal flotation circuit was established. SG 4.40 product was taken as a concentrate and the SG value of tailing was reduced to 2.81.