Sarkuysan Elektrolitik Bakır Fabrikasının curuflarından bakır ve kalayın kazanılması

Abstract

Bu tez çalışmasında, ülkemizin önemli elektrolitik bakır üreticisi olan Sarkuysan A.Ş.'in cufurların dairi bakır ve kalayın kazanılma olanakları araştırılmıştır. Sarkuysan fabrikasından alman bakır cürufu % 22 Cu ve % 2 Sn kalay içermektedir. Mineralojik incelemeler sonucunda, cüruf numunelerinin yapısal özelliklerinde farklılıklar gözlenmiştir. Bunun nedeni cüruf numunesinin alındığı yığının, farklı zamanlarda rafinasyon işlemi sırasında alman cürufların karışımı olmasıdır. Metalik bakır tanelerinin kırma ve öğütme esnasmda yassı plakalar haline gelmesi, kırma ve öğütmeden sonra yapılacak boyuta göre sınıflandırma ile bakırın kazanılacağını göstermektedir. Bu amaç doğrultusunda boyut küçültme ve boyuta göre sınıflandırma ile deneysel çalışmalara başlanmış, bakırın yam sıra kalayın davranışı da incelenmiştir. %44.42 Cu içerikli ve %82.70 Cu içerikli iki konsantre kazanılmıştır. Numunenin manyetik özeliğinden yararlanılarak yapılan manyetik ayırma deneylerinde ve gravite zenginleştirme deneylerinde istenilen nitelikte konsantreler elde edilememiştir. Flotasyon deneylerinde, optimum flotasyon koşullan araştınlmıştır. Optimum flotasyon koşullarında yapılan deney sonucunda %31.85 Cu içerikli bir kaba konsantre elde edilmiştir. Kaba flotasyon konsantresinin temizlenmesi ile %45.49 Cu içerikli bir konsantre, % 17.08 Cu içerikli bir ara ürün ve %6.50 Cu içerikli bir artık elde edilmiştir. Flotasyon deneylerinde kalayın artıkta kaldığı görülmüştür. Arakta kalan bakır ve kalayın kazanılması için bir seri üç deneyleri yapılmıştır. Deneyler sırasında çözücü cinsi ve miktarı, sıcaklık, süre gibi parametrelerin metal çözündürme verimi üzerindeki etkileri incelenmiştir. 150 gr/ton HC1 kullamlarak 80° C'de 2 saat sürede yapılan liç deneyi sonunda bakır çözünme verimi % 100'e ve kalay çözünme verimi %90'a ulaşmıştır. Bu çalışma, konusu itibariyle bundan sonra yapılacak çalışmalara yol gösterici nitelik taşımaktadır.

Recovery of Copper and Tin from Copper Fire-Refining Slags Summary The large growth in free world metal consumption was accompanied by a corresponding increase in world mine production. The increased growth in all major metal production has a gradual loss on reserves of mine deposits. Therefore, additional metal resources need to be explored by finding new ore bodies, recycling and investigating new methods on the beneficiation concentration tailing and metallurgical slags. Thus, natural resources would be evaluated more efficiently from environmental and economical viewpoints. Within the framework of this concept, slag samples, produced during the fire- refining of blister copper in Sarkuysan A.S. ( one of the major electrolytic copper producers in Türkiye ) were used in the experimental work which covered size reduction, flotation and leaching tests. Fire-refining of blister copper prior to electrolytic refinning is a required step for removing oxygen and sulfur in blister Cu in order to have smooth anode surfaces during the refining. Both oxidation and reduction processes are necessary in fire- refining in order to manage to remove some additional impurities such as; Fe, Bi, As, Sb and Zn. This process is carried out either in a reverberatory type furnace or in a Thomas ( tromel ) type furnace. Charge components include; blister copper, scrap copper, anod slimes, recycling raffinate copper and flux. Elements such as S, As, Sb, Bi, Pb, Fe and Zn are oxidized. During the oxidation step some part of the elements volatilized while others pass into the slag. Oxide copper is reduced back to metallic copper with carbon in the reduction step. Sample used in the experiments was taken from the slag produced during the fire-refining of blister copper in thomas furnace of Sarkuysan A. S., an electroytic copper production company. They contain about 22% Cu and 3% Sn. This experimental study was aimed at investigating the possibilities of recovering of Cu and Sn present in slag. Experiments were performed in five parts: size reduction and classification according to the particle size ranges, magnetic and gravite separation, flotation and leaching. Metallic copper shows plate-like shapes during crushing. Therefore, this is an advantage from the viewpoint of separating copper by classifying samples according to the particle sizes. The maximum particle size of the slag was around 150 mm, as received. They were first crushed under 25 mm by using primary and secondary jaw crushers. Later, they were crushed under 2 mm by using cone and role crushers. Particle size distributions of crushed samples and distributions of Cu and Sn in relation to the X partide size ranges are shown in Table 1. As seen from the table, 3.3% of sample retained on the 2 mm screen contain 44.42% Cu and 1.69% Sn. Therefore, this could be circulated in copper pruduction. Following experiments were performed with the samples under 2 mm in size. Table 1. Distributions of particle size, Cu and Sn for samples crushed under 2 mm After separating samples over 2 mm in size, samples under 2 mm were subjected to grinding experiments using ball mill at 65% density and for 30, 45, 60 and 75 minutes. As a result of grinding experiments, 3.2% of the sample with 80.1% Cu and 0.69 Sn content remained over 212 micron screen size after 30 minutes of grinding while 4.2% of the sample with 82.7% Cu and 0.66 Sn content remained over 150 micron screen size after 45 minutes of grinding. 3.7% of the sample with 87.3% Cu and 0.50 Sn content remained over 150 micron screen size after 60 minutes of grinding where 5.5% of the sample with 85.5% Cu and 0.44 Sn content remained over 106 micron screen size after 75 minutes of grinding time. As seen from Table 2, samples over 150 microns contain about 82.7% Cu and 0.66% Sn. This means there is no mineralogical and physical connection between Cu and Sn compounds. Table 2. Distributions of particle size, Cu and Sn for samples ground for 45 minutes XI Magnetic and garvite separation experiments were performed to recover Cu and Sn present in the sample after separating the samples over 106 microns particle size. The results of experiments show that there is no beneficition. Flotation experiments were performed to recover Cu and Sn present in the sample after separating the samples over 150 microns particle size. In the experiments, the effects of collector type, the amount of collector addition, grinding time and Na2S addition on the flotation were investigated. In order to determine the most suitable collector type, four types of collectors are tried, namely, K-amil Xanthate, Na-isobutyl xanthate, Hostafloat X-231 and Aerofloat 238. Four stages of flotation experiments were conducted at natural pH, after separating metallic copper over 150 micron and grinding samples for 45 minutes. Results are listed in Table 3. As seen from table, Hostafloat X-231 seems to be the most suitable collector type. A concentrate containing 30.31% Cu and 2.03% Sn was produced with 82.26% Cu and 42.73% Sn efficiencies. Tabel 3. Effect of collector type on flotation of slag samples Experiments were performed with hostafloat X-23 1 at natural pH. The results of flotation experiments carried out with the samples ground for different times of 45, 60 and 75 minutes are shown in Table 4. As seen from this table, increasing grinding time did not affect much the metal contents and recorveries in the flotation concentrates. Therefore, 45 minutes of grinding time would be sufficient for the liberation of Cu and Sn compounds. xn Table 4. Effect ofgrinding time on flotation of slag samples Experiments were performed with the samples ground for 45 minutes and by using Hostafloat X-23 1 as a collector and at natural pH. Results are shown in Table 5. The best results obtained when collector addition was 100 g/t. Table 5. Effect of the amount of collector on flotation slag samples Experiments were performed with the samples ground for 45 minutes, at natural pH and by using Hostafloat X-23 1 as a collector. Results are shown in Table 6. Increasing Na2S additions increased the metal contents of flotation concentrate with xm decreasing recoveries. 300 g/t Na2S addition in the flotation resulted in the best Cu flotation recovery. Table 7 shows the products produced as a result of size reduction and classification together with flotation experiments. Results given in table 8 are obtained when the products over 2mm and 150 micron in size added to flotation concentrate and middling. As seen from that Table, 71.40% Sn stayed in tailings with 2.59% Sn content concentrate containing 49.45% Cu and 1.71% Sn is produced with 84.74% Cu and 28.40% Sn efficiencies as a result of size reduction and flotation tests. Tabel 6. Effect of Na2S addition on flotation of slag samples Tabel 7. Products of size reduction and flotation test xrv Tabel 8. Calculated flotation results Leaching experiments were carried out with flotation tailings in order to recover Cu and Sn. In the leaching experiments, the effect of solvent concentration, temperature and leaching time on the metal recoveries were investigated in order to determine the most suitable solvent type. Three different types of solvents are tried at 25° C and one hour leaching period. Results are in table 9. As seen from table 9,.HC1 seems to be the most suitable solvent type Table 9 Effect of differnt type solvents on the metal dissolution at 25° C Metal leaching recoveries increased with increasing of the leaching time and temperature. As seen from the table 10,at 80° Cu and Sn dissolutions were faster than the other temperatures. According to leaching time, the result of 2 hours leaching period, copper dissolution is % 100 and tin dissolution is %90.3. Tabel 10. Effect of temperature and time on the metal dissolution XV Changing HC1 concentration showed that metal leaching recoveries decreased with decreasing HC1 concentaration Results in table 11. As aresult of inventigating parameters, optimum leaching conditions were found as. HC1 concentration 150 g/t, leaching temperature 80° C, leaching time 2 hours, solid/liquid ratio 1/10. The following metal leaching recoveries were observed in the experiments run at optimum leaching conditions: Cu %100 and Sn %90. Table 11. Effect of Hcl consantration on the metal dissolution at 80° C As a conlustion of this experimental study, it was shown that Cu and Sn in the foe-refining slags could be recovered efficiently with the separation according to the particle size range, flotation and leaching. This could be considered as a sucress from the viewpoint of recyling.