Refrakter gümüş cevherlerinin siyanürasyonunda koruyucu alkali cinsinin çözündürmeye etkisinin incelenmesi
Refrakter gümüş cevherlerinin siyanürasyonunda koruyucu alkali cinsinin çözündürmeye etkisinin incelenmesi
Dosyalar
Tarih
1998
Yazarlar
Boylu, Feridun
Süreli Yayın başlığı
Süreli Yayın ISSN
Cilt Başlığı
Yayınevi
Fen Bilimleri Enstitüsü
Institute of Science and Technology
Institute of Science and Technology
Özet
Bu tez kapsamında, Kütahya-Gümüşköy l00.Yıl Gümüş İşletmesinde çalışılan gümüş cevherlerinden, Pasa cevher numunesi üzerinde, siyanür ile çözündürmede koruyucu alkali olarak kullanılan; Ca(OH)2, NaOH ve KOH gibi bazların, çözündürmeye etkisi araştırılmışın Deneylere esas olan cevher numunesinde ; nabit gümüş, pirarjirit, arjantit ve gümüşlü tetraedrit başlıca gümüş minerallerini oluşturmakta ve gümüş sülfürlü minerallerle birlikte bulunmaktadır. Cevherin gümüş içeriği ise 460 g/t Ag dir. Deneylerin başlangıç safhasında, numunenin boyutu 0.112 mm'ye indirildikten sonra, boyut dağılımı belirlenmiş ve siyanür ile çözündürme deneylerinde kullanılmak üzere, yüksek Ag içerikli numune elde etmeye yönelik ön zenginleştirme amaçlı toplu sülfür flotasyonu yapılarak, %1.064 Ag içerikli ön konsantre elde edilmiştir. Toplu sülfür flotasyonu sonucu elde edilen ön konsantre ile; farklı koruyucu alkali kullanılarak üç grubta deneyler yapılmış ve her bir deney grubunda; çözündürme süresi, koruyucu alkali konsantrasyonu, siyanür konsantrasyonu ve pülp sıcaklığı gibi faktörlerin çözündürmeye etkisi incelenmiştir. Koruyucu alkali olarak Ca(OH)2 'nin kullanıldığı deneyler sonucunda; farklı çözündürme sürelerinde deneyler yapılarak ; çözündürmenin uzun sürelerde gerçekleştiği tespit edilmiş, 48 saatlik çözündürme sonrasında %61.75 lik Ag çözünme verimine ulaşılmıştır. 24 saatlik sabit çözündürme süresinde, farklı Ca(OH)2 konsantrasyonlarında yapılan deneyler sonucunda ise 1.0 g/l Ca(OH)2 kullanılması ile Ag çözünme verimi % 71.84 'e yükseltilmiştir. NaCN konsantrasyonunun 2.0 g/l'den 4.0 g/I'ye arttırılmasıyla Ag çözünme verimi üzerinde artış sağlanamamış, %71.84 olan Ag çözünme verimi % 69.73 'e düşmüştür. 8 saatlik çözündürmede pülp sıcaklığı arttırılarak ; pülp sıcaklığının 20 °C den 80 °C ye yükseltilmesiyle Ag kazanma veriminde yaklaşık % 8 artış elde edilmiştir. Koruyucu alkali olarak NaOH 'in kullanıldığı deneylerin sonucunda; 32 saatlik çözündürme süresinin yeterli olduğu saptanmış ve bu süre sonunda % 58.73 Ag çözünme verimi elde edilmiştir. Sabit koşullarda ve sadece koruyucu alkali konsantrasyonu arttırılarak yapılan 24 saatlik çözündürme deneylerinde yüksek NaOH konsantrasyonunun Ag çözünme verimi üzerinde olumsuz etkisi saptanmıştır. NaCN konsantrasyonu 2.0 g/l'den 4.0 g/l 'ye yükseltilmiş, %56.84' lük Ag çözünme verimi elde edilmiştir.Ayrıca, pülp sıcaklığının 20 °C den 80 °C 'ye çıkarılmasıyla Ag çözünme verimi yaklaşık % 15 arttırılmıştır. Koruyucu alkali olarak KOH'in kullanıldığı deneylerde; 32 saatlik çözündürme süresinin yeterli olduğu saptanmış ve bu çözündürme süresi sonunda % 65.18 lik Ag çözünme verimi elde edilmiştir. Farklı KOH konsantrasyonlarının etkisinin incelendiği deneylerde 24 saatlik çözündürme sonunda, KOH konsantrasyonunun 0.6 g/l'den 0.8 g/I'ye çıkarılmasıyla % 56.73 olan Ag çözünme verimi % 62.97 'ye yükseltilmiştir. NaCN konsantrasyonunun 2.0 g/l'den 4.0 g/I'ye çıkarılmasının Ag çözünme verimi üzerinde olumlu etkisi görülmemiştir. Ayrıca, pülp sıcaklığının 20 °C'den 80 °C'ye çıkarılmasıyle Ag çözünme verimi üzerinde yaklaşık % 23 seviyesinde bir artış sağlanmıştır. Tüm koruyucu alkalilerle yapılan siyanürle çözündürme deney sonuçları birbirleriyle karşılaştırılmış koruyucu alkali olarak kullanılan Ca(OH)2'nin gerek reaktif tüketimleri gerekse Ag çözünme verimleri açısından daha iyi sonuçlar verdiği belirlenmiştir.
Silver metal has been known since ancient time and it is considered a dense and commercialy a precious metals. The principal uses of silver are for photographic materials and electrical products with subsidiary uses in jewelery and alloys. Abaout 50 % of the silver consumed in the United States was used in the manufacturing of photographic products; 20 % in electrical and electronic products, 10 % in electroplated ware, sterling ware and jewelery, 20 % in other uses. Althoug silver occurs in the native form and as an alloy with gold (i.e. electrum) it generally occurs with sulphide minerals. The common silver sulphides are argentite (Ag2S), proustite, (Ag3AsS3), pyrargyrite (Ag3SbS3), and argentiferrous tetrahedrite [(Cu, Fe, Zn, Ag)12Sb4S13]. Silver is also substituted for metals, such as Zn in sphalerite, Pb in galena and Cu in chalcopyrite. The early metallurgy of Silver ores was almost totally involved with gravity seperation because of their conveniently high specific gravity. Another early development was the amalgamation process. During most of the 1800's the chlorinating process became popular. In 1887, Scotsmen, John S. Mac Arthur a metalurgical chemist and two doctors; Robert and William Forrest of Glasgow obtained the British patent another in 1888 on the use of fine zinc particles as a precipitant for gold and silver from cyanide solutions. In 1900, at Sirena, Mexico the cyanide process was first applied to a silver sulfide ore. Kütahya 1 00th Year Silver Plant which is located in Köprüören region of Kütahya Province in Turkey has a cyanide process to treat silver ores having avarage 180 g/t Ag in content. Cyanadation is an effective process for the treatment of precious metals like silver. It includes the reactions between cyanide and silver minerals. In Cyanadation process, there must be enough amount of free cyanide yons for dissolution of silver in cyanide solutions. It is able to maintain the amount of free cyanide ions with high pH by using protective alkalines such as Ca(OH)2, NaOH, KOH to prevent hydrolysis of the cyanide. The aim of this study is to determine effects of the protective alkalines such as Ca(OH)2, NaOH, KOH in cyanidation of refractory silver ores. Experimental works include particle reduction, preconcentration (flotation) and cyanidation studies. The ore sample which was taken from Kütahya-Gümüşköy ore deposits contains 460 g/t Ag. The main silver minerals in the ore are native silver, pyrargyrite, argentite and tetraedrite. The ore sample which was maximum 35 mm in size was initialy crushed and ground under 0.112 mm in size and preconcentrated by bulk flotation (collective sulphur flotation) in order to obtain preconcantrate with high content of silver was to be used in cyanadation studies. The cyanidation studies was carried out in three groups by using different protective alkalines in each group. Some factors in cyanidation such as leaching time, pulp temperature and concentration of cyanide and protective alkalines were examined. In the experiments using Ca(OH)2 as a protective alkaline, cyanidation was made in different leaching times. The dissolving of the silver raised proportionaly depending on the leaching time. It was obtained that silver recovery was 61.75 % with leaching in 32 hour. In 24 hour leaching time and constant conditions the effects of the Ca(OH)2 concentration (0.2, 0.4, 0.6, 0.8, 1.0 g/l) was examined by using different Ca(OH)2 concentration. It was observed that the silver recovery was raised proportionaly depending on the Ca(OH)2 concentration. It was observed that the silver recovery was raised proportionaly depending on the Ca(OH)2 concentration. The silver recovery was obtained as 71.84 by usingl.O g/l Ca(OH)2. In the following step where the cyanide concantretion effect was examined, it was observed a decrease on silver recovery; silver recovery was reduced to 69.73 by increasing cyanide concantration from 2.0 g/l to 4.0 g/l. In 8 hour leaching time and constant conditions, an increase in level of 7% on silver recovery was obtained by increasing the pulp temperature from 20 °C to 80 °C. In the experiments carried out on NaOH as a protective alkaline, firstly the effect of leaching time was examined and it was determined that the sample ore was required to 32 hour for leaching and with 32 hour as a leaching time, silver recovery was obtained as 58.73 %. Further experiments were carried out on different NaOH concentration and consant conditions during 24 hour as a leaching time, to determine effect of the NaOH concentration, it was determined that high NaOH concentration had a bad effects on silver recovery; by reducing NaOH concentration from 0.6,g/l to 0.2 g/l, silver recovery was increased 43.24 % to 56.65 %. XI In the following step, NaCN concentration was increased from 2.0 g/l to 4.0 g/l with in satisfactory increases ; the silver recovery was 56.84 %. In the last step of this group experiments, pulp temparature was examined and it was observed an increase in level of 15 % on silver recovery by increasing pulp temparature from 20 °C to 80 °C. In the experiments carried out on KOH as a protective alkaline, firstly the effect of leaching time was examined and it was determined that the sample ore required 32 hour for leching and with 32 hour as an eneough leaching time, the silver recovery was 65.18.Yn the constant conditions during 24 hour as a leaching time, it examined the effect of the KOH concantration and an increase from 56.73 % to 62.97 % on silver recovery was obtained by increasing KOH concantration from 0.6 g/l to 0.8 g/l. Yn the following steps which the effects of NaCN concantration and pulp temperature was examined on, an increase on silver recovery by increasing the NaCN concantration from 2.0 g/l to 4.0 g/l was not sufficient. Whereas an increase approximately in level of 23 on silver recovery was obtained by increasing the pulp temparature from 20°C to 80°C. Finally, the experimental results generally indicate that Ca(OH)2 used as a protective alkaline gives better results based on either reagent consumption or silver recovery compared to other protective alkalines (Figure I, II, III, IV). o EC L. 0) > OT 0) 12 16 20 24 28 32 36 40 44 48 52 Leaching Time, hour Figure l-Relation Between Leaching Time and The Silver Recovery (for each Protective Alkaline) xn o 0) DC > m O) 80 70 + 60 50 40 30 -|- 20 10 -I 0 J- - I ( H- 1 0.2 0.4 0.6 0.8 1 Protective Alkaline Concentration, g/l Figure ll-Relation Between Protective Alkaline Concentration and The Silver Recovery (for each Protective Alkaline) 0.2 0.4 0.6 0.8 Protective Alkaline Concentration, g/l Figure Ill-Relation Between Protective Alkaline Concentration and The NaCN Consumption (for each Protective Alkaline) xm 0* o 0) DC 0>,> W 70 60 50 40 30 - 20 -- 10 0 20 40 Pulp temperature 60 80 100 Figure IV-Relation Between Pulp temperature extention and The Silver Recovery (for each Protective Alkaline
Silver metal has been known since ancient time and it is considered a dense and commercialy a precious metals. The principal uses of silver are for photographic materials and electrical products with subsidiary uses in jewelery and alloys. Abaout 50 % of the silver consumed in the United States was used in the manufacturing of photographic products; 20 % in electrical and electronic products, 10 % in electroplated ware, sterling ware and jewelery, 20 % in other uses. Althoug silver occurs in the native form and as an alloy with gold (i.e. electrum) it generally occurs with sulphide minerals. The common silver sulphides are argentite (Ag2S), proustite, (Ag3AsS3), pyrargyrite (Ag3SbS3), and argentiferrous tetrahedrite [(Cu, Fe, Zn, Ag)12Sb4S13]. Silver is also substituted for metals, such as Zn in sphalerite, Pb in galena and Cu in chalcopyrite. The early metallurgy of Silver ores was almost totally involved with gravity seperation because of their conveniently high specific gravity. Another early development was the amalgamation process. During most of the 1800's the chlorinating process became popular. In 1887, Scotsmen, John S. Mac Arthur a metalurgical chemist and two doctors; Robert and William Forrest of Glasgow obtained the British patent another in 1888 on the use of fine zinc particles as a precipitant for gold and silver from cyanide solutions. In 1900, at Sirena, Mexico the cyanide process was first applied to a silver sulfide ore. Kütahya 1 00th Year Silver Plant which is located in Köprüören region of Kütahya Province in Turkey has a cyanide process to treat silver ores having avarage 180 g/t Ag in content. Cyanadation is an effective process for the treatment of precious metals like silver. It includes the reactions between cyanide and silver minerals. In Cyanadation process, there must be enough amount of free cyanide yons for dissolution of silver in cyanide solutions. It is able to maintain the amount of free cyanide ions with high pH by using protective alkalines such as Ca(OH)2, NaOH, KOH to prevent hydrolysis of the cyanide. The aim of this study is to determine effects of the protective alkalines such as Ca(OH)2, NaOH, KOH in cyanidation of refractory silver ores. Experimental works include particle reduction, preconcentration (flotation) and cyanidation studies. The ore sample which was taken from Kütahya-Gümüşköy ore deposits contains 460 g/t Ag. The main silver minerals in the ore are native silver, pyrargyrite, argentite and tetraedrite. The ore sample which was maximum 35 mm in size was initialy crushed and ground under 0.112 mm in size and preconcentrated by bulk flotation (collective sulphur flotation) in order to obtain preconcantrate with high content of silver was to be used in cyanadation studies. The cyanidation studies was carried out in three groups by using different protective alkalines in each group. Some factors in cyanidation such as leaching time, pulp temperature and concentration of cyanide and protective alkalines were examined. In the experiments using Ca(OH)2 as a protective alkaline, cyanidation was made in different leaching times. The dissolving of the silver raised proportionaly depending on the leaching time. It was obtained that silver recovery was 61.75 % with leaching in 32 hour. In 24 hour leaching time and constant conditions the effects of the Ca(OH)2 concentration (0.2, 0.4, 0.6, 0.8, 1.0 g/l) was examined by using different Ca(OH)2 concentration. It was observed that the silver recovery was raised proportionaly depending on the Ca(OH)2 concentration. It was observed that the silver recovery was raised proportionaly depending on the Ca(OH)2 concentration. The silver recovery was obtained as 71.84 by usingl.O g/l Ca(OH)2. In the following step where the cyanide concantretion effect was examined, it was observed a decrease on silver recovery; silver recovery was reduced to 69.73 by increasing cyanide concantration from 2.0 g/l to 4.0 g/l. In 8 hour leaching time and constant conditions, an increase in level of 7% on silver recovery was obtained by increasing the pulp temperature from 20 °C to 80 °C. In the experiments carried out on NaOH as a protective alkaline, firstly the effect of leaching time was examined and it was determined that the sample ore was required to 32 hour for leaching and with 32 hour as a leaching time, silver recovery was obtained as 58.73 %. Further experiments were carried out on different NaOH concentration and consant conditions during 24 hour as a leaching time, to determine effect of the NaOH concentration, it was determined that high NaOH concentration had a bad effects on silver recovery; by reducing NaOH concentration from 0.6,g/l to 0.2 g/l, silver recovery was increased 43.24 % to 56.65 %. XI In the following step, NaCN concentration was increased from 2.0 g/l to 4.0 g/l with in satisfactory increases ; the silver recovery was 56.84 %. In the last step of this group experiments, pulp temparature was examined and it was observed an increase in level of 15 % on silver recovery by increasing pulp temparature from 20 °C to 80 °C. In the experiments carried out on KOH as a protective alkaline, firstly the effect of leaching time was examined and it was determined that the sample ore required 32 hour for leching and with 32 hour as an eneough leaching time, the silver recovery was 65.18.Yn the constant conditions during 24 hour as a leaching time, it examined the effect of the KOH concantration and an increase from 56.73 % to 62.97 % on silver recovery was obtained by increasing KOH concantration from 0.6 g/l to 0.8 g/l. Yn the following steps which the effects of NaCN concantration and pulp temperature was examined on, an increase on silver recovery by increasing the NaCN concantration from 2.0 g/l to 4.0 g/l was not sufficient. Whereas an increase approximately in level of 23 on silver recovery was obtained by increasing the pulp temparature from 20°C to 80°C. Finally, the experimental results generally indicate that Ca(OH)2 used as a protective alkaline gives better results based on either reagent consumption or silver recovery compared to other protective alkalines (Figure I, II, III, IV). o EC L. 0) > OT 0) 12 16 20 24 28 32 36 40 44 48 52 Leaching Time, hour Figure l-Relation Between Leaching Time and The Silver Recovery (for each Protective Alkaline) xn o 0) DC > m O) 80 70 + 60 50 40 30 -|- 20 10 -I 0 J- - I ( H- 1 0.2 0.4 0.6 0.8 1 Protective Alkaline Concentration, g/l Figure ll-Relation Between Protective Alkaline Concentration and The Silver Recovery (for each Protective Alkaline) 0.2 0.4 0.6 0.8 Protective Alkaline Concentration, g/l Figure Ill-Relation Between Protective Alkaline Concentration and The NaCN Consumption (for each Protective Alkaline) xm 0* o 0) DC 0>,> W 70 60 50 40 30 - 20 -- 10 0 20 40 Pulp temperature 60 80 100 Figure IV-Relation Between Pulp temperature extention and The Silver Recovery (for each Protective Alkaline
Açıklama
Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 1998
Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 1998
Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 1998
Anahtar kelimeler
Alkaliler,
Cevher,
Gümüş,
Refrakter,
Siyanür,
Çözülme,
Alkalies,
Ore,
Silver,
Refractory,
Cyanide,
Thawing