مشخصه يابي و فرآوري كانسنگ طلاي ازغد با اثرناگت بالا

Ore Characterization and processing of high nugget effect Azghad gold ore

ﯾﮑﯽ از ﭼﺎﻟﺶﻫﺎي ﭘﯿﺶرو در ﺷﻨﺎﺳﺎﯾﯽ و ﻣﺸﺨﺼﻪﯾﺎﺑﯽ ﻏﺎﻟﺐ ﮐﺎﻧﺴﻨﮓﻫﺎي ﻃﻼي رﮔﻪاي، وﺟﻮد اﺛﺮ ﻧﺎﮔﺖ ﺑﺎﻻ اﺳﺖ. ﺑﻬﺮهﺑﺮداري از اﯾﻦ ذﺧﺎﯾﺮ ﭼﻪ در ﻣﺮﺣﻠﻪ ﺑﺮآورد ذﺧﯿﺮه و ﭼﻪ در ﻣﺮﺣﻠﻪ ﻓﺮاوري ﺑﺎ ﭘﯿﭽﯿﺪﮔﯽﻫﺎي ﺑﺴﯿﺎري روﺑﻪرو اﺳﺖ. در اﯾﻦ ﭘﮋوﻫﺶ ﮐﺎﻧﺴﻨﮓ ﻃﻼي ازﻏﺪ ﺑﺎ اﺛﺮ ﻧﺎﮔﺖ ﺑﺎﻻ ﺑﺎ ﺑﻪﮐﺎرﮔﯿﺮي روشﻫﺎي ﻧﻮﯾﻦ ﻋﯿﺎرﺳﻨﺠﯽ ﺑﺮرﺳﯽ ﺷﺪه اﺳﺖ. ﻣﻌﺪن ازﻏﺪ ﺳﻪ رﮔﻪ اﮐﺴﯿﺪي، ﺷﯿﻠﯽ و ﺳﯿﻠﯿﮑﺎﺗﯽ دارد. داده-ﻫﺎي ﻋﯿﺎرﺳﻨﺠﯽ اوﻟﯿﻪ ﺑﻪ روش ﻗﺎلﮐﺎري وﺟﻮد اﺛﺮ ﻧﺎﮔﺖ ﺑﺎﻻ را ﺗﺎﺋﯿﺪ ﮐﺮد. ﺑﺎ ﻣﻘﺎﯾﺴﻪ روشﻫﺎي ﻣﺨﺘﻠﻒ ﻋﯿﺎرﺳﻨﺠﯽ، روش ﻟﯿﭽﯿﻨﮓ ﮐﺎﻣﻞ ﺑﺎ ﺷﺮاﯾﻂ 5 ﮐﯿﻠﻮﮔﺮم ﻧﻤﻮﻧﻪ ﺑﻪ اﺑﻌﺎد زﯾﺮ 75 ﻣﯿﮑﺮون و ﻣﯿﺰان ﺳﯿﺎﻧﻮر ﺳﺪﯾﻢ 1/5 ﮔﺮم ﺑﺮ ﻟﯿﺘﺮ در pH ﺑﺮاﺑﺮ 10/5 ﺑﻪﻋﻨﻮان روش ﻣﻨﺎﺳﺐ ﺑﺮاي ﻋﯿﺎرﺳﻨﺠﯽ اﯾﻦ ﻧﻤﻮﻧﻪ ﺗﻌﯿﯿﻦ ﺷﺪ. ﺑﺮ اﯾﻦ اﺳﺎس ﻋﯿﺎر ﻃﻼ در رﮔﻪﻫﺎي اﮐﺴﯿﺪي، ﺳﯿﻠﯿﮑﺎﺗﯽ و ﺷﯿﻠﯽ، ﺑﺮاﺑﺮ 4/7، 0/4 و 0/25 ﭘﯽﭘﯽام ﺗﻌﯿﯿﻦ ﺷﺪ. ﻫﻤﭽﻨﯿﻦ ﻣﻄﺎﻟﻌﺎت ﻓﺎزﺷﻨﺎﺳﯽ ﻃﻼ ﺑﻪ روش ﻟﯿﭽﯿﻨﮓ ﺗﺸﺨﯿﺼﯽ ﻧﺸﺎن داد ﮐﻪ 75/7 درﺻﺪ ﻃﻼ آزاد، 18/0 درﺻﺪ درﮔﯿﺮ در ﻓﺎزﻫﺎي ﺳﻮﻟﻔﯿﺪي و 6/3 درﺻﺪ ﻃﻼ در ﻓﺎزﻫﺎي ﺳﯿﻠﯿﮑﺎﺗﯽ ﺗﻮزﯾﻊ ﯾﺎﻓﺘﻪ اﺳﺖ. آزﻣﺎﯾﺶﻫﺎي ﻓﺮاوري ﺑﻪﻣﻨﻈﻮر ﺗﻮﺳﻌﻪ ﻓﺮاﯾﻨﺪ ﻣﻨﺎﺳﺐ در اﯾﻦ ﮐﺎﻧﺴﻨﮓ اﻧﺠﺎم ﺷﺪ. ﺑﻬﯿﻨﻪﺳﺎزي ﭘﺎراﻣﺘﺮﻫﺎي ﻋﻤﻠﯿﺎﺗﯽ ﻣﺆﺛﺮ، ﻣﯿﺰان ﺧﺮداﯾﺶ d80=75 ﻣﯿﮑﺮون، ﻣﺼﺮف ﺳﯿﺎﻧﻮر ﺳﺪﯾﻢ 1/41 ﮔﺮم ﺑﺮ ﻟﯿﺘﺮ و 30 درﺻﺪ ﺟﺎﻣﺪ در 10/5=pH و ﻣﺪتزﻣﺎن 24 ﺳﺎﻋﺖ را ﺗﺎﺋﯿﺪ ﮐﺮد. ﻣﯿﺰان ﺑﺎزﯾﺎﺑﯽ در اﯾﻦ ﺷﺮاﯾﻂ ﺑﺮاﺑﺮ 82/9 درﺻﺪ ﻃﻼ ﺑﻪدﺳﺖ آﻣﺪ. ﻧﺘﺎﯾﺞ اﯾﻦ ﺗﺤﻘﯿﻖ ﻣﯽﺗﻮاﻧﺪ ﺑﻪ ﻧﺤﻮ ﻣﺆﺛﺮي در ﺷﻨﺎﺳﺎﯾﯽ، ﻣﺸﺨﺼﻪﯾﺎﺑﯽ و ﻓﺮاوري ﮐﺎﻧﺴﻨﮓﻫﺎي ﻃﻼي ﺑﺎ اﺛﺮ ﻧﺎﮔﺖ ﺑﺎﻻ اﺳﺘﻔﺎده ﺷﻮد

Nugget effect is a common feature of many vein-style gold deposits. This style of mineralization results in complication in many exploitation stages including resource and average grade estimation, representative sample selection, ore characterization as well as processing. Accurate and reliable ore characterization is a vital stage in any mineral processing project. Ore characterization in high nugget effect gold ores is so complex due to uncertainties associated with representativity of the selected sample. The main challenge is to provide a representative sample for identification of each process mineralogy parameter such as average grade, liberation, grinding size, mineral association, floatability, etc. Here, different protocols are collected and compared to draw a comprehensive picture of the available methods. The results are examined on a high nugget effect gold ore from Northeast of Iran, Azghad mine. Processing experiments were conducted to develop a process suitable for Azghad gold mine. To investigate the feasibility of pre-concentration, gravity methods using a Nelson separator was applied on the oxide sample as the main gold vein. 43.3% of total gold was concentrated in the gravity concentrate with only 2% weight recovery, suggesting gravity concentration can be considered as an efficient method in this ore. Gold preg-robbing experiments were performed for Shale sample due to the organic matter, clay minerals and mica. Preg-robbing potential of the shale ore was determined to be 1.1 ppm. Optimization of operating parameters was performed by central composite design method for the combined oxide and shale samples.