الكواشف المستخدمة في تثبيط استخلاص النحاس في عملية سيانيد خام الذهب الحامل للنحاس

INإنتاج

السيانيد is a widely used and effective method for استخراج الذهب من الذهب - bearing ores, especially in the case of النحاس - محمل خامات الذهب. فمن الفئة الأساسيةd on the ability of أيون السيانيدs to form مستقر complexes with gold, allowing for the dissolution of gold from the ore MAtrix. The fundamental تفاعل كيميائي في عملية السيانيد for gold is 4Au + 8ناCN+O_2 + 2H_2O=4Na[Au(CN)_2]+4NaOH. This process has been the cornerstone of the صناعة التعدين الذهب for over a century due to its relatively high كفاءة and well - understood technology.

لكن عند التعامل مع copper - محمل خام الذهبs, the presence of معدن النحاسs poses significant challenges. Common معادن النحاس associated with gold, such as الكالكوبرايت (CuFeS_2), chalانباite (Cu_2S), malمنظمة العمل ضد الجوعite (Cu_2(OH)_2CO_3), and azurite (Cu_3(OH)_2(CO_3)_2), are quite reactive in محلول السيانيدs. For instance, in a السيانيد - containing medium, chalcocite can react as follows: Cu_2S + 4NACN=2Na[Cu(CN)_2]+Na_2S. These رد فعلs قيادة إلى استهلاك بكمية كبيرة السيانيد. إستهلاك مفرط of cyanide not only increases the تكلفة الانتاج ولكن لديه أيضًا بيئةal implications due to the سمية of cyanide.

Moreover, the dissolution of copper can interfere with the subsequent العمليات of انتعاش الذهب. High levels of copper in the cyanide solution can reduce the efficiency of مجمع الذهب والسيانيد formation, thus decreasing the gold معدل الاستخلاص. This is because copper comحيوان اليفes with gold for أيونات السيانيد and oxygen in the solution, disrUPقصديرg the chemical equilibrium required for efficient إذابة الذهب. In some cases, the presence of copper can also cause problems in downstream processes such as zinc - أسمنتation or carbon - in - لب (CIP) لل انتعاش الذهبمما يؤدي إلى انخفاض معدل استرداد الذهبs and poor product quality.

Therefore, finding effective الكواشف to inhibit the الرشح of copper during the زرقة of copper - bearing خام الذهبs is of great significance. Such الكواشف can help to optimize the عملية السيانيد، والحد من استهلاك السيانيد, and improve the overall efficiency of استخراج الذهب، جعل عملية التعدين more economically viable and صديق للبيئة. In the following sections, we will explore various الكواشف that have been studied and used for this purpose.

استخدم الرشح Characteristics of Copper in Cyanide Solutions

In cyanide solutions, معادن النحاس associated with gold exhibit disقصديرct leaching behaviors. Common primary معدن النحاسق مثل الكالكوبيريت (CuFeS_2) and chalcocite (Cu_2S), along with malachite (Cu_2(OH)_2CO_3), azurite (Cu_3(OH)_2(CO_3)_2), bornite (Cu_5FeS_4), cuprite (Cu_2O), and native copper, are relatively قابل للذوبان.

These copper المعادن can be leached at room temperature (25^{\circ}C). The معدل الاستخلاص of copper varies widely, ranging from 5 - 10% to over 90%. For example, malachite and azurite, which are copper - carbonate المعادن, are quite reactive in cyanide solutions. The chemical reaction of malachite with cyanide can be expressed as Cu_2(OH)_2CO_3+4ناكن + H_2O = 2Na[Cu(CN)_2]+Na_2CO_3 + 2NaOH. This shows that under the action of cyanide, the copper in malachite can be effectively dissolved.

When dealing with high - copper مركزات الذهبأطلقت حملة عملية الاستخلاص أثناء السيانيدn has some "clinical" symptoms. The consumption of cyanide becomes extremely high. Generally, for different copper المعادن, the dissolution of 1 gram of copper requires the consumption of 2.3 - 3.4 grams of سيانيد الصوديوم. At the same time, the dissolution of copper also consumes oxygen in the solution. For instance, in the عملية الاستخلاص of chalcocite, the reaction 2Cu_2S+8NaCN + O_2+2H_2O = 4Na[Cu(CN)_2]+2Na_2S + 4NaOH occurs, which not only consumes a large amount of cyanide but also a significant amount of oxygen.

Moreover, the leaching effect becomes relatively poor. High levels of copper in the cyanide solution can reduce the efficiency of gold - cyanide complex formation. Copper competes with gold for أيونات السيانيد and oxygen in the solution. As a result, the chemical equilibrium required for efficient إذابة الذهب is disrupted. This leads to a decrease in the معدل استخلاص الذهب and can also cause problems in subsequent gold - استرجاع عمليات مثل زنك - أسمنتation or carbon - in - pulp (CIP), ultimately resulting in lower gold - معدل الاستردادs and reduced product quality.

مشترك كاشفs for Inhibiting ترشيح النحاس

أملاح الرصاص

Lead salts are often used as الكاشفs to inhibit copper leaching in the cyanidation of copper - bearing gold ores. The commonly used lead salts include lead nitrate (Pb(NO_3)_2), lead acetate (C_4H_6O_4Pb\cdot3H_2O), and أكسيد الرصاص (PbO).

Take lead acetate as an example. Research has shown that adding lead acetate before استخلاص السيانيد can effectively inhibit the leaching of copper, enhance the leaching of gold and فضي, and reduce the consumption of سيانيد الصوديوم. For a certain مركز الذهب with a copper content of 4.92%, when 150 g/t of lead acetate is directly added before leaching, under the conditions of a طحن fineness of -0.037 mm particle size accounting for 95%, a وقت الاستخلاص of 48 h, a تركيز سيانيد الصوديوم of 0.5%, a pH of 12, and a pulp concentration of 40%, the درجة الذهب in the leaching residue can be reduced to 1.20 g/t, the استخلاص الذهب rate reaches 97.55%, the silver معدل الاسترداد هو 60.28٪ ، و استهلاك سيانيد الصوديوم is 14.37 kg/t. This clearly demonstrates the positive effect of lead acetate in this process.

استخدم المانعy MEChanism of lead salts may be related to the formation of insoluble compounds. For example, lead can react with sulfur - containing substances in the ore to form insoluble كبريتيد الرصاص. This reaction reduces the amount of sulfur - containing substances that can react with copper minerals, thereby inhibiting the dissolution of copper minerals. In addition, lead salts may also affect the surface عقارات of copper minerals, reducing their reactivity in the cyanide solution.

عوامل كيلات (على سبيل المثال، حمض الستريك)

عامل خالبs, such as citric حامض, can also play a role in inhibiting copper leaching during cyanidation. The chelating - type leaching - aid agents like citric acid work through a unique mechanism. Citric acid contains carboxyl and مجموعة الهيدروكسيلس، والتي يمكن الماسك with harmful ions such as Cu^{2 +}, Zn^{2+}, Fe^{2+}, and Fe^{3+} in the pulp to form stable الماسكs.

For instance, the carboxyl group in citric acid can coordinate with ايونات المعادن through the lone - pair electrons of oxygen atoms, forming a ring - like structure. By chelating these metal ions, citric acid can eliminate their negative imPACts on the عملية الاستخلاص بالسيانيد, such as reducing their consumption of oxygen in the solution. Moreover, citric acid can inhibit the dissolution of معادن العصابات مثل الكلسيوم - and magnesium - containing minerals. It can interact with the surface of these معادن العروق, changing their surface charge and hydrophilic - hydrophobic properties, making them more difficult to dissolve in the cyanide solution. This كبت of gangue minerals can also improve the "effective active oxygen" in the pulp. When the gangue minerals are less likely to dissolve, they consume less oxygen, and more oxygen is available for the cyanidation of gold, which is beneficial to the leaching of gold. In general, the addition of citric acid can help to create a more favorable chemical envحديدment for the cyanidation of gold, reducing the interference of other metal ions and improving the efficiency of استخراج الذهب.

آخرون (مقدمة موجزة)

In addition to the above - mentioned reagents, controlling the concentration of أيون السيانيدs can also be an effective way to weaken the dissolution of copper. When the concentration of أيون السيانيدs is properly controlled within a certain range, the reaction rate of copper minerals with cyanide can be reduced. For example, for some gold ores with a relatively high content of easily - soluble copper minerals, by keeping the concentration of free CN^ - ions at a relatively low level (such as 0.05% - 0.10%), the dissolution rate of copper minerals can be significantly slowed down, while the dissolution rate of منجم ذهبrals is still relatively high, so that the cyanide mainly acts on the dissolution of منجم الذهبrals.

Another method is to use the غاز الأمونيا - cyanide system. In the ammonia - cyanide system, ammonia can form complexes with أيونات النحاس, which can inhibit the leaching of copper to a certain extent. However, due to the high التقلبات of ammonia, it is difficult to maintain a stable concentration in the انتاج صناعي process, which limits its large - scale تطبيق الصناعي. Although this method has the advantage of reducing copper leaching, the challenges in practical operation and فعالية التكلفة need to be further addressed.

العوامل المؤثرة على تأثير الكواشف

The effectiveness of reagents used to inhibit copper leaching during the cyanidation of copper - bearing gold ores is influenced by several factors, which are crucial to understand for optimizing the عملية السيانيد.

خصائص خام

1. نوع معادن النحاس

1. Different copper minerals have distinct reactivities in cyanide solutions. For example, copper - carbonate minerals such as malachite (Cu_2(OH)_2CO_3) and azurite (Cu_3(OH)_2(CO_3)_2) are relatively more reactive compared to some primary sulfide copper minerals like chalcoالبيريت معدن (CuFeS_2). Malachite readily reacts with cyanide according to the reaction Cu_2(OH)_2CO_3+4NaCN + H_2O = 2Na[Cu(CN)_2]+Na_2CO_3 + 2NaOH. This high reactivity means that when using reagents to inhibit copper leaching, a higher جرعة might be required for ores rich in such reactive copper minerals.

2. In contrast, chalcopyrite has a more complex structure and requires more energy and specific reaction conditions to dissolve in cyanide solutions. However, under certain conditions, it can still contribute to significant استهلاك السيانيد. Understanding the dominant copper - mineral type in the ore is the first step in deterتعدين the appropriate reagent and its dosage.

2. محتوى معادن النحاس

1. The higher the copper - mineral content in the ore, the greater the potential for copper leaching and the corresponding consumption of cyanide. For instance, in a gold - bearing ore with a copper content of 5%, the amount of cyanide consumed by copper - leaching reactions will be much higher than in an ore with a copper content of 1%. As a result, the reagent needed to inhibit copper leaching must be proportionally adjusted. A higher - copper - content ore may require a larger amount of lead salts or عامل خالبs to effectively suppress copper dissolution. Research has shown that for every 1% increase in the easily - soluble copper content in the ore, the consumption of a lead - salt - based المانع may need to be increased by 10 - 20 g/t to maintain the same level of copper - leaching كبت.

شروط العملية

1. تركيز السيانيد

1. The concentration of cyanide in the solution plays a dual - role in copper leaching and the effectiveness of inhibitors. When the تركيز السيانيد is low, the rate of copper - leaching reactions is reduced. For example, if the free - تركيز السيانيد (CN^ -) is maintained at 0.05% - 0.10%, the dissolution rate of copper minerals can be significantly slowed down. However, if the cyanide concentration is too low, the معدل الاستخلاص of gold may also be negatively affected.

2. عند استخدام كواشف مثل أملاح الرصاص، قد يختلف تركيز السيانيد الأمثل لفعاليتها. في بعض الحالات، قد يلزم تركيز سيانيد أعلى قليلاً (حوالي 0.15% - 0.20%) لضمان قدرة مثبط أملاح الرصاص على تكوين مركبات غير قابلة للذوبان مع مواد تحتوي على الكبريت في الخام، مما يمنع بفعالية استخلاص النحاس. أما إذا كان تركيز السيانيد مرتفعًا جدًا، فقد يُعزز إذابة معادن النحاس على الرغم من وجود المثبطات.

2. قيمه الحامضيه

1. The pH of the cyanide solution is critical for both copper leaching and the action of inhibitors. In general, the cyanidation process is carried out in an قلوي medium, usually with a pH in the range of 10 - 11. At this pH range, the استقرار ل أيون السيانيد is maintained, and the hydrolysis of cyanide is minimized.

2. بالنسبة للعوامل المخلبية، مثل حمض الستريك، يؤثر الرقم الهيدروجيني للمحلول على قدرتها على التخلّب. يحتوي حمض الستريك على مجموعات كربوكسيل وهيدروكسيل تتفاعل مع أيونات المعادن. في الوسط القلوي، يتم تعزيز تفكك هذه المجموعات الوظيفية، مما يعزز قدرتها على التخلّب مع أيونات النحاس. ومع ذلك، إذا كان الرقم الهيدروجيني مرتفعًا جدًا (أعلى من 12)، فقد يسبب تفاعلات جانبية قد تقلل من فعالية العامل المخلبي. على سبيل المثال، في محلول شديد القلوية، قد تتحلل بعض معقدات المخلّب المعدني، مما يؤدي إلى إطلاق أيونات النحاس المخلّبة مرة أخرى في المحلول.

3. وقت الاستخلاص

1. The leaching time can influence the DEGree of copper leaching and the هاملت of inhibitors. As the leaching time increases, more copper may dissolve if not effectively inhibited. For example, in a short - term عملية الاستخلاص (less than 12 hours), the amount of copper leached may be relatively small, and the inhibitor can more easily control the copper - leaching rate. But if the leaching time is extended to 48 hours or more, the cumulative effect of copper - leaching reactions may become more significant.

2. In the case of lead - salt inhibitors, a longer leaching time may require a higher initial dosage of the inhibitor. This is because over time, the lead - containing insoluble compounds formed may gradually be consumed or their effectiveness may decline due to the continuous presence of reactive substances in the cyanide solution. So, the leaching time needs to be carefully considered when deterتعدين the amount and type of reagent to use for copper - leaching inhibition.

دراسات الحالة عملي التطبيقات

Case 1: Application of Lead Salts in a Gold Mine in جنوب أفريقيا

A gold mine in South أفريقيا وكان معالجة a copper - bearing gold ore with a copper content of approximately 3%. Before using lead salts as an inhibitor, the cyanidation process faced several challenges. The consumption of cyanide was extremely high, reaching up to 15 kg/t of ore, and the ترشيح الذهب rate was only around 80%. The high copper content in the ore led to significant copper dissolution during cyanidation, which not only consumed a large amount of cyanide but also interfered with the gold - leaching process.

After adding lead nitrate (Pb(NO_3)_2) at a dosage of 200 g/t of ore, remarkable changes were observed. The استهلاك السيانيد was reduced to 8 kg/t of ore, a decrease of about 47%. The ترشيح الذهب rate increased to 90%. The منافع اقتصادية were significant. Considering the price of cyanide and the value of the additional gold recovered, the mine saved approximately $50 per ton of ore processed. From an envحديدmental perspective, the reduced cyanide consumption meant less المخاطر البيئية associated with cyanide leakage and disposal. The amount of cyanide - containing waste was also reduced, which was beneficial for the local ecological envحديدمنة.

الحالة الثانية: استخدام عامل التخلّب (حمض الستريك) في منجم ذهب في أستراليا

في منجم ذهب أسترالي، احتوى الخام على كمية كبيرة من معادن النحاس، وخاصة الكالكوبيريت وبعض معادن كربونات النحاس. بلغت نسبة استخلاص الذهب من عملية السيانيد الأولية، دون استخدام عامل استخلاب، 75%، بينما بلغت نسبة استخلاص النحاس 30%. وقد أدى ارتفاع معدل استخلاص النحاس إلى استهلاك كبير للسيانيد، بلغ حوالي 12 كجم/طن من الخام.

When citric acid was added to the cyanidation process at a dosage of 1 kg/t of ore, the situation improved. The copper leaching rate was reduced to 10%, and the gold leaching rate increased to 85%. The consumption of cyanide decreased to 6 kg/t of ore. Economically, the cost of citric acid addition was relatively low compared to the savings in cyanide consumption and the increased انتعاش الذهب. The mine estimated that it could increase its annual profit by about $300,000. Environmentally, the reduced copper leaching meant less copper - containing wasteماء, which was easier to treat and had less impact on water resources in the surrounding area.

الحالة 3: تطبيق مثبط جديد (MZY) في منجم ذهب صيني

A gold mine in الصين was dealing with a عنيد copper - bearing gold ore. The traditional cyanidation process had a gold leaching rate of only 70% and a high copper leaching rate, which caused a large amount of cyanide consumption. After adding a new inhibitor MZY at a certain dosage, along with optimized process conditions including the addition of 18 kg/t of الليمون الأخضر and 1.2 kg/t of سيانيد الصوديوم, the gold leaching rate reached 83% - 84%, and the copper leaching rate was reduced to 4% - 5%.

This new process not only improved the gold - كفاءة الاستخلاص but also significantly reduced the cyanide consumption. The economic benefits were two - fold: the increased استعادة الذهب added more value to the إنتاج, and the reduced cyanide consumption saved costs. In terms of حماية البيئة, the lower cyanide consumption and less copper - containing waste reduced the environmental burden, making the عملية التعدين more sustainable. These case studies clearly demonstrate the practical value of using reagents to inhibit copper leaching in the cyanidation of copper - bearing gold ores, both in terms of economic benefits and حماية البيئة.

خاتمة

في عملية معالجة خامات الذهب المحتوية على النحاس بالسيانيد، لا يؤدي استخلاص النحاس إلى استهلاك كبير للسيانيد فحسب، بل يؤثر سلبًا أيضًا على معدل استخلاص الذهب وعمليات استخلاصه اللاحقة. لذلك، يُعد استخدام الكواشف لمنع استخلاص النحاس أمرًا بالغ الأهمية.

أملاح الرصاص، مثل نترات الرصاص، وخلات الرصاص، وأكسيد الرصاص، قادرة على تثبيط ترشيح النحاس بفعالية من خلال تكوين مركبات غير قابلة للذوبان مع مواد تحتوي على الكبريت في الخام، أو تغيير خصائص سطح معادن النحاس. كما أن عوامل الاستخلاب، مثل حمض الستريك، قادرة على استخلاب أيونات النحاس وأيونات المعادن الضارة الأخرى، مما يقلل من آثارها السلبية على عملية السيانيد. بالإضافة إلى ذلك، فإن التحكم في تركيز السيانيد واستخدام نظام الأمونيا-السيانيد يمكن أن يلعب دورًا في إضعاف ذوبان النحاس إلى حد ما.

The effectiveness of these reagents is influenced by various factors. Ore properties, including the type and content of copper minerals, determine the reactivity of copper in the ore and thus affect the amount of reagent required. Process conditions such as cyanide concentration, pH value, and leaching time also have a significant impact on the performance of reagents. For example, an appropriate cyanide concentration and pH value can ensure the استقرار of the cyanide solution and the effectiveness of the reagent, while the leaching time can affect the cumulative effect of copper - leaching reactions.

Through case studies, we have seen the practical application value of these reagents. In South Africa, the use of lead nitrate in a gold mine reduced cyanide consumption and increased the gold leaching rate, bringing significant economic benefits and environmental advantages. In Australia, the addition of citric acid in a gold mine effectively reduced copper leaching and cyanide consumption while increasing the gold leaching rate, which was beneficial for both economic and environmental aspects. In a Chinese gold mine, the use of a new inhibitor MZY, along with optimized process conditions, improved the gold - كفاءة الاستخلاص and reduced the copper - leaching rate, achieving good economic and environmental results.

In general, when dealing with the cyanidation of copper - bearing gold ores, it is necessary to comprehensively consider the characteristics of the ore and the متطلبات الدراسة of the process, and select the appropriate reagent and operating conditions. Future research can focus on further exploring more efficient and الكواشف الصديقة للبيئة, as well as optimizing the combination of reagents and process parameters to achieve more efficient, economical, and environmentally sustainable gold - عملية الاستخراجوفاق.