The toxic cyanides in cyanide residues produced from cyanidation process for gold extraction are harmful to the environment.Pyrite is one of the main minerals existing in cyanide residues.In this work,the interaction ...The toxic cyanides in cyanide residues produced from cyanidation process for gold extraction are harmful to the environment.Pyrite is one of the main minerals existing in cyanide residues.In this work,the interaction of cyanide with pyrite and the decyanation of pyrite cyanide residue were analyzed.Results revealed that high pH value,high cyanide concentration,and high pyrite dosage promoted the interaction of cyanide with pyrite.The cyanidation of pyrite was pseudo-second-order with respect to cyanide.The decyanation of pyrite cyanide residue by Na_(2)SO_(3)/air oxidation was performed.The cyanide removal efficiency was 83.9% after 1 h of reaction time under the optimal conditions of pH value of 11.2,SO_(3)^(2-) dosage of 22 mg·g^(-1),and air flow rate of 1.46 L·min^(-1).X-ray photoelectron spectroscopy analysis of the pyrite samples showed the formation of Fe(Ⅲ)and FeSO_(4) during the cyanidation process.The cyanide that adsorbed on the pyrite surface after cyanidation mainly existed in the forms of free cyanide(CN^(-))and ferrocyanide(Fe(CN)_(6)^(4-)),which were effectively removed by Na_(2)SO_(3)/air oxidation.During the decyanation process,air intake promoted pyrite oxidation and weakened cyanide adsorption on the pyrite surface.This study has practical significance for gold enterprises aiming to mitigate the environmental impact related to cyanide residues.展开更多
Cyanide poisoning is one of the most dangerous poisonings, and it can be absorbed into the body through the mouth, inhalation and through the skin. A 32-year-old female patient was admitted to our poison control cente...Cyanide poisoning is one of the most dangerous poisonings, and it can be absorbed into the body through the mouth, inhalation and through the skin. A 32-year-old female patient was admitted to our poison control center because of high fever, severe vomiting, and seizures. Physical examination found that the patient was drowsy, had a high fever of 40 degrees Celsius, pulse of 140 beats/minute, and increased tendon and bone reflexes. Exploiting the patient’s information, it was discovered that the patient bought Cyanide to drink with the intention of committing suicide. The patient was quickly treated with gastric lavage and activated charcoal. Echocardiography recorded EF: 35%, reduced movement of the entire myocardium. CK blood test: 4562 U/L. The patient’s condition rapidly deteriorated and the patient was made ECMO, IHD and CVVHDF. After 3 days of treatment, the patient’s condition did not improve, so the family asked for the patient to go home. This article aims to describe the rapidly progressing and severe damage to the heart and muscles of patients with cyanide poisoning.展开更多
The optimization system, which was the subject of our study, is an autonomous chain for the automatic management of cyanide consumption. It is in the phase of industrial automation which made it possible to use the ma...The optimization system, which was the subject of our study, is an autonomous chain for the automatic management of cyanide consumption. It is in the phase of industrial automation which made it possible to use the machines in order to reduce the workload of the worker while keeping a high productivity and a quality in great demand. Furthermore, the use of cyanide in leaching tanks is a necessity in the gold recovery process. This consumption of cyanide must be optimal in these tanks in order to have a good recovery while controlling the concentration of cyanide. Cyanide is one of the most expensive products for mining companies. On a completely different note, we see huge variations during the addition of cyanide. Following a recommendation from the metallurgical and operations teams, the control team carried out an analysis of the problem while proposing a solution to reduce the variability around plus or minus 10% of the addition setpoint through automation. It should be noted that this automatic optimization by monitoring the concentration of cyanide, made use of industrial automation which is a technique which ensures the operation of the ore processing chain without human intervention. In other words, it made it possible to substitute a machine for man. So, this leads us to conduct a study on concentration levels in the real world. The results show that the analysis of the modeling of the cyanide consumption optimization system is an appropriate solution to eradicate failures in the mineral processing chain. The trend curves demonstrate this resolution perfectly.展开更多
Background: Cassava tuber crop is a staple food rich in carbohydrates and utilized in various forms by millions of Nigerians. The storage root of the cassava contains linamarin, a cyanogenic glycoside that is easily h...Background: Cassava tuber crop is a staple food rich in carbohydrates and utilized in various forms by millions of Nigerians. The storage root of the cassava contains linamarin, a cyanogenic glycoside that is easily hydrolyzed to release cyanide salt compounds which is toxic to the nervous system especially the optic nerve, sometimes leading to optic neuropathy and visual impairment. Aim: The aim of this study is to find out the impact of selected processing methods of high-level cyanide in cassava on optic neuropathy in Wistar albino rats. Methodology: Twenty-four Wistar albino rats were fed with different concentration and duration of predetermined high-cyanide content cassava root cultivar which was processed using different processing methods adopted by various communities in Rivers State, Nigeria (for human consumption). A control group of 3 Wistar albino rats was fed with normal “Growth Mesh” meals. The pre and post weights of the animals and the fundoscopic optic nerve status of the rats were evaluated after 30 and 60 days. SPSS Version 25 was employed for descriptive and inferential statistical analyses. A p-value of ≤0.05 was considered statistically significant. Results: The Cassava species available in Rivers State have high cyanide content (2336.79 mg CN<sup>-</sup>/kg dry weight of cassava). There was statistically significant reduction in the cyanide content (p = 0.000) depending on the various common processing methods (into garri for human consumption): 24 hours, 48 hours, fermentation;with and without red palm oil additive. The individual weights as well as the mean weight of the 24 rats in the experimental group increased gradually from the first week to the 9<sup>th</sup> week with a slight weight reduction on the third and fourth weeks which was not statistically significant (p = 0.092). However, there was a steady increase in the weights of the animals in the control group throughout the 9 weeks. Varying degrees of optic neuropathy occurred, worse with the rats that had 24-hour fermented cassava twice daily for 60 days. The intra and inter group differences in the optic disc changes was statistically significant (p = 0.000). Conclusion: Longer duration of processing cassava roots into garri for human consumption reduces its cyanide content and minimizes the adverse impact on the optic nerve.展开更多
A safe and environmentally friendly cyaniding method has been developed to mitigate the toxic impacts of cyanide salts on the environment during conventional cyaniding. The method entails in-situ diffusion of nascent ...A safe and environmentally friendly cyaniding method has been developed to mitigate the toxic impacts of cyanide salts on the environment during conventional cyaniding. The method entails in-situ diffusion of nascent cyanide from mature cassava leaves into the surface of mild steel components via pack-cyaniding. Both high-temperature in-situ diffusion into austenite and low-temperature in-situ diffusion into ferrite were explored. Results from light and scanning electron microscopic studies showed that surface hardness of the steel components was substantially increased. The waste product was a harmless biodegradable organic compound that posed no disposal threats. This study is important for increasing the wear resistance of ferrous parts for a longer service life in application without polluting the environment.展开更多
Pretreatment of high content of Si- and Al-containing cyanide tailings by water leaching to remove some impurities, such as the major impurities minerals of Si and A1, as well as its effect on Fe extraction in the wat...Pretreatment of high content of Si- and Al-containing cyanide tailings by water leaching to remove some impurities, such as the major impurities minerals of Si and A1, as well as its effect on Fe extraction in the water leaching process was investigated. The effects of different parameters on iron recovery were studied, and the reaction parameters were proposed as follows： sodium carbonate content of 30%, water leaching at 60 ~C for 5 min, liquid/solid ratio of 15：1, and exciting current of 2 A. Under these optimal conditions, magnetic concentrate containing 59.11% total iron and a total iron recovery rate of 76.12% was obtained. In addition, the microstructure and phase transformation of the process of water leaching were studied by X-ray powder diffraction technique （XRD）, Electronic image of backscattering （BEI）, X-ray fluorescence （XRF）, and energy dispersive spectrometry （EDS）. The results indicate that the soluble compound impurities generated in the roasting process are washed out, and the dissoluble substances enter into nonmagnetic materials by water leaching, realizing the effective separation of impurities and Fe.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52274348)the Major projects for the“Revealed Top”Science and Technology of Liaoning Province,China(No.2022JH1/10400024)the National Key Research and Development Program of China(No.2018YFC1902002).
文摘The toxic cyanides in cyanide residues produced from cyanidation process for gold extraction are harmful to the environment.Pyrite is one of the main minerals existing in cyanide residues.In this work,the interaction of cyanide with pyrite and the decyanation of pyrite cyanide residue were analyzed.Results revealed that high pH value,high cyanide concentration,and high pyrite dosage promoted the interaction of cyanide with pyrite.The cyanidation of pyrite was pseudo-second-order with respect to cyanide.The decyanation of pyrite cyanide residue by Na_(2)SO_(3)/air oxidation was performed.The cyanide removal efficiency was 83.9% after 1 h of reaction time under the optimal conditions of pH value of 11.2,SO_(3)^(2-) dosage of 22 mg·g^(-1),and air flow rate of 1.46 L·min^(-1).X-ray photoelectron spectroscopy analysis of the pyrite samples showed the formation of Fe(Ⅲ)and FeSO_(4) during the cyanidation process.The cyanide that adsorbed on the pyrite surface after cyanidation mainly existed in the forms of free cyanide(CN^(-))and ferrocyanide(Fe(CN)_(6)^(4-)),which were effectively removed by Na_(2)SO_(3)/air oxidation.During the decyanation process,air intake promoted pyrite oxidation and weakened cyanide adsorption on the pyrite surface.This study has practical significance for gold enterprises aiming to mitigate the environmental impact related to cyanide residues.
文摘Cyanide poisoning is one of the most dangerous poisonings, and it can be absorbed into the body through the mouth, inhalation and through the skin. A 32-year-old female patient was admitted to our poison control center because of high fever, severe vomiting, and seizures. Physical examination found that the patient was drowsy, had a high fever of 40 degrees Celsius, pulse of 140 beats/minute, and increased tendon and bone reflexes. Exploiting the patient’s information, it was discovered that the patient bought Cyanide to drink with the intention of committing suicide. The patient was quickly treated with gastric lavage and activated charcoal. Echocardiography recorded EF: 35%, reduced movement of the entire myocardium. CK blood test: 4562 U/L. The patient’s condition rapidly deteriorated and the patient was made ECMO, IHD and CVVHDF. After 3 days of treatment, the patient’s condition did not improve, so the family asked for the patient to go home. This article aims to describe the rapidly progressing and severe damage to the heart and muscles of patients with cyanide poisoning.
文摘The optimization system, which was the subject of our study, is an autonomous chain for the automatic management of cyanide consumption. It is in the phase of industrial automation which made it possible to use the machines in order to reduce the workload of the worker while keeping a high productivity and a quality in great demand. Furthermore, the use of cyanide in leaching tanks is a necessity in the gold recovery process. This consumption of cyanide must be optimal in these tanks in order to have a good recovery while controlling the concentration of cyanide. Cyanide is one of the most expensive products for mining companies. On a completely different note, we see huge variations during the addition of cyanide. Following a recommendation from the metallurgical and operations teams, the control team carried out an analysis of the problem while proposing a solution to reduce the variability around plus or minus 10% of the addition setpoint through automation. It should be noted that this automatic optimization by monitoring the concentration of cyanide, made use of industrial automation which is a technique which ensures the operation of the ore processing chain without human intervention. In other words, it made it possible to substitute a machine for man. So, this leads us to conduct a study on concentration levels in the real world. The results show that the analysis of the modeling of the cyanide consumption optimization system is an appropriate solution to eradicate failures in the mineral processing chain. The trend curves demonstrate this resolution perfectly.
文摘Background: Cassava tuber crop is a staple food rich in carbohydrates and utilized in various forms by millions of Nigerians. The storage root of the cassava contains linamarin, a cyanogenic glycoside that is easily hydrolyzed to release cyanide salt compounds which is toxic to the nervous system especially the optic nerve, sometimes leading to optic neuropathy and visual impairment. Aim: The aim of this study is to find out the impact of selected processing methods of high-level cyanide in cassava on optic neuropathy in Wistar albino rats. Methodology: Twenty-four Wistar albino rats were fed with different concentration and duration of predetermined high-cyanide content cassava root cultivar which was processed using different processing methods adopted by various communities in Rivers State, Nigeria (for human consumption). A control group of 3 Wistar albino rats was fed with normal “Growth Mesh” meals. The pre and post weights of the animals and the fundoscopic optic nerve status of the rats were evaluated after 30 and 60 days. SPSS Version 25 was employed for descriptive and inferential statistical analyses. A p-value of ≤0.05 was considered statistically significant. Results: The Cassava species available in Rivers State have high cyanide content (2336.79 mg CN<sup>-</sup>/kg dry weight of cassava). There was statistically significant reduction in the cyanide content (p = 0.000) depending on the various common processing methods (into garri for human consumption): 24 hours, 48 hours, fermentation;with and without red palm oil additive. The individual weights as well as the mean weight of the 24 rats in the experimental group increased gradually from the first week to the 9<sup>th</sup> week with a slight weight reduction on the third and fourth weeks which was not statistically significant (p = 0.092). However, there was a steady increase in the weights of the animals in the control group throughout the 9 weeks. Varying degrees of optic neuropathy occurred, worse with the rats that had 24-hour fermented cassava twice daily for 60 days. The intra and inter group differences in the optic disc changes was statistically significant (p = 0.000). Conclusion: Longer duration of processing cassava roots into garri for human consumption reduces its cyanide content and minimizes the adverse impact on the optic nerve.
文摘A safe and environmentally friendly cyaniding method has been developed to mitigate the toxic impacts of cyanide salts on the environment during conventional cyaniding. The method entails in-situ diffusion of nascent cyanide from mature cassava leaves into the surface of mild steel components via pack-cyaniding. Both high-temperature in-situ diffusion into austenite and low-temperature in-situ diffusion into ferrite were explored. Results from light and scanning electron microscopic studies showed that surface hardness of the steel components was substantially increased. The waste product was a harmless biodegradable organic compound that posed no disposal threats. This study is important for increasing the wear resistance of ferrous parts for a longer service life in application without polluting the environment.
基金Projects(ZR2010EL006,Y2007F60) supported by the National Science Foundation of Shandong Province of ChinaProject(J12LA04) supported by High Education Science Technology Program of Shandong Province,China
文摘Pretreatment of high content of Si- and Al-containing cyanide tailings by water leaching to remove some impurities, such as the major impurities minerals of Si and A1, as well as its effect on Fe extraction in the water leaching process was investigated. The effects of different parameters on iron recovery were studied, and the reaction parameters were proposed as follows： sodium carbonate content of 30%, water leaching at 60 ~C for 5 min, liquid/solid ratio of 15：1, and exciting current of 2 A. Under these optimal conditions, magnetic concentrate containing 59.11% total iron and a total iron recovery rate of 76.12% was obtained. In addition, the microstructure and phase transformation of the process of water leaching were studied by X-ray powder diffraction technique （XRD）, Electronic image of backscattering （BEI）, X-ray fluorescence （XRF）, and energy dispersive spectrometry （EDS）. The results indicate that the soluble compound impurities generated in the roasting process are washed out, and the dissoluble substances enter into nonmagnetic materials by water leaching, realizing the effective separation of impurities and Fe.
