Interaction mechanism of cyanide with pyrite during the cyanidation of pyrite and the decyanation of pyrite cyanide residues by chemical oxidation

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.

Interface behavior of chalcopyrite during flotation from cyanide tailings

The interface characteristics of cyanide tailings are different from those of the raw ore. In this study, valuable elements could not be thoroughly recovered via the flotation of cyanide tailings from Shandong, China. The interface and floatability of these tailings were investig- ated by phase analysis and flotation tests. The chalcopyrite in the cyanide tailings was fine and had a porous surface. The floatability of 68% chalcopyrite was similar to that of galena in the presence of a collector. A layer of fine galena particles compactly wrapped the chalcopyrite. The chalcopyrite recovery sharply decreased as the nonpolar oil residue in cyanide tailings was extracted using alcohol;however, this removal had no effect on the galena. The remaining chalcopyrite in the flotation tailings was covered with an oxidation layer consisting of O, Fe, S, Pb, Cu, Zn, and Si.

Therapeutic strategies of targeting nonapoptotic regulated cell death (RCD) with smallmolecule compounds in cancer

Regulated cell death(RCD)is a controlled form of cell death orchestrated by one or more cascading signaling pathways,making it amenable to pharmacological intervention.RCD subroutines can be categorized as apoptotic or non-apoptotic and play essential roles in maintaining homeostasis,facilitating development,and modulating immunity.Accumulating evidence has recently revealed that RCD evasion is frequently the primary cause of tumor survival.Several non-apoptotic RCD subroutines have garnered attention as promising cancer therapies due to their ability to induce tumor regression and prevent relapse,comparable to apoptosis.Moreover,they offer potential solutions for overcoming the acquired resistance of tumors toward apoptotic drugs.With an increasing understanding of the underlying mechanisms governing these non-apoptotic RCD subroutines,a growing number of small-molecule compounds targeting single or multiple pathways have been discovered,providing novel strategies for current cancer therapy.In this review,we comprehensively summarized the current regulatory mechanisms of the emerging non-apoptotic RCD subroutines,mainly including autophagy-dependent cell death,ferroptosis,cuproptosis,disulfidptosis,necroptosis,pyroptosis,alkaliptosis,oxeiptosis,parthanatos,mitochondrial permeability transition(MPT)-driven necrosis,entotic cell death,NETotic cell death,lysosome-dependent cell death,and immunogenic cell death(ICD).Furthermore,we focused on discussing the pharmacological regulatory mechanisms of related small-molecule compounds.In brief,these insightful findings may provide valuable guidance for investigating individual or collaborative targeting approaches towards different RCD subroutines,ultimately driving the discovery of novel small-molecule compounds that target RCD and significantly enhance future cancer therapeutics.

Pool bio-oxidation and fitting analysis of low-grade arsenic-containing refractory gold ore

To overcome the limitations of geography,climate,and ore characteristics on the ore beneficiation process,biooxidation studies on low-grade arsenic-bearing refractory gold ore by pool leaching were carried out,as well as process fitting analysis.The gold particles are encapsulated by pyrite and arsenopyrite.After 60 days of biooxidation,the oxidation rates of arsenic,sulfur,and gold were 39%~69%,24%~41%,and 49%~83%,respectively.The inoculated Acidithiobacillus ferrooxidans,Ferroplasma acidiphilum,and Leptospirillum ferrodiazotrophum could all mediate the initial pyrite/arsenopyrite oxidation and the Fe^(2+)oxidation reaction,but only the former could mediate the subsequent sulfur compound oxidation.When compared to daily bacterial circulation and bacterial replacement every ten days,aeration improved the gold leaching rate by 14%~22%.The Boltzmann model could fit both the arsenic and sulfur bio-oxidation,with model fit variances greater than 0.98.Based on the experimental and fitting results,the bio-oxidation cycle was determined to be 60 days,and the bio-oxidation mechanisms are summarized.This study has significant practical implications for the rational utilization of gold resources and provides theoretical and practical guidance for similar gold ores.