老窿废弃矿物资源综合回收技术研究

本文在分析研究龙山金锑矿老窿废弃矿物资源赋存特征和矿物性质的基础上,结合矿山生产实际,采用脉外平巷加穿脉群回采方案和部分优先-混合浮选工艺技术,综合回收老窿废弃矿物资源。试验研究表明:该项技术金锑回收率高、回采作业安全性好、经济效益显著,使老窿废弃矿物资源得到了合理开发利用,可供类似矿山提供借鉴。

建筑垃圾磨细粉作矿物掺合料对水泥物理力学性能的影响

研究建筑垃圾磨细粉作水泥、混凝土矿物掺合料的可能性。主要研究建筑垃圾磨细粉对水泥的物理力学性能的影响。为了提高建筑垃圾磨细粉在水泥中的掺量,还研究了碱性激发剂对其的激发作用。研究结果表明:碱性激发剂对建筑垃圾磨细粉的激发效果早期非常明显,但后期效果不是特别明显。

试论混凝土材料中新型矿物掺合料的应用

在21世纪的今天,面对着日益严重的环境恶化问题,世界各国都加强了对环境保护的重视,而对废弃矿物材料的处理和再利用也成为了一个关键问题。在这种背景形势下,对新型矿物掺合料在混凝土中的应用进行研究适应了绿色环保的要求,体现出了显著的经济、社会和环境效益,应该得到我国的充分重视。

矿物掺合量对水工混凝土物理学性能影响研究

矿物种类和掺合量对于水工混凝土的物理力学性能具有重要的影响。通过RCM试验、快速碳化以及微观孔隙结构分析试验,研究成果为:花岗岩和煤矸石对于水工混凝土抗渗及耐久性等方面的影响更为显著,能极大提高混凝土的抗渗性能和耐久性,对于工程安全具有重要作用。

Experimental study on the properties of CMTs-incorporated geopolymers prepared at low temperatures

Considering that copper mine tailings(CMTs)are commonly mixed with ordinary Portland cement,fly ash(FA),and kaolin to produce geopolymers,to make full use of CMTs,the properties of geopolymers manufactured under different material mass ratios and curing methods(standard curing,water bath curing,and 60℃curing)are evaluated with significantly increased dosage of CMTs.Porosity and unconfined compressive strength tests,X-ray diffraction,field emission scanning electron microscopy,and energy dispersive spectroscopy are used to determine the physical and mechanical properties,microstructure,and mineral composition of geopolymers.Finally,costs and CO 2 emissions of specimens with different material mass ratios during the preparation processes are compared.The results show that during the geopolymerization of low-calcium materials,various geopolymer gels,including calcium silicate,calcium silicoaluminate,and mainly sodium silicoaluminate gels,coexist.The solid waste,cost,and carbon dioxide emission reductions can reach 100%,166.3 yuan/t,and 73.3 kg/t,respectively.Under a curing condition of 60℃,the sample with a CMTs mass fraction of 70%and an FA mass fraction of 30%meets the requirements of porosity,compressive strength.The resource utilization of CMT and FA is realized in a more economical way.

Soil properties in reclaimed farmland by filling subsidence basin due to underground coal mining with mineral wastes in China

Reclaimed mining-induced subsidence area soils (RMSs) could restore soil quality and crop productivity in coal mining area. This study was conducted to evaluate the effects of mineral-processing wastes (fly ash vs coal gangue) as backfill substrates on soil chemical and microbial properties in mining-induced subsidence area. A general higher water holding capacity (WHC) and pH had been observed in fly ash than coal gangue reconstructed soil. Soil microbial biomass C (MBC) and N (MBN), MBC/TOC (total organic carbon) ratio (qmic) were higher under the influence of the fly ash, while contents of As, Cr, C/Nbio, the basal respiration per unit of microbial biomass (QCO2) were higher under the coal gangue reconstructed mode in 0-10, 10-20, 20-50 cm layers. The microbial basal respiration was higher in 0-10, 10-20, 0-50 cm layers, while was lower in 20-50 cm layer under fly ash than that of coal gangue reconstructed mode. The lower QCO2 of fly ash mine soil suggested the lower maintenance energy requirement of the microbial community. Moreover, the contents of metals may possibly have negative implications for soil microbial and enzyme activities in reconstructed soil.

Commelina communis L.: Copper Hyperaccumulator Found in Anhui Province of China

Commelina communis L. growing over some new copper mining wastelands at Bijiashan, Tongling City of Anhui Province, China, was found to be a copper hyperaccumulator. Its copper concentrations were 2707-6159 (4439±2434) mg kg-1, 369-831 (731±142) mg kg-1, and 429-587 (547±57) mg kg-1, respectively, in the roots, stems, and leaves. The soils supporting the growth of the species had a copper concentration ranging from 4620 to 5020 mg kg-1 and averaging 4835±262 mg kg-1, suggesting that the species could not only grow on heavily copper-contaminated soils but also accumulate extraordinarily high concentration of copper. Thus, it shows great potential in the phytoremediation of copper-contaminated soils,the restoration of mined land, geochemical prospecting, and the study of environmental pollution changes.

A landfill based approach to surface mine design

Surface mining operations extract a large quantity of waste material,which is generally disposed into a dump area.This waste can cause a series of environmental problems ranging from landscape deterioration to acidic water generation and water pollution.Therefore,mine waste management is a significant task in mining operations.As known,in strip mining,the overburden is not transported to waste dumps but disposed directly into adjacent strip which was mined out.This concept can be adapted for mine planning of relatively horizontal deposits through a mixed integer programming(MIP)model.The main idea behind this work is that,in one pit,production voids created in early year of mining are used for waste landfilling in late years of production.In other words,in addition to external dumping,a landfilling option within the same pit is proposed for mine design optimization.The problem is formulated as maximization of the net present value(NPV)of the mining project under the constraints of access,landfill waste handling,mining and processing capacities.A case study using a data set was carried out to see the performance of the proposed approach.The findings showed that this approach could be used in waste management incorporating a landfilling option into mine planning.As a result,material handling costs decrease,and environmental compliance increases due to less external waste quantity.

Valorization of mining waste and tailings through paste backfilling solution, Imiter operation, Morocco

Mine waste and process tailings storage is one of important challenge for which mining operations are increasingly confronted. Treatment discharges of plants and main part of waste rock development are generally stored on surface areas. The volume and chemical characteristics of these materials generate serious problem for required storage spaces and mainly environmental degradation. Paste backfill(PBF) is one of ingenious solutions to minimize the quantity of tailings to store. PBF is basically defined as a combination of mine processing tailings, binder, and water mixing. The purpose of this paper is to present backfilling components characterization and formula verification for a waste valorization solution through paste backfilling technology in Imiter operation. Obtained results and realized analysis demonstrate PBF conformity and adequacy with assigned underground functions. However the studied recipe can be more ameliorated to obtain an optimal mixture ensuring the required mechanical strength.

Catalytic effect of silver-bearing solid waste on chalcopyrite bioleaching:A kinetic study

Silver ion can be useful in improving chalcopyrite bioleaching efficiency.In this work,leaching kinetics of this process was investigated using silver-bearing solid waste under different chalcopyrite/solid waste ratios.Bioleaching behavior indicates that silver-bearing solid waste can enhance the bioleaching process,and the redox potential is much higher than the proposed appropriate range(380−480 mV vs Ag/AgCl)with the solid waste added.There is a positive correlation between temperature and copper extraction rate.The kinetics data fit well with the shrinking-core model.Under these leaching conditions,the bioleaching of chalcopyrite is controlled by internal diffusion with calculated apparent activation energy(Ea)of 28.24 kJ/mol.This work is possible benificial to promote the industrial application of silver catalyst in leaching of chalcopyrite.

Ash-and-Slag Wastes of Energy Sector as Raw Material for Production of Rare-Earth Metals and Alumina

The results to develop a complex technology of co-extraction of germanium and gallium from the ash-and-slag wastes of coal combustion in Ukraine were presented. Based on the study of phase changes occurring in initial raw materials as a result of its processing, it was proposed to carry out a preliminary enrichment of the raw materials in order to produce secondary sublimates. Their further processing involves a combination of leaching soluble material with distillation of germanium in the form of tetrachloride. The resulting acidic solutions are trended to the gallium extraction. Optimum conditions of carrying out of processes are recommended.The chemical and phase composition of the resulting dump products and solutions have been defined. On the basis of it ways of their processing for the purpose of reception of alumina and building materials are recommended.

Mine rocky desertification： Another type of rocky desertification coexisting with Karst rocky desertification in Karst region

Mine rocky desertification is another type of rocky desertification which coexists with Karst rocky desertification, suggested firstly by professor SONG Jian-bo, Guizhou University. Mine rocky desertification is a process and result that the earth＇s surface is similar to desert landscapes after rock is exposed gradually, owing to mine wastes discharged at will which consist of waste residue, waste liquid and waste gas. On the basis of introducing Karst rocky desertification simply, we clarify the concept of Mine rocky desertification systemically, analyze its danger and compare the differences between Mine rocky desertification and Karst rocky desertification. Finally, we make preliminary discussion on the study significance of comprehensive treatment of Mine rocky desertification

The Effect of the Grinding Time on the Mechanical Activation of MnO2 Ore and Tea Plant Waste Carbonization Product

In this study, pyrolusiteore （MnO2） was subjected to mechanical milling with a high-energy mill with carbonized tea plant wastes and the effect of grinding time on the crystal structure of the material was investigated. The ratio of Mn/Fe was 8/1, the ratio of C/（MnO2 ＋ Fe3O4） was 2 and the ratio of ball to ore was 10/1. The samples were mechanically ground at 10, 15, 20, 30, 60, 90 and 120 hours. In the processes performed on the attritor, the rotation speed of the mill shaft was determined to be 350 rpm. The results were characterized by TG-DTA, SEM and XRD analyzes. As a result of the experimental studies, it was observed that the samples subjected to mechanical grinding for 120 hours were gradually reduced due to the increasing grinding time at all the diffraction peaks when the XRD peaks were compared with the grinding times. In the thermogravimetric analysis, the sample milled for 120 hours, 50% weight loss was observed at 470 ℃, weight loss of up to 56% was observed at progressive temperatures.

Abandoned Mine, Potential Home for the People： A Case Study of Jos Plateau Tin-Mining Region

This paper seeks to examine the JPTMR （Jos Plateau Tin-Mining Region） as an abandoned mine that provides land for housing by examining the impact of the tin-mining activities due to the presence of heavy metals and radioactive substances and analyzing the level and availability of these substances and their effects on human health and the built environment within JPTMR. Utilizing secondary data, which map out 10 different locations in the region, the paper highlights the level of radioactive substances （X-ray, beta-ray and gamma-ray） and presence of heavy metals in the environment. The results show that there are traces of X-ray, beta-ray and gamma-ray as well as the heavy metals such as Pb, As, Cu, Cr and Ni which exceeded the international standards. This is particularly significant as people use the contaminated soils as building materials for their homes as well as for farming and food production. The inhabitants of the area are often without any knowledge about the perils of the contaminated soils, water as well as air which is serious long-term human catastrophe. Drawing from international experience, the paper argues that it is possible to develop housing in former tin-mining areas but requires careful remediation and engagement by the public and private sector.