Components Of Tailings Research Articles

Current situation and prospects for the clean utilization of gold tailings

Gold tailings are characterized by low-grade, complex composition, fine embedded particle size, environmental pollution, and large land occupation. This paper describes the mineralogical properties of gold tailings, including chemical composition, phase composition, particle size distribution, and microstructure; summarizes the recycling and utilization of components such as mica, feldspar, and valuable metals in gold tailings; reviews harmless treatment measures for harmful elements in gold tailings; and adumbrated the research progress of gold tailings in the application fields of building materials, ceramics, and glass materials. Based on these discussions, a new technology roadmap that combines multistage magnetic separation and cemented filling is proposed for the clean utilization of all components of gold tailings.

Environmentally friendly disposal of the full components of gold tailings: feldspar recovery and cemented filling

ABSTRACT Due to the extremely low-grade of gold in natural ores, a huge amount of gold tailings is produced in the beneficiation progress, which caused the disposal of tailings becomes extremely urgent because of the increasingly stringent environmental protection factors. The present study focuses on the innovative full component disposal of gold tailings, which including the recovery of useful feldspar and safe filling of the remaining low-value component. However, the Fe content of feldspar concentrate is strictly limited, and the Fe removal process is preferred. Firstly, a clean physical (physical-chemical) separation method, magnetic separation, and flotation were combined to remove harmful Fe elements. In addition, Fe removal characteristics of narrow particle size were analyzed. Subsequently, the deslimed gold tailings (+0.045 mm) were used for the recovery of feldspar by flotation in acidic environment. Finally, the ultrafine grained tailings (−0.045 mm), flotation tailing, and iron impurity were backfilled underground by cementation. Separation results show that magnetic field strength and particle size have a significant positive correlation with Fe removal. As the particle size decreases from 0.5–0.25 mm to −0.045 mm, the total Fe content (TFe) increases from 0.23% to 0.35% under 1.4 T field strength, accompanied by the reduction of TFe removal from 68.73% to 61.34%. Flotation can further reduce the TFe to 0.09%–0.21%. Further, feldspar concentrate was successfully recovered with dodecylamine as collector. The grades of Na2O and K2O can reach 7.55% and 3.73% with dosage of 1000 g/t, with recovery of 86.63% and 74.63%. When the tailings pulp concentration is greater than 56%, the curing strength can exceed 0.5 MPa at 3 d. Therefore, feldspar concentrate meeting ceramic standards with whiteness of 58.63 is obtained, and the remaining low value components are filled back to the ground, making it a secondary resource rather than a waste with environmental threats.

Thermodynamics and mechanisms of silver tailings roasting processes

To separate and extract all the useful components of tailings, taking silver tailings as the object, the thermodynamics of silver tailings during the roasting processes was investigated, and the phases transformation mechanism of major minerals were obtained. Based on the mineralogy characteristics of silver tailings, the standard Gibbs free energy changes for the chemical reactions in the roasting processes were calculated; the thermal chemical behaviors and the mineral phases transformation were investigated using TG/DTG-DSC and XRD; and the microstructure changes with chemical composition of microregions were characterized through SEM-EDS. The thermochemical reaction characteristics for the roasting activation of tailings and sodium carbonate at different temperatures were as follows: at 450–650 °C, the ankerite, siderite and sulfide in tailings were oxidized and decomposed, while the crystal transformation of quartz and chlorite occurred; at 650–750 °C, quartz, muscovite and chlorite decomposed to form soluble sodium silicate, sodium aluminum silicate, diopside, sodium ferrite and copper ferrite etc; at 750–800 °C, due to the increase in products with low melting point, the roasted samples melted. During the roasting processes, the surface of minerals depressed and the structures were destroyed. These results can provide a theoretical foundation for thoroughly resource utilization of tailings.

Exploration on Comprehensive Utilization Technology of Mine Tailings

With the stable and sustained development of the domestic economy, the demand for various mineral resources is increasing. Mineral resources have great value for social and economic development. Mineral resources provide the vast majority of raw materials for domestic economic development. However, in the actual mining process, many beneficial substances are discarded in the form of tailings. After a long period of extensive mining, the amount of domestic minerals has gradually decreased. Outdated mining methods lead to a substantial increase in costs, while leaving many mine tailings. The insufficient utilization of tailings has formed many obstacles to the sustainable development of the industry. Many components of tailings are still valuable, so they must be turned into waste. Vigorously carry out the recycling of resources and promote the common development of the economy and the environment. We are supposed to attach importance to the ecological environment and adverse effects of tailings, and adopt scientific measures to reduce the adverse effects of tailings on the ecological environment.

Effects of oil sands process water mixtures on the mayfly Hexagenia and field-collected aquatic macroinvertebrate communities.

Extraction of Canada's oil sands has created 1 billion m3 of tailings, which are stored in on-site tailings ponds. Due to limited storage capacity, the planned release of tailings into the surrounding environment may be required. This represents an environmental management challenge, as the tailings contain contaminants that are known toxins to aquatic communities. Of particular concern are naphthenic acids and their metallic counterparts, as they are the principal toxic components of tailings, are relatively soluble, and are persistent in aquatic environments. This study examines the acute toxicity of environmentally relevant 10:1 mixtures of two process water components: naphthenic acid and sodium naphthenate. We assess the effects of these simplified oil sands process water (OSPW) mixtures under planned and unplanned tailings release scenarios, using traditional and cutting-edge bioindicators for aquatic invertebrate taxa. We found that safe concentrations for mayflies and other aquatic macroinvertebrates were less than 1 mg/l, as no mayfly taxa survived repeated exposure to this dose in either the 48-h or 72-h acute toxicity test. In the 72-h test, no mayflies survived treatment levels greater than 0.5 mg sodium naphthenate/l. In the mesocosm study, even a 90% dilution of the OSPW mixture was not sufficient to protect sensitive macroinvertebrate communities. The results of this study highlight the potential environmental damage that will occur if OSPW is not carefully managed. This information will aid with the development of a management plan for oil sands tailings ponds, which will provide insight into the potential for process water release into the surrounding environment while conserving unique ecosystems downstream of development in the oil sands region.

A practice of ultra-fine tailings disposal as filling material in a gold mine

A practice of cemented backfill technology with ultra-fine tailings in a gold mine was comprehensively presented, and a series of tests were conducted in accordance with the peculiar properties of ultra-fine tailings and the mining technology conditions. The test results show that, the tailings from Shuiyindong Gold Mine have a great grinding fineness, with the average particle diameter 22.03 μm, in which the ultra-fine particles with the diameter below 20 μm occupying 66.13%. The analysis results of chemical components of tailings indicate that the content of SiO2 is relatively low, i.e., 33.08%, but the total content of CaO, MgO and Al2O3 is relatively high i.e., 36.5%. After the settlement of 4–6 h, the tailing slurry with the initial concentration of 40% has the maximum settling concentration of 54.692%, and the corresponding maximum settling unit weight is 1.497 g/cm3. During the field application, the ultra-fine tailings and PC32.5 cement were mixed with the cement-tailings ratios of 1:3–1:8, and the slurry concentration of 50 wt% was prepared. Using the slurry pump, the prepared cemented backfill slurries flowed into the goaf, and then the strength of the cemented backfill body met the mining technique requirements in Shuiyindong Gold Mine, where the ore body has a smooth occurrence, with the average thickness of approximately 2 m and the inclination angle ranging from 5 to 10°.

Effects of mechanical activation on the structural changes and microstructural characteristics of the components of ferruginous quartzite beneficiation tailings

The effects of mechanical activation in a planetary mill on the structural changes and microstructural characteristics of the components of ferruginous quartzite beneficiation tailings generated by wet magnetic separation process were studied using X-ray and laser diffraction methods. The results revealed the relationship between variations in the mean particle size of activated powders and the milling time. The crystallite size, microstrain, lattice parameters and unit cell volumes were determined for different milling times in powder samples of quartz, hematite, dolomite, and magnetite from the beneficiation tailings. The main trends in the variation of the crystallite size of quartz, hematite, dolomite, and magnetite as a function mean particle size of powder samples were revealed. Changes in the particle shape as a function of the activation time was also investigated.

Study on Production of Burning-Free Brick Using Chinese Kuancheng Iron Ore Tailings

Based on the analysis of components of Chinese Kuancheng iron ore tailings, burning-free brick test block were produced using local iron ore tailings and blast furnace slag as raw material, portlant cement as mineral glue, and parget as mineral activator. The optimum formula and production process were obtained with experiment of compressive strength of test blocks. The optimum ratio of iron ore tailing to blast furnace slag is between 5:5 and 6:4, parget composition is between 6% and 8%, and cement usage can be reduced to 10%. After curing, burning-free brick compressive strength of 17.5Mpa can be reached without sandiness phenomenon, and performance far exceeds the M10 burning-free brick standards. The formula of burning-free brick proposed in this paper can solve the problem of mineral waste pollution in Kuancheng area

An assessment of the impact of copper mine tailings disposal on meiofaunal assemblages using microcosm bioassays

Microcosms were used to assess the impact of copper mine tailings disposal on the littoral meiofaunal assemblages of the Atacama region of northern Chile. The specific purpose was to establish a cause and effect relationship between the elevated copper concentrations and altered meiofaunal assemblages observed at the study sites. Meiofaunal assemblages were exposed to a series of copper concentrations to assess general toxicity, both densities and taxa diversities decreased with increasing copper. Natural coarse sediments were mixed with a tailings substitute to assess the physical impact of the tailings dumping on meiofaunal assemblages. Meiofaunal assemblage densities increased with increasing amounts of tailings substitute, entirely due to an increase in surface utilising foraminiferans. However, taxa diversities decreased as the interstitial spaces became blocked. Finally, the microcosms were used to conduct bioassays of sediments and seawaters from the impacted sites. The sediments from the impacted sites proved to be toxic resulting in reduced meiofaunal densities and taxa diversities. Seawater samples did not prove to be significantly toxic. The use of microcosms has allowed the effects of the physical and chemical components of tailings to be assessed individually, which was not possible in the field. Additionally, it allowed a cause and effect relationship to be established between elevated concentrations of porewater copper observed in the field and the reduced densities and taxa diversities of the meiofaunal assemblages observed at the same sites.

Application of fly ash in the agglomeration of reactive mine tailings

Agglomeration is one of the most effective methods of dealing with reactive mine tailings in the prevention of acid mine drainage. The agglomeration process, accomplished with the use of a conventional binder such as Portland cement, immobilizes the reactive components of the mine tailings and results in the formation of strong pellets which remain impervious to weathering and leaching. The objective of this study was to evaluate the fly ash as a binder, either by itself or in combination with cement, in the mitigation of acid mine drainage caused by the reactive tailings. Two different acid mine tailings samples differing in their reactivities were chosen. These tailings were obtained from Noranda, Quebec, Canada and Cyprus Thompson Creek, Clayton, Idaho. The fly ash was obtained from Mineral Specialities Inc., Billings, Montana. Agglomeration tests were performed with fly ash and Portland cement. The crushing strength and the leachability of the cured agglomerates were evaluated. Preliminary results indicate that the use of fly ash significantly reduces the requirement of cement without any decrease in strength and immobilization effect. In fact, it was shown that the fly ash improved crushing strength of the agglomerates. This increase was substantial in the case of reactive tailings (Noranda). The leaching (simulated TCLP) tests performed on the Noranda Tailings agglomerates prepared using fly ash/cement resulted in the much lower level of extractable ions concentration and well below the regulatory level than from the agglomerates prepared using either fly ash or cement alone.

Leaching of 226Ra from components of uranium mill tailings

A sequential extraction procedure was used to characterize the geochemical forms of 226Ra retained by mixtures of quartz sand and a variety of fine-grained rock and mineral species. These mixtures had previously been exposed to the sulfuric acid milling liquor of a simulated acid-leach uranium milling circuit. For most test cases, the major fraction of the 226Ra was extracted with 1 mol/1 NH 4Cl and was deemed to be exchangeable. However, 226Ra retained by the barite-containing mixture was resistant to both 1 mol/1 NH 4Cl and 1 mol/HCHCl extraction.