湿法炼锌含铁溶液水热矿化沉铁行为研究

在常规湿法炼锌过程中,采用黄钾铁矾法、针铁矿法除铁工艺时存在铁渣中铁质量分数低而锌质量分数高、渣量大、无害化处理成本高等难题,为此,本文开展湿法炼锌含铁溶液水热矿化沉铁行为研究。研究结果表明:升高反应温度有利于Fe3+水解生成赤铁矿(Fe2O3),同时促进铁矾物相(MFe3(SO4)2(OH)6)向赤铁矿的转化,铁渣中铁质量分数显著升高;延长反应时间可提高Fe3+沉淀率,并使更多的黄钾铁矾(KFe3(SO4)2(OH)6)转化为赤铁矿;提高氧分压将加快Fe2+氧化成Fe3+的速率,促进赤铁矿物相的形成。在反应温度为180℃,氧分压为0.8 MPa、反应时间为3 h且控制碱金属离子浓度的优化条件下,溶液中94.29%的铁以赤铁矿(Fe2O3)形式沉淀入渣,沉铁渣中铁质量分数为57.75%、锌质量分数为0.82%。对比黄钾铁矾工艺,铁渣量减少约60%,铁渣中锌质量分数降低6.5%。采用水热矿化沉铁工艺,可在低酸条件下实现溶液中铁的矿化沉淀,得到铁质量分数满足氧化铁行业标准且可实现资源化利用的赤铁矿沉铁渣,可助力湿法炼锌行业向绿色低碳方向发展。

Φ500—Φ400mmMS型沉降分级机的研制与应用

论述了该沉降分级机研制时对设备的要求,结构参数的确定与工作原理。经过对该机性能的试验,说明该机具有结构简单,性能优良,造价低廉等优点,适合在边磨边浸氰化一步提金工艺流程中应用。

Monitoring large-area mining subsidence by GNSS based on IGS stations

In order to monitor large-area mining subsidence accurately, a high-precision global navigation satellite system （GNSS） monitoring network was established based on the nearby international GNSS service （IGS） stations taken as reference points. Given the non-linear motions of IGS stations, the robust Kalman filtering （RKF） model was presented to determine the datum of multi-period monitoring network considering the velocity and weekly solution of IGS stations. The theory proposed was applied to monitoring mining subsidence in northern Anhui coal mine in China. According to the case study, the RKF model to establish monitoring datum is better than the prediction method and the weekly solution from IGS analysis centers （ACs）, and the corresponding precision of deformation can reach up to millimeter level with 4 h observation. The research provides an efficient and accurate approach for monitoring large-area mining subsidence.

Characteristics of gravity anomalies and prediction of volcanosedimentary boron deposit distribution in the Xiongba area,Tibet

Volcanosedimentary boron deposits are present within Tertiary lacustrine sediments and volcanic rocks in Xiongba, Tibet. Boron deposits are characterized by low density relative to country rocks; thus, it is possible to locate them by gravity measurements. We conducted a 1：50000 high-precision gravity survey in the Xiongba area, Tibet, and obtained the Bouguer and residual gravity anomalies. We analyzed fault systems and the distribution of sedimentary and volcanic rocks and their relation to the volcanosedimentary boron deposits. The processing of the gravity data revealed local gravity variations and fault structures. We applied preferential downward continuation and wavelet transform to the gravity data, and in conjunction with geological data, we predicted the distribution of volcanosedimentary boron deposits.

Negative effects of dissolved organic compounds on settling performance of goethite in Bayer red mud

Goethite, a typical iron-containing monomineral in red mud, was synthesized under the simulated Bayer digestion condition during the alumina production. The effects of dissolved organic compounds including sodium formate, sodium acetate, sodium oxalate, sodium salicylate and disodium phthalate on the settling performance of goethite slurries were studied. The settling performance of the slurries was also investigated with the addition of self-made hydroxamated polyacrylamide flocculant （HCPAM）. The adsorption mechanism of dissolved organic compounds on the goethite surfaces was studied by FT-IR and XPS, respectively. The results show that the addition of organic compounds lowers the settling performance of the slurries and a deterioration in settling performance is observed in the order of sodium oxalate 〉 sodium salicylate （~ disodium phthalate） 〉 sodium formate 〉 sodium acetate. Moreover, HCPAM can efficiently eliminate the negative effects of sodium formate, sodium acetate and sodium oxalate on the settling performance of the goethite slurries, but it can only partially improve the settling performance of the goethite slurries containing sodium salicylate or disodium phthalate. FT-IR and XPS results show that these organic compounds are chemically adsorbed on the goethite surface.

Relation between Atmospheric Deposition and Accumulation of Heavy Metals in Rice in Mining Areas of Guangxi

Firstly, the concept, sources and damage of atmospheric deposition were introduced, and then the relation between atmospheric deposition and accumulation of heavy metals in rice in Guangxi was analyzed to provide reference for the implementation of effective risk early warning of pollution from heavy metal deposition and safe production of rice in mining areas of Guangxi.

Recovery of iron from waste ferrous sulphate by co-precipitation and magnetic separation

Magnetite concentrate was recovered from ferrous sulphate by co-precipitation and magnetic separation. In co-precipitation process, the effects of reaction conditions on iron recovery were studied, and the optimal reaction parameters are proposed as follows： n（CaO）/n（Fe2＋） 1.4：1, reaction temperature 80 ℃, ferrous ion concentration 0.4 mol/L, and the final mole ratio of Fe3＋ to FJ＋ in the reaction solution 1.9-2.1. In magnetic separation process, the effects of milling time and magnetic induction intensity on iron recovery were investigated. Wet milling played an important part in breaking the encapsulated magnetic phases. The results showed that the mixed product was wet-milled for 20 min before magnetic separation, the grade and recovery rate of iron in magnetite concentrate were increased from 51.41% and 84.15% to 62.05% and 85.35%, respectively.

Time series ground subsidence inversion in mining area based on CRInSAR and PSInSAR integration

The subsidence of the mining area was monitored by analyzing the phase of permanent scatters （PS） which maintained high coherence in magnitude of SAR images.A hew method of spatial unwrapping was presented which used the subsidence rates calculated on comer reflector （CR） points as constraints for PS network to perform the spatial unwrapping using the parametric adjustment method.The algorithm achieved the integration of CR data and PSInSAR algorithm.The colliery dense distributed area around Baisha reservoir was chosen as the study area in the experiment.The time series of subsidence from February in 2007 to February in 2010 is successfully inversed by using the periodic function to simulate the linear and nonlinear components of the deformation.The simulation results show that the accuracy can be ± 2.1 mm with the leveling data being used as the external validation data.

Cemented backfilling technology with unclassified tailings based on vertical sand silo

A new technology characterized by rapidly non-mechanical settlement of unclassified tailings was developed based on a large number of tests, and dynamic settlement and continual slurry preparation without hardening in vertical sand silo were eventually realized by the addition of an effective flocculating agent (NPA). The results show that the sedimentation velocity of interface between unclassified tailings and water after the addition of NPA increases by 10-20 times, the sedimentation mass fraction of unclassified tailings at the bottom of vertical sand silo is up to 64%, the solid particle content of waste water meets the national standard, and the side influences of NPA can be removed by the addition of fly ash. The industrial test result shows that the system, the addition manner and the equipments are rational, and the vertical sand silo is used efficiently. This developed system is simple with large throughput, and the processing cost is 2.2 yuan(RMB)/m3, only 10%-20% of that by mechanical settlement.

A new approach to predicting mining induced surface subsidence

There are many parameters influencing mining induced surface subsidence. These parameters usually interact with one another and some of them have the characteristic of fuzziness. Current approaches to predicting the subsidence cannot take into account of such interactions and fuzziness. In order to overcome this disadvantage, many mining induced surface subsidence cases were accumulated, and an artificial neuro fuzzy inference system(ANFIS) was used to set up 4 ANFIS models to predict the rise angle, dip angle, center angle and the maximum subsidence, respectively. The fitting and generalization prediction capabilities of the models were tested. The test results show that the models have very good fitting and generalization prediction capabilities and the approach can be applied to predict the mining induced surface subsidence.

Ground subsidence induced by pillar deterioration in abandoned mine districts

When roadways are constructed above or adjacent to heavily mined regions, the ground subsidence caused by pillar collapse inflicts severe damage on these roadways. In this study, some surface subsidence events were first reviewed to present roof caving characteristics caused by pillar failure. The bearing characteristic and failure pattern of a single pillar with or without effect of discontinuity were further numerically simulated using distinct element code(3 DEC). It was found that the spalling of pillar or slippage of discontinuity would damage the bearing capacity of pillar during the failure process. The stress at the pillar core could be greater than uniaxial compressive strength of the pillar. However, when a discontinuity runs through a pillar, the slippage of discontinuity would significantly degrade the bearing capacity of the pillar. In pillar support system, if any pillar unexpectedly degrades or loses its bearing capacity, the load transferred from the degraded pillar acts on neighboring pillars, and the shear force also increases at relevant positions. However, the roof cutting and surface subsidence characteristics would perform in different patterns. In some cases, surface subsides slowly;in the worst scenario, shock bump may be induced by pillar and roof collapse.

Sedimentation behavior of indoor airborne microparticles

Experiments on the behavior of airborne microparticle sediments and their adhesion on glass slides were conducted in a laboratory located on the first floor of a teaching building. Clean tiles and glass slides were placed at different angles （0°, 45° and 90°） with respect to the horizontal plane in the laboratory. The sedimentation of microparticles was investigated at certain time intervals （1 d, 3 d, l0 d and 30 d）. The results of testing, at day 30, show that the diameters of particles on the horizontal tiles varied from 20 to 80 μm; few particles with diameter less than 0.5 μm or greater than 100 μm were found. The amount of particle sediment on all the slides increased along over time, while the average diameter of particles was not correlated with time, nor with the angle of placement. The maximum particle size, the total particle surface area, the total perimeter of all particles and the cover ratio of light （the proportion of total area of particles to the observed area of the slides surfaces） did not change significantly within the first 10 days. Inspection of all the samples for the last 20 days, however, showed that these variables increased substantially with the passage of time and were in reverse proportion to the placement angles, which indicates a concentration of particles, as well as physical and chemical changes.

Application of GPS technology to build a mine-subsidence observation station

We propose the design of an observation station to establish a reliable datum for displacement and deformation analysis at the first working-face subsidence observation station of Liuzhuang Mine. The design considers various geologic and mining con-ditions. Having analyzed the aims of the joint survey and the comprehensive survey, we propose design principles, and work modes, for adopting GPS technology as the position measuring technique to be used in these two stages. Baseline vectors and spatial ad-justments of the GPS network were calculated after study of data processing and quality estimation methods. A coordinate system transformation and error estimates of the transformed GPS network data are discussed. The error estimates in all stages show that the GPS control network of the observation station has sufficient accuracy and is highly efficient. The network thus provides a reli-able datum for analyzing the laws of surface displacement and deformation induced by mining.

Geological significance of nickeliferous minerals in the Fule Pb–Zn deposit, Yunnan Province, China

Abstract The Fule Pb-Zn deposit is located in the Sichuan-Yunnan-Guizhou Province, and it is an important and giant low temperature metallogenic domain in China. In our research area, the Pb-Zn deposits are mainly hosted in the Permian Yangxin Formation and are composed of dolostone and limestone. The distance between the ore bodies and the Permian Emeishan basalt ranged from 50 to 160 m. In this study, the nickel rich minerals, including vaesite, polydymite and millerite, were reported for the first time in the Fule deposit. These minerals occurred as xenomorphic mineral aggregate and were sporadically distributed in the sphalerite-galena-calcite vein, which is the main ore type in the deposit. Our study indicated that the paragenetic sequence of minerals in the Fule deposit is the following order： polydymite → vaesite → mil- lerite → sphalerite → galena → tetrahedrite （tennantite）. The geological occurrence characteristics of those nicke- liferous minerals suggested that the Permian Emeishan basalt is a possible barrier layer of Pb-Zn ore-forming fluid, and it is an important source for the Ni and part of the Cu in the deposit. The Sichuan-Yunnan-Guizhou Pb-Zn mineralization province is a world-class production base of Pb and Zn, in which the Permian Emeishan basalt and Pb- Zn deposits have uniformly spatial distribution, but the relationship of mineralization between them is still under debate. This report provides new evidence for understanding the relationship between Pb-Zn mineral- ization and Permian Emeishan basalt in the Sichuan- Yunnan-Guizhou Pb-Zn mineralization province.

Investigation and characterization of mining subsidence in Kaiyang Phosphorus Mine

In Kaiyang Phosphorus Mine, serious environmental and safety problems are caused by large scale mining activities in the past 40 years. These problems include mining subsidence, low recovery ratio, too much dead ore in pillars, and pollution of phosphorus gypsum. Mining subsidence falls into four categories: curved ground and mesa, ground cracks and collapse hole, spalling and eboulement, slope slide and creeping. Measures to treat the mining subsidence were put forward: finding out and managing abandoned stopes, optimizing mining method (cut and fill mining method), selecting proper backfilling materials (phosphogypsum mixtures), avoiding disorder mining operation, and treating highway slopes. These investigations and engineering treatment methods are believed to be able to contribute to the safety extraction of ore and sustainable development in Kaiyang Phosphorus Mine.

Quantitative prediction of mining subsidence and its impact on the environment

This study is focused on the prediction of mining subsidence and its impact on the environment in the Hongqi mining area. The study was carried out by means of a probability integral model based, in first instance based on field surveys and the analysis of data collected from this area. Isolines of mining sub- sidence were then drawn and the impact caused by mining subsidence on the environment was analyzed quantitatively by spatial analysis with Geographic Information System （GIS）. The results indicate that the subsidence area of the first working-mine can be as large as 2.54 km2, the maximum subsidence is 3440 mrn which will cause 1524 houses to be relocated. The entire subsidence area of the mine can reach 8.09 km2, with a maximum subsidence of 3590 ram. Under these circumstances the value of the loss of ecosystem services Will reach 5.371 million Yuan and the cost of relocating buildings will increase to 6.858 million Yuan.

Extracting mining subsidence land from remote sensing images based on domain knowledge

Extracting mining subsidence land from RS images is one of important research contents for environment monitoring in mining area. The accuracy of traditional extracting models based on spectral features is low. In order to extract subsidence land from RS images with high accuracy, some domain knowledge should be imported and new models should be proposed. This paper, in terms of the disadvantage of traditional extracting models, imports domain knowledge from practice and experience, converts semantic knowledge into digital information, and proposes a new model for the specific task. By selecting Luan mining area as study area, this new model is tested based on GIS and related knowledge. The result shows that the proposed method is more pre- cise than traditional methods and can satisfy the demands of land subsidence monitoring in mining area.

Study on relation between tectonic stress and coal-mining subsidence with similar material simulation

Using a minitype and stress-type test device for similar material simulation of coal-mining subsidence, the relation between tectonic stress and coal-mining subsidence was successfully simulated, furthermore, the test period of similar material simulation was obviously shortened and the test process was more dexterous and convenient. To do simi-lar material simulation with the minitype and stress-type test device was feasible and high-efficient. Bringing two models with the same geological and mining conditions to bear lateral compressive stress and tensile stress respectively and simulating the process of underground mining, the test results indicate that: under the compressive stress, the col-lapse of the coal roof occurs belatedly and the damaged range in cover of coal seam is smaller, therefore the movement and deformation of the cover and its damage to the ground geological environment are not evident; whereas under tensile stress, the situation is contrary to which mentioned above. A conclusion was obtained from the test that the ground environment hazards in coal mining areas were controlled by the regional geo-logical tectonic stress field.

Characteristics of the main polluting trace elements in the water environment of mining subsidence pools

Mining subsidence pools are water bodies formed by soil subsidence near mines. We studied the impact the surrounding coal production activities and power plants have on these waters by measuring the concentrations of harmful trace elements in these waters. The concentration of the four elements F, Hg, Se and As increased by 0.92%, 0.78%, 0.70% and 0.81%, respectively, in the Datong mining subsidence pool from November 2004 to November 2006. The four elements increased by 1.58%, 1.23%, 1.08% and 0.92%, respectively, in the Xie’er mining subsidence pool and 1.16%, 1.06%, 1.02% and 1.01%, respectively, in the Pansan mining subsidence pool over the same time period. The absolute levels of F, Hg, Se and As in the pool are related to the background levels of the elements. A close relationship between nearby coal mines and power plants and increasing levels of the measured elements is noted.

Trace element composition of magnetite from the Xinqiao Fe–S(–Cu–Au) deposit, Tongling, Eastern China: constraints on fluid evolution and ore genesis

The Xinqiao deposit is one of several polymetallic deposits in the Tongling ore district. There are two types of mineralization in the Xinqiao： skarn-type and stratiform-type. The skarn-type mineralization is characterized by iron oxides such as magnetite and hematite, whereas stratiform-type mineralization is characterized by massive sulfides with small amounts of magnetite and hematite. We defined three types of ores within the strati- form-type mineralization by the mineral assemblages and ore structures. Type Ⅰ ore is represented by magnetite crosscut by minor calcite veins. Type Ⅱ is a network ore composed of magnetite and crosscutting pyrite. Type Ⅲ is a massive ore containing calcite and hematite. Type Ⅰ magnetite is characterized by highly variable trace element content, whereas Type Ⅱ magnetite has consistently higher Si, Ti, V, and Nb. Type Ⅲ magnetite contains more In, Sn, and As than the other two types. Fluid-rock interaction, oxygen fugacity （fO2）, and temperature （T） are the main factors controlling element variation between the different magnetite types. Type I magnetite was formed by more extensive fluid-rock interaction than the other two types at moderate fO2 and T conditions. Type Ⅱ magnetite is thought to have formed in relatively low fO2 and high-Tenvironments, and Type Ⅲ in relatively high fOe and moderate-T environments. Ca ＋ Al ＋ Mn and Ti ＋ V discrimination diagrams show that magnetite in the Xin qiao deposit is hydrothermal in origin and is possibly linked with skarn.