Adsorption of guar gum and CMC on pyrite

The depression of pyrite in sulfide flotation by two types of polysaccharides, CMC and guar, was investigated using micro-flotation tests, zeta potential measurements and adsorption tests. Environmentally and from an occupational safety standpoint – this would be a better processing option than cyanide. The range of variables tested included molecular weight of guar, degree of substitution of CMC, pH and the concentration of calcium ions in the flotation process water. The guar gums depressed pyrite considerably even at low dosages. An optimum dosage of 10 ppm was recommended. The CMC’s were not as effective as the guar gums, and required much higher dosages to achieve pyrite depression. Within the range of CMC’s tested, lower degree of substitution was more effective than high degree of substitution. This was presumably due to lower electrostatic repulsion between the negatively charged CMC and pyrite. When calcium ions were introduced with CMC’s, the adsorption of the CMC was considerably enhanced. No such effect was observed for guar gums. Both CMC and guar gums demonstrated Langmuirian behavior in their adsorption isotherms. Two different adsorption mechanisms were displayed. The guar gum adsorption was attributed to hydrogen bonding and Bronsted acid–base interaction. The CMC was considered to occur through electrostatic interaction in the presence of calcium ions, and Bronsted acid–base interaction depending on pH.     

The effect of regrind mills on the separation of chalcopyrite from pyrite in cleaner flotation

Stirred mills have been widely used for regrinding and are more energy efficient than tumbling mills. These two types of mills present different particle breakage mechanisms and redox environments during grinding. In this study, the effect of regrinding with these two types of mills on the separation of chalcopyrite from pyrite in the cleaner stage was studied. A laboratory rod mill and a laboratory stirred mill were used to regrind rougher flotation concentrates. It was found that chalcopyrite and pyrite exhibited different flotation behavior after regrinding with the rod mill and the stirred mill, resulting in different separability of chalcopyrite from pyrite. The mechanism underpinning this phenomenon was investigated by a range of techniques including dissolved oxygen demand measurements, X-ray photoelectron spectroscopy (XPS) and Time of flight secondary ion mass spectrometry (ToF-SIMS). It was found that the two mills produced different surface oxidation and pyrite activation by copper ions which determined the separation of chalcopyrite from pyrite. This study demonstrates that the selection of a regrind mill should not only depend on its energy efficiency but also the property of surfaces produced for subsequent flotation.     

云浮低品位硫铁矿矿石的重选试验研究

对云浮低品位硫铁矿矿石进行重选试验研究,当原矿约含硫28%、粒度小于4 mm时,采用分级后粗粒跳汰-细粒螺旋选别的重选流程,可以得到最终硫精矿品位37.11%,硫回收率84.06%的选别指标,为低品位硫铁矿矿山的开发指出了一条新路子.     

The influence of pyrite content on the flotation of chalcopyrite/pyrite mixtures

In the flotation of copper ores, several processing plants report that copper recovery is affected by the proportion and reactivity of pyrite in the ore, with the effect becoming more intense when the feed particles are finer as a result of regrinding. In this work, a mixed model mineral system consisting of chalcopyrite (CuFeS₂) and pyrite (FeS₂) with varying pyrite content (20–80 wt.%) was used to investigate the effect of pyrite on the pulp chemistry and chalcopyrite recovery. Flotation tests showed that chalcopyrite flotation rate, recovery and grade, as well as the pulp oxidation potential, decreased with increasing pyrite content whilst pyrite recovery increased. Surface analysis (XPS, ToF-SIMS and EDTA) indicated that copper activation of pyrite increased with increasing pyrite content, facilitating pyrite recovery. The decrease in chalcopyrite recovery can be attributed to increased surface oxidation.     

不同结构羧甲基纤维素对绿泥石的抑制作用及机理

通过浮选、吸附量测试及动电位测量,研究不同结构的羧甲基纤维素对绿泥石浮选的影响,并考察其作用机理。结果表明,绿泥石具有一定的天然可浮性,羧甲基纤维素对绿泥石的浮选具有抑制作用,抑制效果随矿浆pH的升高而增大。羧甲基纤维素的结构对其抑制作用效果影响较大,羧甲基纤维素的取代度越低,分子量越高,对绿泥石的抑制效果越强。动电位测量及吸附量测试结果表明,在弱碱性pH条件下,绿泥石表面荷负电,羧甲基纤维素分子中的羧甲基也荷负电,二者之间存在阻碍羧甲基纤维素吸附的静电排斥作用,羧甲基纤维素取代度越低,分子量越大,在绿泥石表面吸附量越高,对绿泥石的抑制效果越强。     

细粒赤铁矿、石英和绿泥石选择性絮凝分选试验研究

某选厂弱磁选尾矿浓缩溢流的主要矿物为石英、绿泥石、赤铁矿,该尾矿粒度较细,-15μm近60%,TFe品位20.91%,本文以该矿样的化学分析结果为依据,对其主要的有用矿物赤铁矿,脉石矿物石英、绿泥石、进行纯矿物条件试验研究。通过对不同矿浆浓度、p H值、沉降时间、絮凝剂用量以及分散剂用量等一系列条件试验研究,获得单矿物絮凝分选的最佳条件为:矿浆浓度10%,p H值等于8,分散剂六偏磷酸钠用量60 g/t,絮凝剂聚合氯化铝铁用量7 mg/L,沉降时间10 s。在此基础上进行了人工混合矿物的絮凝分离试验。赤铁矿、石英、绿泥石混合矿样的配矿比为3∶5∶2,TFe品位21%,试验得到底流TFe品位49.16%,回收率82.57%,分选效率67.7%。     

The effect of heat treatment on the magnetic properties of pyrite

The effect of thermal treatment on the magnetic properties of pyrite was investigated. Untreated pyrite showed evidence of both paramagnetic and ferromagnetic components. After heat treatment, the saturation magnetisation increased considerably until 800 °C when the magnetisation decreased, and then increased again after 900 °C. These changes are due to phase changes induced by oxidation. The wet magnetic recovery of the untreated sample was 25%, which increased to over 90% after treatment at 500 °C. The recovery of the magnetic fraction plateaus after treatment at higher temperatures, implying that a sample magnetisation greater than 5 kA m⁻¹ leads to a recovery greater than 90% for this size fraction.     

The separation of chalcopyrite and chalcocite from pyrite in cleaner flotation after regrinding

In this study, the differences between the separation of chalcopyrite and chalcocite from pyrite in cleaner flotation after regrinding were investigated. In the rougher flotation prior to regrinding, high chalcopyrite and chalcocite recovery were obtained in conjunction with high pyrite flotation recovery due to the activation of pyrite by copper ions during primary grinding. The rougher flotation concentrate was reground in a rod mill before cleaner flotation. It was found that chalcopyrite and chalcocite exhibited different flotation behavior and also affected pyrite flotation differently in cleaner flotation. The mechanism underpinning these phenomena was investigated by a range of techniques including the polarization of mineral electrodes, X-ray photoelectron spectroscopy (XPS) analyses and ethylene diamine tetraacetic acid (EDTA) extraction. It was found that the flotation behavior of both copper minerals and their effect on pyrite flotation after regrinding were governed by their electrochemical activities and galvanic coupling with pyrite.     

蛇纹石对黄铁矿浮选的影响及机理

通过浮选实验、沉降实验、显微镜下观测、接触角测试和吸附量实验,研究蛇纹石对黄铁矿浮选的影响,并对其机理进行分析。结果表明：矿物粒度在蛇纹石与黄铁矿的浮选分离中起着重要作用,比黄铁矿粒度小的蛇纹石颗粒能够通过异相凝聚作用吸附在黄铁矿表面,改变黄铁矿的表面性质,影响黄铁矿的浮选。机理研究表明：蛇纹石表面是亲水的且不吸附捕收剂戊黄药(PAX)。蛇纹石吸附在黄铁矿表面,降低了黄铁矿表面疏水性和戊黄药在黄铁矿表面的吸附量,使黄铁矿浮选回收率降低。增加戊黄药在黄铁矿表面的吸附量能够一定程度上恢复被抑制黄铁矿的浮选回收率,但蛇纹石用量较高时,黄铁矿浮选回收率仍降低。因此,微细粒蛇纹石通过异相凝聚作用在黄铁矿表面附着,降低黄铁矿表面疏水性是蛇纹石影响黄铁矿浮选的主要原因。     

Application of complexing reagents to flotation separation of the varieties of pyrite

It is considered how the organic reagents, complexing agents, change floatability of the varieties of pyrite with different content of goal. The authors continue studying the flotation effect of the reagent PROX capable to selectively decrease floatability of some pyrite varieties in the presence of xanthogenate due to formation of a hydrophilic complex compound with ferric iron at the phase interface of the mineral surface — liquid, and to reduce sorption of xanthogenate. A phytogenous reagent is suggested as an alternative to the multi-component PROX. The new reagent mechanism is described by examining the chromatographic behavior of the compound of this reagent and ferric iron salt. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 4, pp. 111–120, July–August, 2007.     

The effect of temperature on the pulp and froth phases in the flotation of pyrite

The effect of temperature on the flotation of pyrite has been investigated. At temperatures below ambient an increase in temperature results in an increase in the rate of flotation of fast-floating particles but has a minimal effect on that for slow-floating particles. At temperatures greater than ambient the dominant effect of increasing temperature is to decrease the viscosity of the water thus increasing the rate of elutriation of the gangue back to the pulp. In general an increase in temperature resulted in an increase in the rate of pyrite recovery and the sulphur grades and a decrease in the water recovery and size of the bubbles in the pulp.     

干坝子洗选厂重介质旋流器选硫实践

干坝子洗选厂为利用磁铁矿粉实现从高密度煤矸石中选硫,分析了常用磁铁矿粉分类和技术要求。煤矸石中分选出黄铁矿需要更高且稳定的分选密度,一般控制在2.2~2.75 g/cm3。针对该段密度利用磁铁矿粉难以实现和控制的问题,从磁铁矿粉、磁选机精矿、重介质旋流器参数及合格介质桶内介质密度四方面进行合理的控制。干坝子洗选厂生产实践表明,利用磁铁矿粉实现高密度煤矸石选硫,不仅保证了从煤矸石分选出的沸腾煤和硫精砂的产品质量,而且提高了资源综合利用率。     

硫酸渣直接还原熔分制备珠铁

硫酸渣是一种富含铁的二次资源,如何高效利用硫酸渣中的铁资源,实现硫酸渣固废的资源化利用意义重大。基于直接还原熔分工艺,在实验室条件下采用无烟煤作还原剂,用消石灰调整渣相碱度,同时外加适量CaF_2助熔。选取内配碳比为1.2,在1250 ℃还原10 min后升至1500 ℃进行熔分。探索了熔分时间和碱度对硫酸渣含碳压块还原熔分最终效果及脱硫脱磷的影响。研究发现,熔分时间和碱度对最终硫酸渣含碳压块的还原熔分效果影响明显。在保证熔分时间的前提下,随着碱度的升高铁的金属化率先上升后下降。本次硫酸渣自还原试验表现出了较高的脱硫和脱磷能力。在R=2时,总脱硫率达到92.77%,总脱磷率随碱度变化规律与总脱硫率相似,平均总脱磷率达60%左右。这对直接采用煤基自还原含铁矿渣,并分离渣铁及同步脱硫脱磷,提供了一定的指导意义。     

The colouring effect of pyrrhotite and pyrite on micronised calcium carbonate slurries for the paper industry

Brightness (R457) is the main quality parameter in the production of ground calcium carbonate (GCC) slurries for the paper industry. In order to study how the presence of trace amounts of pyrrhotite (Fe_(1−x)S) and pyrite (FeS₂) affect the brightness of GCC slurries, experiments were performed in which a high quality calcite concentrate was spiked with these sulphides prior to micronisation and subsequent spectrophotometric measurements. The results show that even very small additions (<0.05 wt%) have a significant detrimental effect on the brightness of the product. Pyrrhotite reduces the brightness of the product more than pyrite, probably as an effect of differences in inherent optical reflectivity, specific surface area after micronisation and smearing. In addition, the experiment shows that when brightness is presented as a function of iron concentration, magnetite (Fe₃O₄) produces a different result compared to the sulphides. This indicates that a simple iron analysis is not sufficient to predict brightness of the GCC slurry when several iron-bearing minerals are present. The particle size distribution of the contaminant phase has proven to have a significant effect, as brightness is reduced when the contamination becomes more finely distributed.     

The effect of reagent addition strategy on the performance of coal flotation

The recovery and grade of concentrates obtained by flotation is partly dependent upon froth structure. The flotation froth structure can be modified, and hence the flotation performance modified, by the addition of reagents.A direct control system was developed which permitted pre-determined addition profiles of reagent and water to be added to a cell. A series of experiments were performed using different strategies of reagent (Triton x-405) addition for the flotation of Bickershaw coal.A transputer enhanced Micro-Vax Computer was employed to grab images of flotation froths and to process them quantitatively in a parallel procedure. Using image processing techniques characterization of froth structures was achieved. The image processing procedures that were intended to run on-line, were examined and developed using video tapes of experimental runs, off-line.An essential stage in the development of such a system is the understanding of the adsorption behaviour of the reagent in terms of the kinetics, the distribution of reagent between the solid and solution phases, and the resulting effect on the froth structure. A kinetic model was developed to describe the adsorption of the reagent on the particles. The experimental recoveries and froth structure were investigated in terms of reagent distribution and the froth structure.     

关于提高新兴选煤厂磁选机分选效果的探讨

本文针对新兴选煤厂磁选机分选效果差的问题,首先介绍了磁选机的结构及工作过程,然后分析了影响磁选机分选效果的各种因素,并提出了技术改造方案.最后进行了技术指标对比和经济效益分析,得出该技术改造方案可以为该厂每年节约洗选成本180万元.     

铜陵有色某矿山黄铁矿与磁黄铁矿分步回收试验研究

铜陵有色某矿山硫矿物以黄铁矿和磁黄铁矿为主,其中黄铁矿可浮性较好,磁黄铁矿可浮性相对较差,在浮选过程中容易氧化、掉槽,且磁黄铁矿与脉石矿物可浮性相近,采用浮选工艺很难获得高品质的硫精矿。根据黄铁矿和磁黄铁矿可浮性的差异、及其磁黄铁具有弱磁性的性质特点,采用分步浮选工艺,优先回收可浮性较好的黄铁矿,中矿以“强磁+浮选”工艺回收可浮性相对较差的磁黄铁矿,实现了对黄铁矿和磁黄铁矿的综合回收。闭路试验指标为：以黄铁矿为主的“硫精矿1”含硫47.78%、含铁43.83%,硫回收率为57.11%;以磁黄铁矿为主的“硫精矿2”含硫36.40%、含铁55.60%,硫回收率为22.12%;总硫精矿含硫43.94%、含铁47.80%,“全硫+铁”品位为91.74%,硫回收率为79.23%。总硫精矿经烧酸后,硫酸烧渣中铁品位在65%以上,附加值大大提高,具有广泛的经济效益和社会效益。     

聚丙烯酰胺对含富镁粘土的铁尾矿絮凝作用影响因素的研究

以鲁中冶金矿山公司选矿厂尾矿为研究对象，分别在去离子水和生产实际用水环境下研究了聚丙烯酰胺对该尾矿的絮凝作用规律，在不同因素条件下得出一些规律性认识。试验结果表明：实际用水中的几种离子对絮凝作用影响是不显著的，聚丙烯酰胺是该尾矿有效的絮凝剂。     

操作参数对煤的振动逆流干法分选效果的影响

介绍了振动逆流干法选煤技术的工作原理及试验系统,应用振动逆流干法分选机进行了煤的分选试验研究,分析讨论了分选床倾角参数、气流参数、激振参数、处理量参数4个主要操作参数对分选效果的影响,为该技术的进一步优化奠定基础.     

Surface study of the effect of sulphite ions on copper-activated pyrite pre-treated with xanthate

X-ray photoelectron spectroscopy and time of flight secondary ion mass spectrometry have been used to determine the specific effect of sulphite ions on the surface chemistry of copper-activated pyrite pre-treated with isobutyl xanthate in flotation experiments with nitrogen and air purging at pH 7. The results from these spectroscopic techniques illustrate that sulphite ions affect the surface chemistry of pyrite similarly whether nitrogen or air purged. It was found that sulphite ions interact with adsorbed collector species, as well as with the pyrite surface itself. A reduction in the adsorbed collector concentration and a commensurate increase in surface hydrophilicity explain the low flotation recovery of pyrite in the presence of sulphite. As expected, this effect was more pronounced in the flotation experiments with air purging.