水中Ca2+和Mg2+对镜铁矿和绿泥石可浮性的影响机理

为研究水质对镜铁矿和绿泥石分离效果的影响,通过单矿物浮选实验、Zeta电位测量、玻尔兹曼理论分析、溶液化学计算和分子动力学模拟,分别在去离子水和自来水浮选环境中,研究了十二胺(DDA)体系中镜铁矿和绿泥石的浮选行为及Ca2+, Mg2+对镜铁矿和绿泥石浮选规律及作用机理。结果表明,自来水对镜铁矿和绿泥石有一定的抑制作用,与去离子水浮选环境相比,镜铁矿和绿泥石的回收率分别下降了8.01和8.99个百分点;模拟自来水环境中,Ca2+, Mg2+使镜铁矿回收率分别下降11.91和18.88个百分点,绿泥石回收率分别降低7.44和15.45个百分点。自来水浮选环境中镜铁矿和绿泥石可浮性降低主要由于自来水中Ca2+, Mg2+的抑制作用。Ca2+, Mg2+对镜铁矿的抑制作用比绿泥石强,且Mg2+的抑制效果比Ca2+明显。机理检测结果表明,Ca2+, Mg2+吸附使镜铁矿和绿泥石表面电位升高,减弱了DDA与矿物之间的静电吸附作用,促使镜铁矿和绿泥石接触角减小亲水性增大、界面层内RNH3+浓度降低,使DDA与镜铁矿和绿泥石的吸附间距增大,且DDA分子分布松散度增大,一定程度上抑制了镜铁矿和绿泥石的上浮。     

旋流微泡浮选柱在涡北选煤厂的应用

分析了涡北选煤厂煤泥粒度组成,发现煤样矸石存在泥化现象,高灰细泥含量较高,对浮选不利。进行了浮选机的单因素浮选试验、两因素三水平正交试验以及最优药剂条件下的分步释放试验,同时进行了浮选柱的煤泥浮选试验。结果表明,当煤泥矿浆质量浓度为45 g/L,复合药剂为1.10 kg/t时,精煤灰分为10.97%,精煤产率为72.62%,浮选完善指标最高为53.43%,浮选机煤泥浮选效果最好;浮选柱可以分选出各种质量的精煤,精煤灰分可调性大,可以适应市场变化。最后进行了浮选机和浮选柱的综合对比试验,在精煤灰分相近的情况下,浮选柱不同程度地提高了精煤回收率和浮选完善指标,具有明显优势。     

煤用复合药剂浮选效果研究

以七台河桃山煤泥和新建煤泥为例,研究了药剂配比、加药方式、表面活性剂对煤泥浮选的影响,重点研究了KJ复合药剂的煤泥浮选效果.研究证明,KJ复合药剂是一种良好的煤用浮选药剂.     

煤泥浮选中用药合理性的探讨

在分析影响煤泥浮选剂用量的诸多工艺因素的基础上,探讨了为降低浮选剂用量的工艺途径,提出了煤泥浮选剂用量的理论指标。     

新型起泡剂对望峰岗选煤厂煤样的实验研究

浮选药剂能扩大煤和其他矿物质的表面差异,从而改善和强化煤泥浮选过程。浮选药剂的种类和用量对浮选效果起着极其重要的作用。以望峰岗选煤厂煤泥为研究对象,选用1号、2号2种新型起泡剂对其进行单元浮选实验,经过不同实验研究,对比考察了其浮选效果,从而证明了新型浮选药剂提高精煤产率、降低精煤灰分的优良性能。     

提高煤泥浮选捕收剂性能的试验研究

针对煤泥浮选捕收剂分散难、选择性差、用量大等问题,利用不同化工产品及表面活性剂,将煤油制备成复合捕收剂用于煤泥浮选。分别进行了煤油、复合捕收剂的优选试验及浮选速度试验。优选试验表明:当煤油用量为900 g/t,仲辛醇用量为450 g/t时,煤油浮选效果最佳;当Fy-4复合捕收剂用量为500 g/t,仲辛醇用量为450 g/t时,精煤灰分为9.96%,精煤产率为88.72%,可燃体回收率为94.82%,在精煤灰分相近的条件下,Fy-4复合捕收剂的用量比煤油降低了44.44%,精煤产率和可燃体回收率分别提高了0.06%和0.16%。浮选速度试验表明:Fy-4复合捕收剂不仅节省了药剂用量,而且提高了煤泥浮选活性,提升了精煤浮选速度。最后探讨了无机电解质NaCl对复合捕收剂浮选效果的影响,当NaCl浓度为0.05 mol/L时,煤泥颗粒Zeta电位更趋近零电点,降低了煤泥颗粒的相对接触角,改善了煤泥浮选效果。     

气浮法实现选煤厂煤泥水闭路循环的试验研究

笔者对气浮法和沉淀法处理煤泥水作循环水的效果进行了比较。从试验所得的数据来看,用气浮法处理煤泥水作循环用水的方法是可行的,气浮法在回收煤泥方面要明显优于沉淀法,特别是当煤泥水浓度较高或较低时,但如果煤泥水要达标排放,则还需进一步处理。     

煤泥浮选药剂的优化研究

望峰岗选煤厂煤泥浮选系统存在浮选精煤灰分高、药剂消耗量高的问题;通过采用4种典型的国内外浮选药剂进行一系列的单元浮选试验及分步释放试验,确定了适合于望峰岗选煤厂煤泥浮选的最佳药剂种类和用量。     

碳酸钠在云南胶磷矿正浮选中的作用效果探索

碳酸钠作为一种无机调整荆,在胶磷矿选矿中被广泛用作pH调整剂、脉石细泥分散剂、活化剂等.本文对云南胶磷矿进行了加与不加碳酸钠对比试验,结果表明:在相同的刮泡时间内,加碳酸钠浮选流程的精矿产事为81.04%、累积回收率为90.97%,而不加碳酸钠的两次纯水玻璃浮选工艺漉程试硷的精矿产率分别为70.49%和74.28%、累积回收率分别为80.07%和74.85%,说明碳酸钠在胶磷矿正浮选中的活化作用非常明显.     

Some aspects of the electrochemistry of the flotation of pyrrhotite

The iron sulfide mineral, pyrrhotite (Fe_(1–x)S), has long been known to be more difficult to recover by flotation from alkaline slurries than many other base metal sulfide minerals. This paper summarizes the results of an electrochemical study of the surface reactions that occur during the flotation of nickeliferous pyrrhotite in the recovery of nickel and the platinum group metals. Mixed potential measurements conducted with natural pyrrhotite electrodes in various stages of an operating flotation plant showed that the mineral potential is positive to the equilibrium potential of the xanthate/dixanthogen couple. Similar results were obtained during batch flotation experiments and in synthetic solutions in the laboratory. Cyclic voltammetric and potentiostatic current/time transient experiments were used to investigate the oxidation of pyrrhotite under various conditions. In addition, the reduction of oxygen, the reaction of copper ions and the oxidation of xanthate ions at the mineral surface were investigated. The formation of dixanthogen on pyrrhotite surfaces is thermodynamically favourable in plant flotation slurries. However the interaction with xanthate at pH values above 7 is inhibited by a surface species formed during the conditioning prior to xanthate addition. In acidic solutions copper ions react readily with pyrrhotite to form a species, possibly CuS that can be oxidized at potentials above 0.4 V. At pH 9 this species does not form and there is no electrochemical reaction between pyrrhotite and copper ions. The beneficial effects of copper ions to flotation performance appear to be related to an enhancement of the oxidation of xanthate.     

FJC20-4A喷射式浮选机在望峰岗选煤厂的应用

通过对煤泥粒度组成及原煤小浮沉试验的研究可知,望峰岗选煤厂入选原煤属难选煤,浮选入料煤泥为极难浮煤。针对KHD浮选机存在的操作复杂,微泡析出量不足,浮选药剂用量大等问题,分析了FJC20-4A喷射式浮选机的工作原理及主要特点,并对两者的应用效果进行了对比。结果表明:与KHD浮选机相比,FJC20-4A型浮选机浮选精煤产率、尾煤灰分、可燃体回收率、浮选完善指标及浮选数量效率分别提高了22.04%、43.83%、26.51%、23.07%和18.08%,浮选抽出率增加了63.64%左右,浮选药剂消耗量降低了0.03 kg/t。最后对选煤厂效益进行了分析,说明FJC20-4A浮选机的应用使选煤厂生产工艺更加灵活,降低了工人的劳动强度和作业难度,增加了浮选剂的使用效率,选煤厂实际增加经济效益7219.96万元/a。     

Zn2+存在体系中菱锌矿与石英浮选分离的研究

以油酸钠为捕收剂,通过单矿物浮选试验、ξ-电位测试、吸附量测定及溶液化学分析,研究了水玻璃与六偏磷酸钠对Zn2+存在体系中菱锌矿与石英浮选分离的影响,并对其机理进行了讨论.结果表明,难免离子Zn2+对石英的活化是二者不能分离的主要原因.在矿浆中优先加入水玻璃,无法使二者有效分离;六偏磷酸钠的加入,可以明显减弱捕收剂在石英表面的吸附,使其可浮性显著下降,增大与菱锌矿的可浮性差异,从而实现菱锌矿与石英的分离.     

分级浓缩浮选工艺探讨

针对选煤厂目前使用的浮选工艺分选精度低、高灰细泥污染严重的问题,提出了分级浓缩浮选工艺;采用分级旋流器组将煤泥分级,粗颗粒用浮选机分选,细颗粒经浓缩后用浮选柱浮选;提高了煤泥的浮选精度和精煤产率,增加了企业经济效益。     

煤泥超声浮选的试验研究

超声处理对煤泥浮选的影响是多方面的.笔者对煤泥超声处理前后浮选的精煤产率、浮选脱硫效果、浮选速度等方面进行了试验研究.试验结果表明,在相同药剂制度情况下,经过超声处理浮选的精煤产率提高了10%以上;浮选脱硫完善度提高了20%;浮选速度也较超声处理前有了明显的提高.     

“2+2”模式重介质选煤系统煤泥及煤泥水处理首创工艺技术

"2+2"模式重介质选煤系统煤泥两级浮选、精煤泥两段脱水、尾煤泥水两段浓缩两段回收首创工艺技术,在多座选煤厂的应用结果表明,该工艺可解决我国炼焦煤选煤厂长期存在的以浮选精煤为主的精煤泥灰分、水分偏高的难题,可实现煤泥全部厂内回收、洗水闭路循环。     

小型选煤厂的煤泥处理方式

随着煤炭及焦炭市场竞争的加剧,小型选煤厂要取得更好的经济效益,必须对煤泥进行分选处理;灰分较低的粗煤泥宜选用沉淀槽,反之则选用螺旋分选机,细煤泥处理设备有浮选旋流器、圆形离心浮选机和浮选柱,应根据条件选择;煤泥产品的脱水可采用筛分设备加沉淀池工艺。     

华恒选煤厂煤泥浮选的可行性研究

针对华恒选煤厂选煤方式单一、煤泥回收困难等问题,通过筛分试验、标准分步释放试验和煤泥浮选试验验证煤泥浮选的可行性。结果表明:煤泥中+0.5 mm产率较低,为0.18%,-0.25 mm产率为99.23%,符合煤泥浮选入料粒度要求;轻柴油和GF质量比9∶1,药剂用量为1000 g/t时,煤泥浮选效果最好,此时精煤产率为46.28%,精煤灰分为11.76%,可燃体回收率最高为73.99%,煤泥浮选可行。结合选煤厂实际情况分析了煤泥浮选的必要性,预测了增设煤泥浮选的经济效益,说明增设煤泥浮选系统在施工空间和工艺布置方面完全可行,增设煤泥浮选系统可优化选煤工艺,适应市场变化。浮选精煤可与精煤掺配销售,保持精煤水分稳定,减少因水分损失带来的亏吨现象,减少煤泥积压,缓解企业压力,增加销售收入1530.9万元/a。     

浮选柱与浮选机分选煤泥的对比试验研究

通过浮选柱和浮选机对不同煤泥的浮选试验，分析比较了２种浮选方法在分选煤泥时的各自优缺点，证实了浮选柱在浮选细粒细煤泥时具有良好的发选效果；并通过试验，给出了各自最佳的浮选粒度范围。     

Mechanism of Selective Flotation of Sodium-Calcium Borates with Anionic and Cationic Collectors

Abstract

The major boron minerals, colemanite and ulexite, are frequently found together in boron deposits. Similarities in their chemical compositions create problems in the selective flotation of these minerals. The surface properties of the above boron minerals have been determined by solubility, microflotation, and zeta potential measurements using typical anionic and cationic surfactants. The isoelectric point (iep) of colemanite is 10.5, while ulexite exhibits no iep in a practical pH. Anionic surfactants thus easily float colemanite but fail to float ulexite at a natural pH. This knowledge is used to find the optimum conditions for the selective separation of colemanite from ulexite at a natural pH of 9.3. Cationic surfactants work well but are adversely affected by the presence of clay-type minerals in the boron ore which hinder the floatability of borates by the formation of a slime coating. The mechanism of slime coating onto boron minerals is also elucidated.     

A simple model for the calculation of entrainment in flotation

Theoretical and experimental studies have been performed to analyze the entrainment of both hydrophilic and hydrophobic particles in flotation. A new model is proposed for the entrainment based on the water recovery trend. Two sets of timed flotation experiments were carried out to validate the model. These experiments were realized with quartz and pyrite as the only mineral in the pulp and with various frother concentrations and pulp densities. The chemical conditions of the pulp were adjusted to float pyrite as hydrophobic and to depress quartz as hydrophilic mineral. The solids recovery for each size fraction and water recovery was measured in these experiments. The proposed empirical model equation was checked against experimental observations. It was observed that the model equation well represented the entrainment-water relationship. Since hydrophilic mineral recovery mainly depends on the entrainment, the data obtained from quartz only tests were first fitted to the entrainment equation. The fit for quartz data was found to be satisfactory. This shows that the proposed model could be used to define the behavior of hydrophilic particles in a batch flotation test. The same model was applied for pyrite only tests and contribution of entrainment to hydrophobic mineral recovery was calculated. The results provided accurate interpretation of hydrophobic mineral entrainment, which is difficult to directly measure.