超声波处理对煤泥特性的影响研究

为了提高煤泥浮选的效率和选择性，提出了在浮选前对煤泥进行超声波预处理的方法．利用扫描电镜、激光粒度仪和图像识别软件等研究了超声处理对煤泥特性的影响．比较了超声波处理前后相同粒级煤泥的产率、硫分、灰分和圆形系数，分析了超声波处理前后煤泥颗粒的表面状态，并用真空浮选试验进行了验证．浮选速度试验结果表明，超声处理后精煤的硫分、灰分较超声波处理前分别降低了33．84％和32．09％，前2min的精煤产率平均提高了约10％．试验证明超声处理改变了煤泥颗粒的大小、形状以及煤粒表面的状态，促使煤粒与黄铁矿、矸石解离，因此超声波预处理是煤泥浮选脱硫降灰的一种有效方法．     

Coal flotation using wash oil as a new type of collector

The use of wash oil as a coal collector is proposed to overcome the disadvantages of regular collectors in coal slime flotation. These disadvantages include high price, limited sources and high consumption. The effect of additives on flotation was studied and an innovative "one rough separation-one cleaning separation" flotation technology was developed. The experimental results show that the clean coal ash content decreases by about 1.36% and the clean coal yield declines by around 10% with the application of the depressant. There is an increase of 3.76% in the yield of clean coal and a decrease of 0.40% in the ash content caused by utilizing a dispersant. An ultimate product having an ash content of 10.78% and yield of 70.12% can be attained using a combination of dispersant and depressant. The use of this new technology decreases the ash content by 1.21%, decreases the yield by 2.80% and an increases the coal flotation perfect index by 2.03%. Compared to common flotation, the utilization of the new technology reduces ash by 0.17%, increases yield by 5.3% and increases perfect index by 4.18%.     

Coal petrology characteristics of middlings from Qianjiaying fat coal mine

The objective of this paper is to evaluate the coal petrology characteristics of slack middlings (13–0.5 mm) of dense media separation and flotation middlings from Qianjiaying fat coal preparation plant. Phase composition, macerals distribution, microlithotype and mineral occurrence of the two middlings were studied by XRD analysis and polarized light microscopy observation. Macerals distribution and wettability of the float-and-sink products separated from the middlings after grinding was investigated to determine the liberation degree. Studies show that there are more vitrinite and mineral, but less inertinite in slack middlings than in flotation middlings. Macerals associated with mineral in slack middlings is 69.85%, by volume, which is 17.86% higher than that in flotation middlings. Minerals in slack middlings are dominated by pyrite and clay, which are disseminated with the diameter less than 2 μm. The main mineral in flotation middlings is clay with size range of 2–20 μm. Single macerals in the slack middlings are difficult to liberate due to the fine-grained minerals. After grinding, macerals associated with minerals in the slack middlings decrease to 46.73%, by volume, which is higher than in flotation middlings by 25.89%, by volume. For slack middlings with poor liberation degree, density fractions below 1.8 g/cm³ is hydrophobic with contact angle above 71.5°. For the well liberated flotation middlings, there is significant wettability difference among the float-and-sink products. This research is the theoretical basis to realize re-separation of middlings.     

Research on Effect of Magnetized Pulp on Coal Slime Flotation

Effect of magnetization on oxygen concentration, pH, surface zeta potential, and wet heat of flotation pulp were researched. The result shows that magnetization treatment can improve the floatablility of coal and increase the difference in wet heat among coal, refuse, and pyrite, which is favorable for slime flotation and for removing sulfur and ash from coal.     

Study of Enhanced Fine Coal De-sulphurization and De-ashing by Ultrasonic Flotation

The feasibility of using ultrasound to enhance the performance of de-sulphurization and de-ashing during slime flotation was investigated. The Setararn C80 calorimeter, the contact angle gauge DCAT21 and an electrophoresis apparatus were used to study the surface nature of coal, pyrite and refuse before and after ultrasonic conditioning. The yield, ash and sulfur contents of equally sized coal slimes were also measured before and after ultrasonic conditioning. The results show that ultrasonic conditioning can drive the separation of pyrite and refuse from coal. After ultrasonic conditioning the hydrophobicity of coal and hydrophilicity of pyrite and refuse increase. The perfect index of flotation, the perfect index of de-sulphurization and the percentage of de-sulphurization increase by 22.51%, 25.36% and 2.49%, respectively. This study shows that ultrasonic conditioning can enhance the performance of de-sulphurization and de-ashing of coal flotation methods.     

Rheological behaviors of coal slime produced by filter-pressing

It is an effective way to use coal slime as fuel for circulating fluidized bed boilers, which will not only solve its pollution to the environment, but also turn waste to treasure. In order to provide basic technical information for transportation of coal slime from the coal preparation plant to the boiler, this paper experimentally studied the rheological behaviors of coal slime produced by filter-pressing. By using a rotational viscometer, the influences of water content, temperature, and shear time on the rheological behaviors of coal slime were investigated. Experimental results show that the coal slime will behave like Bingham plastics with low water content and like Bingham pseudo-plastics with 37.5% water content,while like pseudo-plastics with 40% water content. This indicates that the water content of coal slime must be controlled in consideration of both transportation resistance and combustion efficiency. Study results also show that, the apparent viscosity of coal slime at 5℃ is about 1.5–1.7 times of that at 40℃ for water contents 32%–37.5%, while the influence of temperature can be neglected when the water content is 40%. With increasing of water content, the influences of shear time on the apparent viscosity of coal slime becomes less. When the water content is more than 30%, the effect of shear time is negligible. It indicates that water content has the most important influence on the rheological behaviors of coal slime. There must be an optimal water content in considering conveying resistance and combustion efficiency. The environmental temperature must also be considered in coal slime transportation.     

磁西一号勘查区上煤组煤质特征及成煤环境

通过对磁西一号勘查区上煤组的研究,弄清了区内煤质特征及其变化规律:区内各煤层多为半暗型-半亮型煤,光亮型煤次之;煤的有机组分以镜质组为主,惰质组次之,壳质组含量很少,无机组分以粘土矿物为主;2号煤层原煤硫分,介于0.09%-1.54%之间,平均0.36%;4号煤层硫分介于0..98%-3.80%之间,平均2.50%,6号煤层硫分介于0.24%-4.18%之间,平均2.44%;区内各煤层原煤灰分产率较高,变化幅度亦较大,从低灰至高灰煤均有分布.通过分析硫分、灰分、煤岩组分与成煤环境之间的关系,得出了本区上煤组成煤环境为碳酸盐台地、障壁岛-泻湖和潮坪基础上发育的泥炭沼泽和三角洲平原发育的泥炭沼泽.     

药剂使用方式与浮选速度关系的探讨

药剂使用方式是浮选的重要工艺因素之一。文章通过对纯矿物、人工混合矿以及天然矿泥为研究对象介绍药剂品种、药剂组合、加药方式等因素对浮选速度的影响。试验结果表明这些因素改变之后,直接影响矿物的可浮性参数k及(-α),从而改变浮选速度系数K。在这几个研究对象当中,矿泥K值的变化不像纯矿物那样单纯,尤其低品位矿泥更为复杂.然而,找到合理的加药方式对于同一种同用量药剂时即能够最大限度地提高浮选速度,从而改善浮选指标。     

Synthesis of glycerine-xanthate and its depressing mechanism in separation of marmatite from arsenopyrite

A small molecular organic depressor glycerine-xanthate was synthesized. The effect of glycerine-xanthate on the flotation of sulfide minerals was investigated based on a function of pH value and concentration of glycerine-xanthate through flotation experiments in the presence and absence of Cu^2＋. The results show that glycerinee-xanthate has a strong dressing effect on marmatite at pH〉6 and on arsenopyrite in weak acid and base conditions with butyl-xanthate as collector. In the presence of glycerine -xanthate, marmatite is activated by addition of Cu^2＋, but arsenopyrite cannot be activated and remains unfloatable. So the selective separation can be achieved for two minerals. The depression of glycerine-xanthate on sulfide minerals was discussed based on the radical electronegative calculation and the theory of HSAB. Infrared spectrum shows that there are some -OH and-CSS-in glycedne-xanthate molecule, which competes with butyl-xanthate on the mineral surface. As a result of many hydrophilic groups in glycerine-xanthate, the surfaces of marmatite and arsenopyrite become hydrophilic, thus the flotation of marmatite and arsenopyrite is depressed. The collector is adsorbed preferentially on the surface of marmatite and it shows a better floatability in the presence of Cu^2＋, whereas, the surface of arsenopyrite absorbs glycerine-xanthate and the flotation of arsenopyrite is depressed by glycerine-xanthate.     

酸雨对河道淤泥气泡混合土工程性质的影响

通过渗滤法考察模拟酸雨对河道淤泥气泡混合土的侵蚀作用,试验过程中测定混合土试样的物理力学指标、渗滤液的pH值和Ca²⁺浓度值以及矿物组分受酸雨渗滤影响后的变化规律,研究考察酸雨对混合土性质的影响。试验结果表明：酸雨导致河道淤泥气泡混合土中的矿物水解并以Ca²⁺离子形式析出,导致混合土中性化。酸雨的酸性越强,土体中性化程度越高,在中性化过程中又有新的矿物生成,使混合土中矿物相对含量发生改变,导致混合土物理力学性质的变化;与正常雨水作用相比,经酸雨作用后的河道淤泥气泡混合土含水率和密度升高,强度降低,破坏模式向脆性化发展,并且酸雨的酸性越强,物理力学性质的变化越明显。     

Effect of the column height on the performance of liquid–solid fluidized bed for the separation of coarse slime

A liquid–solid fluidized bed separator, used for the separation of coarse slime, was developed. Test particles sized in the range from 0.25 to 0.5, 0.5 to 1.0, and 0.25 to 1.0 mm were separated in the liquid–solid fluidized bed. Beds with column heights of 1200, 1500, and 1800 mm were tried. The clean coal and the tailings were subsequently analyzed by float–sink testing. The results showed that the ash and yield of clean coal both decreased with increasing column height, for all three size fractions, and that the ash of the clean coal obtained from tests on the broader size fraction was less than that from the narrower sized fractions. The separation density decreased with increasing column height. The lowest E value was seen for a column height of 1500 mm, for which conditions the separation density was 1.45 g/cm³. The E value was 0.084 for the 0.25–0.5 mm fraction but the corresponding separation density was 1.48 g/cm³, and the E value 0.089, for the broader 0.25–1.0 mm fraction.     

Nanobubble generation and its applications in froth flotation (part Ⅱ):fundamental study and theoretical analysis

Froth flotation is a commonly employed technology to improve the quality of raw coal and minerals. Coal and minerals particle size and surface hydrophobicity are two main parameters that affect three key steps in froth flotation process: particle-bubble collision, adhesion, and detachment. This paper fundamentally investigated the effects of nanobubble on coal and phosphate flotation. It has been found that the presence of nanobubble in flotation pulp could widen the coal and phosphate flotation particle size range, increase the particle surface hydrophobicity, and thus improve the coal and phosphate froth flotation recovery.     

Nanobubble generation and its applications in froth flotation(part Ⅱ):fundamental study and theoretical analysis

Froth flotation is a commonly employed technology to improve the quality of raw coal and minerals.Coal and minerals particle size and surface hydrophobicity are two main parameters that affect three key steps in froth flotation process:particle-bubble collision,adhesion,and detachment.This paper fundamentally investigated the effects of nanobubble on coal and phosphate flotation.It has been found that the presence of nanobubble in flotation pulp could widen the coal and phosphate flotation particle size range,increase the particle surface hydrophobicity,and thus improve the coal and phosphate froth flotation recovery.     

极细粒煤泥分选新方法：选择性絮凝

采用选择性絮凝剂,对煤中可燃体与非可燃体进行分离,称为选择性絮 凝。笔者对大屯、八一、大武口等5个选煤厂和煤矿的极细粒煤泥进行了大量的 试验,证明该法可作为极细粒煤泥的分选方法,并具有较好的选择性。经分选, 一般精煤灰分为12-13％,最低为5.73％,可燃体回收率达90％以上,两产品 之间灰分差一般在50％左右,效果较好。因此,是一种较有前途的方法,可用 在分级浮选中,作为极细粒煤泥的分选方法。     

Mechanical property and microstructure of alkali-activated Yellow River sediment-coal slime ash composites

This work focuses on the production of a new composite material using Yellow River sediment and coal slime ash via alkali-activating method. XRD, FTIR and SEM/EDS were used to characterize the alkali-activated products and microstructure of the composite material. Compressive strength was tested to characterize the mechanical property of the composite material. It is found that the compressive strength of the Yellow River sediment-coal slime ash composites increases as the added Ca(OH)₂ content grows. The compressive strength increases fast in the early stage but slowly after 28 days. The strength of the composites can be significantly improved via the addition of small amount of NaOH and gypsum. The products (C-S-H, ettringite and CaCO₃), especially C-S-H, make much contribution to the enhancement of strength. The highest strength of the composites can reach 14.4 MPa after 90 days curing with 5% Ca(OH)₂, 0.2% NaOH and 7.5% gypsum. The improved properties of the composites show great potential of utilizing Yellow River sediment for inexpensive construction materials.     

TGA-DTA-DSC联用对秸秆与煤混烧灰化行为的研究

运用TGA-DTA-DSC联合技术研究了生物质与煤不同掺混比例下的燃烧特性、灰热解特性。通过对热重分析仪运行进行四段式设置,实现了安全燃烧和灰热解的连续进行。实验结果表明,秸秆与煤掺混后燃烧特性得到改善,并且在低于20％掺煤比时表现出脱灰效应,而40％掺煤比的混烧则表现出增灰效应;灰的高温热解过程随掺混比的变化规律分为两类,低掺混比混烧灰中无机物间的耦合反应加剧了脱灰效应,而掺煤40％的混烧灰中耦合反应加剧了增灰效应。这些反应与灰中含氯组分／CaS0。／CaCO。的质量分数有关。低掺煤比对混烧电厂解决积灰具有明显的优势,可指导生物质与煤掺混燃烧灰化行为的研究和灰问题的解决。     

Research on Mathematical Model of Fine Coal Flotation

通过大量试验,研究了浮选泡沫产品中细粒煤含量与水量关系,探讨了浮选过程中水流的机械夹带对细粒煤浮选的影响,考察了水浮选速率常数K     

长治盆地东南地区15~#煤中元素分布特征

通过对长治盆地东南地区15#煤层钻孔煤样进行显微煤岩组分分析、工业分析以及微量元素化样的分析统计,得出钍与氢氧化铝关系密切,主要存在于水铝石中;镓、铀的相对含量较高,与粘土矿物关系密切;二氧化硅与氧化铝呈现相似性变化,是组成粘土矿物的主要部分,也是构成灰份的主要成分;氧化铁与氟呈负相关性。     

长治盆地东南地区15#煤中元素分布特征

通过对长治盆地东南地区15#煤层钻孔煤样进行显微煤岩组分分析、工业分析以及微量元素化样的分析统计,得出钍与氢氧化铝关系密切,主要存在于水铝石中;镓、铀的相对含量较高,与粘土矿物关系密切;二氧化硅与氧化铝呈现相似性变化,是组成粘土矿物的主要部分,也是构成灰份的主要成分;氧化铁与氟呈负相关性。     

Occurrence mechanism of silicate and aluminosilicate minerals in Sarcheshmeh copper flotation concentrate

The Sarcheshmeh copper flotation circuit is producing 5×104 t copper concentrate per month with an averaging grade of 28% Cu in rougher,cleaner and recleaner stages.In recent years,with the increase in the open pit depth,the content of aluminosilicate minerals increased in plant feed and subsequently in flotation concentrate.It can motivate some problems,such as unwanted consumption of reagents,decreasing of the copper concentrate grade,increasing of Al2O3 and SiO2 in the copper concentrate,and needing a hi...