霍林河14~#煤中微量元素的分布赋存特征研究

运用反射偏光显微镜和扫描电镜等手段研究霍林河14#煤中矿物分布特征,运用浮沉实验和煤岩组分定量统计方法研究了煤中6种微量元素的分布赋存特征以及有机亲和性.结果表明,霍林河14#煤中矿物含量较高,以伊利石黏土矿物为主;霍林河煤中微量元素As,Cr和Hg含量较高,Pb,Cd和Se含量较低;元素As,Cr,Hg和Pb明显富集于矿物中,主要为无机态,与有机组分亲和性较低,而元素Cd和Se与有机组分亲和程度比其他4种元素高,基本上均匀分布于有机组分和矿物中.     

大同侏罗纪10-11#煤中微量元素分布赋存特征

讨论了大同 1 0 - 1 1 #煤中 36种微量元素的含量分布 ,通过浮沉试验及煤岩组分定量统计 ,运用 Salori方法 ,计算了 1 4种有害微量元素在大同煤不同煤岩组分中的分布 ,进而分析了其赋存状态及其在煤炭洗选过程中的脱除潜力 .结果表明 ,大同煤中大部分微量元素含量较低 ,但As,Hg,Cr,Sb等元素的有机组分含量偏高 ;大部分微量元素主要分布于矿物中 ,而 B,Be,Cd,Co,Ni和 Sb等有害元素含量偏高 ;同时 ,相对而言 ,As,B,Ba,Cd,Co,Cr,Mn和 Ni等元素在镜质组中含量较高 ,而 Be,Li,Pb和 Sb等元素在丝质组中含量较高 .浮沉试验表明 ,微量元素在煤炭洗选过程中的迁移、脱除行为主要受其赋存特征影响     

乌鲁木齐市商品燃煤中汞等有害微量元素含量及分布特征

对乌鲁木齐市13个煤矿、22个用煤单位商品燃煤中Hg、As、Pb、Co、Zn、Ni、Cd、Cu和Cr含量,相关性及区域分布特征进行了研究。结果表明,各元素含量均在中国煤各元素含量范围内,Cu和Cr含量算术平均值略高于中国煤中算术平均值,其他微量元素含量算术平均值低于中国煤中算术平均值;各元素含量之间无高度相关,两组元素含量之间显示中度正相关,6组元素含量之间显示低度正相关;南部煤矿Hg和As算术平均值明显高于其他区域,西部煤矿Cd算术平均值明显低于其他区域,各区域各元素含量范围多数差异较大,未显示出区域一致性。     

微波消解-ICP-AES/ICP-MS测定南果梨中微量元素

采用HNO3和H2O2的混合溶剂作为消解液微波消解南果梨样品,电感耦合等离子体发射光谱法(ICP-AES)和电感耦合等离子体质谱法(ICP-MS)测定了南果梨中14种有益、有害微量元素Ca、Fe、K、Mg、P、Cu、B、Mn、Zn、Mo、Cr、Pb、Cd、As的含量.各元素标准曲线相关系数均大于0.999 3,标准偏差...     

层栽红托竹荪重金属污染特征

通过添加不同剂量活性炭改良剂进行红托竹荪层架栽培试验,分析改良剂使用后红托竹荪土壤和竹荪不同组织部位中Pb、Cd、Cr、Hg、As的含量,判断竹荪种植土壤的污染状况和竹荪不同组织部位富集Pb、Cd、Cr、Hg、As能力大小与改良剂之间的关系。结果表明:基质土壤元素含量差异明显分别为Pb:27.48～51.65 mg/kg,Cd:0.28～0.56 mg/kg,Cr:94.37～126.19 mg/kg,Hg:0.05～0.14 mg/kg,As:13.43～22.18 mg/kg,Cr和As的超标现象较严重在土壤中的累积特征显著。研究区基质土壤中Pb、Cd、Cr、Hg、As的Eir和RI均属于轻微水平,潜在风险较小。红托竹荪对Cd的富集能力最强,需要引起重视。     

动态反应池电感耦合等离子体质谱法同时测定烟用香精香料中的微量元素

采用微波消解电感耦合等离子体质谱法同时测定烟用香精香料中的Cr、Ni、Cu、Ge、As、Se、Sr、Nb、Mo、Cd、Hg、Cs、Tl和Pb的含量。以钇(Y)和钍(Th)作为内标来补偿基体效应,采用动态反应池技术消除Cr、Ni、Se质谱干扰,采用茶叶标准物质对方法进行验证。结果表明,相对标准偏差均小于10%,回收率为84.9%～110.3%,检出限为0.002～0.854μg/L。该方法操作简单、分析速度快、灵敏度高、准确度好,适用快速、准确测定烟用香精香料中微量元素。     

煤中微量元素在煤制甲醇工业装置中的迁移规律分析

煤中微量元素在煤的燃烧和气化过程中会发生复杂的物理和化学变化,研究了煤中微量元素在煤制甲醇工业装置中的迁移规律。结果显示:粗合成气中F和Cl元素极易被洗涤下来,溶解进入水相,As、Hg、Pb、Cd等元素基本不会被洗涤进入灰水中,也基本不会被净化工段甲醇溶液吸收而累积,其一部分随气化灰渣进入固相、一部分被变换催化剂和甲醇合成保护床触媒吸收,另外透过净化工段的部分微量元素中,绝大多数会在甲醇合成反应过程中与甲醇合成催化剂的活性成分(如Cu、Zn、Cr等)结合,被固定、积累在装置内,微量的重金属元素随净化单元硫化氢酸性气体带入制酸装置,进入浓硫酸产品中。     

煤炭洗选脱除煤中有害微量元素的实验研究

利用浮沉试验研究了通过煤炭洗选技术脱除煤中有害微量元素的可能性。结果表明,煤中有害微量元素在选煤过程中的行为取决于其有机亲和性。大多数煤中As、Cr、Hg、Mn、Ga、Ta、Ti、W、Cs等元素均可得到较高的理论脱除率,而B、Mo、Y等元素理论脱除率在各种煤中均较低。Be、Se、Pb等元素理论脱除率在不同煤中变化幅度较大,主要是由于其在不同煤中赋存状态不同而造成的。     

微波消解-电感耦合等离子体质谱法测定藏茵陈中的微量元素

采用ICP-MS法测定了青海产藏茵陈中As、Pb、Cd、Hg、Cr和Cu 6种微量元素的含量,运用碰撞/反应池技术消除了Cr、As和Cu在样品中存在的潜在干扰.方法检出限为0.010 ～0.044 ng/mL,精密度为3.2％ ～6.6％,加标回收介于90％ ～ 110％之间.     

印刷纸质食品包装材料中Pb、Cd、Cr及Hg含量的测定及其来源分析

利用电感耦合等离子体-质谱法(ICP-MS)对从国内不同纸质食品包装材料供应商收集到的13种印刷纸质食品包装材料以及3种相对应未印刷纸样中重金属——铅(Pb)、镉(Cd)、铬(Cr)以及汞(Hg)的含量进行了分析,其中Pb2.045～5880.261μg.L-1,Cd0.124～5.945μg.L-1,Cr2.464～1430.863μg.L-1,Hg0.170～11.378μg.L-1。对结果进行分析发现,Pb与Cr的含量明显高于Cd与Hg的含量,并且与未印刷过的样品相比,印刷过的样品中,各种重金属的含量均较高,并且纸张表面处理所用的石蜡以及造纸填料中,在理论上不含有重金属,所以认为其主要来源为印刷油墨。为了进一步确定,同时对印刷用四色油墨——黄(Y)、品(M)、青(C)与黑(K)进行了分析,结果发现,各种油墨中都含有一定量的Pb、Cr以及Hg,而不含有(低于检测限)或含有很少量的Cd。从而可以认为印刷过的纸质食品包装材料中的Pb、Cr以及Hg主要来自于印刷油墨,而Cd则有可能主要来源于造纸原料、造纸设备以及用水等。     

Distribution of potentially hazardous trace elements in coals from Shanxi province, China

Shanxi province, located in the center of China, is the biggest coal base of China. There are five coal-forming periods in Shanxi province: Late Carboniferous (Taiyuan Formation), Early Permian (Shanxi Formation), Middle Jurassic (Datong Formation), Tertiary (Taxigou Formation), and Quaternary. Hundred and ten coal samples and a peat sample from Shanxi province were collected and the contents of 20 potentially hazardous trace elements (PHTEs) (As, B, Ba, Cd, Cl, Co, Cr, Cu, F, Hg, Mn, Mo, Ni, Pb, Sb, Se, Th, U, V and Zn) in these samples were determined by instrumental neutron activation analysis, atomic absorption spectrometry, cold-vapor atomic absorption spectrometry, ion chromatography spectrometry, and wet chemical analysis. The result shows that the brown coals are enriched in As, Ba, Cd, Cr, Cu, F and Zn compared with the bituminous coals and anthracite, whereas the bituminous coals are enriched in B, Cl, Hg, and the anthracite is enriched in Cl, Hg, U and V. A comparison with world averages and crustal abundances (Clarke values) shows that the Quaternary peat is highly enriched in As and Mo, Tertiary brown coals are highly enriched in Cd, Middle Jurassic coals, Early Permian coals and Late Carboniferous coals are enriched in Hg. According to the coal ranks, the bituminous coals are highly enriched in Hg, whereas Cd, F and Th show low enrichments, and the anthracite is also highly enriched in Hg and low enrichment in Th. The concentrations of Cd, F, Hg and Th in Shanxi coals are more than world arithmetic means of concentrations for the corresponding elements. Comparing with the United States coals, Shanxi coals show higher concentrations of Cd, Hg, Pb, Se and Th. Most of Shanxi coals contain lower concentrations of PHTEs.     

西部煤中环境敏感性痕量元素的燃烧迁移行为

应用仪器中子活化( INAA)、电感耦合等离子体原子发射光谱( ICP- AES)和原子吸收光谱( AAS)对我国西北部五个电厂原煤、底灰和飞灰中环境敏感性痕量元素的含量进行了系统测定,通过不同电厂原煤与燃烧产物中痕量元素的含量变化特征,揭示了痕量元素在不同燃烧产物中的相对富集规律.以痕量元素在不同燃烧产物中的相对富集系数为评价标准,建立了燃烧产物中痕量元素的分配模型.结合痕量元素的原始赋存状态,总结了痕量元素燃烧的迁移富集机理和环境效应.     

Volatility and chemistry of trace elements in a coal combustor

The volatility of 16 trace elements (TEs) (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se, Sn, Te, Tl, V, Zn) during coal combustion has been studied depending on the combustion conditions (reducing or oxidizing) and type of coal (high- or low-ash coal), together with their affinities for several active gaseous atoms: Cl, F, H, O, and S.

The elements can be divided into three groups according to their tendencies to appear either in the flue gases or in the fly ashes from a coal combustor:

Group 1: Hg and Tl, which are volatile and emitted almost totally in the vapor phase.

Group 2: As, Cd, Cu, Pb and Zn, which are vaporized at intermediate temperature and are emitted mostly in fly ashes.

Group 3: Co, Cr, Mn and V, which are hardly vaporized and so are equally distributed between bottom ashes and fly ashes. In addition, Sb, Sn, Se and Te may be located between Groups 1 and 2, and Ni between 2 and 3.

At 400 and 1200 K, the 16 TEs behave differently in competitive reactions with Cl, F, H, O and S in a coal combustor.     

Partitioning of elements in a entrained flow IGCC plant: Influence of selected operational conditions

The partitioning of trace elements and the influence of the feed conditions (50:50 coal/pet-coke feed blend and limestone addition) was investigated in this study. To this end feed fuel, fly ash and slag samples were collected under different operational conditions at the 335 MW Puertollano IGCC power plant (Spain) and subsequently analysed. The partitioning of elements in this IGCC plant may be summarised as follows: (a) high volatile elements (70->99% in gas phase): Hg, Br, I, Cl and S; (b) moderately volatile elements (up to 40% in gas phase and ?60% in fly ash): As, Sb, Se, B, F, Cd, Tl, Zn and Sn; (c) elements with high condensation potential: (>90% in fly ash): Pb, Ge, Ga and Bi; (d) elements enriched similarly in fly ash and slag 30-60% in fly ash: Cu, W, (P), Mo, Ni and Na; and (e) low volatile elements (>70% in slag): Cs, Rb, Co, K, Cr, V, Nb, Be, Hf, Ta, Fe, U, Ti, Al, Si, Y, Sr, Th, Zr, Mg, Ba, Mn, REEs, Ca and Li. The volatility of As, Sb, and Tl and the slagging of S, B, Cl, Cd and low volatile elements are highly influenced by the fuel geochemistry and limestone dosages, respectively.     

Sulfur variability and element geochemistry of the No. 11 coal seam from the Antaibao mining district,China

The roof, bottom and 24 coal ply samples were collected by finely partitioning No. 11 coal seam from Antaibao mining district, Shanxi, China in terms of lithotypes. Proximate and sulfur analyses, ICP-AES, ICP-MS, AFS, XRD, SEM–EDX techniques were used on these samples, in order to investigate the vertical variability and origin of sulfur and also the geochemistry of major and trace elements in the seam. The weighted mean content of total sulfur of the 24 coal plies is 2.4 wt%, belonging to the medium-sulfur coal, but there are great differences in the contents of total sulfur and forms of sulfur between the 24 plies: total sulfur content >3.0 wt% for 5 plies, organic sulfur content >1.0 wt% for 13 plies and pyritic sulfur content >2.0 wt% for 4 plies. It is found that the differences were mainly caused by the degree of marine influences and the contents of clay minerals as well as the organic matter. The ply 21 has an abnormal high content of inorganic sulfur (pyritic sulfur 9.45 wt% and sulfate sulfur 5.97 wt%). This was caused by the presence of bauxite minerals-bearing kaolinite in the underlying ply 22 blocking the further infiltration of sulfate from the overlying plies during the deposition. The seam is dominated in kaolinite and, to a lesser extent, in pyrite, and there also exist minor amounts of szomolnokite, diaspore, boehmite, calcite, siderite, dolomite, magnesite, feldspar, gypsum. Szomolnokite and gypsum possibly resulted from the oxidation of pyrite. The seam is greatly characterized by finely-grained pyrite concentrating in cutinite. Hazardous trace elements Hg, Pb and As are mainly concentrated in pyrite, so that they can be partially removed by physical coal cleaning with an aim of removal of sulfur, while thalassophile elements Br, Ca, Cl, Mg and Sr, are clearly associated with the organic sulfur, reflecting that their contents can be decreased by coal blending means due to a partial organic affinity.     

Volatilisation of trace elements for coal–sewage sludge blends during their combustion☆

The influence of sewage sludge addition on the volatility of 37 trace elements (Ag, As, Au, B, Ba, Bi, Cd, Ce, Co, Cr, Cs, Cu, Ga, Hf, Hg, La, Li, Mn, Mo, Nb, Ni, Pb, Rb, Sb, Sc, Se, Sn, Sr, Ta, Te, Th, Tl, U, V, Y, Zn, Zr) during coal combustion was studied. For this purpose, a bituminous coal from the Asturian Central Basin and sewage sludge treated with Ca(OH)₂ and FeCl₃, as well as 10 and 50 wt% sludge–coal blends were used. Combustion experiments were performed in a laboratory electric furnace at 800, 900, 1000 and 1100 °C. The results have confirmed that the high Cl contents of the sludge can produce a pronounced effect on the volatilisation of some trace elements (Ag, Cd, Cs, Cu, Li, Pb, Rb and Tl) due to the probable formation of volatile chlorides, while the high CaO concentrations increase the retention of some elements in ash as As, Se and Te. The above opposite effects of Cl and CaO on trace element volatilisation were generally inappreciable for the 10 wt% blend, while they were more significant, but not as noticeable as expected, for the 50 wt% blend.     

Trace elements (Mn,Cr, Pb,Se, Zn,Cd and Hg) in emissions from a pulverized coal boiler

The concentrations of seven trace elements (Mn, Cr, Pb, Se, Zn, Cd, Hg) in raw coal, bottom ash and fly ash were measured quantitatively in a 220 tons/h pulverized coal boiler. Factors affecting distribution of trace elements were investigated, including fly ash diameter, furnace temperature, oxygen concentration and trace elements' characteristics. Modified enrichment factors show more directly element enrichment in combustion products. The studied elements may be classified into three groups according to their emission features: Group 1: Hg, which is very volatile. Group 2: Pb, Zn, Cd, which are partially volatile. Group 3: Mn, which is hardly volatile. Se may be located between groups 1 and 2. Cr has properties of both Groups 1 and 3. The smaller the diameter of fly ash, the higher is the relative enrichment of trace elements (except Mn). Fly ash shows different adsorption mechanisms of trace elements and the volatilization of trace elements rises with furnace temperature. Relative enrichments of trace elements (except Mn and Cr) in fly ash are larger than that in bottom ash. Low oxygen concentration will not always improve the volatilization of trace elements. Pb forms chloride more easily than Cd during coal combustion.     

Concentration and distribution of sixty-one elements in coals from DPR Korea

Fifty coal samples (28 anthracite and 22 lignites) were collected from both main and small coal mines in DPR Korea prioritized by resource distribution and coal production. The concentrations of 61 elements in 50 coal samples were determined by several multielement and element-specific techniques, including inductively coupled plasma atomic emission spectrometry (ICP-AES), and inductively coupled plasma mass spectrometry (ICP-MS), ion chromatogram (IC), cold-vapor atomic absorption spectrometry (CV-AAS), and hydride generation atomic absorption spectrometry (HGAAS). The ranges, arithmetic means and geometric means of concentrations of these elements are presented. A comparison with crustal abundances (Clarke values) shows that some potentially hazardous elements in the coals of DPR Korea are highly enriched Li, B, S, Cl, Zn, As, Se, Cd, Sn, Sb, W, Te, Hg, Ag, Pb, and La, Ce, Dy, Tm, Ge, Mo, Cs, Tl, Bi, Th and U are moderately enriched. A comparison of ranges and means of elemental concentrations in DPR Korea, Chinese, and world coals shows the ranges of most elements in DPR Korea coals are very close to the ranges of world coals. Arithmetic means of most elements in DPR Korea coals are close to that of American coals. Most elements arithmetic means are higher in Jurassic and Paleogene coals than coals of other ages. In DPR Korea coals, only seven elements in early Permian coals are higher than other periods: Li, Zn, Se, Cd, Hg, Pb, and Bi. Only five elements B, As, Sr, Mo, W in Neogene coals have arithmetic means higher than others. SiO₂ and Al₂O₃ in ashes are more than 70% except six samples. The correlation between ash yields and major elements from high to low is in the order of Si>Al>Ti>K>Mg>Fe>Na>Ca>P>S. Most elements have high positive correlation with ash (r>0.5) and show high inorganic affinity.