稀土渣絮凝剂的制备及其在印染废水中的应用

以赣南稀土渣为主要原料,用酸改性稀土渣与聚羟基铝离子溶液反应制备了稀土渣絮凝剂,并以江西某纱染厂回收染料后的废水为处理对象,考察了该絮凝剂的脱色性能。正交试验结果表明,在酸改性时间为10h、盐酸浓度为15％、改性稀土渣与聚羟基铝离子溶液的体积比为1：5的条件下聚合反应24h,所制备的稀土渣絮凝剂具有良好的脱色性能。试验结果还表明,对于色度为100倍的染料废水,在稀土渣絮凝剂粒径为0．25～2mm、投药量为1．5g／L、水样pH=6～7、水温为35—50℃时,静沉30min后其脱色率〉95％,经处理后的硫化染料废水出水水质可达印染行业排放标准。     

废石膏硫酸烧渣砖的研制

通过正交实验和复核实验,确定了较优的原材料配合比及成型压力,研制出的废石膏硫酸烧渣砖抗压强度达10 MPa以上.对其耐久性能作了测定和分析,并简要阐述了复合双免砖的激发固化机理.为低品质废石膏和硫铁矿渣的直接利用开辟了一条新的途径.     

水解酸化/SMBR处理含PVA退浆废水的研究

采用水解酸4E／SMBR工艺处理含PVA退浆废水。结果表明，当进水COD为1000mg／L左右、BOD5／COD值为0．15～0．20时，该工艺对COD的平均去除率在95％左右，其中SMBR的贡献为75％左右；当水解酸化池的水力停留时间为20、16、10h时，对COD的去除率分别为20％、18％和13％，其SMBR中最大COD有机负荷分别为0．33、0．29和0．20kgCOD／（kgVSS·d）；采用水洗＋酸洗＋碱洗的方式对膜进行清洗，效果最好，可使膜通量恢复到新膜的92％。     

光-Fenton试剂预处理低浓度H酸废水

采用光－Fenton试剂预处理低浓度H酸废水（COD为300－500mg/L，色度为400－600倍，pH值为4.5-5.5)的试验结果表明，在最佳预处理条件[pH值为5，FeSO4(10g/L)用量为0．5％，H2O2（3％）用量为2．2％，催化剂m-TiO2的用量为0．02％，反应时间为90min]下对COD的去除率为52．4％－62．7％，对色度的去除率＞82％，废水的CDOB／COD值显著提高。     

混凝沉降硅藻土吸附处理印染废水的研究

本研究利用混凝沉降硅藻土吸附处理印染废水,使处理后的废水达到国家行业一级排放标准。研究结果表明：每处理100mLCOD为211．74mg／L的废水需加入浓度为10％的聚合氯化铝0．5mL,搅拌20min,进行混凝沉降,处理后的废水COD为155．08mg／L。每处理100mLCOD为155．08mg／L的废水需加入2．0g硅藻土,搅拌20min,处理后的废水COD为60mg／L,色度为10,达到国家一级排放标准。此法相对于其他处理方法具有工艺简单、沉降速度快、吸附处理效果好等优点,具有广阔的应用前景。     

电石渣脱硫的方法

电石渣作为工业废弃物,主要成分为Ca(OH)<,2>,其资源化利用一直没有得到有效的发展.本方法采用化工厂的废弃物电石渣为主要原料,加水调成浓度为20%～30%电石渣浆作为脱硫剂,喷入火电厂烟气脱硫塔内与烟气中的SO<,2>反应生成脱硫石膏,达到以废治废的目的.     

电石渣改良路基过湿土的微观机制研究

 为揭示电石渣改良路基过湿土的强度增长机制,通过无侧限抗压强度、酸碱度、压汞和热重分析试验,从微观角度出发,探讨改良土强度与pH值、孔径分布、火山灰反应产物含量的内在联系,并与石灰改良土进行比较。结果表明,电石渣改良路基过湿土早期强度与生石灰改良土接近,而后期强度为生石灰改良土的1.05～1.16倍;电石渣细粒含量约为生石灰的1.72倍,比表面积大5倍,可保障电石渣与土颗粒接触更充分;电石渣活性Al,Si成分含量约为生石灰的1.71倍,且电石渣改良土pH值可维持在12.4～12.6(而生石灰改良土pH值低于12.4),为火山灰反应提供较好的碱性环境,水化反应更持久;28和120 d龄期时,电石渣改良土的火山灰反应产物含量约为生石灰改良土的1.06和1.10倍,且微孔隙(＜0.007 μm)和小孔隙(0.007～0.900 μm)的体积百分比之和分别约为生石灰改良土的1.05和1.23倍,结构更致密。     

常温下UASB处理鱼粉加工废水启动特性研究

针对鱼粉加工废水经过混凝处理后仍含有较高浓度的COD（50g／L以上）、氨氮（4g/L以上）、盐分（5g/L以上）的问题,从有机负荷、进水和出水pH、挥发性脂肪酸、氨氮、盐分等方面,研究了常温下UASB的启动特性及其处理效果。结果表明,UASB反应器对鱼粉加工废水具有较好的处理效果,反应器内能形成大量的颗粒污泥,启动迅速、运行稳定,具有较强的酸、碱缓冲能力,未出现氨氮和脂肪酸的积累和抑制微生物活性的现象。当进水COD为15～20．5g／L、容积负荷为8～9kg／（m^3&#183;d）时,出水COD为2500mg／L（对COD的去除率〉85％）,产气量为0．46L/gCOD（CH4含量〉80％,具有较高的利用价值）。颗粒污泥呈黑色椭圆状,粒径主要分布在0．315—3mm,污泥浓度为35g／L,MLVSS／MLSS为0．908,颗粒污泥的沉速为52．5～138m／h（沉降性能良好）。     

内循环反应器处理异维生素C钠工业废水的启动试验

采用内循环反应器处理异维生素C钠工业废水,废水水质为COD：8500mg／L;BOD：3400mg／L;pH：3-5。通过中试启动进行了现场试验研究,结果表明：经过56天的启动试验,当内循环反应器接种污泥浓度为21g／L时,反应器C0D负荷为25kg COD／（m3&#183;d）～30kgCOD／（m3&#183;d）,在整个启动过程,反应运行稳定,出水COD在800mg／L以下,COD去除率始终在91．5%以上,pH值保持在6．8～7．6之间,挥发酸（VFA）始终未超过450mg／L。     

强化混凝工艺深度处理含聚采油废水

利用强化混凝对含聚采油废水进行深度处理。在以PFS作为主混凝剂,Potenflo1315和Potenflo1365作为助凝剂的强化混凝实验中,分别考察了pH值、PFS投加浓度以及有机助凝剂Potenflo1365和Potenflo1315的投加浓度对含聚采油废水的处理效果。实验结果表明：在pH值为5.0时,当投加浓度为150 mg/L的PFS与2.5 mg/L的Potenflo1365复配后,对含聚采油废水的处理效果最佳,CODCr去除率达到88.8％,浊度去除率达到98.1％,经处理后废水主要指标可以达     

黄铁矿烧渣的综合利用途径与问题分析

黄铁矿烧渣是用黄铁矿生产硫酸时排出的废渣,大量废渣的产生不仅污染环境还会造成 资源的浪费.黄铁矿烧渣的综合利用有很多方式,但目前在我国利用率还很低,还没有找到在技术 上和经济上均非常良好的处理方式.笔者对烧渣处理利用的现状与问题进行了评析,并提出了几 点建议和对策.     

In situ calcite formation in limestone-saturated water leaching of acid rock waste

The result of leaching of a 75% acid rock/25% limestone column with limestone-saturated solution has shown that the pH of the effluent recovered from 2.5, after apparent loss of acid neutralizing capacity after 4 years with water leaching, to pH 7 in less than 3 years. Bulk assay results, XRD and SEM/EDS analyses of samples from the column at 384 weeks (pH 3.6) and 522 weeks (pH 6.9) during this recovery have suggested that this is due to formation in situ of fine calcite. Calcite, initially blended to the column material at 25 wt.% was not found in the XRD of the 384 week sample but is clearly found in the 522 week XRD. This increased calcite content appears to be derived from the limestone-saturated water as finely divided solid precipitated in the drying cycles in the column. This result is confirmed by assessment of the 522 week sample as non-acid forming. Loss of some reactive aluminosilicate minerals, formation of secondary, precipitated, surface-attached gypsum and loss of fine secondary jarosite occurs across this pH range but fine, surface-attached jarosite is still found in the 522 week sample implying relatively slow dissolution kinetics. In comparison with the 384 week sample, armouring of highly reacted pyrite particles by surface layers of iron oxyhydroxides and aluminosilicates has become more extensive at 522 weeks after return of the pH to neutral values. This is consistent with results from Freeport field samples from limestone blended test pads where pyrite armouring was also substantially increased at higher pH. The results suggest that it may be possible to effectively maintain neutral pH and passivate pyrite, reducing oxidation rates by more than an order of magnitude, using limestone-saturated solution dump feed rather than bulk limestone blending or covers.     

Effect of dry-wet cycles on leaching behavior of recovered soil collected from tsunami deposits containing geogenic arsenic

Geogenic contaminants, such as arsenic, are often found in soil recovered from coastal areas. These contaminants may leach out when the soil is used as embankment material. Moreover, the leaching of such contaminants might be influenced by environmental changes, such as dry-wet cycles, and higher environmental risks due to a larger amount of leaching are anticipated in some cases. In this study, therefore, soil recovered from tsunami deposits was subjected to dry-wet cycles under three different drying conditions to investigate how environmental changes affect the leaching behavior. To evaluate the physical and chemical changes in the soil surface, microscopic/spectroscopic studies were conducted. Batch leaching tests revealed that dry-wet cycles slightly alter the leaching behavior of most elements, such as Fe, Si, Na, Ca, etc. Arsenic leaching was seen to increase in certain dry-wet cycles before decreasing, and microscopic/spectroscopic confirmed that this increase was likely due to pyrite oxidation. These dry-wet cycles can disintegrate pyrite morphology and cause pyrite oxidation, leading to a more acidic leaching condition that accelerates arsenic leaching. After a certain oxidation procedure, the resulting ferric hydroxide may prevent the pyrite surfaces from further oxidation. The Fe oxides and hydroxides can also act as arsenic adsorbents, preventing the increase in arsenic concentration.     

Temporal variations of mineral character of acid-producing pyritic coastal sediments, Southeast Queensland, Australia

The lower Pimpama River catchment possesses many features of morphology, geology and landuse, typical for Southeast Queensland. Pimpama River and its main tributary Hotham Creek meander over a coastal plain which developed during the last several thousand years as a result of sea level fluctuations and changing fluvial and estuarine regimes which provided ideal conditions for the formation of sedimentary pyrite. A complex mixture of natural and human factors triggers and controls the oxidation and hydrolysis of this pyrite. The consequent production of sulfuric acid and leaching of metals from the pyrite-rich sediments represent main environmental issues of this coastal setting. This study aimed to determine the lithological character of the coastal unconsolidated sediments, and identify changes produced by acidity over a long period of time in a natural system and over a short period of time in a laboratory system. The mineral composition of the estuarine sediments of the coastal plain reflects the lithology of their source, the geological basement, and also the enhanced weathering rate due to acid production. The primary minerals present in the sediments consist of quartz and feldspars (primarily albite, K-feldspars to a lesser extent and minor anorthite) the product of physical weathering of bedrock material, mainly sandstone. Kaolinite is the dominant clay mineral and represents the product of intense leaching of feldspars promoted by acid conditions. Kaolinite is fairly ordered in structure in fresh and weathered bedrock and it becomes disordered in the estuarine sediments. Illite is mainly present in bedrock-related samples and the highest amounts are associated with muscovite. In the tidal sediments, illite is present to a lesser extent and is not found in the lower estuary. The distribution of mixed layers of smectite-illite is highly variable and their deposition is mainly controlled by the hydrodynamic conditions of the environment. Only low energy tidal settings favour the deposition of smectites. Pyrite is present at many sites and is always accompanied by oxidation products such as jarosite and gypsum. The laboratory experiment showed that in the short-term, changes induced by acid production mainly involved the: (1) decomposition of oxidation products such as gypsum and jarosite, (2) weathering of feldspars (mainly plagioclase), and (3) increased amount of kaolinite and possible increased structural disorder. These observations are of significance when considering wetlands as a method of remediating acid-producing areas by re-establishment of reducing conditions. Jarosite is quite widespread and can represent a source of acid over a short period of time in water-saturated, partially oxidized pyrite-rich sediments. The initial several months of a wetland establishment may, however, be dominated by secondary acid production and metal leaching from preexisting oxidation products like jarosite and natrojarosite.     

Effects of titanium dioxide industry waste dumping on sea water chemistry

An investigation was made to determine the influence of the dumping of a 1000 ton day⁻¹, on the average, of acid-iron waste from the titanium dioxide industry into the shallow but turbulent Southern Bight of the North Sea. This waste contains some 20% sulfuric acid and 2% iron. After the passage of the barge that discharges 10 ton of waste min⁻¹ into its wake, the vertical and horizontal distributions of the pH, iron-concentration and turbidity were measured as a function of time. It appeared that a few seconds after the discharge and for a very brief period, the pH was down to approx. 4 and the Fe-concentration was 13 mg l⁻¹. More than 1 min after the discharge a pH below 6 and an iron-level above 3 mg l⁻¹ could not be detected anywhere. The measured factor for waste dilution by sea water, based on the observed acid and iron concentration in the waste and in the discharge track, were around 5000 after 5 min, 9000 after 10 min and 80,000 after 20 min. Before and long after the dumping, the total iron-concentration in this Southern Bight area was around 100 μg l⁻¹, but this high level might be due to natural causes.     

Comparative evaluation of short-term leach tests for heavy metal release from mineral processing waste

Evaluation of metal leaching using a single leach test such as the Toxicity Characteristic Leaching Procedure (TCLP) is often questionable. The pH, redox potential (E(h)), particle size and contact time are critical variables in controlling metal stability, not accounted for in the TCLP. This paper compares the leaching behavior of metals in mineral processing waste via short-term extraction tests such as TCLP, Field Leach Test (FLT) used by USGS and deionized water extraction tests. Variation in the extracted amounts was attributed to the use of different particle sizes, extraction fluid and contact time. In the controlled pH experiments, maximum metal extraction was obtained at acidic pH for cationic heavy metals such as Cu, Pb and Zn, while desorption of Se from the waste resulted in high extract concentrations in the alkaline region. Precipitation of iron, caused by a pH increase, probably resulted in co-precipitation and immobilization of Cu, Pb and Zn in the alkaline pH region. A sequential extraction procedure was performed on the original waste and the solid residue from the E(h)-pH experiments to determine the chemical speciation and distribution of the heavy metals. In the as-received waste, Cu existed predominantly in water soluble or sulfidic phases, with no binding to carbonates or iron oxides. Similar characteristics were observed for Pb and Zn, while Se existed mostly associated with iron oxides or sulfides. Adsorption/co-precipitation of Cu, Se and Pb on precipitated iron hydroxides was observed in the experimental solid residues, resulting in metal immobilization above pH 7.     

Effect of acid and surfactant treatment on activated sludge dewatering and settling.

The effect of pretreating activated sludge with sulfuric acid and surfactant on its exocellular polymer(ECP), dewaterability and settleability was investigated. It was observed that the centrifugal dewatering efficiency was increased with the decrease of sludge pH value, and which was further improved if the surfactant was simultaneously applied. However, to the filtration dewatering, the water content reached the minimum in the case of pH 2.5, and the additional use of surfactant was also favorable. The water content of sludge dewatered with filtration reached 73.99% when a pH 2.5 and a 0.1 g surfactant were employed, which was reduced by around 2% as compared with surfactant unused. Experimental results indicated that the sludge sedimentation rate was significantly accelerated under pH 2.5 condition, and which was increased once more by the utilization of surfactant. Further studies revealed that treating activated sludge with sulfuric acid at pH 2.5 or combined with surfactant was an effective method to remove the polymers from sludge surface and induced the decrease of ECP, which resulted in the improvement of dewaterability and settleability. This study suggested the potentiality of improving activated sludge mechanical dewaterability by the use of sulfuric acid to control its pH at 2.5 or together with a surfactant.     

利用非金属矿研制酸气吸附剂的试验研究

本文主要探讨一些非金属矿对盐酸、硫酸、高氯酸等酸气的吸附脱除试验。研究结果表明,用非金属矿复合制成的吸附剂对废酸气具有较好的吸附脱除作用。     

综述钢铁企业钢铁渣的综合利用与发展方向

以发展循环经济,保护生态环境为主,阐述了工业废渣—钢铁渣的综合利用技术,分析了宣钢钢铁渣的利用情况及未来发展方向,以合理的利用工业废渣,变废为宝,促进社会和谐发展。     

改性拜耳法赤泥制备聚合氯化铝铁的研究

以改性拜耳法赤泥为原料,通过盐酸浸溶制备高效絮凝剂--聚合氯化铝铁(PAFC),并探讨了酸溶浸出过程的最佳工艺条件.结果表明,酸溶浸出过程的最佳工艺条件是:盐酸浓度为6 mol/L、盐酸与改性拜耳法赤泥的液固比为3:1、反应温度为95℃、反应时间为1.5h;自制PAFC的絮凝性能较单一聚铁、聚铝的好,且其絮体较大、致密、沉降速度快、除浊效果好.该工艺为拜耳法赤泥的综合利用开辟了一条新途径,具有良好的市场前景和社会效益.