Optimization of phosphate removal in anodizing aluminium wastewater

The wastewater produced after brightening and anodizing aluminium has high concentrations of phosphates and sulphates. The addition of MgO in a first physico-chemical wastewater treatment step makes the selective recovery of phosphates in the form of magnesium phosphates feasible, which may be reused as fertilizer. The proposed wastewater treatment process allows manufacturers to reduce more than 70% of the volume of the precipitate in the sedimentation reactor and more than 50% of the weight of the final disposal sludge. In this study, the use of an alternative low-grade MgO (LG-MgO) as a source of magnesium, which is cheaper than pure MgO, is investigated. The phosphate concentration and pH of the treated wastewater is controlled by the formation and precipitation of newberyite or bobierrite as a function of the magnesium source added. According to experimental data, a reaction mechanism is proposed. Although LG-MgO reacts more slowly than pure MgO and it is necessary to add 3-4 times the stoichiometric amount, this procedure has considerable economic and technical advantages.     

蛋白类缓凝剂对建筑石膏的适应性

分析比较了4种分子结构相近的蛋白类缓凝剂对脱硫建筑石膏(FGD)和磷建筑石膏(PG)的缓凝效果.结果表明:具有不同酰胺键类型的蛋白类缓凝剂,其缓凝度受建筑石膏类型影响,且随建筑石膏pH值的增加而增大;当蛋白类缓凝剂的酰胺基团主要为仲酰胺时,其缓凝度随着H_2PO_4~-含量的增加而降低,当蛋白类缓凝剂的酰胺基团主要为伯酰胺时,其缓凝剂不易受H_2PO_4~-的影响;用于FGD的蛋白类缓凝剂宜选用仲酰胺为主的酰胺基团,用于PG的蛋白类缓凝剂宜选用伯酰胺为主的酰胺基团.     

二（2—乙基己基）磷酸和磷酸三丁酯对钙的协同萃取机理

研究了二（２乙基己基） 磷酸（ＨＡ） 以及二（２乙基己基） 磷酸和磷酸三丁酯（Ｂ） 的磺化煤油溶液从硫酸盐和氯化物混合溶液中对Ｃａ（ Ⅱ） 的萃取机理。研究结果表明, 二（２乙基己基） 磷酸和磷酸三丁酯对Ｃａ（ Ⅱ） 具有协同萃取效应, 其萃合物的组成分别为ＣａＡ２·４ ＨＡ 和ＣａＡ２·３ＨＡ·Ｂ。根据实验数据求算了萃取平衡常数, 它们分别为ｌｇ Ｋ１ ＝ － ０ ．４３３ 和ｌｇ Ｋ２ ＝ ０ ．２８２ 。     

Selective heavy metals removal from waters by amorphous zirconium phosphate: behavior and mechanism

Selective removal of heavy metals from water has been of considerable concern for several decades. In the present study, the amorphous zirconium phosphate (ZrP) was synthesized and characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron micrography (SEM), thermogravimetric analysis (TGA) as well as pH-titration experiments. Uptake of heavy metals including lead, cadmium, and zinc onto ZrP was studied by using a polystyrene sulfonic-acid exchanger D-001 as a reference sorbent and Ca(2+) as a competing cation due to its ubiquity in natural or industrial waters. The results indicated that the uptake of heavy metals onto ZrP is essentially an ion-exchange process and dependent upon solution pH. In comparison with D-001, ZrP exhibited more favorable sorption of heavy metals particularly in terms of high selectivity, as indicated by the distribution coefficients of ZrP even several orders higher than D-001 towards heavy metals when calcium ion coexisted at a high level in solution. The Fourier transform-infrared (FT-IR) spectroscopic investigation indicated that the uptake of calcium, cadmium, and zinc ions onto ZrP is only driven by the electrostatic interaction, while that of lead ion is possibly dependent upon the inner-sphere complex formation with ZrP. XPS results further elucidated that ZrP displays different sorption affinity towards heavy metals in the same order as selectivity sequence of Pb(2+)>Zn(2+) approximately Cd(2+)>Ca(2+), which can be explained by hard and soft acids and bases (HASB) theory. Moreover, uptake of heavy metals onto ZrP approached to equilibrium quickly and the used ZrP could be readily regenerated for reuse by the dilute HCl solution. Thus, all the results suggest that amorphous ZrP has excellent potential as a sorption material for water treatment.     

Impact of the wastedump ecosystem (phosphate ore dressing manufacture,Aswan, Egypt) on the surrounding environment

This study deals with evaluation of the impact of wastedump resulting from the phosphate ore dressing near the Mahamead Village (120 km north Aswan City), Aswan Governorate, Egypt, on the surrounding environment. The results indicate that the waste dump ecosystem contains elevated concentrations of Ca, Na, Cl～, SO^” and HCOJ as well as, relatively high concentrations of Fe, Mn, Pb and Cd. High pH (8.28–8.97) in all samples minimized the adverse effect on the soil and groundwater. The aerial parts of emergent weeds growing in the waste dump which used in this region as animal feed accumulate permissible limits of toxic metals. The wastedump can be a potential hazard to health and wildlife, if drainage from this dump (waste water) enters the Nile river.     

海口磷矿擦洗原矿配矿工作实践

海口某磷矿矿山开采地段已处于末期,随着采剥工作的延伸,开采条件愈来愈差,且开采地段处风化带边缘,矿石质量变化大,已满足不了生产及市场要求。通过配矿方法保证原矿质量,稳定产品矿质量,可以减少资源浪费,确保矿山的生产和销售。     

On‐site wastewater treatment using reactive filter media

The aim of this study is to reduce the phosphate concentration in treated wastewater using a small amount of the reactive filter media, Filtralite P. Biologically treated wastewater was passed through a filter with 215 g of Filtralite P. In the laboratory, the phosphate removal efficiency was 51% at a flow speed of 0.87 m/h. Under real conditions, in an experimental stand filled with 0.5 m³ of Filtralite P, the phosphate removal efficiency was 85% and the removal efficiency of total suspended solids was 57% after a 5‐month period. The residual phosphate concentration in the filtrate from the experimental stand was 1 mg/L of PO₄‐P after the 5‐month period. The experimental filtration plant was buried in the ground, and it did not freeze and worked well under winter conditions. The results of this study can be useful in the design and development of tertiary wastewater treatment plants in view of their sustainability potential.     

四川绵竹红岩什邡式磷矿地质特征及找矿标志

绵竹是中国四大磷矿基地之一,区内磷矿分布集中,但对其成因认识、找矿标志还存在不同认识.为此,选择在地质工作程度较高的绵竹红岩地区,对磷矿矿层、矿体特征及变化规律进行总结,以期为绵竹地区下一步找矿工作提供借鉴.工程揭露显示下泥盆统沙窝子组一段(D3s1)为赋矿地层,矿体与地层产状基本一致,呈层状、似层状产出,走向北东-南...     

透紫外、高应变点磷酸盐光学玻璃的研究进展和应用

透紫外、高应变点的磷酸盐玻璃材料是特种功能玻璃材料的重要研究方向之一,主要用于紫外探测器的窗口制备,要求具有紫外透过率高、热稳定性好、热膨胀系数低以及机械性能好、硬度高、耐刮伤等特点。本文从光学性能和热学性能两个方面对该类透紫外玻璃材料进行综述,分析影响紫外透过性能的四个因素和影响热稳定性的两个因素。     

Phosphate removal in agro-industry: Pilot- and full-scale operational considerations of struvite crystallization

Pilot-scale struvite crystallization tests using anaerobic effluent from potato processing industries were performed at three different plants. Two plants (P1 & P2) showed high phosphate removal efficiencies, 89 ± 3% and 75 ± 8%, resulting in final effluent levels of 12 ± 3 mg PO₄³⁻-P L⁻¹ and 11 ± 3 mg PO₄³⁻-P L⁻¹, respectively. In contrast, poor phosphate removal (19 ± 8%) was obtained at the third location (P3). Further investigations at P3 showed the negative effect of high Ca²⁺/PO₄³⁻-P molar ratio (ca. 1.25 ± 0.11) on struvite formation. A full-scale struvite plant treating anaerobic effluent from a dairy industry showed the same Ca²⁺ interference. A shift in the influent Ca²⁺/PO₄³⁻-P molar ratio from 2.69 to 1.36 resulted in average total phosphorus removal of 78 ± 7%, corresponding with effluent levels of 14 ± 4 mg P_total L⁻¹ (9 ± 3 mg PO₄³⁻-P L⁻¹). Under these conditions high quality spherical struvite crystals of 2-6 mm were produced.