搅拌槽内絮凝动力学研究

采用激光粒度仪在线测定并研究了搅拌槽内聚丙烯酰胺与磷矿酸解渣的絮凝动力学。考察了不同浓度的酸解液，絮凝剂加入量，温度，酸解渣原始平均粒径和搅拌强度对絮凝动力学影响。在实验研究范围，絮凝初始速度随温度升高，絮凝剂加入量及搅拌强度的增加而提高，但随着酸解液的粘度增加和酸解渣原始平均粒径的增大而降低，体系中存在最佳的絮凝剂加入量。通过酸解渣的电泳试验，用自合成的阴离子，阳离子改性絮凝剂以及非离子型絮凝剂与酸解渣的絮凝试验发现，在中性的水中，酸解渣与不同荷电类型的絮凝剂的絮凝速度大小依次为：阳离子型＞非离子型＞阴离子型。而在磷酸酸解料浆中絮凝速度与絮凝剂的荷电类型无关。磷矿酸解渣与聚丙酰胺絮凝剂的作用主要表现为架桥机理。     

磷矿酸解料浆与高分子絮凝剂形成的絮团特性研究

用光学连续摄像技术研究了不同絮凝条件下磷矿酸解渣与聚丙烯酰胺形成的絮团特性。实验结果表明酸解料浆与聚丙烯酰胺絮凝剂形成的絮团具有分形几何特征。应用分形理论得到絮团降落速度与絮团孔隙度和絮团密度的关系式。用激光粒度分布仪在线测定了流体力学条件对该体系团强度的影响。在湍流情况下絮团最大平均粒径取决于酸解渣原始平均粒径和体系的能量耗散。较大的絮团破坏主要以裂解为主,在最小的湍流漩涡区也存在相当程度的剥离破坏。试验发现絮团强度随聚合物分子量的增加而提高,对于获得最大平均粒径的稳定絮团存在最佳的絮凝剂加入量。．     

盐酸分解高硅混合型胶磷矿工艺研究

中低品位磷矿的开发利用是中国磷化工产业可持续发展的基本保障。采用盐酸浸取高硅磷矿,通过单因素实验对其酸解工艺和过滤强化过程做了研究。结果表明,磷矿粒径≤180 μm、在反应温度为40 ℃、酸比（实际投入的盐酸量与理论耗酸量的质量比）为1.1、盐酸质量分数为20%以上、浸取10 min,此时P₂O₅浸取率可达到99%以上。盐酸浸取速率快,酸解率高。高硅磷矿酸解料浆中二氧化硅含量高、粒度小、沉降速度慢,导致过滤困难。添加非离子型聚丙烯酰胺絮凝剂,控制絮凝剂为酸解料浆质量的1.0%,沉降2 min之后,可显著强化过滤。     

氧氯化锆生产中转型料酸解与絮凝脱硅过程

以锆英石碱分解所得烧结料经水洗、转型后的转型料为原料,研究其盐酸酸解与酸解液絮凝脱硅过程中主要工艺参数对脱硅效果的影响,并采用红外与核磁共振表征水洗料转型、转型料酸解及酸解液絮凝过程中硅酸聚合状态. 实验获得优化的酸解与絮凝条件为：酸解温度微沸,酸解时间5 h,酸解酸度5.20 mol/L(以HCl计),锆液浓度125 g/L[以Zr(Hf)O2计],絮凝温度40℃,絮凝时间1 h,絮凝剂为阳离子聚丙烯酰胺类CPAM-1,絮凝剂浓度1%(w),加入量4%(j). 在该条件下进行5 L规模实验,氧氯化锆水溶液硅含量稳定降至(35~50)′10-6(w),锆含量及酸度分别为120 g/L[以Zr(Hf)O2计]和5.10 mol/L(以HCl计),由该水溶液蒸发浓缩结晶所得氧氯化锆产品指标与市售普通级产品相当.     

盐酸法饲料磷酸氢钙工艺中酸解渣过滤强化的研究

针对国外某磷矿为原料的盐酸法饲料磷酸氢钙工艺,通过分析酸解渣的粒度分布、物相及zeta电位等物理性质,研究了磷矿酸解渣过滤困难的原因,探索了强化过滤的途径。研究结果表明：在盐酸中加入少量硫酸,可显著提高酸解渣的过滤强度,最适宜的硫酸用量为混酸中W（H2SO4）0．67％。另外,加入适量的滤液于酸解液中,能降低酸解液中酸解渣颗粒之间排斥力,可显著提高酸解渣的絮凝效果及沉降速度。     

阳离子聚丙烯酰胺复合Ti~(4+)的絮凝性能探究

研究了阳离子聚丙烯酰胺复合Ti~(4+)的絮凝性能,通过对絮凝性能进行评价,得出复合絮凝剂加入量对絮凝效果的影响以及对实际水样的絮凝效果。     

裂化催化剂生产废水中悬浮物的去除试验

用配制的分别以阴离子聚丙烯酰胺、氯化铝和阳离子聚丙烯酰胺为主剂的三种絮凝剂对裂化催化剂生产废水进行絮凝研究,考察了絮凝剂的加入量、废水pH值和絮凝沉降时间对絮凝沉降效果的影响。试验结果表明:在一定的操作参数下,以阴离子聚丙烯酰胺为主剂絮凝剂的用量较少,效果最好。     

聚硅酸氯化铁的混凝实验研究及在海水预处理中的应用

用自制聚铁和硅酸钠制备的聚硅酸氯化铁处理模拟水样。考察了絮凝剂的加入量、处理水样的pH值、搅拌速度和搅拌时间等对絮凝效果的影响,同时对自制絮凝剂与市售聚铁铝絮凝剂对海水的絮凝效果做了比较。结果表明:该絮凝剂在加入量为42mg/L、快搅速度为240r/min、慢搅时间为16min、静置30min、酸碱度为中性或略碱性时絮凝效果较好。对海水的探索性实验中,自制絮凝剂优于其它几种。     

CPAM在污泥脱水工艺中的絮凝效果研究及应用

以生活污水为絮凝对象,研究了不同的原水浊度、pH值和温度条件下,阳离子聚丙烯酰胺(CPAM)的投加量、搅拌时间对絮凝效果的影响。实验结果表明,CPAM作为污泥脱水工艺中的净水絮凝剂,在絮凝反应中加入0.3~0.6 mg/L,搅拌时间占总絮凝反应时间的2/3时,可获得最佳絮凝沉淀效果。分析了在实际生产过程中CPAM溶解方式、投加方式对絮凝效果的影响,应用结果表明,该工艺可使水厂出水水质得到明显提高,在保证水质和不增加净水成本的前提下,还可以使生产能力大幅度提高。     

复合絮凝剂PAFSC-PAM对化工制药废水的絮凝效果

采用复合絮凝剂PAFSC-PAM(聚硅酸铝铁-聚丙烯酰胺)对化工制药废水进行絮凝处理,考察了絮凝剂投加量、反应温度、pH值、快速搅拌转速对絮凝效果的影响.结果表明,复合絮凝剂PAFSC-PAM(质量比为10:1)的絮凝效果优于PAFSC,在PAFSC-PAM(质量比为10:1)投加量为160 mg·L-1、反应温度为4...     

磁絮凝技术深度处理焦化废水的试验研究

采用磁絮凝技术对焦化废水生化出水进行试验研究,以CODCr、氨氮、浊度去除率为考察指标,讨论了聚合硫酸铁(PFS)投加量、聚丙烯酰胺(PAM)投加量、磁粉投加量、沉降时间、投加方式等因素对处理效果的影响。结果表明:先投加磁粉,再投加PFS,最后加絮凝剂PAM的投加方式最好,磁粉最佳投加量为400 mg/L,PFS最佳投加量为800 mg/L,PAM最佳投加量为8 mg/L,最佳沉降时间为20 min。CODCr、氨氮、浊度去除率分别达到62.5%、22.3%和92.2%。采用该技术既可提高絮凝效果,又缩短了沉降时间,有很好的现实意义。     

季铵型阳离子田菁胶与聚丙烯酰胺在处理生活污水中的絮凝效果比较研究

从田菁胶及其衍生物系列中优选出了一种新型高分子絮凝剂一季铵型阳离子田菁胶（QACSG）,并对QACSG和聚丙烯酰胺（PAM）在处理生活污水中的絮凝效果作了系统比较。研究结果表明：在相同的混凝条件下（以聚合硫酸铁为主混凝剂）,QACSG的最佳投药量仅为PAM的三分之二,而浊度去除率和COD去除率分别提高了20％～30％和5％～10％,处理后的废水达到了国家一级排放标准。     

Polyacrylamide induced flocculation of a cement suspension

The use of cellulose, instead of asbestos, in the fibre cement composites manufacture, using the Hatschek process, reduces cement retention and makes necessary to use a flocculant which is crucial for the plant productivity. The use of different types and doses of polyacrylamides (PAM) as well as the addition process, have been studied to obtain an in-depth knowledge of floc properties. A real-time methodology has been used to study size, shape, strength and reversibility of formed flocs, based on a focused beam reflectance measurement (FBRM) system. The results have been corroborated by particle vision and measurement (PVM) analysis. This paper shows that anionic PAM (A-PAM) are the most suitable to induce cement flocculation and to obtain optimal properties of the formed flocs. This is because the flocculation process is enhanced by the interaction of the Ca²⁺ ions, produced by the cement hydration, with the carboxylic groups of the polymer chains. Cations not only increase the stiffness of the chains, improving floc strength, they also enhance the importance of the patching aggregation mechanism when the initial bridges are broken. Higher molecular weight polymers improve initial aggregation but the effect of anionic charge is more important for a stable flocculation with time under variable shear conditions. Results show that the optimal dosage is between 100 and 200 ppm.     

Homogeneous synthesis and characterization of polyacrylamide‐grafted cationic cellulose flocculants

In this work, cationic cellulose (CC) with different degrees of substitution (DS) was successfully synthesized by the reaction between cellulose and 3‐chloro‐2‐hydroxypropyl‐trimethylammonium chloride (CHPTAC) in a 7 wt % NaOH and 12 wt % urea aqueous solution. The structure of the CC was characterized by using elemental analysis, ¹H‐NMR, and FTIR. The DS values of CC ranged between 0.18 and 0.50, which could be obtained by adjusting the reaction temperature, reaction time, and molar ratio of CHPTAC to anhydroglucose unit of cellulose. The cationic cellulose–graft–polyacrylamide flocculant (CC‐g‐PAM) based on CC and polyacrylamide (PAM) was also synthesized in a homogeneous aqueous solution. The flocculation characteristics of CC and CC‐g‐PAM were evaluated in a kaolin suspension. The results showed that CC‐g‐PAM was an effective flocculant for the kaolin suspension under acidic or neutral conditions, and the flocculation efficiency was over 90%, while the CC showed better flocculation performance under alkaline conditions. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43106.     

Optimising the dewatering behaviour of clay tailings through interfacial chemistry, orthokinetic flocculation and controlled shear

The effect of shear on dewatering behaviour and particle interactions of Na-exchanged smectite and kaolinite clay dispersions has been investigated at pH 7.5, using hydrolysable Ca(II) and Mn(II) ions as coagulants and high molecular weight anionic and non-ionic polyacrylamide (PAM A and PAM N, respectively) and polyethylene oxide (PEO) flocculants. Metal ion addition enhanced the flocculation performance by dramatically reducing the magnitude of the particle zeta potential and, in the case of smectite pulp, suppressing osmotic swelling. Under optimum orthokinetic flocculation conditions of controlled agitation rate and duration, PAM A and PEO-based flocs settled faster than those of PAM N whilst kaolinite pulps produced higher sedimentation rates than smectite pulps. The settling rates are nearly an order of magnitude greater than those observed under standard flocculant-pulp mixing/flocculation methods of inversion and plunging. The difference in the flocculant behaviour is attributed to the more expanded conformation of PAM A and PEO polymer chains in contrast to PAM N, whilst the lower yield stresses, reflecting inter-particle bridging and floc network structure strength that are conducive to faster clarification, were displayed by kaolinite pulps. Following shear, similar consolidation enhancement of ≈ 5-7 wt.% solid for both pulps was achieved at an optimum agitation range of 100-200 rpm. This was accompanied by decreased yield stress in the case of PAM A-based pulps, indicating non-reversible disruption of polymer mediated particle and floc network structure. In contrast, the yield stresses of PAM N and PEO flocculated dispersions indicated similar and stronger particle interactions, respectively, upon consolidation following shear. The findings show clear links between effect of shear, interfacial chemistry and polymer structure on pulp particle interactions and dewaterability.     

微波辅助法合成高分子量聚丙烯酰胺

以丙烯酰胺(AM)为单体,水为溶剂,过硫酸铵(APS)和偶氮二异丁基脒盐酸盐(AIBA)为复合引发体系,采用微波辅助法制备聚丙烯酰胺(PAM)。研究了微波辐照功率、辐照时间、单体浓度、引发剂用量对聚丙烯酰胺分子量和单体残留率的影响,采用红外光谱(FT-IR)表征了聚合物产物结构,最后考察了剪切作用对PAM性能的影响。结果表明:采用微波辅助法制备的PAM反应时间短、能耗低、分子量高、单体残留率低;当微波功率为100 W,辐照时间为8 min,单体浓度为25%,引发剂用量为0.05%时产物分子量可达1050×104,并且单体残余量低;PAM的降解随着剪切时间的延长和剪切速度的加快而加快。     

油田含聚丙烯酰胺废水的絮凝处理研究

油田聚合物驱采油废水中聚丙烯酰胺的去除是实现废水回用的关键。采用絮凝法去除模拟废水中的聚丙烯酰胺。以聚合氯化铝（PAC）作为絮凝剂,研究了投加量、pH值、搅拌时间、沉降时间等主要操作条件对絮凝效果的影响。结果表明：在絮凝剂投加量300 mg/L、pH值为中性、快搅时间1.5min、慢搅时间15min、沉降时间15min的条件下,PAM去除率达96.88%,废水中PAM浓度可达3.74mg/L。     

Synthesis and characterization of grafted carboxymethyl guar gum

Graft copolymers of carboxymethyl guar gum (CMGG) and polyacrylamide (PAM) have been synthesized by grafting polyacrylamide chains onto carboxymethyl guar gum backbone using a ceric‐ion‐induced solution polymerization technique. By varying the amount of initiator, three different grades of graft copolymers are synthesized. The characterization of graft copolymer is carried out by FTIR, NMR, intrinsic viscosity measurement, SEM, SLS, DTG, and rheology. A comparison of flocculation efficiency of CMGG and its graft copolymer shows that the graft copolymer exhibits better flocculation performance. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011