四种有机抑制剂对倍半氧化物的抑制性能

采用一粗一精正浮选工艺,研究了小分子有机酸（ST-1）、阴离子淀粉（AS）、萘磺酸盐甲醛缩合物（NFSC）、羧甲基纤维素钠（CMC）4种有机抑制剂对胶磷矿中类型为水云母、褐铁矿的倍半氧化物的抑制性能. 结果表明,NFSC用量为0.35 kg/t时,磷精矿品位达到31.36%,回收率在80.22%,倍半氧化物的质量分数降低到3.48%;CMC用量为0.20 kg/t时,磷精矿中倍半氧化物的质量分数可以降至3.20%,但磷精矿回收率仅为26.24%;当分别使用AS、ST-1作为抑制剂时,精矿中倍半氧化物的质量分数变化都不明显. 因此,NFSC在分离倍半氧化物脉石与磷矿物时抑制性能最好;CMC对倍半氧化物脉石有很强的抑制性,但选择性差;ST-1、AS作为抑制剂对倍伴氧化物的抑制作用较弱. 关键词:正浮选;倍半氧化物;有机抑制剂;抑制性能     

羟乙基纤维素和羧甲基纤维素溶液的稳定性

羟乙基纤维素(HEC)溶液的表面张力和视粘度很少受添加剂的影响,很稳定.羧甲基纤维素(CMC)溶液的稳定性则明显较差.但是,HEC:CMC=8:2(重量比)的溶液有与HEC溶液相近的稳定性.     

黄原胶/CMC复合稳定剂对酪蛋白乳液稳定性的影响

研究了黄原胶/羧甲基纤维素钠复配比例及体系pH值对酪蛋白乳液ζ-电位、粒径、黏度、乳析稳定性及微观结构的影响,揭示了多糖稳定乳液或促进乳液失稳的机理。研究发现:中性条件下,两种阴离子多糖均未吸附到酪蛋白稳定的油滴表面,未吸附的多糖分子诱发了液滴的排斥絮凝,在宏观上表现为乳液的快速分层;酸性条件下,带负电荷的黄原胶或羧甲基纤维素钠分子吸附于酪蛋白包裹的油滴表面,提高了液滴间的静电斥力及空间位阻,在一定的复配比例下(羧甲基纤维素钠∶黄原胶=1∶1,3∶1,总添加量为乳液质量的0.4%),乳液的稳定性提高,在室温下存放两周,分层现象不明显。     

Flotation behavior of four dodecyl tertiary amines as collectors of diaspore and kaolinite

The flotation of diaspore and kaolinite by one of a series of tertiary amines (DRN, DEN, DPN and DBN) was investigated. The tertiary amines show better floating recovery for kaolinite compared to diaspore. The maximum recovery D-value is 45% over a pH range from 3 to 8. FT-IR spectra confirm the presence of hydroxyl groups on the surface of kaolinite and diaspore. Zeta potential measurements show that the mineral surfaces are negatively charged over a wide pH range. Ionization of hydroxyl groups mainly accounts for the surface charging mechanism. The adsorption of tertiary amines onto the mineral surface is due mainly to electrostatic effects and the difference in electrostatic effect between a collector and the two minerals can explain the flotation separation. Inductive electronic and steric effects from the substituent groups result in different collecting powers for the four tertiary amines.     

羧甲基纤维素与海藻酸钠的相容性研究

采用稀溶液粘度法研究不同混合比例的羧甲基纤维素钠与海藻酸钠的相容性,发现羧甲基纤维素钠含量在5～15%范围内时两者是相容的,超出这个范围则是不相容的。通过测定混合溶液的落球粘度,利用红外光谱和扫描电子显微镜等表征了二者的相容性,并从理论上分析了其相容性随羧甲基纤维素钠含量变化的原因。     

CMC在珠光颜料涂布纸中的应用试验

对添加羧甲基纤维素钠改善水性珠光涂布纸云母系列珠光涂料的性质做了初步研究．试验结果表明，羧甲基纤维素钠不仅能改善涂料的稳定性，提高涂层的表面拉毛强度，还能起到辅助胶粘剂的作用．通过优化试验得到了较理想的羧甲基纤维素钠配比．     

Absorption Capability Comparison of Two Kinds of Super Absorbent Resins from Carboxymethyl Cellulose

The two kinds of super absorbent resins from carboxymethyl cellulose were synthesized with the potassium persulphate and methylenebisacrylamide as initiator and cross linker respectively by radical polymerization in aqueous solution. Thestructures of the two resins were characterized with Fourier transform infrared spectroscopy FTIR, scanning electron miscroscopy （SEM）, and environment scanning electron miscroscopy （ESEM）, the results indicate that the fibriform of the carboxymethyl cellulose （CMC） is disappeared and the crusslink networks in eopolymer of carboxymethyl cellulose-graft-polyacrylic acid（CMC-g-PAA） are denser than that of eopolymer of carboxymethyl cellulose-graft-poly （acrylic acid-co-N-vinyl Pyrrolidone） （CMC-g- PAA-co-PVP）. The comparison between the two resins in absorption capacities is that CMC-g-PAA is better in the water-keep capability being heated, while CMC-g-PAA-co-PVP is better in the water absorbency and salt resistance.     

SYNERGISTIC EFFECT OF MINERAL SURFACE CONSTITUENTS IN DEXTRIN ADSORPTION

Abstract:As part of a systematic research on the interaction mechanismbetween polysaccharides and mineral surfaces,we extend the studies ondextrin adsorption to real minerals such as oxides and salt-type minerals,based on previous studies of model systems(surface-modified quartz).Theminerals tested include hematite,rutile,fluorite,calcite,apatite,etc.Itis obseroed that dextrin adsorption on these minerals is strongly pH-depen-dent,with adsorption maxima appearing at pH values around the isoelec-tric points of the minerals,indicating interactions with surface metal hydroxide species.X-ray photoelectron spectroscopy(XPS)measurements re-veal electronic binding energy shifts or Auger parameter changes Of miner-al surface elements after dextrin adsorption,pointing to a chemical mecha-nism of interaction.Furthermore,it is observed that the reaction of miner-als with moderate amounts of fatty acids prior to dextrin addition resultsin an increase in dextrin adsorption,whereas excessive fatty acids do theOpposite     

催化臭氧化降解水中硝基苯的机制

为揭示蜂窝陶瓷催化臭氧化降解水中硝基苯的反应机理,从臭氧与非均相表面的作用方式上推测催化氧化过程中HO.的引发历程.采用XRD、FT-IR和SEM等手段对催化剂进行表征,结果表明,催化剂主晶相为2MgO.2Al2O3.5SiO2,是标准的α-堇青石;催化剂表面存在表面羟基,其含量为9.13×10-6mol/m2,催化剂表面的pHzpc=6.60,本实验条件下(pH=6.87),表面羟基是以游离羟基或氧负离子形式存在.催化剂含有碱性氧化物MgO及酸性氧化物Al2O3和SiO2,其表面存在金属离子Lewis酸位和表面羟基.当催化剂在水溶液中进行催化臭氧化反应时,Lewis酸优先与水配位而使水离解形成表面羟基,而臭氧与金属离子Lewis酸配位作用就会大大降低.臭氧会进一步与表面羟基形成配位键和氢键,而后经由—HO2-、O3·-和HO3·等活性物质生成HO·.     

ANALOG STUDY ON THE DEPRESSING MECHANISM OF TANNIN TO DIOPSIDE

The depression mechanisms of tannin on thediopside surface have been studied by the use of Infraredspectroscopy(IR),simulated pulp and mixed solution tests,Itis found that the first order hydroxy complexes of calciumare able to interact with tannin,and to form chemical com-plexes.The functional groups in tannin molecules participat-ing in the chemical complexation are the hydroxyl groups,andcarboxyl groups derived form the hydrolysis of hydroxylgroups.     

Study on interaction energy between flotation reagent and mineral surface

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电解质浓度对电化学氧化后碳纤维表面基团含量的影响

用ＸＰＳ研究了粘胶基碳纤维在不同硝酸浓度条件下氧化后表面基团的变化规律。结果表明;随着电化学氧化中硝酸浓度的增加,碳纤维表面羟基的数量逐渐下降,羰基和羧基的数量则逐渐增加。碳纤维表面含氧基团总数随着硝酸浓度的增加,呈现下降趋势。     

用动态法研究气升式环流反应器中氧传递规律的平推流模型

假设气升管内气液以平推流向上流动，下降管液体环流时溶氧浓度按时间滞后，求出气升式环流反应器中溶氧动态传质模型的解析解，实验结果表明对粘度较高的ＣＭＣ水溶液／空气系统，当循环速度较快时，平推流模型与实验数据吻合较好。     

Adsorption behavior and mechanism of copper ions in the sulfidization flotation of malachite

Malachite is one of the main minerals used for the industrial enrichment and recovery of copper oxide resources, and copper ions are unavoidable metal ions in the flotation pulp. The microflotation, contact angle, and adsorption experiments indicated that pretreatment with an appropriate concentration of copper ions could improve the malachite recovery, and the addition of excess copper ions reduced the hydrophobicity of the malachite surface. The results of zeta potential tests indicated that sodium sulfide and butyl xanthate were also adsorbed on the surface of malachite pretreated with copper ions. X-ray photoelectron spectroscopy (XPS) results indicated that —Cu—O and —Cu—OH bonds were formed on the surface of the samples. After pretreatment with an appropriate concentration of copper ions, the number of —OH groups on the mineral surface decreased, whereas the number of Cu—S groups on the mineral surface increased, which was conducive to the sulfidization of malachite. After adding a high concentration of copper ions, the —OH groups on the mineral surface increased, whereas the number of Cu—S groups decreased, which had an adverse effect on the sulfidization flotation of malachite. Time-of-flight secondary ion mass spectrometry showed that pretreatment with copper ions resulted in a thicker sulfidization layer on the mineral surface.     

分光光度法评价低固含量颜料及涂料的稳定性能的研究

颜料与涂料的稳定性对涂布过程和涂布纸的质量有较大影响,但现有的稳定性能研究方法不能满足生产需要.作者介绍了一种新的颜料与涂料的稳定性能研究方法——分光光度法,采用此方法探讨了颜料配比、PVA、淀粉及CMC用量对涂料稳定性的影响.分光光度法采用线性回归,对测试样品进行离心处理,采用722分光光度计测定上层液体的浓度,通过比较上层涂料的浓度得知被测样品的稳定性能.研究表明,采用分光光度法测定低固含量和低黏度涂料的沉降稳定性是可行的.     

Flotation behavior and adsorption mechanism of fine wolframite with octyl hydroxamic acid

Flotation behavior and adsorption mechanism of octyl hydroxamic acid(OHA)on wolframite were investigated through flotation experiments,adsorption tests,zeta-potential measurements,infrared spectroscopy and solution chemistry calculations.Results of flotation and adsorption experiments show that the maximum values of flotation recovery and adsorption capacity occur around p H 9.In term of the solution chemistry calculations,the concentration of metal hydroxamate is greater than that of metal tungstate and metal hydroxyl,and metal hydroxamate compounds are identified to be the main species on wolframite surface at p H region of 8-10,contributing to the increase of OHA adsorption and flotation performance.Results of zeta-potential and IR spectra demonstrate that OHA adsorbs onto wolframite surface by chemisorptions.Hydroxamate ions can bond with Mn_2+/Fe_2+cations of wolframite surface,forming metal hydroxamate compounds,which is a key factor in inducing the hydrophobicity of wolframite under the conditions of maximum flotation.     

CHEMICAL PROPERTIES OF AMINO-CARBOXYLMETHYL CELLULOSE AND ITS DEPRESSING MECHANISMS ON STIBNITE

This paper presents a study on the chemical properties ofamino-carboxylmethyl cellulose(ACMC)and the mechanisms of the reac-tion of ACMC with copper ions and the depression of ACMC on CuSO_4-ac-tivated stibnite.The results of XPS and IR analyses show that after CMCis treated by aqueous ammonia,amino-carboxyl groups form in CMCmolecules by H-bonding action which can complex selectively with copperions to form copper-amino-carboxymethyl cellulose.On the surface ofCuSO_4-activated stibnite,ACMC is also able to complex strongly with cop-per ions and forms a strong hydrophilic depression film.Because there arethe obvious difference of reactions between ACMC with Cu~(2+) and ACMCwith Hg~(2+),the separation of cinnabar from stibnite is successfully realizedusing ACMC as depressant and CuSO_4 as activator.     

沉积TiO2膜的成型活性炭的制备及性能研究

以粉末活性炭为基料,煤焦油为粘结剂,淀粉为造孔剂,添加适量的羧甲基纤维素（CMC）,经稳定化、炭化、活化等工艺制备成型活性炭（FAC）,并在表面沉积具有光催化活性的TiO2膜。考察原料组成及热处理温度对FAC机械强度、透水性及吸附性能的影响。当成型活性炭原料配比（质量分数）为粉末活性炭60%,焦油28%,淀粉6%,CMC6%,稳定化温度为270℃,炭化温度500℃,活化温度800℃,FAC性能较好。TiO2膜的沉积提高了FAC的强度,吸附性能和透水性变化不大。     

浮石催化水中臭氧分解研究

为考察浮石表面化学性质对水中臭氧分解的影响,测定了浮石催化水中臭氧分解的速率常数并探讨催化臭氧分解的途径．结果表明:浮石促进水中臭氧一级分解速率常数提高了37.4％;利用叔丁醇捕获生成的羟基自由基,催化臭氧分解速率常数降低了45.2％,浮石催化臭氧分解生成了羟基自由基;浮石表面羟基密度与催化臭氧分解率成正相关;随着溶液初始pH值增大,单独臭氧分解和浮石催化臭氧分解率均增加;由浮石pH_pzc决定的表面电荷状态与催化臭氧分解效果有关,表面接近电中性时对催化臭氧分解有利．水中臭氧分解主要发生在浮石表面,浮石表面的金属氧化物可能是催化水中臭氧分解的活性物质．     

柠檬酸改性Hβ分子筛酸性中心的调变与解析

采用不同浓度柠檬酸对Hβ分子筛进行改性,运用XRD、Ar吸附等温线等方法对其织构性质进行表征,并通过NH3⁃TPD和Py⁃FTIR关联改性Hβ分子筛的酸性质,以吡啶为探针分子,分析吡啶分子与Hβ分子筛各活性组成单元的作用形式。结果发现,Hβ分子筛除存在与硅铝桥羟基相关的B酸中心外,还存在与非骨架铝羟基基团有关的弱L酸中心以及缺陷位处三配位的Al羟基物种和AlO+有关的强L酸中心。非骨架铝物种与临近的硅铝桥羟基间存在协同作用,吡啶分子可以吸附在其L酸中心并与临近B酸中心产生键合,在高温时不易脱附。吡啶分子会优先吸附在酸性较强的硅铝桥羟基和缺陷位处三配位的Al羟基活性位上,而与非骨架铝羟基基团作用较弱。经柠檬酸处理后,分子筛中部分非骨架铝羟基物种被选择性移除,且未对骨架铝造成严重破坏。Hβ分子筛经柠檬酸酸处理后仍存在强L酸中心,此强L酸中心的存在方式可能与AlO+和缺陷位的三配位的Al物种有关。