钨浮选尾水回用对铜钨浮选指标的影响

钨浮选过程中使用的捕收剂、抑制剂组合,导致选矿废水中细粒物质难以自然沉降,且有机物含量超标,严重影响尾水回用。对含铜硫钨矿物依次经浮选后形成的溢流水,采用石灰调节pH值,聚丙烯酰胺和粉煤灰絮凝沉降,能去除水中的有机污染物、降低重金属离子浓度,实现尾水回用并进行循环试验。结果表明,回水循环30天后,上清液中COD含量和Cu、Pb离子浓度没有显著的累积效应;与原水开路试验对比,铜粗精矿中铜品位仅细微波动,但产率降低了2.15个百分点,回收率降低了1.67个百分点;钨粗精矿中钨品位降低了0.4个百分点,而产率和回收率分别提升了0.32和1.02个百分点。回水闭路浮铜试验以原矿作为原材料,能获得产率为1.92%、品位为19.12%、回收率为85.22%的铜精矿;回水闭路浮钨试验以钨浮选给矿为原材料,能获得产率为9.38%、品位为3.88%、回收率为95.71%的钨粗精矿。     

碳酸钠对白钨矿自载体浮选的影响及机理

-10 μm白钨矿的浮选回收率低, 导致大量白钨矿损失于尾矿中, 造成资源浪费, 而载体浮选是提高-10 μm白钨矿回收率的有效方法之一.根据粒级以及粒级组成对白钨矿浮选的影响, 通过浮选试验、理论计算和仪器检测等方法研究了-10 μm细粒级白钨矿的自载体浮选, 同时研究了载体比例、载体含量和碳酸钠对白钨矿自载体浮选的影响.研究结果表明, 油酸钠为捕收剂时, 在合适的载体粒度和载体比例下, 自载体浮选是提高-10 μm白钨矿回收率的有效方法, 碳酸钠可强化白钨矿的自载体浮选, 扩大载体比例和载体粒度范围.机理研究表明, 白钨矿      

浅论抑制剂添加顺序对浮选的影响

通过锡石浮选及铜铅锌多金属硫化矿浮选试验与工业生产指标对比，阐明了在工业生产中因抑制剂添加地点不适而导致的药剂添加顺序和浮选顺序混乱，乃是造成浮选指标下降的主要原因。得出：正确选定抑制剂添加地点，是实现浮选顺序、药剂添加顺序和获得良好技术指标的重要措施。     

金属离子对矿物浮选行为影响的研究进展

在矿物浮选过程中,由于矿物的粉碎溶解、药剂的添加、回水的循环利用等原因,矿浆中难免会存在一些金属离子,这些金属离子往往会对矿物的浮选行为产生重要影响.在对相关文献分析和总结的基础上,概述了金属离子对氧化物矿物、硫化物矿物、硅酸盐矿物浮选和分离的影响.金属离子在不同pH条件下会形成络合物或沉淀,通过消耗捕收剂,抑制捕收剂分解来抑制矿物浮选,矿浆中离子浓度增大到一定程度也会抑制矿物浮选,单种离子不同组分或不同离子组合对浮选效果有较大影响.      

消除矿泥对汤丹难选氧化铜矿浮选影响的研究进展

基于汤丹矿泥的组成和浮选特性针对矿泥对汤丹难选氧化铜矿的影响进行了长时间的试验研究，主要是通过寻找新的浮选药剂及符合新药剂特性的浮选工艺，使浮选指标获得了改善。     

明矾对氟碳铈矿与独居石浮选分离的影响

在氟碳铈矿与独居石浮选分离中，明矾作调整剂能强烈抑制独居石而使氟碳铈矿与独居石得到有效分离,在白云鄂博混合稀土精矿浮选分离中取得了良好结果.本文讨论明矾对氟碳铈矿与独居石分离的影响。     

黄铁矿对铅锌硫硫化矿浮选工艺的影响

作者根据国内铅锌硫硫化矿矿石的选矿实践,论述了黄铁矿对铅锌硫浮选流程和药剂制度的影响。     

水质对铝土矿浮选指标的影响

前言introduction鉴于我国铝土矿大部分为高铝、高硅、中低铝硅比的一水硬铝石型铝土矿,中国铝业中州分公司采用选矿-拜耳法高新技术生产氧化铝,并获得了产业化生产的成功。为了节约用水和充分提高水资源利用率,降低工业废水外排造成的污染,选矿回水大部分返回生产流程再利用,而浮选回水的特点是:含有较多的有机和无机药剂,组成比较复杂,水质变化较大;因此,使用时必须考虑它们对浮选过程的影响。本文根据中州分公司浮选工艺流程,在实验室进行了水质对铝土矿浮选指标的影响研究,提出了铝土矿浮选回水的控制指标。原矿性质Character of the p…     

反浮选工艺对程潮铁精矿球团质量的影响

以程潮铁矿反浮选前和反浮选后的铁精矿为原料,通过对比试验,研究了反浮选工艺对球团质量的影响.结果表明,在相同膨润土配比和造球条件下,用反浮选后精矿造出的球团,其多项质量指标均不如使用反浮选前精矿所造的球团,在膨润土用量0～3.0%范围内,生球落下强度下降最大值达1.9次/个;生球抗压强度最高下降1.4 N/个;熟球抗压强度最高下降1 280 N/个;生球爆裂温度呈上升趋势.     

古尔胶和鞣酸添加方式对硫化矿浮选的影响

通过浮选实验研究了两种不同结构的有机抑制剂古尔胶和鞣酸以及这两种药剂与乙基黄药不同添加顺序对方铅矿、黄铜矿及黄铁矿浮选行为的影响.当先加入古尔胶时,古尔胶对三种硫化矿抑制作用较强;而古尔胶后于乙基黄药加入时,古尔胶对三种硫化矿的抑制作用明显减弱.鞣酸与乙基黄药不同的添加顺序不影响鞣酸对黄铁矿和方铅矿的抑制作用.紫外光谱研究表明,古尔胶对乙基黄药在三种硫化矿表面吸附没有影响,而鞣酸能够阻碍乙基黄药在硫化矿表面吸附.红外光谱研究表明,鞣酸通过化学作用吸附在方铅矿表面,因此能够抑制吸附了乙基黄药的硫化矿.     

An investigation of the flotation mechanism in the aerosol column flotation machine

It is shown that the induction time decreases as the temperature decreases if there is air bubble adhesion to hydrophobic and hydrophilic particles; if there isn’t, the time decreases where hydrophobic particles stick to one another and increases in the case of adhesion of hydrophilic particles. The established difference in the stability of wetting and symmetric films that depend on temperature can be explained by the fact that hydrophobic forces (involving those acting from a “hydrophobic” bubble) have a larger action radius of action than the forces of hydrophilicrepulsion. The revealed mechanisms allowed the development of a new flotation technique, namely, flotation with a steam-air mixture. The essence of this technique is that only a surface layer of the bubble, where the effect of structural forces is localized (rather than the entire slurry volume) is heated due to steam condensation. The efficiency of this technique is shown by the example of flotation concentration of minerals of different origins.     

Synergistic adsorption mechanism of styryl phosphoric acid and nonyl alcohol on the rutile surface and effects on flotation

Styryl phosphoric acid (SPA) is considered to be one of the best selective collectors for rutile flotation. Yet high consumption and considerable environmental pressure have limited its wide applications. In this study, n-nonyl alcohol (NNA) was used as the auxiliary collector to reduce SPA dosage. The experimental results indicated that when SPA was used as the single collector, the rutile flotation presented an optimum index of recovery being 52.26% and the grade being about 45% with a SPA concentration of 0.4?×?10^?4?mol?L^?1. But when 0.4?×?10^?4?mol?L^?1 SPA and 0.4?×?10^?4?mol?L^?1 NNA were used as the mixture collectors, the resulting recovery increases to 82%, and the grade reached 47%. The synergistic adsorption mechanism was investigated by foam properties measurements, zeta potential measurements and FT-IR analysis. NNA increased the foam amount and improved its stability, and quickly reduced the surface tension of the solutions. On the other hand, SPA was first adsorbed on the rutile surface, and then NNA chemically reacted with SPA in the form of hydrogen bond.     

脂肪胺浮选捕收剂的光化学降解

对水体中脂肪胺阳离子浮选捕收剂(癸烷基丙基醚胺、十二烷基丙基醚胺、十二胺和十八胺)的降解方法与效果进行了研究.生物降解性(BOD/COD_Cr比值)实验研究表明,这四种脂肪胺浮选捕收剂均难以生物降解.UV/H₂O₂/air氧化法是一种降解脂肪胺浮选捕收剂的有效方法,其降解率高、反应条件温和、操作简易,无二次污染.降解率大小顺序为:癸烷基丙基醚胺>十二胺>十二烷基丙基醚胺>十八胺,与COD去除率大小顺序一致.在pH为4.5、起始质量浓度为10 mg·L-1、1%的H₂O₂作为光催化剂、紫外光照15 min的条件下,癸烷基丙基醚胺的降解率为99.99%,COD去除率为78.06%.测定了十二烷基丙基醚胺和十八胺两种典型脂肪胺浮选捕收剂模拟废水降解前后的红外吸收谱图,初步探讨了UV/H₂O₂/air光化学氧化法处理脂肪胺浮选捕收剂模拟废水的降解机理.     

Induction of lipid peroxidation during heavy metal stress in Saccharomyces cerevisiae and influence of plasma membrane fatty acid unsaturation

The degree of plasma membrane fatty acid unsaturation and the copper sensitivity of Saccharomyces cerevisiae are closely correlated. Our objective was to determine whether these effects could be accounted for by differential metal induction of lipid peroxidation. S. cerevisiae S150-2B was enriched with the polyunsaturated fatty acids (PUFAs) linoleate (18:2) and linolenate (18:3) by growth in 18:2- or 18:3-supplemented medium. Potassium efflux and colony count data indicated that sensitivity to both copper (redox active) and cadmium (redox inactive) was increased in 18:2-supplemented cells and particularly in 18:3-supplemented cells. Copper- and cadmium-induced lipid peroxidation was rapid and associated with a decline in plasma membrane lipid order, detected by fluorescence depolarization measurements with the membrane probe trimethylammonium diphenylhexatriene. Levels of thiobarbituric acid-reactive substances (lipid peroxidation products) were up to twofold higher in 18:2-supplemented cells than in unsupplemented cells following metal addition, although this difference was reduced with prolonged incubation up to 3 h. Conjugated-diene levels in metal-exposed cells also increased with both the concentration of copper or cadmium and the degree of cellular fatty acid unsaturation; maximal levels were evident in 18:3-supplemented cells. The results demonstrate heavy metal-induced lipid peroxidation in a microorganism for the first time and indicate that the metal sensitivity of PUFA-enriched S. cerevisiae may be attributable to elevated levels of lipid peroxidation in these cells.     

Influence of adaptation to supercooling on the fatty acid composition of rat tissue lipids

Adaptation to supercooling produces a considerable effect on composition and quantitative content of certain fatty acids in all the studied tissues. In lipids of the myocardium and skeletal muscles adaptation causes an increase in the content of unsaturated fatty acids in particular of polyenic ones. In lipids of the lungs, vice versa, the content of saturated fatty acids increases, chiefly due to palmitic acids. In lipids of the liver a ratio of certain unsaturated fatty acids changes noticeably: the content of monoenic acids rises but the content of polyenic acids is more than 5 times as low.     

Influence of the nutrient medium on the total lipid fatty acid composition of Actinomyces canosus

GLC was used to study the composition of endocellular fatty acids of Actinomyces canosus 89 grown on a chemically defined medium and on a complex medium to which various components were added. Total lipids of the culture contain saturated and unsaturated fatty acids, from C13 to C18, with one or two double bonds. Addition of components to the medium stimulated the biosynthesis of myristic, stearic, oleic, and linoleic fatty acids. Changes in the composition of the growth medium modify the ratio between saturated and unsaturated fatty acids of total lipids, increasing the content of unsaturated fatty acids due to a higher rate of synthesis of linoleic and oleic fatty acids. An increase in the content of unsaturated fatty acids is a positive factor because these acids are involved in important physiological functions of both this organism and other living organisms.     

Fatty acid profile and physical properties of milk fat from cows fed calcium salts of fatty acids with varying unsaturation

Holstein cows (n = 24) averaging 42 d in milk were used in a randomized complete block design during a 4-wk trial. A control total mixed ration (TMR) was compared with TMR supplemented with Ca salts of fatty acids from canola oil, soybean oil, or linseed oil. The three vegetable oils were progressively more unsaturated; the dominant fatty acids were, respectively, cis-delta-9-C18:1, C18:2, and C18:3. Apparent total tract digestibility of dry matter, crude protein, ether extract, and neutral detergent fiber was higher for rations containing Ca salts than for the control ration. Milk yield increased linearly as the unsaturation of the dominant fatty acid in the Ca salts increased. Milk fat percentage was reduced when Ca salts were added to the rations. The addition of Ca salts to the ration decreased the proportions of saturated fatty acids that contained C6 to C16 and increased the proportions of C18:0, cis-delta-C18:1, and trans-delta-11-C18:1 in milk fat. Proportions of C18:2 and C18:3 increased linearly, and cis-delta-9-C18:1 decreased linearly, as the unsaturation of the dominant fatty acid in the Ca salts increased. The proportion of fat that was liquid at 5 degrees C was higher for butter from cows fed diets containing Ca salts, but the proportion of liquid fat at 20 degrees C was not affected. Calcium salts of unsaturated fatty acids added to the diets of dairy cows improved the thermal properties of milk fat.     

On the mechanism of long chain fatty acid transport in cardiomyocytes as facilitated by cytoplasmic fatty acid-binding protein

Fatty acid-binding protein (FABP) is abundantly present in the cytoplasm of the cardiomyocyte, i.e. the cell which causes the contractile activity of the heart. Although FABP is thought to act as an intracellular long chain fatty acid (FA) carrier, definite experimental proof on this putative function has yet to be obtained. In the present study, experimental results from several authors were combined in an attempt to elucidate the precise physiological function of heart-type FABP in cardiac FA transport. It was calculated that, under normal conditions, the major part of FA in the cardiomyocyte is dissolved in lipid bilayers and that the presence of FABP in the heart enhances the aqueous solubility of FA more than 700-fold despite the fact that only a minor part (< 2%) of the total FABP content is then complexed with FA. Moreover, it is shown that, as a result of the enhanced cytoplasmic solubility, the FA flux from sarcolemma (the cellular membrane of the cardiomyocyte) to mitochondria is increased at least 17-fold in the presence of physiological amounts of FABP compared with the hypothetical situation in which FABP is absent. These calculations indicate the involvement of FABP in the transport of FA from the sarcolemma to those mitochondria lying in the innermost region of the cardiomyocyte. The extent to which FABP facilitates FA trafficking through the cytoplasm of the cardiomyocyte under physiological circumstances remains, however, to be established.     

Influence of salt concentration on the cellular fatty acid composition of the moderately halophilic bacterium Halomonas salina

CONTEXT: Little is known about the problems physicians may be encountering in gaining access to managed care networks and whether the process used by managed care plans to select physicians is discriminatory. OBJECTIVE: To investigate the incidence and predictors of denials or terminations of physicians' managed care contracts and the impact these denials and terminations had on primary care physicians' involvement with managed care. DESIGN: Cross-sectional mail survey of a probability sample of primary care physicians. SETTING: A total of 13 large urban counties in California. PARTICIPANTS: Primary care physicians (family practice, internal medicine, obstetrics and gynecology, or pediatrics) who work in office-based practice. MAIN OUTCOME MEASURES: Denial or termination from a contract with an independent practice association (IPA) or health maintenance organization (HMO) and managed care contracts. RESULTS: Of the 947 respondents (response rate, 71%), 520 were involved in office-based primary care. After adjusting for sampling and response rate, 22% of primary care physicians had been denied or terminated from a contract with an IPA or HMO, but 87% of office-based primary care physicians had at least 1 IPA or direct HMO contract. Solo practice was the strongest predictor of having experienced a denial or termination and of having neither an IPA nor a direct HMO contract. Physician age, sex, and race did not predict the level of involvement with managed care. However, physicians' patient demographics were associated with managed care participation; physicians in managed care had significantly lower percentages of uninsured and nonwhite patients in their practices. Physicians experiencing a denial or termination had fewer capitated patients in their practice. CONCLUSIONS: Denials and terminations, although relatively common, do not preclude most primary care physicians from participating in managed care. Managed care selective contracting does not appear to be systematically discriminatory based on physician characteristics, but it may be biased against physicians who provide greater amounts of care to the underserved.