逆流浸取低品位磷矿的工艺研究

本文以P2O5含量为15%的低品位磷矿为原料,不经过磷矿富集,直接进行逆流浸取实验,获得实验室条件下的最佳工艺条件为:反应温度80℃,液固比12:1,反应时间2h,磷酸质量分数(P2O5)20%.实验还探讨了逆流浸取中SO3质量浓度对低品位磷矿酸解率的影响,获得实验用矿在逆流浸取中的最佳SO3质量浓度为35～40g/L.     

硝磷混酸酸解低品位磷矿的工艺研究

采用正交实验,研究了高倍半氧化物含量的中低品位磷矿在磷酸与硝酸混酸中的酸解行为,并确定了实验室最佳工艺条件:反应温度65℃,液固比14∶1,磷酸浓度(P2O5)20%,硝酸浓度9.50 g/L,添加物KDD浓度5.50 g/L,反应时1 h.P2O5浸取率大于92%,Fe2O3浸取率及Al2O3浸取率均小于17%.     

中低品位磷矿直接制湿法磷酸技术研究

对晋宁地区的中低品位磷矿直接制备磷酸技术进行了系统研究,以磷、铁铝镁浸取率为主要指标,考察了反应温度、反应时间、反应固液比和SO3质量浓度的影响,确定酸解较优工艺条件为:反应温度80℃、反应时间4h、SO3质量浓度40g/L,在此条件下进行验证试验,磷的平均浸取率达到了94.77%。     

白肥制磷酸一铵及P_2O_5酸浸动力学研究

白肥是湿法磷酸生产饲料级磷酸氢钙过程中产生的杂质质量分数较高的固体产物。本文将白肥视为一种磷矿资源,提出了稀酸浸取白肥,利用其中的P2O5制备肥料级磷酸一铵的工艺路线,以提高磷化工过程总体经济效益。通过实验确定了浸取过程的主要影响因素为酸解温度、时间、H2SO4/P2O5摩尔比、液固比以及白肥初始粒度等。研究发现,优化的酸解条件为:反应温度65~75℃,反应时间为1~1.5h,H2SO4/P2O5=1.4~1.6,反应液固比为3~4.5。在优化条件下白肥中P2O5的浸取率最高可达到97%。本文系统地考察了稀硫酸浸取白肥中P2O5的浸取动力学过程,并建立了数学模型:1/tln1/1-x-γx/t=0.01277exp(-Ea/RT)C0.2821 A0R-0.5737S0。     

磷精矿中P2O5浸出工艺研究

针对贵州某磷矿浮选的磷精矿,研究了磷酸质量分数、硫酸化学计量比、温度、液固比对磷精矿中P2O5浸出率的影响,得出合理的浸出工艺为;磷酸质量分数23%,硫酸化学计量比1.1,温度80℃,液固比4∶1.在此条件下P2O5浸出率为86.84%.     

磷酸化学浸提法脱除磷矿镁杂质工艺研究

以贵州开阳磷矿粉为原料,研究了磷酸化学浸提法脱镁的最佳工艺条件,即脱镁剂稀磷酸溶液P2O5质量分数15%、pH值2.0、反应温度55℃、反应时间2.5h、液固比2.0。在该条件下,Mg脱除率75.67%,P2O5损失率2.33%,镁磷比2.03%。同时研究了磷矿脱镁液氨水沉淀法制备六水磷酸铵镁的最佳工艺条件,即pH值8.5、反应温度40℃、反应时间60min。在该条件下,P2O5回收率99.31%,Mg回收率87.70%。     

用磷酸二氢钙制磷酸二氢钾的磷收率研究

采用单因素实验和二次回归正交实验设计,对磷酸二氢钙与硫酸钾生产磷酸二氢钾反应过程中反应温度、反应时间、硫酸钾与磷酸二氢钙摩尔比以及液固比诸因素对五氧化二磷收率的影响进行了研究,最终得到适宜的工艺条件为:反应温度50℃,反应时间120min,反应液固比4:1,硫酸钾与磷酸二氢钙摩尔比(K2O:P2O5)1.1:1,所得P2O5收率超过70%.     

采用盐酸溶液从废旧锂离子电池正极还原浸取钴

采用盐酸和双氧水体系为浸取液对废旧锂离子电池正极进行还原处理。正交实验表明,影响Co2+浸出率几种因素强度顺序为:HC l浓度>固液比>H2O2-HCl体积比>反应温度>反应时间。最佳浸取条件为:HCl浓度为3 mol/L,H2O2-HCl体积比为1∶15,反应时间90 min,反应温度80℃,固-液比(g/mL)为1∶50。此时,Co2+浸出率达到99.6%。     

高品质磷石膏处理工艺研究

综合利用磷石膏对治理环境和资源循环利用具有重大意义.磷石膏中的五氧化二磷、氟、有机物等杂质影响磷石膏的利用.为了得到高品质磷石膏,研究了用硫酸浸取磷石膏的反应条件,如硫酸质量分数、反应温度、反应时间及液固比等因素对磷石膏中酸不溶五氧化二磷含量的影响.通过单因素分析和正交实验设计,确定了最佳工艺条件.最佳工艺条件为:硫酸质量分数35%;反应温度60℃;液固体积质量比为3 mL/g;反应时间4.5 h.在此条件下磷石膏中酸不溶五氧化二磷质量分数降低到0.01%以下.     

有机溶剂浸取湿法磷酸脱氟渣制备磷酸的研究

脱氟渣是湿法磷酸化学沉淀脱氟过程产生的固体废渣。分别用甲醇、乙醇和丙酮浸取脱氟渣来回收脱氟渣中的磷酸,研究了浸取时间、温度和液固比对于五氧化二磷、氟的浸取率以及浸出液磷氟比［m（五氧化二磷）/m（氟）］的影响,得到了适宜的浸取条件。浸取液经蒸发浓缩回收浸取剂后,浓缩液均可满足饲料级磷酸氢钙生产对于湿法磷酸磷氟比的要求。综合考虑浸取剂成本、五氧化二磷浸取率和浸出液磷氟比,确定甲醇为优选浸取剂,并用响应面法对甲醇浸取工艺条件进行优化。优化工艺条件下五氧化二磷的浸取率为97.13%、浸出液磷氟比为51.62,甲醇在5次循环回收利用后对脱氟渣仍有较好的浸取效果。     

The Effects of Biopolymer Encapsulation on Total Lipids and Cholesterol in Egg Yolk during in Vitro Human Digestion

The purpose of this study was to examine the effect of biopolymer encapsulation on the digestion of total lipids and cholesterol in egg yolk using an in vitro human digestion model. Egg yolks were encapsulated with 1% cellulose, pectin, or chitosan. The samples were then passed through an in vitro human digestion model that simulated the composition of mouth saliva, stomach acid, and the intestinal juice of the small intestine by using a dialysis tubing system. The change in digestion of total lipids was monitored by confocal fluorescence microscopy. The digestion rate of total lipids and cholesterol in all egg yolk samples dramatically increased after in vitro human digestion. The digestion rate of total lipids and cholesterol in egg yolks encapsulated with chitosan or pectin was reduced compared to the digestion rate of total lipids and cholesterol in other egg yolk samples. Egg yolks encapsulated with pectin or chitosan had lower free fatty acid content, and lipid oxidation values than samples without biopolymer encapsulation. Moreover, the lipase activity decreased, after in vitro digestion, in egg yolks encapsulated with biopolymers. These results improve our understanding of the effects of digestion on total lipids and cholesterol in egg yolk within the gastrointestinal tract.     

Methane production from acids in piggery-waste digesters

Results from piggery-waste digestion fit those from a continuous culture of acetate utilising methanogenic bacteria showing that the acid to methane step of this digestion can be regarded as an independent continuous culture behaving as predicted by a simple continuous culture model with a wash-out dilution rate of about 0.4 day^?1 and a K_s value of about 800–900 mg acetic acid dm^?3. However, this was only possible because the waste contained a high concentration of free acid and the application of the results to other digestions is discussed.     

低劣生物质厌氧产甲烷过程的模拟研究进展

低劣生物质厌氧消化可以减少温室气体的排放并且生产生物甲烷作为能源。介绍了关于厌氧消化过程、底物的相关理论,还对目前主要用于厌氧产甲烷过程研究的数学模型以及碳氮磷转化的模拟研究进行了综述。其中,一级动力学模型是最为简单的数学模型,其可以通过简单的计算得到整个过程中甲烷产量随着时间的变化曲线,但是只限于较准确模拟甲烷产率的ADM1模型相对发展最为全面、应用最为广泛,且能够针对具体要研究的对象进行模型的修改。同时总结了较为常见的底物厌氧产甲烷研究模型、研究对象及结果、已有碳/氮/磷转化模拟研究及相关研究,并对开展针对厌氧产甲烷过程中碳氮磷转化的模拟研究进行了展望。     

铜阳极泥脱铜渣中金、银、钯含量测定

建立了连续测定铜阳极泥脱铜渣中金、银、钯含量的分析方法,并与火试金法进行比较。首先,利用硝酸+乙二胺四乙酸（EDTA）+酒石酸消解铜阳极泥脱铜渣,得到含有银、钯和少量金的消解液,考察了硝酸、EDTA和酒石酸用量对消解效果的影响。结果表明,硝酸、EDTA和酒石酸用量分别为30mL、3mL、1.5g时,消解效果最好。然后,利用王水对残渣进行二次消解,得到含有金和少量银、钯的消解液,考察了王水用量对消解效果的影响。结果表明,王水用量为15mL时即可完成消解。最后采用火焰原子吸收光谱仪测定消解液中的金、银、钯含量。采用本方法测定铜阳极泥脱铜渣,Au、Ag、Pd各元素相对标准偏差均小于1%（n=10）,加标回收率在95.57%～98.70%之间,实验结果准确可靠、重现性好,与火试金法测定结果相一致。     

丁辛醇废铑液液相消解铑回收工艺研究

对比研究了硫酸一硝酸体系及硫酸-硝酸钠体系丁辛醇废铑液液相消解铑回收工艺,并对消解酸用量、消解温度进行优化,确定了一条理想的硫酸-硝酸钠废铑液液相消解铑回收工艺,该工艺反应温和、消解效率高、铑损失小于1％。     

A review of the studies on phosphate rock for agricultural use in China

Since the early 1940's, systematic studies on phosphate rock (PR) for agricultural use have been made in China. These covered the following aspects: Mineralogical properties of phosphate rock materials, including svanbergite; Ability of different plants to absorb phosphorus from PR; Effect of soil properties on the availability of PR to plants; Technologies for processing powdered PR.Since these studies are mostly published in Chinese [4, 6, 7, 8, 9, 11, 15, 16, 17, 18], they are virtually unknown to agronomists and soil scientists outside China. The present article is a comprehensive review of the studies on PR for agricultural use carried out in China during the last 50 years.It is shown that because of the easily decomposable properties of certain Chinese PR's, the limited industrial potentialities in present day China (particularly the shortage of sulphuric acid), the large areas of strongly acid red soils in Southern China, the introduction of legume crops in the rotation, and the planting of perennial trees, notably rubber in tropical areas, the direct application of powdered PR for agricultural use appears to be very advisable.     

In Vitro Intestinal Bioaccessibility of Alkylglycerols Versus Triacylglycerols as Vehicles of Butyric Acid

Butyric acid has been the subject of much attention last years due to its bioactivity. However, the potential advantages of butyrate are limited by the problem to reach enough plasma concentrations; therefore, pro-drugs have been proposed as an alternative to natural butyrate. A comparative study on in vitro intestinal digestion of 2,3-dibutyroil-1-O-octadecyl glycerol (D-SCAKG) and tributyrin (TB), as potential pro-drugs of butyric acid, was performed. Aliquots were taken at different times of digestion for studying the extent and rate of hydrolysis of both substrates. The micellar phase (MP) and oily phase (OP) formed in the digestion media were separated and their composition in lipid products was analyzed. Initially, it was confirmed that the in vitro model reproduced physiological results by testing against olive oil as a standard lipid. The progress of in vitro intestinal digestion of D-SCAKG was slower than that of TB. TB hydrolyzed completely to butyric acid, whereas D-SCAKG mainly yielded 2-butyroil-1-O-octadecyl glycerol (M-SCAKG), followed by butyric acid and 1-O-octadecyl glycerol (AKG). The MP from both substrates mainly consisted of butyric acid. Minor levels of M-SCAKG and AKG were also found in the MP after hydrolysis of D-SCAKG, the M-SCAKG being mainly distributed in the OP. Therefore, D-SCAKG produced a stable form of esterified butyric acid as M-SCAKG after in vitro intestinal digestion, unlike TB. Additionally, such a product would integrate both bioactive compounds, butyric acid and alkylglycerol, within the same molecule. Free butyric acid and AKG would be also released, which are lipid products of interest as well.     

微波消解-火焰原子吸收法测定土壤中铜锌铅镍锰

讨论了用原子吸收光度法测定土壤中铜、锌、铅、镍和锰。通过硝酸-氢氟酸-高氯酸以及硝酸-盐酸-过氧化氢体系消解液对土壤样品消解,选择出微波最佳消解条件。对硝酸-氢氟酸-高氯酸体系消解液和硝酸-盐酸-过氧化氢体系消解液进行消解对比试验,发现前者将土壤样品中的铜、镍和锰完全消解,后者能将样品中的锌和铅消解完全。微波消解土壤和传统电热板消解在测定前都需将消解液中剩余的酸赶尽,但与传统电热板消解相比,微波消解操作简便快速,可提高工作效率。     

异辛酸铬中铬的测定

比较分析了异辛酸铬的2种消解方法即湿法消解和干法消解。实验结果表明,湿法消解是通过将样品溶剂蒸干、硫酸炭化、硝酸消化等方法,使样品变成三价铬溶液;干法消解是用合适的有机溶剂稀释样品,精确吸取适量的样品稀释溶液,通过干燥、炭化和干法灰化,再选择适当浓度的硫酸溶解样品等合适的化学处理方法来制备样品试验溶液。在酸性溶液中,以硝酸银作催化剂,用过硫酸铵将三价铬氧化成六价铬,用硫酸亚铁铵滴定法测定六价铬含量。2种方法所得结果误差0.2%。     

作业场所空气中铅测定方法的研究

作业场所空气中铅的测定,除了采样外,酸消化过程也是非常重要的步骤。深入分析酸对铅测量结果的影响,结果表明酸含量对测量结果影响不大,但消化液、高氯酸与硝酸在对测量结果的具体影响上不尽相同,略有差异,总体上都是随着酸含量的增加,测量结果逐渐略微偏低,因此实际的工作中应当尽量把酸蒸发完全。