不同淋洗剂对不同性质污染土壤中镉的浸提效率比较

以三种外源添加Cd的低污染土壤(酸性、石灰性和高有机质土壤)为研究对象,对比了两种螯合剂,两种酸性溶液对Cd的浸提效果。结果表明,螯合剂的浸提效率高于酸性溶液,并呈现出EDTA>EDDS>柠檬酸和HCl的顺序。三种土壤上,在0.05~0.20 mol L-1的浓度范围内,EDTA和EDDS随浓度的升高对Cd的浸提效率差异不显著,表明螯合剂在过量的情况下并不能显著提高Cd的浸提效率;而柠檬酸和HCl对Cd的浸提效率随浓度的升高而增加,尤其在石灰性土壤上,浓度的升高极显著地提高了浸提效率。外源添加Cd污染土壤上Cd浸提效率极显著高于田间无污染土壤。研究结果显示EDTA用于Fe、Ca含量均较低的土壤效果更好,EDDS宜用于有机质和黏粒含量均较低的土壤,而柠檬酸和HCl宜用于酸性土壤。

DTPA和CaCl_(2)浸提方法下土壤中重金属提取效率比较研究

文章对江苏省地区重金属含量较高的5个碱性土壤和5个酸性土壤中的8个重金属元素进行了DTPA浸提和CaCl_(2)浸提试验。无论是在酸性土壤还是碱性土壤中,As,Cr和Hg这3个元素在两种浸提方法下的浸提效率都很低,基本均在0.5%以下,其中Hg的实际浸出含量几乎可忽略不计。Cd,Cu,Ni,Pb和Zn这5个元素总体来说,无论是在酸性土壤还是碱性土壤中,DTPA浸提效率都高于CaCl_(2)浸提效率。其中,酸性土壤中的Cd元素,在两种浸提方法下的浸提率均高于其他几个重金属元素,最容易被浸提出来。土壤的酸碱性和元素本身在土壤中的赋存形式对元素在不同浸提溶液下的提取效率有很大影响。

枸杞逆流浸提工艺的研究

以浸提效率作为评价指标,就枸杞逆流浸提工艺过程中的浸提温度、浸提时间、浸提级数及固液比进行了研究,得出了优化的逆流浸提工艺条件。

黑玉米色素提取方法的研究

以黑玉米为原料 ,通过单因子试验研究了诸多因素对提取色素效率的影响。结果表明 ,提取最优方案是以等体积 95 %乙醇与 0 .1mol/ L HCl的混合物为浸提剂 ,按黑玉米与浸提剂重量比 1∶ 4投料 ,在 80℃下浸提两次 ,每次 2 4h,提取总效率达 18.4%

荔枝加工副产物高值化利用技术

一、技术概述荔枝加工过程中产生的副产物果皮和果渣中含大量的酚类物质。本技术利用多重粉碎技术将副产物破碎至极细小颗粒，从而有效增加溶剂浸提效率．利用乙醇或水为浸提溶剂，高效提取果皮和果渣中的酚类物质。

Extraction of nickel from molybdenum leaching residue of metalliferous black shale by segregation roasting and acid leaching

The recovery of nickel from molybdenum leach residue by the process of segregation roasting-sulfuric acid leaching-solvent extraction was investigated. The residue was characterized by microscopic investigations, using X-ray fluorescence spectrometry （XRF） and X-ray diffractometry （XRD） techniques and the residue after segregation roasting was characterized by chemical phase analysis method. A series of experiments were conducted to examine the mass ratio of activated carbon （AC） to the residue, segregation roasting time and temperature, sulfuric acid concentration, liquid-to-solid ratio, leaching time, leaching temperature, addition amount of 30% H2O2, stirring speed （a constant） on the leaching efficiency of nickel. A maximum nickel leaching efficiency of 90.5% is achieved with the mass ratio of AC to the residue of 1：2.5, segregation roasting time of 2 h, segregation roasting temperature of 850 ℃, sulfuric acid concentration of 4.5 mol/L, liquid-to-solid ratio of 6：1, leaching time of 5 h, leaching temperature of 80 ℃, addition of 30% H202 of 0.6 mL for 1 g dry residue. Under these optimized conditions, the average leaching efficiency of nickel is 89.3%. The nickel extraction efficiency in the examined conditions is about 99.6%, and the nickel stripping efficiency in the examined conditions is about 99.2%.

Manganese extraction from high-iron-content manganese oxide ores by selective reduction roasting-acid leaching process using black charcoal as reductant

Reduction roasting-acid leaching process was utilized to process high-iron-content manganese oxide ore using black charcoal as reductant. The results indicate that, compared with the traditional reductant of anthracite, higher manganese extraction efficiency is achieved at lower roasting temperature and shorter residence time. The effects of roasting parameters on the leaching efficiency of Mn and Fe were studied, and the optimal parameters are determined as follows: roasting temperature is 650 °C, residence time is 40 min, and black charcoal dosage is 10%(mass fraction). Under these conditions, the leaching efficiency of Mn reaches 82.37% while that of Fe is controlled below 7%. XRD results show that a majority of MnO2 and Fe2O3 in the raw ore are reduced to MnO and Fe3O4, respectively.

山茱萸浸提过程的动力学研究

目的:初步建立中草药浸提过程的动力学模型和温度影响因素模型,探讨溶剂倍量、原料颗粒粒度、浸提温度及浸提时间等对浸提效率的影响及相关性。方法:以山茱萸中马钱素为浸提对象,绘制马钱素标准曲线,并进行定性鉴定;分别讨论不同粒度下浸提时间、不同溶剂倍量下浸提时间、不同浸提时间下山茱萸粒度、不同浸提时间下溶剂倍量与马钱素浓度的关系。结果:浸提时间越长,浸提温度越高,山茱萸粒度越小,溶剂倍量越大,则越有利于山茱萸中马钱素的提取。结论:实验结果与动力学模型是相符合的,可为山茱萸有效成分提取工艺选择操作条件提供依据。