从赤泥中回收铁的工艺研究

赤泥是氧化铝产生过程的副产品，每产出1t氧化铝，产出1～1．6t的赤泥。赤泥中含有大量的有价金属元素，是一种宝贵的二次资源。本论文针对高铁的赤泥中铁和稀土含量高的特点，提出了一种新的回收铁富集稀土的工艺流程，还原磁选铁，稀土富集在分离渣中。     

某含硫高碳难处理金矿工艺研究

高硫、高碳难处理金矿是目前常见的金矿资源,对传统浸出工艺带来巨大挑战。针对某企业的含硫高碳金矿,在工艺矿物学的基础上,了解自然金的富存状态,采用“浮选+焙烧+浸出”工艺处理该金矿。试验结果表明,在浮选阶段当磨矿细度-200目占比80%时,以硫酸铜为活化剂,丁基黄药+丁铵黑药作捕收剂时,得到Au品位25.31g/t、Au回收率91%的精矿。再将精矿在600℃环境中焙烧1h,浸出剂绿金30g/t,浸出液pH=12-13,液固比8的条件下浸出36h,精矿中金的浸出率达到89.38%,显著提高金的浸出率。为此类型难处理金矿提供借鉴。     

LiCoO_2在酸性焙烧环境中元素赋存形式的演变规律及分布特征研究

系统地了解钴酸锂(LiCoO_2)在不同介质环境中的物理化学性质有助于从理论上指导该物质的合成工艺设计以及报废LiCoO_2再利用的工艺设计。本实验将LiCoO_2与Na HSO_4·H_2O、LiCoO_2与Na2S2O7分别按摩尔比1:3、1:1.5的比例混合后进行酸性焙烧,采用TG-DSC-MS、XRD、SEM、EDS研究了焙烧过程中元素赋存形式的演变规律以及元素分布特征。结果表明:LiCoO_2与Na HSO_4·H_2O、Na_2S_2O_7的混合物在焙烧过程中发生了明显的化学反应。焙烧产物中Na元素的赋存形式有Na_2SO_4、LiNaSO_4和Na6Co(SO_4)_4,Li元素的赋存形式为LiNaSO_4,Co元素的赋存形式为Na_6Co(SO_4)_4。焙烧产物致密,形状不规则,Co元素在焙烧产物中分布均匀。     

Shelf-life of infrared dry-roasted almonds

Infrared heating was recently used to develop a more efficient roasting technology than traditional hot air roasting. Therefore, in this study, we evaluated the shelf-life of almonds roasted with three different approaches, namely infrared (IR), sequential infrared and hot air (SIRHA) and regular hot air (HA). Nine medium roasted almond samples produced by the aforementioned heating methods were processed at three different temperatures (130, 140 and 150 °C), packed in paper bags and then stored at 37 °C for three, six or eight months. Shelf-life of the roasted almonds was determined by measuring the changes in colour, peroxide value, moisture content, water activity, volatile components and sensory quality. No significant difference was observed in moisture content and water activity among the almond samples processed with different roasting methods and stored under the same conditions. GC/MS analysis showed that aldehydes, alcohols, and pyrazines were the main volatile components of almonds. Aliphatic aldehydes such as hexanal, (E)-2-octenal, and nonanal were produced as off-odours during storage. Although the overall quality of roasted almonds produced with SIRHA and HA heating was similar during the first three months of storage, their peroxide value and concentration of aliphatic aldehydes differed significantly for different roasting methods and increased significantly in all roasted samples during storage. We postulate that hexanal and nonanal might be better indicators of the shelf life of roasted almonds than the current standard, peroxide value.     

浅谈如何提高沸腾焙烧炉可溶锌率

文章阐述了如何提高沸腾焙烧炉可溶锌率,可溶锌率的高低直接影响到浸出率,对湿法炼锌的经济效益具有深远的意义。     

攀钢密地选矿厂总尾矿深度回收方案的探讨

针对福建某氰化尾渣,采用浮选、焙烧、浸出、磁选进行金、铁以及硫的回收利用。试验先进行黄铁矿的浮选,得到硫品位38.63%,回收率86.97%硫精矿,其中含金5.26g/t,金回收率为74.59%。然后硫精矿进行焙烧制硫酸,硫总体回收率为85.80%,烧渣进行还原焙烧后进行浸金,金浸出率为95.49%,浸出后进行弱磁磁选,得到品位为61.56%的铁精矿,铁总体回收率为73.15%。有效的回收利用了氰化尾渣中的有价元素。     

Effects of grilling and roasting on the levels of polycyclic aromatic hydrocarbons in beef and pork

The concentrations of seven polycyclic aromatic hydrocarbons (PAHs) viz. chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perylene, and indeno(1,2,3-c,d)pyrene in 150 samples of commercial meat products were determined. The PAHs were extracted with hexane, purified with Sep-Pak Florisil cartridges and determined by high-performance liquid chromatography using a fluorescence detector. Levels of PAHs were dependent on the method of cooking and type of heat source used. Relatively high levels of PAHs, 10.2 μg/kg on average, were found in charcoal-grilled pork samples. Average PAH levels in beef did not exceed 0.80 μg/kg. Charcoal grilling of pork samples resulted in extremely high levels of benzo(a)pyrene (3.0 μg/kg), while the average benzo(a)pyrene levels in charcoal-grilled beef samples were 0.15 μg/kg. These data can be used to estimate the dietary exposure of consumers to PAHs and to assess any potential risk associated with the ingestion of these foods.     

低品位磷矿的选矿方法

阐述了我国磷矿石床的分类,分析并总结了不同类型磷矿石的选矿方法。     

油籽炒籽条件对油脂中多环芳烃含量影响的研究

以花生仁和芝麻籽为原料,研究了炒籽温度和炒籽时间对其油脂中16种多环芳烃含量的影响。结果表明,随着炒籽温度的提高及炒籽时间的延长,花生油和芝麻油中Bap、PAH4、PAH16的含量都呈明显上升趋势。对照GB2716及欧盟No 835/2011中对Bap、PAH4的限量规定,花生仁的合理炒籽温度为不超过160℃、炒籽时间不超过20 min,芝麻的合理炒籽温度为不超过180℃、炒籽时间不超过20 min。在优化的炒籽条件下,花生油中Bap、PAH4、PAH16含量(μg/kg)分别从原料中的0.31、4.60、16.69增加至1.07、11.98、48.86,芝麻油中Bap、PAH4、PAH16含量分别从原料中的0.63、5.23和21.84增加至0.93、8.28和47.95。     

某硫尾矿磁选精矿铁硫分离再选试验

为分离某硫铁矿尾矿经弱磁选后所得精矿中主要以磁铁矿和磁黄铁矿形式存在的铁和硫,使该资源得到利用,对其进行了再选试验。试验结果表明,采用浮选-弱磁选-焙烧工艺可达到分离目的：原磁选精矿经浮选后,可获得硫品位为31.08%、硫回收率为82.91%的硫精矿;浮选尾矿经弱磁选和焙烧后,可获得铁品位为62.61%、硫含量为0.21%、SiO₂含量为3.87%、对原磁选精矿铁回收率为31.03%的铁精矿。将所得硫精矿模拟制酸焙烧后对烧渣进行检测,烧渣铁品位为61.08%、硫含量为0.23%、SiO₂含量为5.09%,可直接作为铁精矿利用。