硫酸化焙烧从锰矿中回收钴── I.硫酸化焙烧动力学

以Ｈ２ＳＯ４为酸化剂，研究了低品位含钴菱锰矿（钴以硫化钴形式存在）的焙烧动力学，考查了温度、粒度对反应速率的影响，发现硫化钴的硫酸化焙烧过程属固膜扩散控制，其反应速率常数与矿物粒径平方的倒数成线性关系，得出反应的表观活化能为１４．３ｋＪ／ｍｏｌ，并建立了硫化钴硫酸化焙烧的宏观动力学方程．对反应机理作了初步探讨．     

PID技术在氧化铝焙烧炉上的应用

针对氧化铝焙烧温度采用人工手动控制存在精度低、温度波动范围大、稳定性差的缺点,利用经典闭环控制理论以及DCS自带的PID控制模块设计了温度闭环PID控制系统.该系统通过输入PID参数进行运算,由控制执行机构来精确控制燃料和炉内氧化铝量,从而实现氧化铝灼烧温度的稳定控制,保证了氧化铝的生产质量.     

A comparative study of chemical attributes and levels of amines in defective green and roasted coffee beans

Differences in chemical attributes (proximate composition, water activity, sucrose, acidity and pH levels) and amine levels between defective and healthy coffee beans were studied. Before roasting, significant differences (p < 0.05) were observed for the ash contents of the coffee samples, with the highest values found for black beans. Moisture content was higher for non-defective beans in comparison to defective beans. Non-defective coffee beans had higher lipids contents than both sour and black beans. There were no significant differences (p > 0.05) for protein levels between defective and non-defective beans. After roasting, protein levels remained constant, there was a small decrease in ash contents and a slight increase in oil contents of black and sour beans. Both black and sour beans had higher acidity levels than immature and non-defective beans. Acidity levels decreased after roasting. Water activity levels also decreased with roasting, with slightly higher levels for defective beans in comparison to non-defective ones. Sucrose levels were much higher in non-defective beans, and the lowest values were in black beans, prior to roasting. After roasting, only traces of sucrose were found. Total amine levels were much lower for black beans, in comparison to the other coffee samples. Putrescine was the prevailing amine in all samples. Histamine was only detected in the defective coffee samples. Small amounts of serotonin, cadaverine and tryptamine were found in some of the samples. After roasting to a light degree, only traces of serotonin were detected and no amines were detected after roasting to medium and dark degrees.     

Evaluation of purine alkaloids and diketopiperazines contents in processed cocoa powder

 This paper describes the evaluation of purine alkaloids and diketopiperazines (DKPs) contents in 24 samples of processed non-alkalinized cocoa powder. The chemical data obtained were related to sensory evaluation and subjected to analysis of variance. During cocoa roasting, the content of DKPs can be increased, resulting in a negative influence on the sensorial quality of cocoa. A pronounced bitter metallic taste can originate from some of these compounds, and becomes stronger when these DKPs are combined with purine alkaloids. The cocoa roasting process at different temperatures (125, 130, 135, 140 and 145  °C) and durations (3, 10, 16 and 20 min) was evaluated by measuring the flavour indices, formol numbers and DKP contents in 24 samples of cocoa powder. The addition of reducing sugars was also evaluated in the same industrial processes in 27 other samples of cocoa powder. The higher the roasting temperature of the cocoa was, the more elevated the flavour index became, except at temperatures up to 140  °C, where DKPs were generated in large proportions. Received: 2 February 1999 / Revised version: 23 April 1999     

天然二氧化锰(NMD)焙烧制备Mn2O3的研究

天然纸品位二氧化锰矿在添加少量无污染添加剂的条件下，在710℃下焙烧2h，可使锰矿石中MnO2转化为M2O3，其转化率达99．5％以上。这种焙烧矿为活性二氧化锰（AMD）的优质原料。采用该焙烧矿并在后续的工艺中采用适当的岐化、氧化条件，可制成优质的AMD。     

Antioxidant properties of roasted apricot (Prunus armeniaca L.) kernel

The antioxidant properties of peeled, defatted and roasted apricot kernel flours were evaluated by determining radical scavenging power (RSP), anti-lipid peroxidative activity (ALPA), reducing power (RP), total phenolic content (TPC), assessed by DPPH test, β-carotene bleaching method, iron (III to II) reducing test and Folin method, respectively. Browning degree of the samples was also measured and found to increase almost linearly with the roasting time. Contrary to browning degree, RSP, RP and TPC did not increase linearly but showed a maximum for 10 min of roasting. Roasting reduced the ALPA values, thus unroasted sample showed the highest ALPA value. RSP, RP and TPC measurements of all samples, were in high correlation (at least, r = 0.92).     

浅谈福建省麟厚锰矿焙烧矿石的实践

福建省麟厚锰矿属风化型氧化锰矿床，多呈土状、粉状、密度小，含水率高。该矿把含锰32％以下的土状矿石经焙烧，提高了品位，销路不错，使低品位资源得到了充分地利用，并总结了麟厚锰矿焙烧矿石的技术和管理经验。     

含金锑锍回转窑焙烧工业性试验研究

本文全面论述了含金锑锍回转窑焙烧工业性试验及其理论基础。通过四次试验,获得如下指标:窑处理能力11t/d,焙烧脱硫率83.5%,金回收率93.8%,锑回收率93.01%,柴油单耗29.7kg/t,电耗133.8kW·h/t,试验指标达到国内领先水平。本工艺已成功应用于生产实践,产生了明显的环境效益和经济效益。     

Amenability for processing of oolitic iron ore concentrate for phosphorus removal

Beneficiation routes aimed at dephosphorisation of oolitic gravity magnetic concentrate and involving a combination of roasting, re-grinding, magnetic separation and water and acid leaching are investigated. Roasting was carried out at 900 °C for 1 h without or with lime or sodium hydroxide as roasting additives. When additives were used, cement phases of Si–Al–Na–Ca–O type were detected as well as the mineral giuseppettite. During the thermal process sodium silicate is liquefied and the newly formed phases coat the oolites and penetrate inside the cracks. Energy Dispersive Spectroscopy analysis has indicated that the zone surrounding the oolites consists of Na, Al and Si phases with part of phosphorus being captured there. As a result of the alkaline roasting, goethite is partly transformed to magnetite and this reduction is reinforced with an increase in sodium hydroxide dosage. Investigation of redistribution of phosphorous shows that it could be only partly separated if leaching is not accompanied by re-grinding and physical separation. The recommended dosage of the reductive agent for the final flowsheet is 8 mass% ratio to concentrate. Grinding to a mean size of 0.040 mm, with water and acid leaching and double magnetic separation creates conditions to obtain a high-quality iron concentrate with 65.97% Fe and recovery of 92.43%, with simultaneous decrease in the phosphorus content from 0.71% to 0.05%.     

焙烧制度对煤泥-浸锌渣冷固结球团还原行为的影响

基于直接还原法探讨了焙烧制度对煤泥-浸锌渣冷固结球团中锌、铅挥发率和铁金属化率的影响,分析了焙烧制度对球团中含锌、铅、铁化合物相变的影响,试验确定了焙砂磨矿-弱磁选回收其中铁的工艺和效果。结果表明：在1 250 ℃焙烧90 min,可使球团中锌、铅的挥发率分别达到98.87%、95.39%,铁的金属化率达到98.66%;焙砂中未见锌、铅单质及其化合物,只存在大量的金属铁,且金属铁颗粒多数大于30 μm;焙砂采用2段磨矿、2段弱磁选流程处理,可同时获得含铁91.20%、回收率为30.32%的金属铁粉和铁品位为61.58%、回收率为50.01%的铁精矿,铁总回收率达80.33%。