湿型砂使用钙基膨润土的可能性

湿型旧砂再生用于制备冷芯盒砂芯的最大困难是钙基膨润土加工磨粉前加入了大量Na2CO3。建议用优质钙基膨润土替代钠化膨润土,以简化旧砂再生过程。     

钙基膨润土的钠化程度对湿型砂性能的影响

实验证明钙基膨润土的钠化程度对膨润土的膨胀性能、热湿拉强度和复用性，都有显著影响。为此，建议生产厂重视并提出钙基膨润土的钠化程度。     

膨润土质量检验的新方法——沉降值法初步探讨

本文通过测定一定重量的圆锥体在含水膨润土中的沉降深度,提出用直线参数p和m估算σ湿压、σ湿拉和σ热湿拉,由此判断膨润土质量优劣。此法亦可用来确定钙基膨润土的活化剂的最佳加入量。     

膨润土的改性及应用

钙基膨润土进行充分钠化处理后,其湿压强度、热湿拉强度、复用性将得到很大提高。钠化处理时,钠化度要低于钠化最高值,才适合铸造使用,新的改性处理使钠化膨润土性能进一步提高。     

简述膨润土在湿型砂工艺中的应用

简要回顾了膨润土作为粘结剂在湿型砂中的应用,结合调研一些采用湿型砂工艺的铸造厂,对其砂样进行了性能测试,提出一些建议。为了提高铸件的质量,合理的使用天然资源、能源类资源,同时考虑环保的要求,应研制具有优良综合性能的膨润土系列产品。     

膨润土及湿型砂生产应用的控制要点

1 膨润土在湿型砂中的性能变化 钠基膨润土在600 ℃以下加热,他的粘结能力基本上不受影响.加热温度超过600 ℃,就急剧地丧失粘接能力.加热到700 ℃以上,差不多完全丧失了粘结能力.钙基膨润土在100 ℃以上,就开始缓慢地失去粘结能力.加热温度再提高,粘结能力的丧失就越来越明显.人工活化不好的钠膨润土,在最初使用时,失效温度仅略低于天然钠基膨润土反复加热后,就与钙基膨润土相近.     

膨润土极限活化量确定方法的研究

介绍了三种确定膨润土极限活化量的适用方法:热湿拉强度法、膨润土液性极限法和高水湿压强度法。膨润土液性极限法和高水湿压强度法对没有热湿拉强度仪的单位更为实用。试验表明,对同一种膨润土用以上三种方法测定的极性活化量基本相同,用膨润值法测定的极性活化量偏差较大。由于各种膨润土的极性活化量不相同,因此在活化膨润土型砂时,活化剂Na_2CO_3加入量一律固定为膨润土量的4~5%是不适宜的。     

减轻湿型铸造黑色污染途径的探索

湿型砂若能减少膨润土的加入量，减轻对结焦率的依赖，便能用浅色的有机混合物代替煤粉，可明显地减轻黑色污染。减少膨润土的加入量，可通过使用共粘结剂和藉桥联反应形成立体网状结构的方法，实现使蒙脱土片晶间充分脱开，满足湿型砂的性能要求     

平山钠基膨润土的抗夹砂能力及其阳离子交换量与各性能关系

前言膨润土是以蒙脱石类矿物为主要成分的粘土岩,它具有阳离子交换性能,按其交换性阳离子种类可分为钠基膨润土和钙基膨润土二大类。钠基膨润土所配制的型砂,具有钙基膨润土所不及的优良铸造工艺性能,如:(1)对水份敏感性小;(2)热湿拉强度高;(3)热强度     

提高气冲造型湿型砂性能的研究

通过测定膨润土及α-淀粉等附加物的技术指标,采用标准试样等方法,研究了各种膨润土和附加物的指标与特性及对湿型砂性能的影响,并进行了生产验证.实验结果表明,人工钠化膨润土R2的各项指标与复用性较高,混制型砂的综合性能最佳;在湿型砂中加入0.3%～0.5%α-淀粉D2对型砂的综合性能较为有利;α-淀粉与纤维素混合加入湿型砂,能抵消α-淀粉对型砂性能的不良影响和提高型砂的保湿性.采用优选的膨润土和附加物并优化配比后,膨润土加入量减少1.5%,湿压强度提高20%～30%,破碎指数提高15%,提高了铸件质量.     

润磨机在球团生产工艺中的应用

介绍润磨机在球团生产工艺中的应用。采用润磨机对铁精矿粉进行润磨，可有效降低膨润土的添加量，提高生球强度，降低炼铁成本。     

湿型砂用膨润土检测技术的评述(一)

膨润土的品质对铸件是否产生砂孔、夹砂等缺陷起关键的作用,对铸件的其他缺陷也有重要影响,因此,应当重视膨润土的检测。本文对膨润土品质的常规检测技术提出补充和推荐意见。第一部分介绍普通黏土、钙基膨润土、钠基膨润土和活化膨润土的简易判断,膨润土含水量测定,膨润土的粒度分析,膨润土湿态黏结力测定和膨润土吸蓝量测定。     

Performance characteristics of EZhou bentonite of Hubei province and its modification

Both the chemical compositions and performance characteristics of the bentonite raw ores in Ezhou area of Hubei province and Honghuoshan area of Liaoning province were compared and analyzed. The properties of these two kinds of bentonites were tested before and after Na+- and Li+-modification. The results show that the Ezhou bentonite ore possesses higher montmorillonite content than the Honghuoshan bentonite ore, but the Ezhou Na-bentonite has weaker castability (e.g. Wet compression strength and hot wet tensile strength) than the Honghuoshan Na-bentonite, while the performance of Ezhou Li-bentonite, such as colloid index, swelling value, swelling volume and mould coating performance, is equivalent to that of the Honghuoshan Na-bentonite.     

粘土湿型砂剪切变形功测试方法及其韧性评价

使用PLC控制的剪切变形功测试仪,记录型砂试样剪切变形过程的变形与强度变化,处理其结果得到剪切功,以表征型砂的韧性.研究了型砂紧实率、膨润土含量、制样锤击次数和淀粉加入量对试样剪切功的影响,并探讨剪切变形中不同阶段剪切功的意义.     

选矿拜耳法精矿SiO2变化对矿浆调配的影响分析及控制措施

本文详细分析了选矿拜耳法精矿SiO2的变化情况和变化原因，以及精矿SiO2变化对矿浆调配的影响，提出了稳定精矿SiO2提高矿浆质量的控制措施。     

铸造用人工钠化膨润土质量控制方法的探讨

为了给铸造厂正确选购膨润土提供指导,对膨润土的控制方法和指标进行了试验研究,对不同钠化工艺及控制参数对膨润土质量指标的影响进行了试验和分析.试验表明,铸造人工钠土的膨润值、吸蓝量、复用性、湿压强度、热湿拉强度等指标对铸造生产非常重要,应重点控制.人工钠土的"湿法"工艺比较可靠,"干法"工艺有待于提高.     

Influence of Deteriorated Bentonite Sediments on the Corrosion Behavior of NiCu Low Alloy Steel

The corrosion evolution of steel disposal container largely depends on the evolution of surrounding bentonite environment in the long-term geological disposal of high-level radioactive wastes. This study focused on the influence of the deteriorated bentonite sediments on the corrosion behavior of NiCu low alloy steel in the top supernatant and bottom slurry formed by Gaomiaozi bentonite and 0.05 M NaHCO₃ + 0.1 M NaCl + 0.1 M Na₂SO₄ solution. In the top supernatant, the cathodic process of the steel corrosion was transformed from the reduction in oxygen to the reduction in ferric corrosion products with time as same as that in the blank solution. While in the bottom bentonite slurry, the cathodic process always maintained as the hydrogen evolution reaction due to the coverage of more bentonite sediments. Meanwhile, the corrosion rate of NiCu steel was obviously decreased. In addition, the localized corrosion tendency of the steel could also be reduced by the large amount of deteriorated bentonite sediments.     

Correlations among factors of sulfide ores in oxidation process at ambient temperature

Spontaneous combustion is one of the serious problems in the mining of sulfide ore deposits. The relevant factors, e.g. oxygen absorption quantity, mass increase, contents of water soluble iron ions and sulfate ion of sulfide ore samples in the oxidation process were investigated both in theory and experiment. The results from the investigation show that there is no general interpretation relation among the oxygen absorption quantity, the contents of sulfate ion and water soluble iron ions during the oxidation process of sulfide ores at ambient temperature. However, there is a linear relationship between the mass increase of the sulfide ore samples in the oxidation process at ambient temperature and the quantity of oxygen absorption. Therefore, the simple and cheap mass scaling method is suitable for predicting the oxygen absorption performance of sulfide ores at ambient temperature in place of the expensive and complicated chemical method used hitherto. Furthermore, combined with other items of breeding-fire test, the mass increase potential can also be used to predict the spontaneous combustion tendency of sulfide ores.     

磷酸盐自硬砂用氧化铁复合固化剂研究

过向单一氧化镁固化剂中加入氧化铁粉末,配制复合固化剂。研究表明使用该种复合固化剂后磷酸盐自硬砂的抗拉强度提高达60%以上,砂型存放稳定性也得到改善。改变氧化铁与氧化镁的配比量,发现其对砂型强度的影响呈非线性关系,当其含20%氧化铁时砂型试样能得到最高抗拉强度,当其含30%氧化铁时砂型试样有最好的存放稳定性。将自硬砂置于高湿（﹥90%RH）环境下超过24 h,自硬砂会变软并且强度下降。