Feasibility of using recycled CRT funnel glass as partial replacement of high density magnetite sand in radiation shielding concrete

The recycled cathode ray tube(CRT)funnel glass was used as replacement of magnetite sand in the concrete,and its mass replacement rates were 0,20%,40%and 60%,respectively.The flowability,apparent density and mechanical properties of the radiation shielding concrete were investigated,while itsγ-ray radiation shielding parameters such as linear and mass attenuation coefficients(μandμm,respectively),thickness values of half-value layer(hHVL)and tenth-value layer(hTVL)were obtained by theoretical calculation,experiment and Monte.Carlo N-Particle(MCNP)simulation code.The experimental results show that the flowability of the concrete increases significantly,whilst its apparent density,compressive strength and static elastic modulus decrease slightly.The calculated,simulated and experimentalμm,μ,hHVL and hTVL values of all concrete samples are very consistent at the sameγ-ray photon energy,and it is feasible to use MCNP code to simulateγ-ray radiation shielding parameters of materials.The calculated results show that in a wide range ofγ-ray photon energy,theμm value of the concrete with CRT funnel glass replacing magnetite sand is improved effectively,and its radiation shielding performances are the same as those of the control concrete(M.1).By comprehensively comparing the flowability,mechanical properties andγ-ray radiation shielding properties,the concrete samples with 20%.40%funnel glass as fine aggregate have good performances.

Effect of sintering temperature on microstructure and properties of glass-ceramics synthesized from waste cathode ray tubes funnel glass

Waste cathode ray tube(CRT)funnel glass(FG)is an important part in the disposal of electrical and electronic waste(e-waste).A novel approach for efficient lead extraction and glass-ceramics synthesized from waste FG through collaboratively smelting FG with coal fly ash(CFA)is proposed.Glass-ceramics materials with 40 wt%-80 wt%FG additions were produced under sintering temperatures of 900-1000℃.The microstructure and phase composition of the produced glass-ceramics were studied using X-ray diffraction(XRD)and scanning electron microscopy(SEM).The density,water absorption,Vicker hardness,chemical resistance and heavy metal leaching characteristics of the glassceramics were measured.The experimental results indicate that the samples can be crystallized at sintering temperatures of 900-1000℃.An elevated sintering temperature is favorable for enhancing the degree of crystallization,while the crystallization process is inhibited at excessively high temperatures.Increasing FG addition can lead to the transformation of the main crystalline phase from diopside to gehlenite.Well-crystallized crystals were generated in the specimens with 50 wt%-70 wt%FG additions.The samples with 40 wt%,50 wt%,60 wt%,70 wt%,80 wt%FG addition exhibit the optimal chemical and physical properties at 975,925,950,925 and 900℃,respectively.Overall results demonstrate that this study provides a feasible strategy for reliably detoxifying and reusing waste FG and CFA.

Corrosion mechanism of magnesia-chromite refractories by ZnO-containing fayalite slags: Effect of funnel glass addition

An efficient approach for lead extraction from waste funnel glass through the lead smelting process has been proposed. To clarify the effect of funnel glass addition on the degradation of magnesia-chromite refractories by ZnO-containing fayalite slag, the corrosion behavior of magnesia-chromite refractories in lead smelting slags with different funnel glass additions from 0wt% to 40wt% was tested. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) was used to acquire the microstructural information of the worn refractory samples. Experimental results showed that the corrosion of magnesia-chromite refractory consisted predominantly of the dissolution of MgO into slag. ZnO and FeO reacted with periclase and chromite to form (Zn,Fe,Mg)O solid solution and (Zn,Fe,Mg)(Fe,Al,Cr)2O4 spinel, respectively. With the addition of funnel glass, the solubility of MgO increased whereas ZnO levels remained stable, thereby resulting in a reduced Mg content and an elevated Zn and Fe content in the (Zn,Fe,Mg)O solid solution and the (Zn,Fe,Mg)(Fe,Al,Cr)2O4 spinel. Considering the stability of the (Zn,Fe,Mg)O solid solution layer and the penetration depth of the slag, the optimal funnel glass addition for lead smelting was found to be 20wt%.

玻璃分相联用机械化学法脱除废旧含铅玻璃中重金属铅

传统分相法采用热酸浸提工艺脱除CRT锥玻璃分相产物中重金属铅,酸浸过程强酸消耗量大,废酸无法回用,易引发酸污染。目的 为了绿色、高效回收CRT锥玻璃分相产物中重金属铅,方法 采用乙二胺四乙酸(EDTA)作为浸提剂,通过机械化学法研究锥玻璃中重金属在快速分相和机械活化浸出过程中的迁移转化规律,揭示影响重金属脱除率的主要因素和作用机制。结果 结果表明:在分相处理过程中锥玻璃所含Pb,K,Ca等元素主要富集在呈连通结构的富B_(2)O_(3)相中。在随后湿法球磨浸提过程中,分相产物中富B_(2)O_(3)相在机械活化作用下快速溶解到水中,同时富B_(2)O_(3)相中所含金属离子与EDTA形成可溶络合物,且可从分相产物中脱除。锥玻璃所含Pb,K,Ca等金属脱除率随EDTA添加量增大、球磨转速提高、球磨时间延长等不断提升,但随液固比增大呈先升高后降低趋势。当EDTA添加量(质量分数,下同)为80%,球磨转速500 rpm,液固比0.8时,球磨处理30 min,分相产物中Pb,K,Ca,Al脱除率分别达到98.79%,94.92%,95.17%,65.71%,获得SiO_(2)质量分数超过92%的高硅氧玻璃粉末。结论 研究结果可为含重金属玻璃绿色、高附加值利用提供借鉴与参考。

CRT含铅玻璃及其冶炼废渣的铅浸出毒性研究

通过评估阴极射线管(CRT)含铅玻璃及其冶炼后废渣的环境影响,有助于CRT玻璃回收和处置.本文采用醋酸缓冲液法(HJ/300-2007)研究了CRT的三种含铅玻璃及其铅冶炼后废渣的铅浸出特性,结果表明锥玻璃、颈玻璃和熔接玻璃铅浸出浓度均超出危险废物浸出标准,其中熔接玻璃中的铅极易溶出,在CRT玻璃中毒性最大;而铅冶炼废渣中的铅也极易溶出,废渣中的含铅量应低于1.5%才可视为一般固体废弃物.除了铅在化合物中的含量,铅的赋存结构使铅化合物浸出毒性差异很大.

阴极射线管锥玻璃真空碳热还原除铅机理研究

阴极射线管(cathode ray tube,CRT)玻璃附加值极低,毒性浸出实验表明CRT玻璃为危险废物,是当前我国电子垃圾处理处置中首要的必须解决的难题。废弃CRT玻璃安全处理处置的关键在于其含铅锥玻璃的处理处置。文章从锥玻璃的组成出发,探讨真空碳热还原除铅的可能性及可行性,计算表明真空碳热还原除铅完全可能,实验结果表明900℃,10 Pa下反应4 h铅的去除率可达93.53%,残余物中铅的质量分数仅为0.9%。该法为解决废弃危险电子垃圾CRT玻璃问题提供了新的思路,具有较强的应用价值。

有机玻璃胸骨悬吊术治疗婴幼儿先天性漏斗胸43例

目的总结有机玻璃胸骨悬吊术治疗婴幼儿先天性漏斗胸的经验。方法2000年10月￣2005年3月采用医用有机玻璃胸骨悬吊术对43例婴幼儿先天性漏斗胸患儿实施胸廓矫形术,其中2例合并先心病患儿行同期根治手术。结果所有患儿均痊愈出院并获随访,除1例胸骨下段轻度凹陷外,其余患儿胸廓形态正常,术后心肺功能逐步恢复正常。结论先天性漏斗胸早期手术具有一定的可行性,有机玻璃胸骨悬吊术治疗婴幼儿漏斗胸方法简单,创伤小,矫形效果良好。

机械活化对CRT锥玻璃中金属铅碱性浸出的影响

为提高CRT含铅玻璃中铅的浸出率,研究了不同样品在氢氧化钠溶液体系中铅的浸出率变化,考察了二氧化硅、还原性铁粉等不同添加剂在机械活化过程中的作用。研究结果表明,添加二氧化硅等物质,并不能改变CRT玻璃的非晶状态,但能起到分散作用,降低样品粒径,提高铅浸出率;还原性铁粉在机械活化中能起分散作用和降低键能的作用,且在浸出过程中有微量置换作用,从而大幅度提高铅浸出率;水是良好的分散剂,湿磨过程中,粉末会与不锈钢球磨罐中的铁发生反应,使铅浸出率显著提高。不添加任何物质机械活化的样品金属铅浸出率仅为40.86%,添加15%铁粉机械活化或湿磨处理后的样品,在4 mol/L的氢氧化钠溶液中反应3 h,铅浸出率可达85%以上。

CRT锥玻璃中重金属与碱金属分相回收机制研究

文章通过研究阴极射线管锥玻璃中重金属与普通金属元素在空气气氛下分相规律,调控分相工艺条件,实现锥玻璃中的多种重金属与普通金属高效脱除,并获得经济价值较高的高硅氧玻璃粉体。锥玻璃经分相处理后形成2个独立相(富B_(2)O_(3)相与富SiO_(2)相),锥玻璃中所含重金属与普通金属主要富集在呈连通结构的富B_(2)O_(3)相中。提高B_(2)O_(3)添加量和提升熔炼温度可以促进各金属元素在富B_(2)O_(3)相中富集程度。当锥玻璃与20%B_(2)O_(3)混合后在1000℃下保温处理30 min,Pb、Ba、Sr、Na、K、Ca、Al在富B_(2)O_(3)相中的分布率分别为99.48%、99.26%、99.56%、99.48%、99.90%、98.98%和81.20%。之后利用热酸溶解分相产物中富B_(2)O_(3)相及其中所含多种金属元素,得到固体残渣为氧化硅含量为97.56%的高硅氧玻璃粉末。

新型高强度玻璃离子水门汀修复漏斗状残根的实验研究

目的:探讨应用新型高强度玻璃离子水门汀对漏斗状残根的修复效果。方法:将45个完整的上颌离体中切牙预备成漏斗状残根,随机分成3组,A组:新型高强度玻璃离子水门汀核联合成品金属螺纹桩修复。B组:双重固化型复合树脂核联合成品金属螺纹桩修复。C组:N i-Cr合金铸造桩核修复。将样本固定于电子万能测试仪上,测试抗折强度并观察折断模式。结果采用方差分析、X2检验。结果:新型高强度玻璃离子水门汀组的牙根抗折强度已达到较高水平,与双重固化型复合树脂组的牙根抗折强度并无显著性差异,而这两组的牙根抗折强度虽然低于N i-Cr合金铸造桩核组,但其折断模式更有利于牙根的重复利用。结论:应用新型高强度玻璃离子水门汀核联合成品金属螺纹桩可用来修复漏斗状残根。

阴极射线管锥玻璃碱性浸出渣制备泡沫玻璃

以废弃的阴极射线管锥玻璃碱性浸出渣及屏玻璃混合粉末为原料烧制泡沫玻璃。考察了发泡温度、屏玻璃加入量、发泡剂种类、发泡剂加入量、稳泡剂添加量对所制备的泡沫玻璃密度及抗压强度的影响。实验结果表明:在发泡温度800℃、屏玻璃加入量50%(w)、稳泡剂硼酸加入量5%(以锥玻璃碱性浸出渣及屏玻璃粉末总质量为基准,下同)、发泡剂SiC加入量15%最佳条件下烧制的泡沫玻璃密度达417 kg/m^3,抗压强度达1.09MPa,可满足建筑用泡沫玻璃的Ⅳ型物理性能指标。本实验烧制的泡沫玻璃的Pb浸出量为1.27 mg/L,Ba浸出量为0.06 mg/L,均满足固体废物的浸出毒性标准。

阴极射线管锥玻璃制备高硅氧玻璃粉末

阴极射线管(cathode ray tube, CRT)锥玻璃是一种典型的危险废弃物,含有大量PbO,BaO,SrO,Al_2O_3等多种重金属氧化物,因此需要对其进行安全处理和处置。本研究采用碳热还原强化玻璃分相方法将CRT锥玻璃制备成不含重金属的高硅氧玻璃粉末。当处理温度为1000℃,B_2O_3的添加量为20%,保温时间为30 min时,CRT锥玻璃中Pb,Ba和Sr 3种重金属的酸浸脱除效率分别为99.81%,95.72%和100.00%,其他金属如Na,K,Ca,Al的脱除率分别为80.19%,99.92%,99.39%和78.56%,酸浸后残渣中SiO_2质量分数为93%左右。本研究为含重金属玻璃的资源化利用开辟了新的途径。

热过滤漏斗的改进设计

热过滤是重结晶实验中关键的步骤,热过滤漏斗则是其中必使用的仪器,原本的铜质夹套过滤漏斗在实验中漏斗颈易堵塞、操作繁琐、载热剂液位无法观测,需较长时间加热,此外需要使用酒精灯加热易出现安全性问题。因此,对传统的铜质夹套热过滤漏斗进行改进,使之操作简便、易过滤、可观测载热剂液位、提升保温效果、降低实验风险性,同时节约酒精的消耗量。改进后的热过滤漏斗可以广泛运用于实验教学实践中,有较高的实用性。

泥沙水样中微塑料纤维的分离与泥沙去除研究

建立了一种泥沙水样中分离微塑料纤维和去除泥沙的方法。选取聚酰胺6(Polyamide 6,PA)、丙烯腈-丁二烯-苯乙烯共聚物(Acrylonitrile butadiene styrene copolymers,ABS)、聚丙烯(Polypropylene,PP)颗粒,制备长度(1±0.25)mm,宽度(200±30)μm的微塑料纤维;分别混合不同质量(0,0.01,0.05,0.25,1.25,6.25 g)经30%过氧化氢消解和饱和氯化钠(1.2 g/mL)、碘化钠溶液(1.8 g/mL)浮选后的自然泥沙;以探究在不同泥沙质量下,静置阶段投加氯化钠颗粒对玻璃漏斗中微塑料纤维分离效率以及泥沙去除率的影响,并与不投加氯化钠和容量瓶浮选法作比较。结果表明,在静置阶段添加氯化钠颗粒效果较优,对3种微塑料纤维的平均分离效率和泥沙的平均去除率分别为87.78%和98.33%。实验结论可为微塑料分离提取方法的优化提供参考。

论大偏转角超薄型彩管的玻壳特点

彩色显像管的超薄型化涉及到两方面的问题,其一是扩大电子束的偏转角,其二是减小玻壳的长度,尤其是锥体玻壳的长度。本文通过论述大偏转角超薄型彩管的玻壳特点,解析彩管的超薄化机理。

机械活化对CRT锥玻璃浸出动力学的影响

通过研究CRT锥玻璃经机械活化后在硝酸溶液体系中浸出反应动力学规律,考察了机械球磨转速、浸出温度以及硝酸初始浓度对锥玻璃中铅的浸出效果影响。研究结果表明,锥玻璃经机械活化预处理后,反应活性显著增强,锥玻璃中铅浸出率大幅度提高。浸出反应的表观活化能和反应级数由109.4 kJ/mol和0.79降至54.3 kJ/mol和0.51。