碳酸钙填充塑料成本分析

碳酸钙粉体经过活化、造粒处理填充到聚乙烯薄膜,可使填充制品成本降低。随着填料的增加,其加工性能逐渐变差,单位质量塑料产品体积减小。经测算,使用填充剂后成本的降低足以弥补因体积减小产生的损失。对于薄膜制品而言,填充量小于10%效益增加不明显;超过30%,则不容易稳定成膜,影响成品质量。     

高纯天然石膏水热法制备硫酸钙晶须研究

以高纯天然石膏为原料，加压水热法制备高品质硫酸钙晶须。采用常规分析方法、XRD和扫描电镜等手段分析和表征石膏原料和硫酸钙晶须产品。结果表明，制备硫酸钙晶须的最优条件为：料浆质量分数为6.0%，转晶剂氯化镁加入量为石膏质量的0.05%，硫酸加入量为水体积的1.0%，反应时间为4.0 h，快速过滤干燥即得硫酸钙晶须产品。分析结果表明：硫酸钙晶须长度最大为280.4 μm，最小为19.59 μm，平均长度为80 μm；硫酸钙晶须直径最大为5.86 μm，最小为0.20 μm，平均直径为2.67 μm；通过统计分析可知，长径比范围为10～80。     

Long-term residual value of North Carolina and Queensland rock phosphates compared with triple superphosphate

The effectiveness of large single applications of North Carolina reactive rock phosphate, Queensland non-reactive rock phosphate, and Calciphos, were compared to the effectiveness of superphosphate in field experiments in south-western Australia for up to 11 years after application. As measured using plant yield, superphosphate was the most effective fertilizer in the year of application, and relative to freshly-applied superphosphate, the effectiveness of the superphosphate residues declined to be about 15 to 65% as effective in the year after application, and 5 to 20% as effective 9 to 10 years after application. Relative to freshly-applied superphosphate, all the rock phosphates were 10 to 30% as effective in the year of application, and the residues remained 2 to 20% as effective in the 10 years after application. The bicarbonate soil test reagent predicted a more gradual decrease in effectiveness of superphosphate of up to 70% 10 years after application. For rock phosphate, the reagent predicted effectiveness to be always lower than for superphosphate, being initially 2 to 11% as effective in the year after application, and from 10% to equally as effective 10 years later. Therefore rock phosphates are unlikely to be economic alternatives to superphosphate in the short or long term on most lateritic soils in south-western Australia.     

氧化物对3CaO·3Al2O3·CaSO4形成的影响

借助XRD测试手段研究了Al2O3、SiO2、Fe2O3以及MgO几种生料中常见氧化物对高温固硫物相3CaO·3Al2O3·CaSO4形成的影响.结果表明,改变Al2O3的含量,不会对3CaO·3Al2O3·CaSO4的形成产生明显影响;Fe2O3及MgO的存在能降低3CaO·3Al2O3·CaSO4的形成温度,但也使其分解温度提前;SiO2的大量存在则会抑制3CaO·3Al2O3·CaSO4的形成.     

实施电石法PVC生产过程中的循环经济

介绍了电石法聚氯乙烯生产过程中水、尾气和电石渣的循环利用及超低含量氯化汞触媒的使用情况。提出了要以“减量化、再利用、资源化”为原则,实现低消耗、低排放、高效率的循环经济。     

GYM系列亿丰磨在非金属矿物超微粉碎中的应用

干法生产超细粉是我国非金属粉体的重要加工工艺之一，传统的粉磨设备难以达到大量生产d97=2—10μm超细粉的要求，且生产效率低。阐述了采用多磨轮、多磨道原理设计的GYM-83型亿丰磨在生产粒径为11μ的碳酸钙干粉时，其累积分布达98％，粒径为2μm的占总质量44．96％，产量达到了1250kg／h，且基建投资少，性价比好。     

氧化锌对阿利特和硫铝酸钙的形成及共存温度范围的影响

借助差热分析、X射线衍射及化学分析等,研究了ZrO对含硫铝酸钙的硅酸盐水泥熟料中阿利特和硫铝酸钙矿物形成及共存温度范围的影响.结果表明:在生料中掺入1%(质量分数)ZnO,可降低阿利特的形成温度,并促进低温下硫铝酸钙矿物的形成;1 300℃时阿利特生成的质量分数达59.23%,较未掺ZnO样品提高14.76%;掺入ZnO后,扩大了硫铝酸钙与阿利特矿物的共存温度范围,达50℃.     

重钙装置改产DAP的工程实践

介绍瓮福重钙装置采用混合工艺改产 DAP的技术改造及试车概况、试车中出现的问题及解决措施。     

ω-十一烯酸改性纳米碳酸钙工艺研究

采用正交实验,以ω-十一烯酸作为表面改性剂,无水乙醇为分散介质,在一定的温度下对纳米碳酸钙粉体进行表面改性研究,确定改性纳米碳酸钙的最佳工艺条件为:改性剂用量3.0%,改性温度60℃,改性时间30min。改性后的纳米碳酸钙的吸油量(液体石蜡)降为40mL/100g,活化率提高到99.52%,表明改性后的纳米碳酸钙粒子亲油性得到显著提高。沉降速率和透射电镜(TEM)测试结果表明:改性后的纳米碳酸钙在亲油性溶剂中的分散性得到显著改善,粒度分布更加均匀。     

Experimental design approach to calcium carbonate precipitation in a semicontinuous process

The production of precipitated calcium carbonate, PCC, by a semicontinuous process of slaked lime carbonation was performed in a bench-scale chemical reactor, fully controlled by means of custom built electronics and software for the personal computer. Calcite crystals, with different characteristic morphologies (rhombohedral, truncated prismatic, scalenohedral, spheroidal or chain-like agglomerates) were produced by varying a range of process parameters, like temperature, supersaturation, gas mixture flow rate, stirring rate and mass concentration of Ca(OH)₂ suspension. In order to identify the effects of the chosen process parameters on the PCC morphology and on the related specific surface area, as well as on the extent of CO₂ conversion, an empirical approach based on the experimental design techniques was employed. A multiple correlation analysis of the obtained data suggests that temperature and conductivity significantly influence the PCC morphology, while CO₂ conversion is principally influenced by stirring rate, conductivity and gas mixture flow rate.