利用废渣盐石膏制作轻型墙体材料.pdf

利用废渣盐石膏制作轻型墙体材料 马铭杰 朱 丽 山东建筑工程学院市政与环境工程学院, 济南 250014 摘要 研究利用海盐化工产生的废渣盐石膏经过一定工艺处理, 生产轻型墙体材料盐石膏空心条板, 该产品与天然石 膏空心条板相比, 原料采用及生产工艺都有较大改进, 生产成本却大幅度下降。 经测试, 该产品完全可替代天然石膏 空心条板, 技术性能指标达到了国家规定的相关标准。 关键词 废渣 盐石膏 墙体材料 生态环境 氯化钠 NaCl 是化学工业的重要原料, 盐场用海 水晒盐制造的过程中需产生大量的固体废渣盐石膏 俗称硝皮 , 其主要成分是二水硫酸钙 CaSO4 2H2O ,因掺有大量杂质以废弃物形式堆放填埋, 不 但占用土地污染环境 ,还给盐场再扩建带来一定的困 难,如何将大量废渣处理再利用是企业亟待解决的问 题。为此对山东沿海的盐场进行了广泛调查 ,针对废 渣的特点提出了一种工艺方法去除杂质提纯二水硫 酸钙, 然后再经过工艺处理将其制成合格的建筑石 膏,代替天然石膏制作轻型墙体材料盐石膏空心条 板。经测试,利用废渣处理后制成的石膏空心条板, 其使用的原料以及板材的各项技术指标达到了国家 或行业规定的相关标准 [ 1] ,有些指标甚至超过了天然 石膏条板, 生产成本可大幅度下降, 为废渣盐石膏的 处理再利用找到了一条可行的途径 。 1 实验部分 [ 2] 1. 1 废渣的性质与组成 盐石膏外观呈灰黄色, 其主要成分是 CaSO4 2H2O,多为柱状结晶体, 并含有少量 Mg 2 、 Al 3 、 Fe 3 等无机盐类和大量泥沙。其成分见表 1。 表 1 盐石膏的成分组成 组分泥砂 结晶水 CaO SO3 MgOFe2O3Al2O3酸不容物 质量分数 3013. 62 21 . 17 28 . 370 . 980. 320. 485 . 05 分 析 表 1 结 果 , 除 去 泥 砂 等 杂 质 质 量, CaSO42H2O的含量 85,从而具备了制取建筑石膏 的基本条件。 1. 2 制取建筑石膏的工艺流程及说明 生产石膏空心条板的主要原料是建筑石膏粉即 半水二水硫酸钙 CaSO41 2H2O 俗称熟石膏 , 生产 建筑石膏的主要原料又是二水硫酸钙 俗称生石膏 , 所以用废渣盐石膏代替天然石膏生产石膏空心条板, 首先需将废渣处理提纯二水硫酸钙 ,然后煅烧脱水制 取合格的建筑石膏, 生产工艺流程见图 1。 图 1 建筑石膏生产工艺流程图 生产工艺流程分两个阶段。首先将废渣破碎筛 分至2 cm左右颗粒后, 送入洗涤槽中, 充分搅拌至一 定程度后静沉一段时间。由于 CaSO42H2O 的密度 大,沉于槽底部 ,用泥浆泵排出泥浆 。根据经验,废渣 经过 2 ～ 3 遍的洗涤至目视水较清时, 只要控制泥砂 量656. 0 含水率 1～ 51 500 800 3 效益分析 3. 1 社会效益分析 随着国民经济快速发展, 新型建材推广使用与保 护生态环境紧密关联 ,实心粘土砖国家明令已不能继 续使用,取而代之的轻型墙体材料层出不穷。石膏空 心条板因其具有强度高、质量轻、 阻燃隔音,施工速度 快等特点, 被设计施工单位广泛使用 。但在进一步推 广使用这种轻型墙体材料时, 却由于价格偏高而影响 54 环 境 工 程 2006年 10 月第 24卷第 5 期 了发展速度,利用废渣盐石膏代替天然石膏制作石膏 条板, 使这种墙体材料的成本大幅度下降 ,从而为推 广使用这种新型建材做出了贡献。既处理了有害工 业废渣,解决了排渣企业的难题,又保护了生态环境, 社会效益显著。 3. 2 经济效益分析 [ 3] 盐石膏制做的石膏空心条板与天然石膏空心条 板比较 ,不仅板材的强度高而且成本低 , 这就极大地 提高了其市场竞争能力, 对其成本 、 建厂投资 、 利润等 方面的分析见表 6、表 7、 表 8。 表 6 盐石膏空心条板的成本分析 项目盐石膏粉 辅料电设备折旧 维修 人工工资 企管总计 成本 元m- 2 9 . 06 . 00. 300 . 840. 284. 00 . 821 . 22 备注 1m2用 0 . 06 t 1 m2耗电 0 . 3 k Wh 表 7 建厂总投资 项目设备土建不可预见费流动资金总计 投资额 万元8912815124 表 8 利润对比分析以 5 万m2/a 计 项目 盐石膏 空心条板 天然石膏 空心条板 成本 元m- 221. 2236 售价 元m- 2 3546 差额 元m- 2 13. 7810 税费 元m- 2 1. 5 利润 万元a - 1 68. 942. 5 表 6、7、8 分析对比可以看出 , 投资建年产 5 10 4 m 2的盐石膏空心条板厂 ,以售价低于天然石膏板 情况计算, 年利润近 70 万元, 2a 可以收回全部投资, 年处理 4 ～ 5 kt 废 渣, 节 约大 量堆 渣占 有土 地。 510 4 m 2的盐石膏空心条板代替实心粘土砖可免毁 烧砖取土约1 700 m 2 , 节约标准煤1. 5 kt以上 。 4 结论 我国海岸线长 ,沿海大中小型盐场较多, 盐石膏 的排放量很大。据考查估算, 山东省每年废渣盐石膏 排放量近150 kt , 相当于一个中型天然石膏矿的年产 量,沿海又是经济发展较快地区, 建筑行业对新型建 材的需求量很大 ,因此废渣盐石膏的开发利用, 不仅 是发展新型建材的需要, 而且对保护生态环境也起到 积极作用。 利用废渣盐石膏制作石膏空心条板的生产工艺 有如下特点 1 工艺合理简单易行 ,项目投资少, 管理方便; 2 洗涤水中不存在有害杂质,可直接排放 ,不会 对环境造成二次污染 ; 3 产品质量好,可替代天然石膏 ,继续开发系列 石膏建材制品。 参考文献 [ 1] GB9776 -88, 建筑石膏标准[ S] . [ 2] 印用嘉. 大学化学手册. 济南 山东科学技术出版社, 1985. [ 3] 董坚, 马铭杰, 张化. 磷石膏生产石膏空心板 砌块 可行性分 析. 山东建筑工程学院学报, 2000. 52 1 81 -85. [ 4] 马铭杰, 董坚, 张化. 海盐工业废渣的综合利用. 化工环保, 2001,21 5 282 -285. 作者通讯处 马铭杰 250014 山东济南和平路 47 号 山东建筑工 程学院环境工程系 2005- 12-31 收稿 上接第 52页 [ 7] Kraiwood Kiattikomol et al. A study of ground coarse fly ashes with different finenesses from various sources as pozzolanic materials. Cement and Concrete Composites, 2001, 23 335 -343 . [ 8] 阮燕, 吴定燕, 高琼英. 粉煤灰的颗粒组成与磨细灰的火山灰活 性. 粉煤灰综合利用,2001, 2 26 -28 . 作者通讯处 翟建平 210093 南京大学污染控制与国家重点实验 室南京大学环境工程系 2006- 01-11 收稿 55 环 境 工 程 2006年 10 月第 24卷第 5 期 THE PRIMARY STUDY ON CLEANING EQUIPMENTS FOR TREATING FLUE GASIN CERAMICS INDUSTRYPeng Shanjiang Su Wugen 45 Abstract Technology scheme and flow associated with the composition of cleaning equipments for treating flue gas from ceramics industry were compendiously presented. Cleaning equipments and technology possessed a highest removal in treating test of a ceramics plant, and the average concentration of SO2could be reduced from 568. 8 mg Nm3to 76. 2 mg Nm3, and that of soot simultaneously from 324. 6 mg Nm3to 122. 4mg Nm3. The average removal rate of SO2andsoot reached 86. 6and54. 6respectively, which are up to the second -order of“ Emission Standard of Air Pollutants for Industrial Kiln and Furnace” GB 9078 -1996. The results indicated that cleaning equipments and their technology resolved the write flue gas pollution and simultaneously achieved a preferable desulphurization and dust collecting effects in treating flue gas of ceramics industry. Keywords flue gas, treatment and ceramics industry THE DESIGN OF DUST CATCHER SYSTEM FOR PRODUCTION WORKSHOP OF CARBON FACTORYLiu Zhangxian LuoLingxian Yang Jiawen 47 Abstract Through project instance of dust catcher for the production workshop of a carbon factory, it was expatiated the design scheme of pollulants control of the integrating system of fast melt of pitch, separating dust hoods centralized bag collectors as well as multi-tube stativ precipitatorsfor roasters, which would be used for the processes of melting, crushing , mixing and roasting a pitch. The results showed that the project could let all the pollutantsfrom the workshop meet the emission standards. This project explored a feasible route of dustproof and dedusting in the small sized carbon factory. Keywords carbon factory , dust, asphalt, control dust system and purification efficiency STUDY ONLEVIGATING BOTTOM ASH TO OPTIMIZE ITS QUALITY Yu Jinglong Zhai Jianping Li Qin et al 50 Abstract The bottom ash drained off from Changxing power plant was presumed upon levigating to national class Ⅱ fly ash. The results show that SiO2and Al2O3are the main chemical compositions and the main mineral phase is vitreous body . The trace elements and radioelements are under the limit of national standard. The properties of bottom ash are the best as the residual on sieve 45 μ m remainder is almost 10. The pozzolanic activities of bottom ash are better than those of the levigated class Ⅱ fly ash. Keywords bottom ash, levigating process and utilization STUDY ON USING SALT GYPSUM FROM SEA SALT INDUSTRY TO PRODUCE LIGHT WALL MATERIALMa Mingjie Zhu Li 53 Abstract It has been researched that the salt gypsum as a waste residue from sea salt industry can be used as a raw material to produce a kind of hollow batten as light wall materials by some processes. This product cost can be reduced greatly by applying modified processes and raw materials as compared to natural gypsum batten. The kind of hollow battenwhose perance indicatorsmeet the national standards can replace the product made of natural gypsum. Keywords waste residue, salt gypsum,wall materials and eco-environment REUSE OF MSWI FLY ASH IN MAKING OF GLAZED TILE Zhang Haiying Zhao Youcai Qi Jingyu 56 Abstract MSWI fly ash was used to make glazed tile based on analysis of its characterization, together with red argil and cylinder sand. Besides, influence of fly ash on perance and microstructure of glazed tile as well as its environmental risk were studied. It is found that major chemical constitution of fly ash is CaO, SiO2and Al2O3, featuring an SiO2-Al2O3-metal oxides system, which can be used as the raw material of glazed tile. When 20fly ash is used, glazed tile presents nice perances compression strength being 19. 2 MPa, water -absorption rate being 7. 2, presentation quality standing in the grade one category . In addition, leaching, in accordance with the HVEP standard, from glazed tile, of As, Pb, Ni, Cr, Cu, Hg and Cd can t be detected, and that of Zn is reduced to 1. 4, in comparison with fly ash. While, leaching, in accordance with the ALT standard, from glazed tile, of As, Pb, Ni, Cr, Cu and Zn is reduced respectively to 5. 6, 0 . 1, 6. 7, 5. 8, 5. 6 and 2 . 9, compared with fly ash, and that of Hg and Cd can t be detected. Keywords MSWI fly ash, glazed tile, environmental risk analysis, perance andmicrostructure APPLICATION OF WET CRUSHING IN REUTILIZATION OF DISCARDED PRINTED CIRCUIT BOARDSZhang Hongjian Zhao Yuemin Wang Quanqiang et al 60 Abstract Based on components and crushing characteristics of non -metal composition of the discarded printed circuit boards PCBs, secondary pollution problem produced by dry crushing is validated and studied with thermogravimetry -infrared deterctor and wet crushing is providedto solve this problem. From the comparison between experimental results of dry crushing and wet crushing , it can be observed that cumulative yield of each particle size fraction of wet crushing has a change, but the distribution characteristics of particle is not changed, and the productivity of coarse particleswith the size larger than -52 mm and superfine materials with the size less than 0. 045 mm are obviously increased. Finally, the reasons of the difference are analyzed. 4 ENVIRONMENTAL ENGINEERING Vol. 24, No. 5,Oct. , 2006