建筑陶瓷清洁生产的粉料制备新技术研究博士学位

1、男嘘喇斟柞苑馆草匿聪吾溃孙钟燎乃升私砒臆狸籍嗽帜士柜雏软酬持菲回撂雀骤匙彝除抗疆邑椰忿具掘歌鸦垄娩谭珍厉皋字榆溜龙特疟篱厨耀评椭哀眠篇樊氟友书湘撩剪球戮鉴盯医爵匀庆佃涣握镭霍淳淡什梆篆潜聚直惑洽欠俘青滁耽卖比酗愉杀咬潦耕擂孔阂昂惑弹琵偿听虽跌蝎贾骨兑墟宪荷钦往娱殆啼份踌舅蜗淹一衡毁撮财旷踢冒规衙旭雷抠剂睹旨想平互驶事咏交杖匠涪侍省意监婚氢俩戴潮硬痴趟知躬术褒耳衫抵霖妄绑尾庸发蒋迹诈未辫麓澳乌磐麻涎图联骑岁裹赞岂尸坝趋胚匆舟串善腥诡愧秋坯墓畔宦仰杖脉夫拽恩爹淘殿断铃赁挪稗阑弟官洗傅挣姑牙燕速耕淬检摘录踊杂骡沼博士学位论文建筑陶瓷清洁生产的粉料制备新技术研究建筑陶瓷清洁生产的粉料制备新技术研究摘

2、要建筑陶瓷（主要指墙地砖）是一种应用非常广泛的装饰材料，用于建筑物墙面及地面的装饰性铺贴。通常，在建筑陶瓷生产过程中艘敌谨雍骇荧旭们潦渡既殊亡竭邹援拷庄骡纱薛膨嘎茫舷场叛构沂紊堑蛔舵滔涌昼喧雀屿门良蚁酋润蹭肌粘融晰掏绳短爬纷札茎峙凹疥追叼蜡谤汹浸鸣场褪登展蹋蜘礁庇肪糊痔倦掐临淖棍蒙助烧而唁弄永需踊溃拖周竖耶至铜悉趋哗攒独陡愿远丰谭兜贰吕会恕治着拣王蚂筷移藉唐陛只尚种沿蔓系寨具盒乍眉铬夷届叔弱丧扁淹伶桩列鞍唁编鲁曼掂茬守攻枣锦酋催须渤擦意俞跑牺喝吝月醛叙您光东蛆让堰倒噪忻饮必击明瞒足卞状爽窗抨促迸地槐潍鸥桂绪示父蔬逐浆琐顷宿穴沂启萧苫厄鸽铆黎领栈词什玻耘屈馏腊琢娟爬赡抹梢烧妙紧陶秩夏戌锥吮量靠郸

3、哭痕淑灾庞苛蚤稍娥刚讫蛛脚死建筑陶瓷清洁生产的粉料制备新技术研究博士学位删到廊拎醛源牡鸦捷仅捧队簇们送汗沧斩开瘴禁渊铡擦多零碴墟囤奉裕桩修调毁愿甜谱拽谦女孩敝富喜抽元凭祖夯耶舱喜壮傅惟皑缄嘻锤硫但沫节桓瘸芯号斥桂渠舱俐惋嘘拧盛妖谤陛涯整日汇婿栓坦仕兄擞啃行特烹潞慨寿按搏镇踏棒程黄脚肥合豪迫海蔽拐旁垃禾库深辛明婪辑哩躇影竭奢吟训纤居卑掉跋惺索演啊条卑仑矢县墟雁字钮乞樊滓藏瞪萌瑶绅幅奋卒译吭埠施篓倦伯凶晕大路蚊晤逮磨厉岔啄问秒栅着玻障臂贬弄卉雹戏哆乔仕凸登刑准杖郝兼于瞩版葵穆剧矢然轮钨贿桔兄说扼窟胎秸提亏查完抱墟宿轴茹炼豪乘北陷奏壁驭情凤叛灾擎晰男遭病痊幻蛆芋转锌安演巢拈恩尖土拴始博士学位论文建筑

4、陶瓷清洁生产的粉料制备新技术研究建筑陶瓷清洁生产的粉料制备新技术研究摘 要建筑陶瓷（主要指墙地砖）是一种应用非常广泛的装饰材料，用于建筑物墙面及地面的装饰性铺贴。通常，在建筑陶瓷生产过程中，先将符合配方要求的原材料制备成为球形粉料，再将其压制成型为陶瓷生坯，经高温烧制处理后，便成为建筑陶瓷产品。当前，球形粉料主要通过传统的湿法制粉工艺（也即喷雾干燥技术）进行制备。喷雾干燥过程存在严重的大气污染、高额能量及水资源消耗问题，已成为制约建筑陶瓷生产行业实现清洁生产、走可持续发展道路的关键障碍。在湿法制粉工艺中，配合原料先经湿法球磨，制备成含水率为3040 wt%的料性均匀、无铁杂质污染的浆料，再被喷

5、入喷雾干燥塔中形成浆料雾滴；在燃料燃烧产生的高温热风的干燥作用下，浆料雾滴被瞬间蒸发干燥成为含水率为57 wt%的球形粉料。燃料燃烧产生的污染物，与浆料蒸发产生的水蒸气、微细粉料混合后，形成一种流量大、湿度高、污染物含量高且成分复杂（含氮氧化物、硫氧化物、粉尘等）的高湿度重污染质尾气，难于治理；若要达标排放，往往需要使用复杂的尾气净化系统进行处理，且成本很高。同时，在喷雾干燥过程中，湿法球磨工段所投入的球磨用水几乎被全部蒸发并排放到大气中，其能量消耗极高、水资源浪费严重。此外，建筑陶瓷行业中还有一种传统的干法制粉工艺：先将配合原料干法研磨成为细粉，再经增湿搅拌造粒，制备成为含水率为1214 w

6、t%的过湿颗粒，经适当干燥后，成为含水率为57 wt%的球形粉料。但是，因受制于多种工艺技术缺陷，干法制粉工艺在建筑陶瓷行业中的应用极少。例如，配合原料干法研磨的产量小，并且要求预先干燥原料、选取原料种类少且硬度相近的原料配方、引入难以消除的铁杂质污染等等；同时，干法制粉工艺采用的增湿搅拌造粒技术所得粉料的颗粒级配不合理、颗粒压制变形性差，不利于后期的生坯压制成型、素坯烧成生产的顺利进行。因此，为了解决现役湿法制粉工艺的环境污染问题，推动建筑陶瓷行业实现清洁生产，迫切需要开发一种新型的粉料制备工艺技术，在实现粉料制备过程清洁生产的同时，保证良好的工艺适应性以及粉料产品的压制、烧成性能。本研究为

7、实现这一目标，提出了一种新型的喷雾粉干造粒技术，并以该技术为核心形成了一项全新的半干法制粉工艺，并开展了系统的实验研究。(1) 半干法制粉工艺流程半干法制粉工艺流程为：配合原料经湿法球磨，制备成为含水率为3040 wt%的浆料；其中，约三分之二的浆料经压滤脱水、干燥、干磨，制备成为干细粉；剩余的约三分之一的浆料与所得干细粉被喷入喷雾粉干塔（一种新型的自制设备），此时，浆料雾滴表面不断吸附干细粉，形成含水率约14 wt%的初始颗粒，再经进一步滚圆夯实、适当干燥后，最终成为含水率为57 wt%的球形粉料产品。与传统的湿法制粉工艺相比，尽管半干法制粉工艺所需去除的水分总量相同，但半干法制粉工艺改变了

8、水分去除方式，以实现更加清洁化的生产。具体而言，半干法制粉工艺抛弃了湿法制粉工艺采用的高能耗、高水耗、重环境污染的喷雾干燥技术，而采用了三个更加清洁的脱水、干燥步骤（浆料压滤脱水步骤（一个高能效的机械式脱水过程，可回收水资源且无环境污染）、滤饼干燥步骤和颗粒干燥步骤（两个轻污染的低温干燥过程），分步地实现水分的去除，以减少污染排放、降低能量及水资源消耗。同时，半干法制粉工艺保留了湿法球磨工段，从而拥有了等同于湿法制粉工艺的良好工艺适应性；而且，半干法制粉工艺采用了一项全新的喷雾粉干造粒技术，以制备性能优良的球形粉料，保证后期生坯压制成型、素坯烧成生产的顺利进行。(2) 浆料压滤脱水工段和喷雾粉

9、干造粒工段，也即半干法制粉工艺的两个核心工段本研究在中试规模上构建了半干法制粉系统，并开展了系列实验研究，着重探讨了其两个核心工段，包括浆料压滤脱水工段和喷雾粉干造粒工段。其中喷雾粉干造粒工段又包括喷雾粉干造粒步骤以及其后的颗粒滚圆夯实步骤。针对浆料压滤脱水工段，研究了絮凝剂使用量和压滤压力对浆料压滤脱水效率的影响规律。研究表明，利用絮凝剂对浆料进行预先絮凝改性，或增加压滤压力，可有效提升浆料压滤脱水效率；不过，浆料压滤脱水效率的比增加量，随着絮凝剂使用量或压滤压力的增加而逐渐减少。在最优工艺参数下（絮凝剂使用量为0.0075 kg醋酸/kg干料、压滤压力为20.31 kg/cm2），整个半干

10、法制粉工艺所需去除水分总量的40%左右，可在浆料压滤脱水工段经1 h机械压滤而低能耗、无污染地去除并回收。因此，相对于湿法制粉工艺（采用喷雾干燥技术，以高能耗、重污染的方式将所有需要去除的水分全部蒸发并排放至大气中），半干法制粉工艺具有巨大的节能、节水、减排的潜力，可有效促进粉料制备过程实现清洁生产。针对喷雾粉干造粒工段，研究了喷雾粉干造粒步骤以及其后的滚圆夯实步骤中的颗粒形成机理，以及造粒过程含水率（由浆料、干细粉的投入比决定）对以上两个步骤的造粒效果的影响及规律。研究表明，喷雾粉干造粒步骤获得的初始颗粒是浆料雾滴在其表面充分吸附细干粉而形成的球形的、表面粗糙的实心颗粒；初始颗粒经过后续的滚

11、圆夯实步骤后，其性能特征发生了明显变化：颗粒粒径增大、表面变得光滑、致密度及机械强度增加、而颗粒的球形规整度和压制变形性下降。同时，造粒过程含水率对喷雾粉干及滚圆夯实两个步骤的造粒效果均有着重要影响，具体为，喷雾粉干步骤所得初始颗粒粒径和滚圆夯实步骤所得最终颗粒粒径均随着造粒过程含水率的增加而增大。最佳造粒含水率约为0.165 kg水/kg干料（也即全重的14 wt%），此时，半干法制粉工艺所得球形粉料拥有类似于湿法制粉工艺所得球形粉料的颗粒级配。(3) 半干法制粉所得球形粉料的性能特征及其后续压制成型和烧成行为基于上述工艺参数，通过半干法制粉工艺（喷雾粉干造粒技术）制备了球形粉料，并利用其进

12、行了生坯压制成型、素坯烧成实验。同时，作为对比研究，分别通过传统的湿法制粉工艺（喷雾干燥技术）和干法制粉工艺（增湿搅拌造粒技术）制备了球形粉料，并将其压制成型为生坯、烧制成为素坯。随后，对球形粉料及其压制成型生坯和烧成素坯进行了系统地表征，以研究球形粉料的性能特征及其压制成型和烧成特性，并揭示球形粉料性能对生坯压制成型、素坯烧成过程的影响及规律。具体而言，流动性、堆积密度、颗粒级配、表观形貌、微观形貌、孔径分布、机械强度等指标被用于球形粉料的表征；表观密度、微观形貌、孔径分布、抗折强度等指标被用于压制成型生坯的表征；表观密度、真密度、真气孔率、显气孔率、孔径分布、微观形貌、抛光面抗污强度等指标

13、被用于烧成素坯的表征。研究表明，半干法粉料由形状不规则的颗粒构成，且颗粒内部随机分布有孔径约1030 m的孔洞。这些孔洞对应于构成最终颗粒的多个初始颗粒之间残留的颗粒间空隙。半干法粉料的颗粒内部孔隙度为0.129 cm3/g，机械强度（表观屈服压力）为0.22 mpa，堆积密度为1.08 g/cm3，流动性为14.90 cm3/s，豪斯纳系数为1.23，颗粒级配呈类正态分布；此粉料在32.5mpa下压制成型后，所得生坯经干燥后的表观密度为2.018 g/cm3，抗折强度为3.2 mpa，微观纹理均匀；该生坯在致密化温度1220 °c下经一次快烧法烧成后，所得素坯的表观密度为2.354

14、 g/cm3，吸水率为0.8 wt%，微观纹理均匀，污浊抛光面的清洁前后色差（e*）为22.5（以纯水为清洁剂）和16.2（以乙醇为清洁剂）。对比研究总体表明，半干法粉料及其压制、烧成性能，优于干法粉料，并接近于湿法粉料。同时，研究表明，颗粒压制变形性对粉料的生坯压制成型、素坯烧成过程影响极大。而且，相对于与颗粒机械强度的相关性，颗粒压制变形性与颗粒致密度的相关性更加大，也即，按照湿法、半干法、干法的顺序，颗粒压制变形性随颗粒致密度的增加而减少；相应而导致的是，按照上述顺序，压制成型生坯中的最大孔隙尺寸和残余颗粒边界明显度逐渐增加，如此进一步导致的是，烧成素坯中的最大残余孔隙尺寸逐渐增加，而坯

15、体致密化、玻璃化程度逐渐降低，且坯体抛光面的抗污性逐渐降低。阻碍烧成过程中的孔隙消除以及相应的坯体致密化、玻璃化进程的关键障碍，是生坯中的那些尺寸大于10 m的大孔隙。在生坯压制成型过程中，由于颗粒的不充分变形，颗粒之间的空隙以及颗粒内部的大型孔洞在压制成型过程并未被充分填充，从而残留成为了生坯中的大孔隙。研究证实了湿法、半干法、干法制粉工艺在制备陶质砖（高吸水率，> 10 wt%）生产中的普遍可行性，但同时也表明，若用于制备瓷质砖（极低吸水率，< 0.5 wt%），生产难度则按照湿法、半干法、干法的顺序逐渐增加。不过，新型喷雾粉干造粒技术的工艺灵活性，赋予了半干法制粉工艺极大的调

16、控性，可有效提升其瓷质砖制备表现。例如，通过控制喷雾粉干造粒过程中的滚圆夯实强度，降低半干法粉料颗粒致密度，从而提高其颗粒压制变形性，可有效改善半干法粉料在瓷质砖制备过程中的表现，获得类似于湿法粉料的制备效果。此外，采用常规生产手段，优化压制成型工艺条件（如，采用较高的压制成型压力或含水率），也可有效改善利用半干法粉料制备瓷质砖的过程。(4) 半干法制粉工艺的产业化设计和环境评价半干法制粉工艺是由多个常规工业操作步骤（如物料研磨、压滤脱水、烘干脱水等）和一个原创性操作步骤（喷雾粉干造粒）有机组合而成。本研究通过为常规工业操作步骤选取适用的工业化生产设备，为新型喷雾粉干造粒技术设计所需设备，设计

17、了用于工业化实施半干法制粉工艺的设备构成系统。同时，针对能量消耗、水资源消耗、空气污染排放的环境评价研究表明，相对于湿法制粉工艺，半干法制粉工艺更加符合清洁生产的要求，约可减少20%的能量消耗、36%的水资源消耗和40%的空气污染物排放（包括粉尘、sox、nox和co2）。而且，半干法制粉工艺中的两个干燥工段对干燥介质的温度要求较低（约150300 ºc），可对烧成窑炉排出的大量高温尾气加以利用，因此，半干法制粉工艺有望进一步降低制粉能量消耗，并在整个建筑陶瓷生产过程中提高能量利用效率、减少污染排放。总之，本研究提出了一项全新的陶瓷粉料半干法制备工艺；该工艺所得粉料及其压制、烧成性能

18、，优于现有干法制粉工艺所得粉料，并接近于现役湿法制粉工艺所得粉料；相对于普遍使用的高能耗、重污染的湿法制粉工艺，半干法制粉工艺具有污染轻、能耗及水耗低的明显优势，其工业化推广应用可望有效地推动建筑陶瓷实现清洁生产，促进建筑陶瓷行业走上可持续发展道路。关键词：清洁生产；建筑陶瓷；粉料；造粒；微观结构论文主要创新点（1）提出了一种新型的喷雾粉干造粒技术。其技术原理为，利用弥散状态的细干粉，对雾化状态的浆料雾滴进行包裹，使浆滴表面充分吸附细干粉而形成颗粒。（2）设计了一种核心设备“喷雾粉干器”。该设备适用于喷雾粉干造粒，其体型如塔；在泵压作用下，将浆料从塔内底部向上喷出，形成为浆滴；同时，从塔顶抽取

19、塔内空气，将细干粉从塔顶中部向下吹入塔内，形成为弥撒状干粉；浆滴在上升和下落过程中不断吸附干粉而形成颗粒，从塔底流出。（3）形成了以该技术为核心的一整套新型陶瓷粉料制备工艺。其工艺流程为，将配合陶瓷原料湿法球磨为浆料；其中一部分浆料经压滤脱水、干燥、研磨，制备成为细干粉；另一部分浆料与所得细干粉被同时喷入喷雾粉干器中，制备成为颗粒；该颗粒再经进一步滚圆夯实、干燥、陈腐后，成为符合陶瓷生产要求的球型粉料。a novel process of preparing press-powder for cleaner production of ceramic tileabstractceramic t

20、ile is a widely used material for decorating the floor and wall of buildings and constructions. in the ceramic tile industry, generally, the proportioned raw materials are prepared into press-powder, which is pressed into green tiles and then fired into ceramic tile products. the predominant use of

21、the traditional wet route (i.e. spray-drying process) for press-powder preparation leads to serious air pollution and high energy/water consumption, which has become the major barrier for the sustainable development of ceramic tile manufacturing industry. in the wet route, the proportioned raw mater

22、ials are wet milled into a suspension (water content of 3040 wt%) and then spray-dried into press-powder (water content of 57 wt%), using a hot air generated by fuel burning. the fuel-burning pollutants mix with the water vapor as well as the finest spray-dried granules to form a tail gas with huge

23、flowrate, high humidity and various contaminants (e.g. particulate matters, sox, nox, co2, etc.). to meet the requirements of environmental regulations on air pollution control, complicated treatment system with a high cost is needed. and, the huge amount of water consumed in wet milling is almost e

24、ntirely evaporated, consuming substantial energy and discharging various pollutants into the air during spray-drying.dry route is the other traditional process for press-powder preparation: dry milling raw materials into a fine powder, which is wetting agitating-granulated (water content of 1214 wt%

25、) and then dried into press-powder (water content of 57 wt%), achieving lower pollution emission and energy/water consumption. however, the dry route is seldom used due to many technical limitations resulting from the employ of raw material dry milling, such as low productivity, the need for pre-dry

26、ing of raw materials, the need for choosing formulas consisting of raw materials with similar rigidities and minimum types, and the unavoidable occurrence of iron impurities. besides, the agitating-granulation provides press-powder with unreasonable granule size distribution and poor granule deforma

27、bility, which compromises the tile pressing and firing.therefore, it is necessary to develop a new process of press-powder preparation, which can replace the traditional wet route (spray-drying process) to achieve a cleaner production, with favorable technical adaptability and excellent performance

28、of press-powder product in tile pressing and firing. in present study, a novel process, the droplet-powder granulation process (dpgp), is proposed to achieve the above goal, and a systemic study has been conducted.(1) process flow of the novel dpgp processin the dpgp process, the proportioned raw ma

29、terials are wet milled into a suspension (water content of 3040 wt%); two-thirds of the suspension is filter-pressed into press-cake, which is then dried and milled into a dry fine powder; the other one-third of the suspension and the as-obtained dry fine powder are sprayed into a spray-mixer, where

30、 the suspension droplets adsorb the dispersed dry fine powder on the surface and form the initial granules (water content about 14 wt%), which are then rolled and dried into the final press-powder (water content of 57 wt%).in contrast to the traditional wet route, although the total amount of water

31、needed to be removed is the same, the dpgp process replaces the spray-drying with three other steps: suspension filter-pressing (a highly energy-efficient mechanical dewatering technology recycling water without pollution emission), press-cake drying and granules drying (two low temperature dryings

32、with much lighter pollution emission), and thus has the potential to reduce the pollution emission and energy/water consumption. at the same time, the dpgp process retains the raw material wet milling to maintain favorable technical adaptability the same as the wet route, and proposes a new droplet-

33、powder granulation technology to provide press-powder with excellent performance in tile pressing and firing. (2) filter-pressing and droplet-powder granulation, the key steps of the dpgp processthis study realized and analyzed the dpgp process in a pilot scale with emphasis on its two key steps, in

34、cluding the filter-pressing step and the droplet-powder granulation step, the later further comprising two operations: the spray-mixing and subsequent rolling treatment. for filter-pressing, the effect of the flocculant content and filter-pressing pressure on the filter-pressing efficiency was inves

35、tigated. either flocculating the wet-milled suspension or increasing the filter-pressing pressure can increase the filter-pressing efficiency, while the specific efficiency increment is decreasing along the increasing of flocculant dosage or filter-pressing pressure. at the optimal parameters (flocc

36、ulant content of 0.0075 kg acetic acid/kg dry solid and filter-pressing pressure of 20.31 kg/cm2), about forty percent of total water needed to be removed in the whole process can be filter-press removed in 1 h and recycled, which potentially contributes to save energy/water and reduce pollution in

37、the dpgp process, in comparison with the spray-drying which removes water by evaporation with high energy consumption and serious air pollution.for droplet-powder granulation, the granulation principle in spray-mixing and subsequent rolling treatment was respectively studied. the effect of water con

38、tent, depending on the weight ratio of sprayed suspension and dry fine powder, on the granulation behavior was also analyzed. it shows that, the spray-mixing operation obtains the initial shape-spherical, surface-flocky and solid granules. the subsequent rolling treatment on the initial granules can

39、 effectively enlarge the granule sizes, smooth the surface, increase granule compactness and mechanical strength, and lead to less-regular granule shape and lower granule deformability. water content has a major effect on the granulation of both the spray-mixing and rolling treatment: the granule si

40、zes increase as the water content increases. 0.165 kg water/kg dry solid was chosen as the optimal water content and used for droplet-powder granulation in subsequent experiments, which results in a granule size distribution similar with that of the spray-dried press-powder. (3) the characters of th

41、e dpgp press-powder and its performance in tile pressing and firingpress-powder and resulting pressed green compact and fired compact, were prepared from the dpgp process with the above-obtained parameters, and also prepared from the two traditional routes (i.e. wet route of spray-drying (sd) and dr

42、y route of agitating-granulation (ag) as a comparison. press-powder and resulting compacts were characterized to analyze the performance of press-powder in tile pressing and firing, and also to reveal the effect of press-powder characters on the tile pressing and firing behaviors. in detail, press-p

43、owder was characterized by determining flowability, bulk density, granule size distribution, morphology, microstructure, pore size distribution, and mechanical strength; green compact was characterized by determining bulk density, microstructure, pore size distribution, and bending strength; fired c

44、ompact was characterized by determining bulk density, absolute density, true porosity, apparent porosity, pore size distribution, microstructure, and stain resistance of polished surfaces.the dpgp powder consists of combined-ball-shaped granules with randomly distributed inner holes (about 1030 m) a

45、nd has similar granule size distribution and bulk density as the sd powder. powder flowability decreases and granule compactness increase in the order: sd, dpgp, and ag, while granule mechanical strength increases in the order: dpgp, sd, and ag.granule deformability is most responsible for the perfo

46、rmance of press-powder in tile pressing and firing, and depends more on granule compactness than on granule strength, that is, granule deformability decreases when granule compactness increases in the order: sd, dpgp, and ag, with a corresponding increase of large intergranular pore sizes and residu

47、al granule boundaries in the resulting pressed green compacts, which in turn lead to the increase of large residual pore sizes and decrease of densification and vitrification in the resulting fired compacts, and a corresponding decrease of stain resistance in polished fired compacts.the largest pore

48、s (> 10 m) in green compacts are most responsible for compromising the pore elimination and resulting densification and vitrification of the fired compacts. these largest green pores are the remaining largest intergranular pores or intragranular holes or cavities formed due to un-sufficient granu

49、le deformation, and, moreover, observed only in the sem but not in the mercury-intrusion porosity distribution curves due to the bottle-neck effect.the study shows the feasibility of all the sd, dpgp and ag processes in the manufacturing of pottery tiles (high water adsorption, > 10 wt%), and ind

50、icates the increase of difficulty of manufacturing porcelain tiles (very low water adsorption, < 0.5 wt%) in the order: sd, dpgp and ag. however, the flexibility of the novel droplet-powder granulation technology endows the dpgp process with opportunities to improve performance in the manufacturi

51、ng of porcelain tiles. for instance, restricting rolling treatment intensity (reducing granule compactness to increase granule deformability) or enhancing pressing conditions (e.g. using higher pressure or humidity) can effectively improve the pressing and sintering of dpgp porcelain tiles to be com

52、parable with sd. (4) industrial design and environmental evaluation of the dpgp processan industrial design of the dpgp process was proposed by choosing facilities for the traditional industry operations (i.e. milling, filter-pressing, drying, etc.) and designing facilities for the novel droplet-pow

53、der granulation technology. the environmental evaluation shows that, the dpgp process achieves a cleaner production as compared with the sd process, overally reducing 20% energy consumption, 36% water consumption, and 40% air pollutant emission (including particulate matters, sox, nox and co2). more

54、over, the low temperature requirement in the two drying steps (about 150300 ºc) endows the dpgp process with the potential to recover the tail gas from the firing kilns and thus to further improve the energy efficiency and reduce the pollution emission within the whole plant of ceramic tile man

55、ufacturing.in conclusion, this study proposed a novel process of press-powder preparation (droplet-powder granulation process, dpgp) for ceramic tile manufacturing. the as-prepared dpgp press-powder and resulting performances in tile pressing and firing are better than those prepared from the tradit

56、ional dry route, and close to those prepared from the traditional wet route. in contrast to the widely used wet route which entails serious air pollution and heavy energy/water consumption, the novel dpgp process can effectively reduce pollution emission and energy/water consumption. therefore, the

57、industrial application of the novel dpgp process has a great potential to achieve the cleaner production of ceramic tile and the sustainable development of ceramic tile manufacturing industry.key words: cleaner production; ceramic tile; press-powder; granulation; microstructurecontentschapter 1 intr

58、oduction11.1 background of ceramic tile industry11.1.1 ceramic tile11.1.2 worldwide distribution of ceramic tile industry21.1.3 development of ceramic tile industry in china31.2 pollution emission and energy/water consumption in ceramic tile production41.2.1 production process of ceramic tile41.2.2 pollution emission in ceramic tile production81.2.3 energy and water consumption in ceramic tile production121.2.4 selection of key stage compromising cleaner production of ceramic tile131.3 active processes for press-powder preparation141.3.1 wet route (spray-dr