简介：

造纸工业是制造各种纸张及纸板的工业部门。它包括用木材、芦苇、甘蔗渣、稻草、麦秸、棉秸、麻杆、棉花等原料制造纸浆的纸浆制造业，制造纸和纸板业以及生产涂层、上光、上胶、层压等加工纸及字型用纸版的加工纸制造业几个方面。造纸是我国的四大发明之一。早在公元前32年到16年西汉成帝时已能制造薄小纸，至公元105年，东汉和帝时蔡伦用树皮、麻头、破布、破鱼网等代替缣帛和絮作原料，大大推动了手工造纸业的发展。世界机器造纸业则开始于18世纪末。

造纸工业是一个与国民经济发展和社会文明建设息息相关的重要产业。
在经济发达国家，纸及纸板消费量增长速度与其国内生产总值增长速度同步。在现代经济中所发挥的作用已越来越多地引起世人瞩目，被国际上公认为“永不衰竭”的工业，在美国、加拿大、日本、芬兰、瑞典等经济发达国家，造纸工业已成为其国民经济十大支柱制造业之一。现代造纸工业的特点不同于一般日用消费品工业，而是技术、资金、资源、能源密集型，规模效益显著，连续、高效生产的基础原料工业。在产品总量中，80%以上作为生产资料用于新闻、出版、印刷、商品包装和其他工业领域，不足20%用于人们直接消费。造纸产业关联度大，涉及林业、农业、机械制造、化工、热电、交通运输、环保等产业，对上下游产业的经济有一定拉动作用。当今世界各国已将纸及纸板的生产和消费水平，作为衡量一个国家现代化水平和文明程度的重要标志之一。

造纸工业使用木材、稻草、芦苇、破布等为原料，经高温高压蒸煮而分离出纤维素，制成纸浆。在生产过程中，后排出原料中的非纤维素部分成为造纸黑液。黑液中含有木质素、纤维素、挥发性有机酸等，有臭味，污染性很强。

超导高梯度磁力
高梯度磁力分离净化技术是用来处理废水的一种新方法，由于它不会产生杂质例如凝絮物，使在短时间内处理大量废水成为可行。
日本Osaka大学能量和环境工程系科技人员研究了采用磁力分离系统处理造纸工厂废水。试验车间处理造纸废水为2000 t/d，进行循环运转达到磁力分离后水中化学需氧量（CODCr）<40 mg/L。超导磁力管NbTi螺旋管长680 mm、内径400 mm。
该系统主要由混合槽（磁力晶种槽，晶种为有机物、纸浆和染料）、沉淀槽和超导磁力管组成。通过超导磁力分离管内的磁力作用，俘获磁力颗粒和有机聚合物如纸浆和颜料，浮选出磁力短纤维和填料，一部分磁力短纤维和填料通过重力沉降作用，在沉淀槽中沉出，有助于减少循环水经过磁力管时的短纤维和填料量。该系统已成功地运转了几个月，取得较为满意的效果。

造纸废水处理法
造纸废水主要来自造纸工业生产中的制浆和抄纸两个生产过程。制浆是把植物原料中的纤维分离出来，制成浆料，再经漂白，这个过程会产生大量的造纸废水；抄纸是把浆料稀释、成型、压榨、烘干，制成纸张，这个过程也容易产生造纸废水。
制浆产生的造纸废水，污染为严重。洗浆时排出废水呈黑褐色，称为黑水，黑水中污染物浓度很高，BOD高达5—40g/L，含有大量纤维、无机盐和色素。漂白工序排出的造纸废水也含有大量的酸碱物质。抄纸机排出的造纸废水，称为白水，其中含有大量纤维和在生产过程中添加的填料和胶料。
造纸废水处理应着重于提高循环用水率，减少用水量和废水排放量，同时也应积极探索各种可靠、经济和能够充分利用废水中有用资源的废水处理方法。例如：浮选废水处理法可回收白水中纤维性固体物质，回收率可达95%，澄清水可回用；燃烧废水处理法可回收黑水中氢氧化纳、硫化钠、硫酸钠以及同有机物结合的其他钠盐。中和废水处理法调节废水pH值；混凝沉淀或浮选法可去除废水中悬浮固体；化学沉淀法可脱色；生物处理法可去除BOD，对牛皮纸废水较有效；湿式氧化法处理亚硫酸纸浆废水较为成功。此外，国内外也有采用反渗透、超过滤、电渗析等造纸废水处理方法。

造纸废水处理剂
聚丙烯酰胺
聚丙烯酰胺在造纸领域中广泛用作驻留剂、助滤剂、均度剂等。它的作用是能够提高纸张的质量，提高浆料脱水性能，提高细小纤维及填料的留着率，减少原材料的消耗以及对环境的污染等。聚丙烯酰胺在造纸中使用的效果取决于其平均分子量、离子性质、离子强度及其它共聚物的活性。非离子型聚丙烯酰胺主要用于提高纸浆的滤性，增加干纸强度，提高纤维及填料的留着率；阴离子型共聚物主要用作纸张的干湿增强剂和驻留剂；阳离子型共聚物主要用于造纸废水处理和助滤作用，另外对于提高填料的留着率也有较好的效果。此外，聚丙烯酰胺还应用于造纸废水处理和纤维回收。

硫酸铝
硫酸铝极易溶于水，硫酸铝在纯硫酸中不能溶解（只是共存），在硫酸溶液中与硫酸共同溶解于水，所以硫酸铝在硫酸中溶解度就是硫酸铝在水中的溶解度。常温析出含有18分子结晶水，为18水硫酸铝，工业上生产多为18水硫酸铝。含无水硫酸铝51.3%，即使100℃也不会自溶（溶于自身结晶水）。不易风化而失去结晶水，比较稳定，加热会失水，高温会分解为氧化铝和硫的氧化物。加热至770℃开始分解为氧化铝、三氧化硫、二氧化硫和水蒸气。溶于水、酸和碱，不溶于乙醇。水溶液呈酸性。水解后生成氢氧化铝。水溶液长时间沸腾可生成碱式硫酸铝。工业品为灰白色片状、粒状或块状，因含低铁盐而带淡绿色，又因低价铁盐被氧化而使表面发黄。粗品为灰白色细晶结构多孔状物。无毒，粉尘能刺激眼睛。

焦亚硫酸钠
焦亚硫酸钠为白色或黄色结晶粉末或小结晶，带有强烈的SO2气味，比重 1.4，溶于水，水溶液呈酸性，与强酸接触则放出SO2而生成相应的盐类， 久置空气中，则氧化成Na2S2O6，故该产品不能久存。高于1500C，即分解出SO2。
焦亚硫酸钠用于生产保险粉，磺胺二甲基嘧啶 安乃近，己内酰胺等 以及氯仿，苯丙砜和苯 甲醛的净化。照相工业用作定影剂的配料。香料工业用于生产香草醛。用作酿造工业防腐剂，橡胶凝固剂和棉布漂白后脱氯剂。有机中间体，染料，制革用作还原剂 用作电镀业，油田的废水处理 以及用作矿山的选矿剂等。工业上用于印染、有机合成、印刷、制革、制药等部门；在食品加工中作防腐剂、漂白剂、疏松剂。（印染和摄影等方面）、用作漂白剂 媒染剂，还原剂 橡胶凝固剂，也用于有机合成制药及香料等。

The paper industry is the industrial sector that manufactures a variety of paper and board. It includes pulp manufacturing for pulp production from wood, reed, bagasse, straw, wheat straw, cotton straw, hemp, cotton, etc., manufacturing paper and paperboard industries, and processing, glazing, gluing, lamination, etc. Paper and font paper processing paper manufacturing in several aspects. Papermaking is one of the four major inventions in China. As early as 32 to 16 BC, when the Western Han Dynasty became Emperor, it was able to make thin paper. By the year 105, the Eastern Han Dynasty and Emperor Cai Lun used bark, hemp, rags, broken fish nets, etc. instead of glutinous rice and floc. Greatly promoted the development of the manual paper industry. The world machine paper industry began in the late 18th century.

The paper industry is an important industry closely related to the development of the national economy and the building of social civilization.
In developed countries, the growth rate of paper and board consumption is in line with the growth rate of GDP. The role played by the modern economy has attracted more and more attention from the world and has been recognized as an “never-depleting” industry in the world. In the developed countries such as the United States, Canada, Japan, Finland, and Sweden, the paper industry has become One of the top ten pillar manufacturing industries of the national economy. The characteristics of the modern paper industry are different from the general consumer goods industry, but the basic raw material industry with technology, capital, resources and energy intensive, significant scale benefits, and continuous and efficient production. More than 80% of the total product is used as production materials for news, publishing, printing, commodity packaging and other industrial sectors, and less than 20% is used for direct consumption. The paper industry has a high degree of relevance, involving forestry, agriculture, machinery manufacturing, chemical, thermal power, transportation, environmental protection and other industries, and has a certain pulling effect on the economy of upstream and downstream industries. The production and consumption levels of paper and paperboard have been regarded as one of the important indicators for measuring the level of modernization and civilization of a country.

The paper industry uses wood, straw, reed, rags, etc. as raw materials, and the cellulose is separated by high-temperature and high-pressure cooking to make pulp. In the production process, the non-cellulosic portion of the final discharged raw material becomes a black liquor for papermaking. The black liquor contains lignin, cellulose, volatile organic acids, etc., which is odorous and highly polluting.

Superconducting high gradient magnetic force
The high-gradient magnetic separation and purification technology is a new method for treating wastewater. Since it does not generate impurities such as flocculation, it is feasible to treat a large amount of wastewater in a short time.
Scientific and technical personnel from the Department of Energy and Environmental Engineering at the University of Osaka, Japan, studied the use of magnetic separation systems to treat paper mill wastewater. The test workshop treated papermaking wastewater at 2000 t/d and carried out the cyclic operation to achieve a chemical oxygen demand (CODCr) of <40 mg/L in the water after magnetic separation. The superconducting magnetic tube NbTi spiral tube has a length of 680 mm and an inner diameter of 400 mm.
The system consists mainly of a mixing tank (magnetic seed tank, seed crystals for organic matter, pulp and dye), a sedimentation tank and a superconducting magnetic tube. Through the magnetic force in the superconducting magnetic separation tube, the magnetic particles and organic polymers such as pulp and pigment are captured, the magnetic short fibers and the filler are floated, and a part of the magnetic short fibers and the filler are deposited by gravity sedimentation, and are deposited in the sedimentation tank. Helps reduce the amount of short fibers and fillers when circulating water passes through a magnetic tube. The system has been successfully operated for several months and has achieved satisfactory results.

Paper Wastewater Treatment Method
The papermaking wastewater mainly comes from the two production processes of pulping and papermaking in the paper industry. Pulping is to separate the fibers in the plant raw material, make a slurry, and then bleach, this process will produce a large amount of papermaking wastewater; papermaking is to dilute, shape, press, and dry the slurry to make paper, this The process is also prone to papermaking wastewater.
The papermaking wastewater produced by pulping is the most polluted. The waste water discharged during washing is dark brown, called black water. The concentration of pollutants in black water is very high, and the BOD is as high as 5-40 g/L, which contains a large amount of fiber, inorganic salt and pigment. The papermaking wastewater discharged from the bleaching process also contains a large amount of acid-base substances. The papermaking wastewater discharged from the paper machine, called white water, contains a large amount of fibers and fillers and compounds added during the production process.
Papermaking wastewater treatment should focus on improving the recycling rate, reducing water consumption and wastewater discharge, and actively exploring various reliable, economical and wastewater treatment methods that can make full use of the useful resources in wastewater. For example, the flotation wastewater treatment method can recover fibrous solid materials in white water, the recovery rate can reach 95%, and the clarified water can be reused. The combustion wastewater treatment method can recover sodium hydroxide, sodium sulfide, sodium sulfate and organic substances in black water. Other sodium salts. The neutralization wastewater treatment method adjusts the pH value of the wastewater; the coagulation sedimentation or flotation method can remove the suspended solids in the wastewater; the chemical precipitation method can decolorize; the biological treatment method can remove the BOD, and is effective for the kraft paper wastewater; the wet oxidation process treats the sulfite pulp Wastewater is more successful. In addition, there are also papermaking wastewater treatment methods such as reverse osmosis, ultrafiltration and electrodialysis at home and abroad.

Paper Wastewater Treatment Agent
Polyacrylamide
Polyacrylamide is widely used as a residence agent, filter aid, leveling agent, etc. in the papermaking field. Its function is to improve the quality of the paper, improve the dewatering performance of the slurry, increase the retention of fine fibers and fillers, reduce the consumption of raw materials and environmental pollution. The effectiveness of polyacrylamide in papermaking depends on its average molecular weight, ionic properties, ionic strength, and activity of other copolymers. Non-ionic polyacrylamide is mainly used to improve the filterability of pulp, increase the strength of dry paper, and increase the retention of fibers and fillers; anionic copolymers are mainly used as dry and wet enhancers and residence agents for paper; cationic copolymerization The material is mainly used for papermaking wastewater treatment and filter aid, and also has a good effect on increasing the retention rate of the filler. In addition, polyacrylamide is also used in papermaking wastewater treatment and fiber recycling.

Aluminium Sulfate
Aluminum sulfate is very soluble in water, aluminum sulfate cannot be dissolved in pure sulfuric acid (only coexisting), and is dissolved in water in sulfuric acid solution together with sulfuric acid, so the solubility of aluminum sulfate in sulfuric acid is the solubility of aluminum sulfate in water. The precipitated at room temperature contains 18 molecules of crystal water, which is aluminum sulfate 18 water, and industrially produces mostly aluminum sulfate 18 water. Containing 51.3% of anhydrous aluminum sulfate, it does not self-dissolve (dissolved in its own crystal water) even at 100 °C. It is not easy to weather and lose crystal water. It is relatively stable, heating will lose water, and high temperature will decompose into oxides of alumina and sulfur. Heating to 770 ° C begins to decompose into alumina, sulfur trioxide, sulfur dioxide and water vapor. Soluble in water, acid and alkali, insoluble in ethanol. The aqueous solution is acidic. After hydrolysis, aluminum hydroxide is formed. The aqueous solution boils for a long time to form basic aluminum sulfate. Industrial products are gray-white flakes, granules or lumps. They are light green due to low iron salts and yellowish due to oxidation of low-cost iron salts. The crude product is a grayish white fine crystal structure porous. Non-toxic, dust can irritate the eyes.

Sodium metabisulfite
Sodium metabisulfite is a white or yellow crystalline powder or small crystal with a strong SO2 odor, a specific gravity of 1.4, soluble in water, and the aqueous solution is acidic. When it is in contact with a strong acid, it releases SO2 to form a corresponding salt. When it is left in the air, it oxidizes. It is Na2S2O6, so the product cannot be stored for a long time. Above 1500C, SO2 is decomposed.
Sodium metabisulfite is used for the production of insurance powder, sulfamethazine, dipyridamole, caprolactam, etc., as well as the purification of chloroform, phenylpropane sulfone and benzaldehyde. The photographic industry is used as a fixative for the fixer. The perfume industry is used to produce vanillin. Used as a preservative for brewing industry, a rubber coagulant and a bleaching agent for cotton bleaching. Organic intermediates, dyes, and tanning are used as reducing agents for electroplating, wastewater treatment in oil fields, and as a mineralizer for mines. Industrially used in printing and dyeing, organic synthesis, printing, tanning, pharmaceutical and other departments; as a preservative, bleaching agent, loosening agent in food processing. (Printing and printing, photography, etc.), used as a bleaching agent, mordant, reducing agent, rubber coagulant, also used in organic synthetic pharmaceuticals and spices.

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