The Role and Prospect of Sodium Humate in Ceramic Industry


    1 humic acid in the ceramic industry application background

    As far as the late Eastern Han Dynasty, the working people of our country mastered the technology of making porcelain, and after a long period of development, from porcelain recipe, clay, roasting to fine painting, both reached a high level of technical and artistic level. The use of ceramic additives, found in the mud with organic matter containing red clay, purple wood section, coal clay, coal gangue, etc., greatly improve the quality of ceramics, and then gradually developed to the use of tannins, oxalic acid, gallic acid, paper Waste liquid as a diluent and plasticizer.

    In 1957 Germany Augustyn first carried out the humic acid ammonium (HANH4) as a ceramic mud thinner test, later France, India, Japan and other countries have carried out this research. Japan has conducted a large-scale test at the company, found that the use of HANa better than HANH4. China's application of humic acid in the ceramic industry in the mid-1970s, when China's southern porcelain raw materials with poor plasticity, low dry strength problems, humic acid industry scientific and technological personnel according to the nature, mechanism and role of humic acid, combined with the South Porcelain with the characteristics of raw materials to porcelain Jingdezhen as the base, the success of HANa applied to porcelain, from the HANa ceramic industry to become an indispensable multi-functional additives [2]. It is estimated that more than 20 provinces and cities nationwide more than 500 ceramic enterprises in the use of HANa, Jiangxi Province, only about 2,000 tons per year, of which more construction porcelain, followed by daily porcelain, porcelain, porcelain, , Box body, gypsum mold, glaze also use HANa. 30 years of practice has proved that HANa than traditional ceramic additives has many unique advantages, showing dilution, plasticization, reinforcement, adsorption, bonding and other five major effects. HANa not only solved many technical problems in the ceramic industry, but also greatly improved the economic benefits of the ceramic industry, the ancient ceramic industry in China to the modernization stage of development.

    2 mechanism of action of sodium humate

        Traditional ceramic raw materials are silicate minerals, such as clay, feldspar, quartz and so on. With the development of the ceramic industry, the production process more and more applications, including non-silicate, non-oxide and other new materials, humic acid on the role of various raw materials more complex principle. The following is only examples of clay such as kaolin as an example of the possible mechanism of action of sodium humate as a ceramic additive.

    2.1 Single layer adsorption of sodium humate on the outer surface of clay minerals

    Kaolin is a 1: 1 type aluminosilicate mineral whose crystals consist of a [Si-O4] tetrahedron and a [AIO2 (OH) 4] octahedral, since its crystal substitution is minimal and not much Cations, so the possibility of forming an ion bridge on the level is not significant. Level of H + in the OH will dissociate, so that the surface with a negative charge, therefore, the level of adsorption of positive ions tend to direct adsorption humic acid anion is unlikely, the key lies in the crystal layer on the Al + and Si + (Mg2 +, Ca2 +, Fe3 +, Al3 +, etc.), and then with the humic acid anion constitute the price of the key to associate with the acid point of the positive position, which is the adsorption of humic acid anions, and in the Si + -O- negative position may adsorb positive ions Or coordination keys. In addition, the O-H bond in the humic acid may be associated with the hydrogen bonding of the clay on the clay surface to produce adsorption, and the aliphatic hydrocarbon groups such as C-H and the clay surface in the humic acid also produce physical adsorption. Cheng Shaoxin [3] and other experiments show that weathered coal humic acid due to more carboxyl, mainly to chemical adsorption, and peat humic acid aliphatic C-H more, about half of the physical adsorption. Na + in addition to the same level of negative charge on the same level, mainly in colloidal solution in the form of counter ions. Chemical adsorption and chemical bonds mainly occur on the edge of the kaolin wafer, which is the determinant of the colloid and physical and mechanical properties of the ceramic clay. 2.2 hydration performance is improved, the suspension stability increased by the electron microscope observation shows that the original kaolin suspension, due to the mutual adsorption between the different charges, resulting in the formation of the wafer into a network structure, this structure not only the double layer was closed , The clay particles agglomerate, and in the "net" contains a lot of free water, so that the clay suspension thickening, fluidity weakened. When humic acid is added to the suspension, part of the humic acid -COO- is first adsorbed on the edge of the positively charged kaolin crystal or on the edge of the polyvalent cation, and the other part of the humic acid, COO- To the solution, which makes the clay charge reversal, negative charge enhancement, and Na + solution in the formation of diffusion double layer, so that the destruction of the network structure of the clay, effectively increasing the colloidal stability, reducing the viscosity, so that the particles are fully dispersed , The adsorption of hydrated film around the cosmid (thickened water) thickened, and the excess free water is released, so that the distance between the clay particles, although close, but like a layer of lubricating oil, free movement Strong, plasticity, and fluidity are also increased, and the relative distance between clay particles is reduced due to the excess free water being removed (this part is not added or less when grouting). When most of the water evaporates, the clay particles become closer together, the porosity decreases and the strength increases.

    Preparation and Application of Sodium Humate for Ceramics

    Humic acid is widely found in soil, peat, lignite or weathered coal, and the fertile soil contains about 10% humic acid. The humic acid content of various coal varies greatly depending on the degree of coalification and the external conditions. Generally peat in the dry humic acid containing 12% to 13%, lignite containing 1% to 85%, weathered coal containing 5% to 80% [5]. In order to make the humic acid sodium to give full play to its porcelain clay, ceramic properties enhance the effect, should minimize the ash, iron and other impurities on the appearance of the quality of porcelain, its purification methods and the general method of purification of sodium humate Different. Wu Renru [6] by alkali-soluble acid extraction can be applied to the field of ceramic humic acid sodium, the practical application shows that its product quality and performance are greatly improved.

    Sodium humate has the following effects in ceramic clay (glaze).

    (1) enhance the role. Can improve the strength of ceramic mud about 80%, to reduce the damage of semi-finished products, is conducive to semi-finished products finishing.

    (2) plasticizing effect. Improve the plastic index of more than 40%, so that the billet easy to shape, reduce semi-finished products cracking, easy to mechanized production.

    (3) dilution effect. Can increase the mud, enamel slurry flow 50%, is a good gelant.

    (4) adsorption. Improve the green body of the other blue glaze adsorption capacity, reduce peeling, pinholes, broken lines, ogliao, shrink glaze and other semi-finished products defects.

    4 Application of sodium humate on ceramics

    At present, sodium humate has been widely used in Jiangxi, Yunnan, Zhejiang, Hunan, Beijing, Tangshan and other provinces and cities in the ceramic production has been widely used, only Tangshan bone china production of humic acid sodium per thousand tons, significant economic and social benefits.

    4.1 Reform of thin porcelain porcelain molding process

    Thin tire porcelain is Jingdezhen popular traditional products, because it is thin as onion skin, was hailed as "just want to blow, but also worry about sun", the process is amazing flower, the production process is highly technical, Large, low yield, and small pieces of products and shaped products can not shape. After the use of humic acid sodium, the process has been reformed, the efficiency has been greatly improved, the yield of the products has been improved, and various tires and vests with a height of from 50 mm to 300 mm and large to 500 mm can be produced.

     4.2 blue and white traditional porcelain quality to improve the blue and white fish dish, known as the "porcelain country pearl", is the most outstanding characteristics of the Chinese culture and traditional porcelain, especially in the unity of folk art aesthetic range, that freehand blue and white Porcelain painting art, and folk blue printed cloth blue and white decorative pattern art echoes harmoniously. Blue and white fish plate molding process, due to serious deformation, low yield, resulting in blue and white tableware supporting difficulties. However, in the pressure grouting mud by adding sodium humate, the first rate was significantly improved, while the body mold release easy, smooth surface, improved billet technology, saving manpower, cost reduction costs, improve labor productivity. Sodium humate in the rolling of the blue and white porcelain continuous operation line, can improve the dryness of mud body strength of about 1 times to improve the plasticity index of 20% to 30%, reduce the moisture content of the body and stripping water content, so that mud adaptation machine Pressure forming operation, non-stick rolling head, easy to mold, reduce the damage of semi-finished products, improve the export tableware 0.36 m lotus mouth fish plate premium rate, to solve the tableware matching problems.

    4.3 to improve the performance of mud, improve the yield

    Jiangxi Ceramics Company in the ordinary Ningcun powder added humic acid sodium production of high-end sets of white porcelain, with high brightness, transparency, color pure, not easy to stale, while the large pieces of porcelain and large pieces of porcelain finished rate greatly improved.

    4.4 for glaze ball milling, to improve the glaze process

    Sodium humate can adjust the consistency of the consistency of the consistency of the glaze slurry to overcome the shortcomings of shrinkage, milling time reduced by 10%. Glaze slurry of humic acid sodium dosage of 0.01% to 0.07%, can improve the efficiency of milling, saving power consumption. Sodium humate is used in enamel color glaze to replace honey as a binder, to reduce charcoal drying processes, to save fuel, and to improve quality.

    4.5 to improve the strength of gypsum mold and extend the life of the mold

    Jingdezhen City, the annual consumption of 8500 tons of gypsum, add humic acid, you can increase the mold strength doubled to extend the service life of 30% to 50%, and in the casting model can be used when the old gypsum, good quality mold surface smooth, Hardness, good wear resistance.

    4.6 breakthrough in the 500 kV UHP porcelain production in the technical difficulties

    Jingdezhen City porcelain electrical company developed ultra-high voltage transmission system with 500 kV high-strength rod-type porcelain, body length, diameter, green body each weighing 200 kg, the strength requirements than ordinary porcelain to more than 1 times, add humic acid Completed the development task, the green body has reached more than 80% pass rate, porcelain qualified rate has reached more than 50%. Zhejiang Cangnan County porcelain factory used in high-voltage ceramic and low-voltage ceramic porcelain production also received a significant effect.

    4.7 to improve the strength of ceramic glazed tile body

    Production of ceramic construction glazed tiles in the formula used in the use of sodium humate sodium can be added without plasticized black mud, so that whiteness increased, while reducing the glazed tile cracking; in the industrial ceramic glaze porcelain body and acid brick in the application, Porcelain hand pass rate, reduce acid brick mud loss, significant economic benefits.

    4.8 realize the industrialization of bone china production

    Bone china (bone china) with porcelain delicate, high whiteness, translucent, and vessel shape regular, bright screen and so on,

    Currently the most popular in the international market. Bone porcelain by the United Kingdom Staffordshire J · Spode in 1794 successfully developed, China Tangshan in 1965 made the first bone china, developed today has become one of the world's few major bone china production base. Tangshan bone china production of raw materials containing more than 50% of cattle, sheep, pigs ashes, because of its poor plasticity, roasted in the easy deformation, porcelain easy to change color, so the production process is complex, difficult technical. But with the rise of humic acid industry, the addition of sodium humate to roll-forming bone china and sticky molding, to solve the milling time is long, mud plastic poor and so on, so that the yield of bone china production line is greater than 95%. To "red roses" as the representative of the Tangshan bone porcelain crystal clear, smooth soft glazed, like the feeling of jade like jade, extremely elegant, "white jade, thin as paper, sound like chime, Ming as a mirror", now Has become the major international luxury hotels, hotels and important business activities of the special porcelain and ultra-luxury signs, as some of the big collectors as Jane's boutique.

    Research and Development of Humic Acid as a Ceramic Additive

    Although the humic acid sodium has been used in a large number of ceramic production, but because it is a polymer non-uniform condensate, thermoplastic and elasticity is very poor, the structure and performance is more complex, the amount of time for some time there is a certain side effects, so that ceramic slurry bonding and cohesion, Reduce the flow, serious lead to flocculation, organic matter at high temperatures and after the excretion of carbon bubbles and holes, so that glazed deterioration of the dark. Therefore, the development of new modified humic acid ceramic additive has become a hot research and application.

    Cao Wenhua, according to the characteristics of ceramic mud, the sodium humate and sodium silicate by a certain proportion of mixing, and add a certain amount of coupling agent complex into a new type of ceramic mud water reducing agent. Experiments show that the effect of the superplasticizer is better than sodium tripolyphosphate, can improve product quality, the cost is only about 1/3 of sodium tripolyphosphate. (HANa-AA-AM) terpolymer was synthesized and synthesized in a ceramic body under different process conditions. The effects of HANa-acrylamide (HANa-AA-AM) Effect of AA - AM Ternary Copolymer on Plasticity of Ceramic Blank and Drying Strength of. Xiangtao Chung reported a kind of ceramic dehumidification enhancer which can make the mud get good flow and improve the strength of the product. It is characterized by adding sodium pentasilate, sodium lignosulfonate and sodium humate to Sodium sulphate, wherein the weight percentage of sodium metasilicate pentahydrate is 50% to 80% by weight. Blaum Simone et al. [11] reported the use of carboxyl group-containing polyethylene polyamine compounds used to accelerate the dehydration of pottery in the production of ceramic flakes. The compound is composed of sodium humate, water, polyethylene polyamine and polyacrylic acid. Liu Dacheng studied the effect of sodium carbonate and sodium humate on the relative viscosity of quartz-water and clay-water system, and determined the appropriate amount of sodium humate when diluted quartz-water and clay-water system. The use of copolymer grafting technology to prepare sodium humate binary and terpolymer, in the construction of sanitary ceramics in the application, the results show that the slurry has a good effect of the solution, while the body has a strong plasticization and Enhance the effect, than a single sodium humate desorption, plasticization, a wide range of enhanced.

    There are many methods of modification of humic acid, such as nitric acid oxidation, sulfomethylation, nitric acid-sulfomethylation, solution blending, esterification, metal complexation, grafting, etc. These techniques have been widely used in other In the field of industrial additives, such as scale and corrosion inhibitor, containing heavy metal ion wastewater treatment agent, drilling fluid treatment agent, high temperature oil-based drilling fluid fluid loss agent, concrete additives, coal slurry dispersant, mainly through In the humic acid molecules to add more strong hydrophilic groups, so that humic acid activity increased dispersion ability, dilution enhanced, so theoretically the above modified technology can be applied to humic acid sodium ceramic additive modification study In order to expand the application of humic acid in the field of ceramics and role, which is humic acid as a ceramic additive worth further research development direction.

    6 humic acid to promote the ceramic industry clean production

    The development of modern ceramic industry is increasingly dependent on the use of additives. They are small, but to improve the process conditions and improve the quality of ceramic products and reduce energy consumption has a very important role. In-depth study of the mechanism of the role of ceramic additives, design and development of new ceramic additives, the development of environmentally friendly green chemicals has become the ceramic industry development direction [7]. With the development of society and the improvement of people's awareness, clean production should be as a basic principle of ceramic industry construction and development, whether it is the construction of new producing areas and the upgrading of the original producing areas, should implement this model and the basic principles, This is in line with the country's industrial policy, but also very much in line with the actual situation of the ceramic industry to achieve the sustainable development of ceramic industry. Humic acid resources in China