Function of Lignosulfonate used for ceramics
Currently building the ceramic body used in the formulation of additives are mainly two: one is body enhancer, mainly used to increase the strength of body, now used mainly for low viscosity carboxymethyl cellulose namely CMC; a coagulant solution species is primarily used to reduce the viscosity of the mud, reducing mud in order to reduce the moisture content of the spray drying tower granulation step in mud the water consumed fuel, it is now used in ceramics manufacturer coagulant mainly sodium silicate solution and three sodium tripolyphosphate.
The above analysis is not difficult to find additives: carboxymethyl cellulose organic polymer genus, adding body formulations played a role in increasing the green strength, but it’s a long chain molecular weight larger structures, will each in the mud kinds of fine raw material particles together, forming a network structure encased in mud free water, so that the mud of fluidity, added more mud of mobility is also worse.
To solve the above problems in production only additional amount of water in the mud, the mud is reduced so that the proportion of the water content increases, the spray granulation step burnup also increases, so carboxymethylcellulose added in the formulation in fact contrary to the purpose of reducing the moisture content of the mud. The sodium tripolyphosphate An inorganic coagulant solution is added to the formulation can only play a role in reducing the discharge slurry flow rate and has no effect on the strength of the green body.
lignosulfonate belong to organic additives and molecular chain is not long, it is added to the formulation not only help reduce the mud flow, but also because it has a certain adhesive properties, can achieve the purpose of increasing the strength of the body. lignosulfonate can be dissolved in water, ionized Na + ions and lignosulfonate ion, lignosulfonate and Na ions adsorbed on the surface of the particles of the raw material from the reaction of Ca2 + Ca- lignin, dissolved in water + instead of Ca2 + absorption in the surface of raw material particles adsorbed on the particle surface portion of the bound water is released, the mud of liquidity thus increased. Further Ca2 + instead of Na + absorption in the raw material potential of the surface of the particles so ξ- material particles increases, the repulsive force between the particles is increased, all things are formed bond between the particles, increasing the amount of free water in the mud, the mud flow will be increased .
The following experiments to determine the effect of lignosulfonate and find the best added amount of lignosulfonate, the experiment is as follows:
1. Experimental basic equipment: Thai QMP3000 × 4650 Type 14 t ball, 3200 ml spray tower and Sacmi PH2800,50 volt velocity cup, stopwatch, Xiangtan Zhongshan Instrument PKZ-600-type body strength meter.
2. Experimental conditions: ball loading weight 15 tons, natural stone ball loading 24 tons; heavy oil fuel spray tower; presses pressed brick dimensions 600 × 600 (mm), the thickness of 11.00mm.
3. Body formula: 24% mud, cold powder 26%, the temperature in powder or sand 40%, 10% hot sand.
4. Methods: The body added with the same formulation by the same weight of different additives were added to a ball mill to a milling fineness standard, when the discharge flow rate of the pulp volts stopwatch measuring cup and mud flow rate each additive separately into 20 balls, then calculate the average , then added different additives slurry experiments were dusting spray tower for heavy oil consumption measurement, calculated per ton of powder spray The amount of heavy oil. Sprayed powder on powder box stale 16 hours evacuation presses pressed into 600 × 600 (mm), the thickness of 11.00mm deleted adobe, measured after drying their green strength.
5. Experimental data shown in Table 1:
6. The results are shown in Table 2:
Note: 1. After several Experiment 4 1.71-1.74 due to keeping mud weight, the slurry flow rate is too small, only about 20 seconds beyond corporate control standards so that the proportion raised to 1.74-1.77.
Through the above experiments it can be concluded:
1. As can be seen from the experiment l, in water glass kept at the original amount without changing the amount of 80 kg, with 20 kg of lignosulfonate replace the original formula of sodium tripolyphosphate 20 kg and 14 kg methyl, body strength to meet the requirements, described with reference to the lignosulfonate is effective to increase the strength of the body. But the experiment a larger flow rate, indicating that the effect of lignosulfonate condensate solution is not as sodium tripolyphosphate. Experiment 2 adds a sharp decline in the amount of slurry flow rate of sodium silicate solution coagulant dosage instructions are not optimal.
2. Comparative Experiment 2 and Experiment 3 Experiment 4 and Experiment 6, in the same amount of sodium silicate, an increase in lignosulfonate can reduce the flow rate of slurry in a small amplitude, indicating that certainly has some lignosulfonate solution coagulation effect, but the effect is limited.
3. From Experiment 3, test 4 and test 5 can be concluded that with the increase of the amount of water glass, plus a slurry flow rate of lignosulfonate in water glass in the minimum amount of 120 kg, the sodium silicate in an amount of 120 kg when decondensation mud to achieve the best effect.
4. As can be seen from the experiment with the intensity when the amount of lignosulfonate growing body of activity is increasing, adding 20,30,40 kg body strength were 0.90MPa, 0.98MPa, 1 .06MPa, description lignosulfonate enhance the role of the more obvious body and advantageous to reduce the mud flow rate, can be used to increase the strength of the green body.
5. After the experimental results, the use of the additive and Experiment 6 Experiment 4 ratio of more appropriate body adopted a new formulation additives significantly improved since the specific gravity than the original mud moisture content reduced by 2% per ton of powder heavy oil reducing consumption by nearly 4 kg, saving more than 10% the amount of heavy oil, the energy saving effect is obvious.
6. Introducing alternative carboxymethylcellulose ,sodium lignosulfonate and sodium tripolyphosphate reduces the cost of blank formula, specific comparison as follows:
As can be seen from the table, the cost is much lower than the cost of a new additive primary additive, even if the choice of additives used in the experiments 6, a ball of cost saving 100 yuan, the ratio reached 36% savings.
As can be seen from the entire experiment, lignosulfonate introduced into the ceramic body building recipes, not only reduces the cost of blank formula, and because it has certain decondensation effect, making mud moisture content was significantly reduced, saving spray tower fuel consumption, coupled with its good adhesion properties, improved dry strength body, reducing the production split brick, semi-finished products to improve the rate of harvest of great benefit, it is indeed a lignosulfonate Species rare ceramic additives. But it is worth noting that different manufacturers lignosulfonate decondensation of Mud and enhancing the role of the body to be different, and this may be the structure and composition of lignosulfonate different manufacturers have great relationship, so in the selection of lignosulfonate when you want to experiment with different lignosulfonate contrast, considering the price and use of effects to choose which manufacturers of lignosulfonate.