Lignosulfonate used for ceramics
Lignosulfonate used for ceramics
Ceramics can be used to reduce the carbon content increases green strength, reduce the amount of plastic clay, mud, good mobility, improve yield 70-90%, the sintering rate was reduced from 70 minutes to 40 minutes.
Lignosulfonate has different compositions and molecular dimensions (because they are polymers that can be modified by the addition of organic or inorganic groups to the molecule). They are anionic derivatives of lignin, water soluble and surfactants. Lignosulfonates can increase mechanical green and dry strength in ceramic pieces. Also, they work as lubricants during extrusion or pressing . Additions of lignosulfonates to ceramic slips can vary from 0.1 to 2.0% and they are relatively inexpensive. For pressed tiles, 1% lignosulfonate can double mechanical strength (however often a black core appears). Lignosulfonates are often used to reduce shrinkage yet maintain after-forming mechanical strength (because reduced amounts of plastic clays are needed).
Lignosulfoante in architectural ceramics Applications
Currently in building ceramic body used in the formulation additives are mainly two: one is body enhancer , mainly used to increase the strength of the body , is mainly used in low viscosity carboxymethylcellulose is CMC; a coagulant solution species are primarily used to reduce the viscosity of the mud , reducing the moisture content of the mud to reduce the spray drying tower granulation step water slurry fuel consumption , is used in ceramic manufacturers coagulant solution of sodium silicate and the three main sodium tripolyphosphate.
Analysis of the above additives difficult to find: an organic polymer carboxymethylcellulose , adding the formulation from the body to increase green strength of the effect, but its molecular weight is larger structures chain is longer , in the mud will each kind of fine raw material particles together to form a network structure in the mud wrap free water , the slurry flow variation , adding more worse flowability of mud . To solve the above problems in production only additional water in the mud , the mud weight that reduces the water content increases, the spray granulation step is also increased burnup , the carboxymethyl cellulose added to the formulations in fact contrary to the the purpose of reducing the moisture content of the mud . The STPP is an inorganic coagulant solution , add in the formula can only play a role in reducing discharge slurry flow rate while no effect on the intensity of the green body .
Lignin sulfonate and organic additives are not long molecular chain , it is added to the formulation not only beneficial to reduce the mud flow , and because it has some adhesive properties, can achieve the purpose of increasing green strength . Lignosulfonate can be dissolved in water , Na + ions ionized and lignin sulfonate ion , lignin sulfonate ions and adsorption on the surface of the raw material particles from the reaction of Ca2 + Ca- lignin , dissolved in water Na + instead of Ca2 + adsorbed on the surface of raw material particles , adsorbed on the particle surface portion of bound water is released, the slurry thus increased mobility . Also instead of Na + Ca2 + adsorbed on the surface of the raw material grains ξ- potential of the particles increases , the repulsive force between the particles increases, face to face with the formation of particles , the slurry to increase the number of free water , the slurry will be increased mobility .
By the following experiments the effect of the use of sodium lignosulfonate and sodium lignosulfonate find best dosage , experimental conditions were as follows:
1 . Experimental basic equipment : Force Thailand QMP3000 × 4650 type 14 t ball , 3200 spray tower and Sacmi PH2800, 50ml volts flow cup , stopwatch , Xiangtan Zhongshan Instrument PKZ-600 -type body strength meter .
2 . Experimental conditions: ball mill loading capacity 15 tons , natural stone balls loading capacity 24 tons ; heavy fuel spray tower ; presses pressed brick size 600 × 600 (mm), the thickness of 11.00mm.
3 . Adobe Recipe: mud 24% , low temperature powder 26% , the temperature in powder or sand 40% , 10% of high sand .
4 . Methods: The plus different additives according to the same formula in the same body weight added to the ball mill grinding to a standard fineness, put pulp volts flow cup and stopwatch measuring the flow rate of the mud additives were each into 20 balls, then calculate the mean , and then add the slurry experiments with different additives were measured for heavy oil consumption dusting spray tower , calculated for each one ton powder spray used heavy volume . The powder discharged in 16 hours old powder box evacuation pressing into a 600 × 600 (mm), thickness of 11.00mm deleted brick , measured green strength after drying .
5 . Experimental data shown in Table 1:
6 . The results are shown in Table 2:
Note: 1, Experiment 4 after several experiments due to keep mud weight 1.71-1.74 , the slurry flow rate is too small , only about 20 seconds and therefore beyond the proportion of corporate control standards raised to 1.74-1.77 .
Through the above experiments it can be concluded :
1 . L from the experiment can be seen in the amount of sodium silicate dosage to maintain the original premise of constant 80 kg with 20 kg of lignin sulfonate replace the original formula of sodium tripolyphosphate and methyl 14 kg 20 kg , body strength to meet the requirements described lignin sulfonate to increase the strength of the body is effective . But the experiment a larger flow rate , indicating that the solution of lignin sulfonate condensate as effective as sodium tripolyphosphate. Experiment 2 increased the amount of sodium silicate slurry flow rate declined sharply solution coagulant dosage instructions are not optimal.
2 . Comparative Experiment 2 and Experiment 3 Experiment 4 and Experiment 6 , in the case where the same amount of sodium silicate , sodium lignin can be increased within the range of decrease in a small flow rate of the slurry described certainly has some lignin sulfonate solution coagulation effect but the effect is limited.
3 . From the Experiment 3 , Experiment 4 and Experiment 5 can be concluded , as the increase of the amount of water glass , plus a slurry flow rate of sodium lignin sodium silicate at 120 kg, the minimum amount of water glass when an amount of 120 kg mud condensate to achieve the best solution .
4 . As can be seen from the experiment sodium lignosulfonate added in an amount as increasing the strength of the body is constantly increasing , adding green strength 20,30,40 kilograms were 0.90MPa, 0.98MPa, 1 .06 MPa, lignin sulfonate described reinforcing effect of the body and is obviously advantageous to reduce the flow rate of the mud , can be used to increase the strength of the body .
5 . From the experimental results , the use of experimental and experimental 6 4 additive ratio more appropriate body formulations using a new additive , because of the apparent specific gravity than the original increase the moisture content of the mud reduced by 2 % per ton of heavy powder consumption reduced by nearly 4 kg of heavy oil savings of more than 10% energy saving effect is very obvious.
6 . Alternate introduction of sodium carboxymethyl cellulose, lignin and sodium tripolyphosphate formulation reduces the cost of the body , specific comparison is as follows :
As can be seen from the table, the new additive additive cost far less than the original cost , even if the choice of additives used in experiment 6 , a ball cost savings of $ 100 savings ratio reached 36%.
As can be seen from the entire experiment , lignin sulfonate is introduced into the ceramic body building formulations, body formulation not only reduces costs, but also because it has a certain effect coagulation solution , so that the moisture content of slurry significantly reduced , saving the fuel consumption of the spray tower , coupled with its good adhesion performance, increase the dry strength of the body , reducing the production of the split bricks , to improve the yield rate semi great benefit , so that in fact, a lignin sulfonate kind of rare ceramic additives. But it is worth noting that different manufacturers lignin sulfonate condensate solution for slurry and its effects on body enhancement role is different, which may be associated with different manufacturers of the structure and composition of lignin sulfonate has a great relationship, so when in the selection of lignin sulfonate sodium lignosulphonate for different experimental comparison , considering the price and the use of effects to choose which manufacturer lignin sulfonate.