The Technology Study On Preparation Of Active Calcium Carbonate Whisker By Carbide Slag

Carbide slag was a kind of industrial solid waste from acetylene gas industry, which wouldtreat difficultly and bring huge environmental pollution. At present the recycling utilization rate ofcarbide slag is very low. There are500million tons of carbide slag been product every year inXinjiang, how to treat carbide slag effectively is a difficult problem of PVC industry. Nanometeractive calcium carbonate whisker is a kind of inorganic additives with the advantages of lowercost, larger productivity, wide application field, it is used in rubber, plastic and coating filed, notonly can reduce the produce cost, but also can improve the properties of strength, toughness, hightemperature, and wear resistant. This experiment used carbide slag as the raw material whichcontained more than70%Ca(OH)2to prepare active calcium carbonate whisker with NH4Cl in thepresence of ultrasound. The effect of morphology and size of calcium carbonate with in differentpolarity of solvent was studied. At the same time, the by-products of NH3and NH4Cl could beenrecycled and achieved the goal of decrease emissions and pollution.Preparation of CaCl2by the reaction of carbide slag and NH4Cl, various reaction conditions,such as the mole ratio of calcium slag to ammonium chloride, the volume of water, reactiontemperature, reaction time were considered. Then we designed orthogonal experiment for the mainfactors, and the optimal mass ratio of ammonium chloride to calcium carbide residue was1:1.7,the volume of water was30mL, the reaction time for40min, reaction temperature was20℃, thestirring rate was200r/min. The yield and purity of calcium chloride was90.26%and95.25%.In the water system, various reaction conditions, such as the concentration of solutions,reaction temperature, dropping speed and so on were considered. Then we designed orthogonalexperiment for the main factors, and obtained the optimum reaction conditions: the concentrationof solution is0.15mol/L, the dosage of sodium stearate is1.25%, the reaction temperature is65℃, the dropping speed is3mL/min, the volume of water is60mL, ultrasonic power is250W,the stirring rate is200r/min, the prolonging time is0h. Active calcium carbonate whisker wasprepared by verification test with the size of136nm, the length to diameter ratio of17.37, theactivation degree of98.86%, oil absorption value of43.75g/100g, and the surface is smooth.In the ethanol-water complax system, various reaction conditions, such as the concentrationof solutions, reaction temperature, and dosage of sodium stearate were considered. Then weobtained the optimum reaction conditions:75%ethanol, the concentration of solution is0.05mol/L, the reaction temperature is50℃, the dosage of sodium stearate is2%. Active calciumcarbonate whisker was prepared by verification test with the size of247nm, the length to diameterratio of17.86, the activation degree of99.26%, oil absorption value of41.6g/100g, and thesurface is uneven, combining with organic medium is better.