A method for preparing tricalcium aluminate rapidly and with low energy consumption

Abstract

The invention relates to a rapid low-energy-consumption preparing method for tricalcium aluminate. The method adopts analytically pure calcium nitrate tetrahydrate (Ca(NO3)<2>.4H2O), analytically pure aluminum nitrate nonahydrate (Al(NO3)<3>.9H2O) and analytically pure citric acid monohydrate (C6H8O7.H2O) as raw materials and includes adding a proper amount of deionized water to prepare a solution, stirring at 50-65 DEG C for 40-60 min, adjusting the pH value of the solution to be 5-7 by utilizing analytically pure concentrated nitric acid (HNO3) and analytically pure stronger ammonia water (NH3.H2O), continuously stirring for 10-20 min, transferring the solution to a high-temperature furnace, heating in an oxygen (O2) atmosphere to 500-510 DEG C, maintaining the temperature for 2 h, taking a product out, grinding, keeping as a precursor for later use, weighing a proper amount of the precursor, preparing into a thin sheet under the pressure of 25-30 MPa, heating the thin sheet to 1050-1150 DEG C, maintaining the temperature for 7 h, taking out, putting in a ventilating position, quenching, and grinding to obtain the tricalcium aluminate. The variety of materials used in the method is less and a synthetic process is simple. A preparing period of the method is 15-20 h less than that of sole gel methods. The sintering temperature of the method is 200-300 DEG C lower than that of solid sintering methods. Energy consumption is reduced by about 23.8%. The method is advantaged by being rapid, efficient and green.

Description

technical field [0001] The invention belongs to the technical field of building materials, and in particular relates to a method for preparing tricalcium aluminate rapidly and with low energy consumption. Background technique [0002] Raw material tricalcium aluminate (molecular formula is Ca 3 al 2 o 6 , the oxide form is 3CaO Al 2 o 3 , referred to as C 3 A) The content in Portland cement clinker is generally 7-15%, and the mass content in Portland cement clinker is second only to tricalcium silicate (3CaO·SiO 2 , referred to as C 3 S) and dicalcium silicate (2CaO·SiO 2 , referred to as C 2 S) is the third largest mineral phase, which is important for the calcination process and production preparation process of Portland cement; the fluidity and coagulation properties of hydrated cement paste; the microstructure, strength and service life of hardened cement paste. Significant influence. [0003] Tricalcium aluminate can reduce the production cost of Portland ceme...

AI Technical Summary

Problems solved by technology

The raw materials used in the solid phase sintering method are mainly calcium oxide CaO, aluminum oxide Al 2 o 3 , calcium hydroxide Ca(OH) 2 and aluminum hydroxide Al(OH) 3 Such as powder, there are disadvantages such as uneven mixing of reactants, high calcination temperature, long time, high energy consumption, and difficult ion diffusion. At least three times of repeated grinding and calcination are required to ensure that the product has a high purity.

The sol-gel method aims at the above shortcomings of the solid-state sintering method, using calcium nitrate Ca(NO 3 ) 2 4H 2 O, aluminum nitrate Al(NO 3 ) 3 9H 2 O and other hydrated nitrates as raw materials, supplemented by hexamethylenetetramine C 6 h 16 N 4 , ethylene glycol C 2 h 6 o 2 , Polyethylene glycol PET and other chemical reagents are made into solutions, so that the dispersion and mixing can reach the molecular level, and it is sintered at a high temperature after standing and aging. The product has high purity and good homogeneity. Low temperature of 200-300 ℃, etc., but there are many kinds of raw materials, long preparation cycle, cumbersome synthesis steps, complex process and high technical requirements, etc.

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