Taking 86 grade homogenized bauxite clinker, Shanxi 88 grade rotary kiln bauxite clinker, and Shanxi 88 grade inverted flame kiln bauxite clinker as the objects, the homogenized bauxite sample numbers are 86#-1 and 86#- 2. 86#-1 homogenized bauxite was produced in 2013. 86#-2 homogenized bauxite is the production of homogenized bauxite in 2014. Among them, the homogenized bauxite clinker samples all adopt the batching homogenization technology, which is first subjected to wet fine grinding, spray drying, and then pressed into shape, and then fired in a tunnel kiln at a firing temperature of 1600 °C and a holding time of 14 hours.
The performance testing methods of the three kinds of bauxite clinker are as follows:
(1) Determination method of phase composition
The phase composition of the sample was measured with an X-ray diffractometer (Philips, Netherlands, model X'PertPro). The relative integral area of the main peaks of each phase in the crystal phase was calculated by MDIJade software, and the relative content of each crystal phase was obtained.
(2) Determination methods of full chemical analysis, crystal phase chemical analysis and glass phase chemical analysis
The full chemical analysis of the samples was analyzed using an ICP-AES Inductively Coupled Plasma Emission Spectrometer (ThermoElemental Company, USA, model IRISAdvantageRadial). Then, HF acid was used to dissolve the glass phase of several kinds of bauxite clinker, and the chemical composition and glass phase content in the crystal phase were determined. The HF concentration is 20wt.%, the particle size is 0.20-0.15mm, the test temperature is 18°C, and the soaking time is 24h. The mass loss percentage of the sample after HF treatment is the glass phase content, and the residual mass percentage is the crystalline phase content. According to the chemical composition of the whole sample and the crystal phase, the chemical composition of the glass phase was calculated, and then the distribution ratio of each oxide in the bauxite clinker in the crystal phase and the glass phase was calculated.
(3) Calculation method of glass phase viscosity
According to the chemical composition of the glass phase, the viscosity module of the FactSage6.2 thermochemical software was used to calculate the viscosity of the glass phase, and the choice of the database was glassdatabase.
(4) Determination method of apparent porosity and bulk density
According to GB/T2997-2000, the apparent porosity and bulk density of the samples were measured by an automatic true density analyzer (Mike Corporation, USA, ACCUPY1330).
(5) Measuring method of cylinder compressive strength
The strength of the aggregate is characterized by the cylinder compressive strength. The experimental method of cylinder compressive strength is as follows: Particles with a particle size of 5~3mm are stacked in a Φ50 mold to a height of 50mm, and the mass of the weighed aggregate is recorded as m0. Then apply a pressure of 50MPa, hold the pressure for 10s, and sieve it with a 3mm sieve after releasing the pressure.
(6) Measuring method of circularity
The particle shape of the aggregate is characterized by circularity. Circularity refers to the relative sharpness of the edges and corners of aggregate particles. The circularity is used to evaluate the shape of fine particles. The larger the value of the evaluation index, the closer the fine aggregate is to a circle, and the better the particle shape is.
(7) Measurement method of size distribution of aggregate particles
The sieve analysis test of bauxite aggregate was carried out according to the regulations of JGJ52-2006.
(8) Microstructure analysis method
The JSM-6610 scanning electron microscope of Japan Electronics Co., Ltd. was used to test the microstructure of the original sample and the sample after HF acid corrosion, and the EDS analysis was carried out with the QUANTAX200-30 electric cooling energy spectrometer of BRUKER company in Germany. Determination of elemental composition.