Research On Wet Modification And Applications Of Sulphureous Industrial Residues

In this paper, aimed to poor stability problem of circulating fluidized bed combustion(CFBC) fly ash caused by its late severe dilatability, pre-expansion material of CFBC fly ash used pre-expansion preparation method by wet milling was prepared, and the material was used to prepare ecological wall materials including ecological building mortars and light weight panels for partition wall;cement and white phosphate fertilizer were chosen as gelled material, a certain amount of phosphogypsum and pyrite cinder was added as aggregate, and these raw materials were used to prepare building blocks. The results showed that under the conditions of room temperature and atmospheric pressure, initial slurry solid-liquid ratio of 1:1, and ball to powder ratio of 3:1, when the wet milling time was 20 minutes, mean diam of CFBC fly ash decreased from about 5000 nm to 1700 nm, Ca SO4 was transformed into Ca SO4·2H2O, the stability test of wet milled ash was qualified. It was known that by wet milling, II-Ca SO4 in CFBC fly ash was dissolved and recrystallized into rod or cone of Ca SO4·2H2O whisker,CFBC fly ash released expansion beforehand, and late inflation concern of CFBC fly ash was eliminated. And wet milling production had simple process, low energy consumption, and no dust. When contents of cement in mortars were from12% to 15% and contents of aggregate in mortars were from 65% to 78%, with cement sand ratio rising, the strength and water consumption of coal gangue and cobblestone of these two series of CFBC fly ash mortars both showed a trend of increase, these two series of mortar strength ranks were both from 5 to 12.5 MPa,and these two series of mortar setting time kept from 180 minutes to 285 minutes and from 260 minutes to 335 minutes, respectively. For strength rank was from 5to 10 MPa of common mortar, mortar prepared with machine-made sand of coal gangue required less dosage of cement. When contents of cement in panels were from 38% to 45% and contents of CFBC fly ash in panels were from 55% to 62%,with the content of cement rising and the content of CFBC fly ash decreasing,density and compressive strength of the light weight panels for partition wall increased from 1402 Kg/m~3 to 1498 Kg/m~3 and from 22.0 MPa to 27.0 MPa,respectively. When contents of white phosphate fertilizer and cement in blocks were both from 20% to 60%, with white phosphate fertilizer cement ratio rising from 1:3 to 3:1 gradually, dry density of the building blocks based on cement and white phosphate fertilizer decreased from 1816 Kg/m~3 to 1410 Kg/m~3, and 7 days strength presented a first growing after decreasing tend, while the maximums of compressive strength and flexural strength of the blocks were 16.7 MPa and 3.0MPa, respectively. It was known that cement and white phosphate fertilizer could form stable composite gelled system. That was applied successfully in blocks.That could transform waste into treasure, save energy and reduce emission, and have a good market application prospect.