Solidification And Stabilization Of Hazardous Ingredients For Ore Tailing & Phosphor-gypsum Of Fine-particle

With the increase of land resources shortage,it is difficult to carry out disposal measures for the temporary storage of massive ore tailing（or slag）in the tailing pond（or tailing yard）.so it is urgent for the R&D of Environmentally Sound and Synergistic Disposal Technologies for massive solid waste.In this dissertation,the green binders based on blast furnace slag（BFS）were used as high-efficiency binding materials for ore tailing and phosphor-gypsum（PG）,and to make them into binding materials for underground mine binding filling（UMBF）and building materials of phosphor-gypsum,respectively.The performances of these materials were characterized systematically.A₁ tailing binder were prepared using BFS powder,fly ash,cement,and activator（mainly by sulfate excitation）.The specimens of UMBF materials were prepared using the mixture of A₁ tailing binder and the slurry of gold ore tailing（GOT）.After their performance characterization,it was found that the introduction of water reducer of calcium lignosulfonate could improve the fluidity of UMBF.As the mass fraction of the water reducer being 0.30%,the 28 d compressive strength（CS）of the resulting specimen of cemented UMBF was 4.02 MPa,and the slump of the specimen of fresh UMBF was 281mm.The properties of above mentioned UMBF specimen met the requirements of gravity filling of underground mine.The CS of the resulting specimens of cemented UMBF was increased with the increase of binder/tailing ratio and solid mass fraction of UMBF,respectively.As both the binder/tailing ratio being 1:6 and the solid mass fraction of UMBF being 58wt%,the 28 d CS of the resulting specimen of cemented UMBF was 2.99MPa,which was 4.6 times higher than that of P.O 42.5 cement.The softening coefficient of the resulting specimens of cemented UMBF was increased with the increase of the binder/tailing ratio from 0.82 to 0.89,implying that the tailing binder cemented UMBF had the prominent water resistance.The shrinkage rate of the resulting specimens of cemented UMBF was decreased with the increase of the binder/tailing ratio from 0.71%to 0.62%,implying that the cemented UMBF body has little shrinks and can fully fill the mine.The specimens of BUMF materials for iron ore mine were prepared using the mixture of A₁ tailing binder and the slurry of iron ore tailing（IOT）.It was found that the CS of the resulting specimens of cemented UMBF of IOT was increased with the increase of binder/tailing ratio and solid mass fraction of UMBF,respectively.As the binder/tailing ratio being 1:6 and the solid mass fraction of UMBF being 70wt%,the 28 d CS was 7.25MPa for the resulting specimen of cemented UMBF,which was 2.6 times higher than that of P.O 42.5 cement.The softening coefficient for the resulting specimens of cemented UMBF was increased with the increase of the binder/tailing ratio from 0.84 to 0.92,which was indicating that the cemented UMBF has prominent water resistance.The shrinkage rate of the resulting specimens of cemented UMBF was decreased with the increase of the binder/tailing ratio from 0.82%to 0.70%,implying that the cemented UMBF body has little shrinks and can fully fill the mine.In addition,the effect of mixing time on the CS of the resulting specimens of cemented UMBF was also investigated,and the CS of them was increased at first and then remained unchanged with the increase of mixing time.As the mixing time being 4.5 min,the CS of the resulting specimen reached the maximum value7.25 MPa among all specimens with variation of mixing time.A₂ slag binder were prepared using BFS powder,fly ash,cement,and activator（mainly by Alkali excitation）.The specimens of PG building materials（PG-BM）were prepared using the mixture of A₂ slag binder and PG slag.After systemic characterization,it was found that the CS of resulting specimens of PG-BM was increased with the increase of molding pressure.The CS of the resulting specimens of PG-BM was decreased with the decrease of the binder/phosphor-gypsum ratio.The softening coefficient of resulting specimens of PG-BM was decreased with the decrease of the binder/phosphor-gypsum ratio from 0.89 to 0.82.The water absorption rate of the resulting specimens of PG-BM was increased with the decrease of the binder/phosphor-gypsum ratio from 1.04%to 1.24%.In addition,the CS of the resulting specimens of PG-BM was decreased at first and then gradually increased with the increase of the number of freeze-thaw cycles.After 18 times of freeze-thaw cycles,the CS was 26.13 MPa for the resulting specimen of PG-BM with binder/PG ratio being 1:1.As the resulting specimens of PG-BM being prepared by partially replacement of PG binder by GOT,it was found that the CS of the resulting specimens was gradually decreased with the increase of the mass fraction of the GOT replacement by PG binder at binder/phosphor-gypsum ratio being 1:1.However,the CS was only decreased by 10%for the resulting specimen with replacement being 20%by GOT for PG binder.The above-mentioned specimens mixed by binder,PG,and GOT together,which had the prominent corrosion resistance against sodium sulfate and sodium chloride solutions.In the leaching solution of the resulting specimen of PG-BM with binder/phosphor-gypsum ratio being 1:1,Cadmium and Lead were not detected,and only tracing amounts of Barium was contained in the leaching solution,which met the requirements of《Identification standards for hazardous waste General rules》（GB5085.7-2019）.