Method for preparing early-strength filling cement from mine tailings

Abstract

The invention relates to a method for preparing early-strength filling cement from mine tailings. Mine tailings are used as a base material, and matched with yellow sand and limestone. The early-strength filling cement is prepared through uniform mixing to prepare cake, high-temperature calcination, quenching and sintering, and crushing and ball milling. The mass ratio of the mine tailings, the yellow sand and the limestone is (130-300):(10-110):(700-770), and the specific operation steps and technological conditions are as follows in sequence: the mine tailings, the yellow sand and the limestone are respectively ground to 200 meshes or below and fully stirred and mixed, the mixture is pressed into cake through a tablet press, and the cake is dried and kept for later use; the test cake isput into a high-temperature furnace, heated to 1300-1400 DEG C, subjected to temperature maintaining for 120 minutes, and quenched to room temperature; then 5% of gypsum is added, and the mixture is ground until the specific surface area is 370 m<2> / Kg to obtain an early-strength filling cement product; the early-strength filling cement and the mine tailings for underground filling are used for filling according to the mass ratio of 1:10 and the filling concentration of 74%. The early-strength filling cement has the advantages of being good in material ratio, low in calcination temperature, beneficial to control over the crystal form of a cementing material, high in compressive strength of a filling test block and the like and is suitable for mine enterprises.

Description

technical field [0001] The invention relates to a method for preparing early-strength filling cement by using mine tailings, which is suitable for application in mining enterprises. Background technique [0002] Mining enterprises will produce a large amount of tailings in the process of beneficiation. Except for a small part of these tailings, they are randomly used for mine filling, and most of them are piled on the ground. This not only causes waste of tailings, but also takes up a lot of land and pollutes the environment. [0003] As an important part of green and scientific mining in mines, filling mining can not only effectively alleviate or prevent surrounding rock movement and surface subsidence, and realize the maximum recovery and utilization of mineral resources, but also gradually turn to deep filling mining to prevent large-scale impact mine pressure and prevent gas accumulation Or goaf spontaneous combustion. Portland cement has the characteristics of stable p...

AI Technical Summary

Problems solved by technology

After the tailings and cement raw meal were ground according to a certain ratio, they were calcined at different temperatures to prepare cement clinker. The results showed that the proportion of tailings and cement raw meal was 2:1, the calcination temperature was 1200°C, and the calcination time was 0.5h. Cement clinker is the best, but tricalcium aluminate is not formed in the clinker phase, and there is excess iron oxide to form calcium ferrite. The initial setting time and final setting time are longer than ordinary cement.

In order to solve the above problems, Chinese patent CN201811310431 discloses "a method of using copper ore tailings to prepare underground goaf filling materials". The mine is cemented and used for filling. The advantage is that the waste resources of the mine are fully utilized, and it has good environmental protection benefits. The disadvantage is that the compressive strength of this method is not large, only 1.1MPa, and its application range in underground filling is limited. Meet the requirements of high filling strength (above 3MPa)

Chinese patent CN201610011611 discloses a "copper slag-based low-silicon iron tailings filling material and its preparation process". materials, sodium hydroxide, and low-silicon iron tailings. Although copper slag and other waste slag resources are fully utilized, the composition materials are not much different from ordinary cement (the composition of ordinary cement is cement clinker, gypsum, slag, etc.). In addition, The filling and cementing material is limited by the region, that is, there is no copper smelting slag around the mine or the transportation distance is long, which will lead to problems such as high filling costs

Chinese patent CN201810810566 discloses "a method for preparing high-strength concrete by using granite waste rock and low-silicon iron tailings". material, calcium carbide slag and phosphogypsum to obtain a composite cementitious material, and mixed with concrete coarse aggregate, concrete fine aggregate, water reducer and water, the water-cement ratio is 0.23-0.26, and then pouring, molding, preparation High-strength concrete, the cementitious material in this concrete is a compound of premix, carbide slag and phosphogypsum, and is mixed with coarse and fine aggregates and reducers, so it can obtain higher strength, which belongs to the field of building materials. There are no experimental cases in downhole filling

Chinese patent CN201410261769 discloses "a method for preparing inorganic mineral polymers from lead-zinc tailings". This patent adopts a wet method to add alkali to calcine the lead-zinc tailings for activation treatment, add metakaolin and sand after stirring, and then add an alkali activator Obtain inorganic mineral polymers, add foaming agent and foam stabilizer to prepare foamed inorganic mineral polymers, belong to the field of building materials, and have no experimental cases in underground filling

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