阅读说明：本技术 一种矿渣尾矿制备矿山充填胶结材料工艺 (Process for preparing mine filling cementing material from slag tailings ) 是由 张晋霞 牛福生 梁银英 冯洪均 杨超 董佳静 陈雨盈 于 2019-09-26 设计创作，主要内容包括：本发明公开了一种矿渣尾矿制备矿山充填胶结材料工艺,属于胶结材料制备领域。一种矿渣尾矿制备矿山充填胶结材料工艺,本发明充填料胶结机理和钢渣掺量对体系结构的影响规律：充填料的胶结剂水化产物主要为钙矾石晶体和C-S-H凝胶,而尾矿砂并未参与水化反应,只起骨料充填的作用。矿渣水化在尾砂周围形成的C-S-H凝胶和钙矾石相互搭接交错,将尾砂胶结在一起,同时填充体系中的空隙,使充填料密实硬化产生强度,达到胶结的效果。充填料胶结效果与胶结剂水化生成的钙矾石含量密切相关。(the invention discloses a process for preparing a mine filling cementing material from slag tailings, and belongs to the field of preparation of cementing materials. The invention relates to a process for preparing a mine filling cementing material from slag tailings, which comprises the following steps of: the cementing agent hydration products of the filling material mainly comprise ettringite crystals and C-S-H gel, and the tailing sand does not participate in hydration reaction and only plays a role in filling aggregate. C-S-H gel and ettringite formed by slag hydration around the tailings are mutually overlapped and staggered, the tailings are cemented together, and gaps in a system are filled at the same time, so that the filling material is densified and hardened to generate strength, and the cementing effect is achieved. The cementing effect of the filling material is closely related to the content of ettringite generated by the hydration of the cementing agent.)

1. a process for preparing a mine filling cementing material from slag tailings is characterized by comprising the following steps: the method comprises the following operation steps:

S1, analyzing and preparing raw materials required by the cement filling system;

s2, placing gypsum slurry, mineral powder or a mixture, steel slag and a tea water reducing agent into a stirrer according to a mixing proportion at the room temperature of 18-22 ℃, dry-stirring for 2min, and then adding graded tailings;

s3, after the addition is finished, dry-mixing for 2min, and after the cementing material and the tailings are fully and uniformly mixed, adding stirring water, and rapidly stirring for 2min to prepare filling body slurry;

s4, after the preparation is finished, detecting the fluidity, the dehydration rate, the mechanical property, the shrinkage rate, the setting time and the pH value of the pore solution;

s5, adjusting the formula according to the detection result, and selecting a proper formula;

S6, preparing filling body slurry according to the formula debugged in S6, and then carrying out backfilling operation.

2. The process for preparing mine cemented filling material from slag tailings according to claim 1, wherein: measuring the fluidity in the S4, namely measuring the fluidity of the slurry by adopting a micro slump meter method, wherein the instrument required by the test is a truncated cone circular die, the diameter of an upper opening is 36mm, the diameter of a lower opening is 60mm, the height is 60mm, a metal product with a smooth inner wall and no joint and flat glass with a smooth surface are adopted; placing the glass plate in a horizontal position, uniformly wiping the glass plate, the truncated cone round die, the stirrer and the stirring pot by using wet cloth to moisten the surface of the glass plate; quickly injecting the mixed slurry into a truncated cone round die, leveling the mixed slurry by using a scraper, lifting the truncated cone round die in the vertical direction, starting a stopwatch to time at the same time, allowing the slurry to flow on a glass plate for at least 30s, measuring the maximum diameter of the flowing part in two mutually vertical directions by using a ruler, and taking the average value as the fluidity of the slurry; the test was passed when the filler slurry fluidity was greater than 208 mm.

3. The process for preparing mine cemented filling material from slag tailings according to claim 1, wherein: the dehydration rate in the step S4 is the percentage of the volume of free water on the surface to the original volume of the slurry after the slurry is sunk to the maximum concentration; injecting a certain volume of sample into the measuring cylinder, recording the volume as v, and placing for a certain time to fully precipitate the sample; the water layer volume v at the surface, i.e. the dewatering value of the slurry, is measured.

4. The process for preparing mine cemented filling material from slag tailings according to claim 1, wherein: the mechanical property detection in the step S4 includes the following steps: adding water into the raw materials according to the proportion, stirring for 5 minutes to prepare slurry, measuring the fluidity, injecting the slurry with certain fluidity into a triple test mold with the thickness of 40mm x 160mm, coating vaseline at the bottom of the periphery of the test mold to prevent slurry leakage, scraping the surface by using a hanging knife, putting the test mold into a curing box, curing for 3d for demolding under the environment with the temperature of 18-22 ℃ and the humidity of 90%, and curing for 7d for demolding if the demolding cannot be carried out for 3 d; after demoulding, putting the mixture into a water bath at the temperature of 18-22 ℃ for continuous curing for 28 days, and then respectively measuring the strength of each curing age.

5. The process for preparing mine cemented filling material from slag tailings according to claim 1, wherein: and the shrinkage test in the S4 is to inject slurry with certain fluidity into a test mold with 70mm x 70mm for molding, scrape the surface, place the molded product into a standard curing box, measure the shrinkage height of the molded product after internal curing to a certain age period at the temperature of 20 ℃ and the humidity of 90 percent, and take the percentage value of the shrinkage height to the original height of the sample as the shrinkage of the sample in the corresponding age period.

6. The process for preparing mine cemented filling material from slag tailings according to claim 1, wherein: crushing a slurry sample with the specified hydration age, grinding the slurry sample by using an agate mortar, sieving the ground slurry sample by using a 0.08mm sieve, and mixing the crushed slurry sample with the water-solid ratio of 1: 5, mixing with distilled water, fully stirring, standing for 15min, performing suction filtration by using a Buchner funnel, and measuring the pH value of the filtrate by using a precision pH meter.

7. The process for preparing mine cemented filling material from slag tailings according to claim 1, wherein: in the S5, an orthogonal design experiment is adopted to optimize the formula, wherein the optimized mineral powder or mixture comprises 20-30% of the mineral powder or mixture, 8-12% of steel slag, 0.2% of a tea water reducing agent and 65-70% of gypsum slurry.

Technical Field

The invention relates to the field of preparation of cementing materials, in particular to a process for preparing a mine filling cementing material from slag tailings.

Background

Chinese land is large and has abundant mineral resources. With the development of economy, mine resources are excessively exploited for a long time without adjustment, and the number of abandoned mines is rapidly increased. The occurring environmental disasters and geological disasters, such as ground collapse, cracking, underground water pollution and the like are occurring or in the process of potential occurrence. The cement and mining waste residues are used as filling materials to be poured into a mine or a mine pit, so that the filling fullness and the combination of all contact surfaces are difficult to ensure, and the top and the original rock structure have a gap, thereby causing the disaster of surface subsidence. Coal resources are main resources in China, and the filling mining method is an effective measure for improving the coal recovery rate, fully utilizing the limited resources, effectively controlling the ground pressure, reducing the surface subsidence and preventing the subsidence.

The existing production process for utilizing the waste incineration fly ash by underground cemented filling and resource utilization is poor in process optimization and cannot utilize slag tailings well.

Disclosure of Invention

the invention aims to solve the problems that the process optimization is poor and slag tailings cannot be well utilized, and provides a production process for utilizing waste incineration fly ash by underground cemented filling in a resource-sharing mode.

In order to achieve the purpose, the invention adopts the following technical scheme:

A process for preparing a mine filling cementing material from slag tailings comprises the following operation steps:

S1, analyzing and preparing raw materials required by the cement filling system;

S2, placing gypsum slurry, mineral powder or a mixture, steel slag and a tea water reducing agent into a stirrer according to a mixing proportion at the room temperature of 18-22 ℃, dry-stirring for 2min, and then adding graded tailings;

s3, after the addition is finished, dry-mixing for 2min, and after the cementing material and the tailings are fully and uniformly mixed, adding stirring water, and rapidly stirring for 2min to prepare filling body slurry;

s4, after the preparation is finished, detecting the fluidity, the dehydration rate, the mechanical property, the shrinkage rate, the setting time and the pH value of the pore solution;

S5, adjusting the formula according to the detection result, and selecting a proper formula;

S6, preparing filling body slurry according to the formula debugged in S6, and then carrying out backfilling operation.

Preferably, the fluidity measurement in S4 is to determine the fluidity of the slurry by using a micro slump tester, and the apparatus used for the test is a truncated cone circular mold, the diameter of the upper opening is 36mm, the diameter of the lower opening is 60mm, the height is 60mm, the inner wall is smooth and has no joint metal product, and the surface is smooth and clean plate glass; placing the glass plate in a horizontal position, uniformly wiping the glass plate, the truncated cone round die, the stirrer and the stirring pot by using wet cloth to moisten the surface of the glass plate; quickly injecting the mixed slurry into a truncated cone round die, leveling the mixed slurry by using a scraper, lifting the truncated cone round die in the vertical direction, starting a stopwatch to time at the same time, allowing the slurry to flow on a glass plate for at least 30s, measuring the maximum diameter of the flowing part in two mutually vertical directions by using a ruler, and taking the average value as the fluidity of the slurry; the test was passed when the filler slurry fluidity was greater than 208 mm.

Preferably, the dehydration rate in S4 is the percentage of the surface free water volume to the original slurry volume after the slurry is settled to the maximum concentration; a volume of sample was poured into the graduated cylinder, the volume was recorded as v, and left for a certain time to allow sufficient sedimentation. The water layer volume v at the surface, i.e. the dewatering value of the slurry, is measured.

preferably, the mechanical property detection in S4 includes the following steps: adding water into the raw materials according to the proportion, stirring for 5 minutes to prepare slurry, measuring the fluidity, injecting the slurry with certain fluidity into a triple test mold with the thickness of 40mm x 160mm, coating vaseline at the bottom of the periphery of the test mold to prevent slurry leakage, scraping the surface by using a hanging knife, putting the test mold into a curing box, curing for 3d for demolding under the environment with the temperature of 18-22 ℃ and the humidity of 90%, and curing for 7d for demolding if the demolding cannot be carried out for 3 d; after demoulding, putting the mixture into a water bath at the temperature of 18-22 ℃ for continuous curing for 28 days, and then respectively measuring the strength of each curing age.

Preferably, the shrinkage rate test in S4 is to inject slurry with a certain fluidity into a 70mm × 70mm test mold for molding, scrape the surface, place the molded product in a standard curing box at 20 ℃ and 90% humidity, measure the shrinkage height after internal curing to a certain age, and take the percentage value of the shrinkage height to the original height of the sample as the shrinkage rate of the sample in the corresponding age.

Preferably, a sample of the slurry at the specified hydration age is crushed, ground with an agate mortar, sieved through a 0.08mm sieve, and mixed according to a water-to-solid ratio of 1: 5, mixing with distilled water, fully stirring, standing for 15min, performing suction filtration by using a Buchner funnel, and measuring the pH value of the filtrate by using a precision pH meter.

Preferably, an orthogonal design experiment is adopted in the S5 to optimize the formula, wherein the optimized mineral powder or mixture is 20-30%, the steel slag is 8-12%, the tea water reducer is 0.2%, and the gypsum slurry is 65-70%.

Compared with the prior art, the invention provides a process for preparing a mine filling cementing material from slag tailings, which has the following beneficial effects:

1. the filler cementing mechanism and the steel slag mixing amount of the invention have the following influence rule on the system structure: the cementing agent hydration products of the filling material mainly comprise ettringite crystals and C-S-H gel, and the tailing sand does not participate in hydration reaction and only plays a role in filling aggregate. C-S-H gel and ettringite formed by slag hydration around the tailings are mutually overlapped and staggered, the tailings are cemented together, and gaps in a system are filled at the same time, so that the filling material is densified and hardened to generate strength, and the cementing effect is achieved. The cementing effect of the filling material is closely related to the content of ettringite generated by the hydration of the cementing agent. With the increase of the mixing amount of the steel slag, the pH value of a liquid phase in the filling material system is continuously improved, so that the hydration of slag in the cementing agent is accelerated, more hydration products are generated by the system to better cement tailings, and the structure of the system is more compact. However, if the steel slag is added in an amount exceeding the limit, the ettringite is over-expanded to cause cracks, so that the microstructure of the hardened slurry is changed, the density is reduced, and the strength development of the filling material is not facilitated.

Detailed Description