Stowing method for goaf of potash salt ore
A method of stowing a goaf of potash salt ore comprising making wall slurry into barricades each have the same area as the sectional area of a tunnel and a thickness of 0.5 to 5 meters inside the underground tunnels in goaf of potash salt ore, with the interval between adjacent barricades being 5 to 100 meters, then stowing the interval between the barricades by using the filling slurry is described. The stowing method uses the wall slurry of high strength that is solidified with a gelling agent as the main bearing material, and uses the solidified filling slurry with a low strength as the main filling material, which has a good effect when compared with conventional filling materials. Moreover, the stowing method effectively utilizes the tail liquids, thereby reducing the addition of other additives, decreasing the cost, avoiding the discharge of liquid waste and relieving the environmental pressure.
1. A stowing method for a goaf of potash salt ore, the method comprising:
making a wall slurry into barricades inside underground tunnels in a goaf of potash salt ore, the barricades have the same area as the sectional area of a tunnel and has a thickness of 0.5 to 5 meters, with an interval between adjacent barricades of 5 to 100 meters; and
filling a filling slurry between said barricades, wherein, said wall slurry is comprised of the following ingredients by weight:
a tail liquid of potash salt ore: 20˜40%;
a tailing of potash salt ore: 30˜60%;
a first gelling agent: 8˜25%; and
a modifier: 2˜8%;
wherein, said filling slurry is comprised of the following ingredients by weight:
a tail liquid of potash salt ore: 17˜46%;
a tailing of potash salt ore: 50˜80%; and
a second gelling agent: 1˜5%.
2. The stowing method of claim 1 , characterized in that, said wall slurry is prepared by a method comprising: adding the first gelling agent and the modifier into the tail liquid of potash salt ore, after stirring uniformly, further adding the tailing of potash salt ore and mixing uniformly so as to obtain the wall slurry;
and that, said filling slurry is prepared by a method comprising:
adding the second gelling agent into the tail liquid of potash salt ore, after stirring uniformly, further adding the tailing of potash salt ore and mixing uniformly so as to obtain the filling slurry.
3. The stowing method of claim 1 or 2 , characterized in that, said filling slurry is prepared in advance and then filled between said barricades, or, said filling slurry is formed by separately filling the raw materials into the interval between the barricades and mixing them therein.
4. The stowing method of claim 1 or 2 , characterized in that, the mass percent of magnesium chloride in the tail liquid of potash salt ore is 29˜36%.
5. The stowing method of claim 1 or 2 , characterized in that, each of the first and second gelling agent is selected from the group consisting of magnesium oxide, calcium oxide, and a mixture thereof.
6. The stowing method of claim 5 , characterized in that, in the wall slurry, the mass percent of magnesium oxide is 0˜17% and the mass percent of calcium oxide is 0˜8%; preferably, the mass percent of magnesium oxide is 10˜16% and the mass percent of calcium oxide is 2˜6%.
7. The stowing method of claim 5 , characterized in that, each of the first and second gelling agent in the stowing slurry is calcium oxide.
8. The stowing method of claim 1 or 2 , characterized in that, the modifier is a mixture of sodium silicate, sodium phosphate and coal ash.
9. The stowing method of claim 8 , characterized in that, in the wall slurry, the mass percent of sodium silicate is 0.5˜1.5%, the mass percent of sodium phosphate is 0.5˜1.5%, and the mass percent of coal ash is 1.0˜5.0%.
10. The stowing method of claim 1 or 2 , characterized in that, the wall slurry and the filling slurry are delivered by means of pumping pressure, automatic flow of slurry or vehicle transportation.
11. The stowing method of claim 1 , wherein the potash salt ore is carnallite.
12. The stowing method of claim 1 , wherein the tail liquid of the potash salt ore comprises 22˜25% MgCl 2 , 3.3%˜4.4% KCl, and 1.8˜3.3% of NaCl.
13. The stowing method of claim 1 , wherein the tailing of the potash salt ore comprises greater than 90% NaCl.