RU2249103C1 - Method for group lixiviation of metals from frozen rocks - Google Patents

Abstract

FIELD: mining industry.

SUBSTANCE: method includes removal of soil from portion, meant for construction of stack of rocks for metals lixiviation, forming of anti-filtering base, mounting equipment for draining productive solution, placing lixiviated rocks on prepared base and feeding working reagents solutions into stack. In base of frozen rocks stack metallic net is placed, above it a layer of roughly broken rocks with thickness equal to fractions of meter, above it a rough fiber is placed in one or several layers, in same layer horizontal perforated polymer pipes are placed, not pressed by higher rocks, for feeding solution of working reagents and admixtures. Then stack is subjected to effect of UHF electromagnetic field of generator plant, displaced along upper stack surface by shuttle method for its even heating. Hot solution of working reagents and admixtures is fed into layer of rocks under pressure along perforated pipes with increase of melted working zone and displacement of melting front upwards, until finishing process of metals lixiviation from the stack.

EFFECT: higher efficiency.

Description

The invention relates to mining and can be used for heap leaching of metals from frozen rocks, mainly in the conditions of permafrost.

A known method of heap leaching of metals in permafrost conditions, including removing soil from a site designated for erecting a stack of rocks intended for leaching metals from them, forming an anti-filtration base, installing equipment for pumping a productive solution, laying leached rocks on a prepared base and feeding in a stack of solutions of working reagents [1]. Prototype.

The disadvantage of this method is the short period of the possibility of using the leaching process, limited by spring thawing of the soil and the onset of low temperatures with freezing of a stack of rocks prepared for leaching of metals from them.

The technical problem is the leaching of metals from frozen rocks and, as a result, the extension of the leaching process for the whole year.

The technical result consists in the formation under the influence of a microwave electromagnetic field in the lower part of the stack of frozen rocks, preferably with associated controlled factors - laying a layer of coarse rocks on the base of the stack and supplying a hot solution of working reagents and additives to it - melt working zone, the upper boundary of which is gradually shifting up to the completion of the leaching process - regardless of the time of year.

The proposed method includes removing soil from a site designated for the construction of a stack of rocks intended for leaching metals from them, forming an antifiltration base, installing equipment for pumping a productive solution, laying leached rocks on a prepared base and supplying reagent solutions to the stack, and provides, that a metal mesh is laid at the base of a stack of frozen or frozen rocks before heap leaching begins, on top of it is a layer of coarse clastic rocks a thickness of a meter, on top of it a burlap or similar fabric in one or several layers, horizontal perforated polymer pipes that are crush-resistant by the pressure of overlying rocks are placed in the same layer to supply a solution of working reagents and additives, then the stack is exposed to a generator’s microwave (microwave) field installation, moved along the upper surface of the stack by shuttle method for uniform heating over the area, into a layer of coarse rocks through perforated pipes od at a time, a hot solution of working reagents and additives begins to be supplied under pressure in an increasing volume as the volume of the melt working zone increases and the thawing front moves up until the process of leaching of metals from the stack is completed.

Introduced in the claims, such an essential feature as the fact that a metal mesh is placed in the base of the stack allows, by inducing Foucault currents in the mesh and reflecting the microwave field from it, to increase the density of the thermal energy released near it and begin to intensify heating and even thaw the stack from below.

Introduced in the claims is such an essential feature as the fact that a layer of coarse clastic rocks with a thickness of a meter is poured into the bottom of the stack, allows you to introduce more solution of working reagents and additives into it and it is easier to accumulate in it and select a productive solution.

Introduced into the claims, such an essential feature as the fact that a hot solution of working reagents and additives is introduced into the coarse-grained rock layer, can significantly increase its electrical conductivity, respectively, the absorption of microwave energy in it and, therefore, its faster heating and thawing.

Introduced into the claims is such an essential feature as the fact that in the layer of coarse clastic rocks at the base of the stack are placed sufficiently strong non-crushing perforated polymer pipes that are crushed under the pressure of overlying rocks, and it makes it possible to pump solutions of working reagents and additives into it under pressure.

Introduced in the claims, such an essential feature as the fact that polymer pipes having low electrical conductivity are used allows avoiding distortion of the microwave field in the stack and thus preserving its uniformity, and hence approximately the same conditions for heating the stack.

Introduced in the claims, such an essential feature as the fact that burlap or other fabric is laid on top of a layer of coarse rocks, allows this layer to be protected from clogging with a thin fraction of rocks and thus preserve its functional properties.

Introduced in the claims, such an essential feature as the fact that the stack is exposed to a microwave electromagnetic field allows using the other factors mentioned above to create a thawed working area at the bottom of the stack, to extend it gradually to the entire volume of the stack, and thus ensure the leaching of metals from originally frozen rocks, and consequently, leaching production throughout the year.

The method is as follows. It includes the removal of soil from the site designated for the construction of a stack of rocks intended for leaching metals from them, the formation of an anti-filtration base, the installation of equipment for pumping a productive solution, laying on a prepared base of leachable rocks and supplying working reagents to the stack, and provides, that a stack of rocks intended for leaching of metals from them is formed either from initially frozen rocks or from thawed with their subsequent freezing. A metal mesh is placed at the base of the stack, a layer of coarse clastic rocks without a fine fraction of a meter thick is poured on top of it, it is covered with burlap or other cloth in one or several layers, perforated polymer pipes that are quite strong and crumpled under pressure from overlying rocks are placed in the same layer. The leaching process begins with exposure to the microwave stack with an electromagnetic field using a generator set, shuttled by shuttle along the top surface of the stack to uniformly warm it over the area and then feed under pressure a hot solution of working reagents and additives - concentrated solutions of readily soluble salts of alkali and other metals with low temperature eutectics - into a layer of coarse clastic rocks. Under the influence of a microwave field that induces Foucault currents in a metal grid and its reflection from this grid with an approximate doubling of its density, the layer adjacent to it heats up more than the entire stack and begins to thaw. Even before this, by supplying a hot solution of working reagents and additives to it, its temperature is increased, while at the same time the temperature of its thawing is lowered, the conductivity of the layer saturated with the solution is increased many times, and due to the same increase in the absorption of microwave energy in it increase its temperature. The combined action of all these factors leads to the formation of a thawed working zone at the base of the stack, the upper boundary of which gradually shifts upward, increasing the volume of the working zone in which the leaching of metals proceeds, up to its completion in the entire volume of the stack.

The advantages of the method are:

- the possibility of leaching metals from frozen rocks, therefore, throughout the year;

- simplicity and cost-effectiveness of the method.

Sourse of information

1. RF patent No. 2183743, E 21 B 43/28, 2002

Claims (1)

A method of heap leaching of metals in permafrost conditions, including removing soil from a site intended for erecting a stack of rocks for leaching metals from them, forming an anti-filtration base, installing equipment for pumping a productive solution, laying leached rocks on a prepared base and feeding solutions into a stack reagents, characterized in that a metal mesh is laid at the base of the stack of frozen or frozen before heap leaching of rocks , on top of it is a layer of coarse clastic rocks a fraction of a meter thick, on top of it a burlap or similar fabric in one or several layers, horizontal perforated polymer pipes that are non-crushable by the pressure of overlying rocks are placed in the same layer to supply a solution of working reagents and additives, then the stack is exposed to microwave (UHF) of the electromagnetic field by a generator set, moved along the upper surface of the stack by shuttle method to uniformly warm it over the area, into a layer of rough full-time rocks through perforated pipes simultaneously begins to be fed under pressure a hot solution of working reagents and additives in an increasing volume as the melt working zone increases and the thawing front moves up until the process of leaching of metals from the stack is completed.