CS199107B1 - Process for increasing energetic efficiency of undergrouud leaching ores especially uranium ores - Google Patents

Description

The invention relates to a process for increasing the energy efficiency of underground leaching, in particular uranium ores, in which the process solutions are concentrated by evaporation.

The underground leaching of useful components, especially metals, represents a modern method of hydrochemical mining, where there has been minimal disturbance of the environment. This method of mining can be carried out with the expense of significantly less investment than in conventional methods and is also applicable in a number of cases where conventional mining technology cannot be applied.

The leach solution is injected into the subterranean bed by eyedema injection holes and after leaching the utility components it is depleted for surface treatment. After the mined component is added, the solution is treated by the addition of chemicals and reused for leaching.

Until now, the methods of hydro-chemical extraction of useful minerals are usually associated with undesirable non-determination of volumes of technological solutions, which occur for a number of reasons, including inflow of overburden or surface water into the reservoir, movement of water at leached horizon, surface treatment into leaching solutions, etc. This increase in the volume of the hydrochemical extraction process solutions is connected and by their dilution and thus the concentration of the chemicals used falls below the technologically suitable level, which must be compensated by further addition of these

199 107 chemicals. At the same time, excess bleach solutions escape beyond the lined bearing contour and thereby lose the useful components contained therein. Other adverse consequences could possibly be groundwater contamination or endangerment of mine workings.

Another undesirable phenomenon of the underground ore leaching process is the increase in the circulation of balaetics in solutions, which is a source of technological difficulties. For these reasons, the possibility of destroying the excess balance of the solutions by concentrating them in the evaporator is considered. However, this method of discharging water from the leaching system is very energy intensive and expensive.

These disadvantages are greatly reduced by the method of increasing the energy efficiency of the underground leaches of the present invention by concentrating the process solutions by evaporation and heating the leaching solution, wherein the vapor vapor, condensate and concentrated solution from the process solution evaporation and heating the leaching solution underground leached.

The process of the invention makes better use of thermal energy since it greatly reduces heat loss in the form of waste heat from the evaporation process. The heat of vapors vapor, condensate and hot concentrated process solutions, which would be practically impossible to use otherwise, heats the leach solution for underground leaching.

Heating of the leaching solution It is a significant intensification factor of hydrochemical extraction. The use of the heated leaching solution ee will result in accelerated filtration processes in the underground deposit and thus faster transport of the leaching reagents 1 of the leached component. Simultaneously ae accelerated other transport aechanlamue and diffusion. Acceleration of transport mechanisms It is especially important for low permeable parts of the deposit to which the maximum mineralization is tied. No less important factor of underground leaching is also the rate of the chemical reaction of Sinidla e rock, which increases ee eyyoucl temperature particularly markedly with hardly leachable ores. The resulting effect of underground leaching at elevated temperature is to increase the yield by about 1% for each degree of Celsius by which the temperature of the ore body increases. Alternatively, the exploitation time of the mining fields can be reduced accordingly. The following are two examples of possible methods of a particular embodiment.

Example 1

14 m ³ / h of aorption waste preheated to 97.8 ° C by vapor vapor and 0.2 MPa of condensate flow into the evaporator are fed to the evaporator at a rate of 2 t / h. In the evaporator ae, evaporate 1,820 kg / h of vapor vapor, which is used to preheat the solution entering the evaporator. The cold vapor vapor condensate represents the discharged excess water from the underground leaching process. 12.18 m / h of vaporized solution at 103 ° C emerges from the evaporator, which, after mixing 30.7 m ³ / h of a 1 ° C sorption waste, yields 42.9 and ³ / h solution at 40 ° C . This solution is dokyeell kyaellnoucair and used for underground leaching.

Example 2

Flows into the evaporator 1000 kg / h of water proaývkových e containing 2% by weight duaičnanu aaonnáho NH ₄ N0 _3, preheated condensate of the heating steam at 99 ° C. Evaporation of 833 kg / h of water is concentrated to a 167 kg / h solution containing 12% by weight ammonium nitrate and reused as an addition to the elution solution. The vaporized vapors are used to heat 17,300 kg / h of leaching solution from 15 to 40 ° C. To heat up the evaporator 1000 kg / h of steam is required at a pressure of 0.2 MPa.

. The invention can be used wherever underground ore leaching is carried out and where waste heat sources from process solution evaporation are available.

Claims (1)

SUBJECT OF THE INVENTION A method of increasing the energy efficiency of an underground leaching of ores, in particular uranium, by concentrating process footoks by evaporation and heating the leaching solution, characterized in that the vapor vapor, condensate and concentrated solution from the process solution evaporation heats the leaching solution for the underground leaching.