CN101341264A

CN101341264A - Bioleaching process control in a stirred tank

Info

Publication number: CN101341264A
Application number: CNA2006800422079A
Authority: CN
Inventors: G·V·罗尔克
Original assignee: BHP Billiton SA Ltd
Current assignee: BHP Billiton SA Ltd
Priority date: 2005-09-15
Filing date: 2006-09-15
Publication date: 2009-01-07
Also published as: WO2008036985A3; WO2008036985A2; AU2006347613B2; CA2628125A1; ZA200803138B; AU2006347613A1; EA013851B1; EA200800805A1; US20080173133A1; AP2008004397A0; EP1937858A2; AP2270A

Abstract

A process of bioleaching a sulphide mineral slurry in a reactor which is controlled by varying the rate of supply of sparging gas to the reactor, and the energy supplied to a motor-driven agitator in the reactor, in response to the measured or inferred oxygen demand of the slurry.

Description

The control of bioleaching process in the stirred pot

Background of invention

[0001] the present invention relates generally to a kind of bioleaching process, more particularly, the present invention relates to when these class methods are implemented in agitator tank reactor it be controlled to cut down the consumption of energy.

[0002] the biological lixiviation process that carries out in agitator tank reactor can be used for making the gold trisulfide enriched material and the oxidation of cupric sulfide enriched material of indissoluble, also is applicable to nickelous sulfide and zinc sulphide.In these operations, compression flows to the air or oxygen institute consuming electric power of reactor, and in reactor the required energy of distribution of gas, promptly be the actual motion cost.

[0003] in stirred pot, will leach the operation slurry feed by the biology that water, nutrition and sulfide enriched material are formed in reactor, there is suitable microorganism can make ferrous and sulfide oxidation in the reactor.This oxidising process needs oxygen.

[0004] oxygen is transported in the reactor with air, the gaseous form such as air or oxygen that are rich in oxygen.This gas feeds the reactor from high reliability downstriker pumping agitator or radial pattern impeller bottom.This device is sheared slurry and inlet air flow is broken into small bubbles.So greatly increase the surface-area of air-flow and increased the speed of oxygen transfer in the slurry.

[0005] transfer rate of oxygen is directly proportional with following situation:

A) add-on of gas is unless gas velocity surpasses the dispersive ability of impeller to it.

B) oxygen partial pressure in the gas; With

C) be sent to the quantity of power of slurry by agitator.

[0006] yet, the transfer rate of oxygen and the dissolved oxygen content in the slurry are inversely proportional to.

[0007] speed of reaction consumes oxygen (oxygen requirement) depends on that sulfide is fed to the speed of this reactor, and this speed itself is subjected to output or be subjected to other influence of enriched material level.

[0008] common, typical bioleaching process disperses functionating under a plurality of restricted conditions such as limit of gas at for example minimum and maximum dissolved oxygen, agitator.In these restricted conditions, there is optimal conditions according to this method of operation of the position of equipment, its size and the decision of its oxygen requirement.Designing the equipment that an assessment feed conditions surpasses part equipment life is conventional practice.

[0009] in fact, equipment moves under away from enriched material rank that designs or feeding rate usually.This be owing to for example mineralogical variation of multiple factor as mining progress, design and actual sulphide flotation and handle the deviation of other ores, because operation reason change enriched material tonnage, mining speed etc.

[0010] if the oxygen requirement in the reactor descends, then being used for the equipment of delivering gas such as compressor or gas blower will be in low-level operation.The energy consumption that Fig. 1 represents every processing kilogram of sulphide changes with the agitator power input of the thermophile bacteria equipment that comprises A reactor and second reactor (thermophile plant).Article two, in the curve, relation aforementioned, when the all-sulphide tonnage is transported to this equipment that following curve has provided, and top curve has provided when this sulfide charging tonnage and reduces 50% and reduce the relation of gas delivery power when compensating.Although reduced the gas velocity of supply arrangement, clearly,, be the sulfide feeding rate that compensation reduces according to the quantity of power that offers agitator, the energy consumption of every processing unit sulphide is increased to 39% from 19%.

[0011] Fig. 2 comprises the similar graph of the air feed mesophile equipment (mesophile plant) that is used for identical performance.Article two, in the curve, following curve representation is expired tonnage sulfide, and top curve representation half tonnage sulfide.Because of the tonnage of sulfide reduces the energy cost of the every processing unit sulphide that rises, be increased to 60% from 26%.

[0012] the present invention relates under these conditions, be intended to reduce the control techniques of every processing unit sulphide energy consumption.

Summary of the invention

[0013] the invention provides the method for carrying out bioleaching process, this method may further comprise the steps: the sulfide ore pulp is fed to reactor, in reactor, whitewash with gas, slurry stirs with electric mixer in reactor, impel the sulfide mineral heap that bio-oxidation takes place, and spray into the delivery rate of gas and the speed of giving the motor energize to reactor: the oxygen requirement of mensuration and the oxygen requirement of supposition according at least a following situation control.

The accompanying drawing summary

[0014] the present invention also is further described with reference to the accompanying drawings by embodiment, in the accompanying drawing:

Fig. 1 and Fig. 2 relate to existing situation and are described;

When Fig. 3 is illustrated respectively in the power of agitator of normal sulphide grade, half sulphide grade and half sulphide grade and reduction, the per unit sulfide energy consumption of the compressor of thermophile bacteria equipment and agitator;

When Fig. 4 is illustrated respectively in the power of agitator of full tonnage, 2/3rds tonnages and 2/3rds tonnages and reduction, the per unit sulfide energy consumption of the compressor of thermophile bacteria equipment and agitator; With

Fig. 5 is a block diagram of realizing the mode of the inventive method.

The description of preferred embodiment

[0015] accompanying drawing 5 is block diagrams of equipment 10, wherein according to principle of the present invention, carries out the biological oxidising process that leaches sulfide in stirred pot.

[0016] this equipment comprises a series of agitator tank reactors, although have only a jar among Fig. 5, is called 12.This jar comprises that agitator is impeller 14 (these terms is used interchangeably in this manual), and it is to use technology known in the art to be driven by electric motor 16.Electric energy is supplied with electric motor by power supply 18.

[0017] gas source 20 is used for and will sprays into the scatterer or the similar device for dispensing 22 of gas importing jar 12 bottoms.The gas that imports can be air, be rich in the air of oxygen or enough pure oxygen.Gas source 20 can comprise one or more compressor, air pump or allied equipment.This can use conventional equipment on the one hand.Gas velocity by gas source supply response jar is monitored by the transmitter 24 that this information can be passed to control computer 26.This controller is accepted from the information input in other sources and can be exercised controlled function, so that the gas velocity of conversion gas source supply response device.

[0018] slurry 28 imports in the jar in a controlled manner.This pulp bales is moisture, nutrition and sulfide mineral enriched material.The application of the principles of the present invention is not limited to concrete mineral type, and these principles can be used for reclaiming the method for gold, copper, nickel and zinc usually.

[0019] the jar A reactor of being discussed not necessarily, and can be to accept the second reactor that the product of A reactor carries out further oxidation.

[0020] jar 12 is equipped with the micropopulation of self keeping, and this micropopulation is used for ferrous and oxidation sulfide as catalyzer.Need oxygen in these reactions, as mentioned above, oxygen can be provided by gas source 20.

[0021] dissolved oxygen levels of slurry will be monitored by suitable transmitter 30 in the jar 12.Discharging the composition of gas is measured by transmitter 32.Oxygen requirement can be by the output data of the gas source 20 that comes from transmitter 24 detections, and the output data of transmitter 32 is calculated, perhaps use output, gas source 20 and the transmitter 30 of suitable algorithm and agitator power supply 18 to estimate, perhaps manually measure oxygen uptake rate by the operator.

[0022] considers total power and the restriction of any air feed that gas is provided to all jars in the equipment, decide as the case may be, the oxygen uptake rate of estimating or measure is used in the suitable algorithm, to set up the most effective power level that to supply with motor 16.Can realize this algorithm automatically or rely on the signal of operator's input of training manually to realize this algorithm by control computer 26.Measure and write down the total energy consumption of all jar agitators and air feed compressor so that follow the trail of.

[0023] the objective of the invention is by the power of control input agitator and the efficient of the gas volume raising oxidising process that control is transported to slurry.

[0024] Fig. 3 represents three points operating, and promptly point of normal operation 40, if half and the agitator power operating point 44 when reducing in right amount falls in operating point 42 and the sulphide grade when not reducing if half and agitator power fall in sulphide grade.

When [0025] Fig. 3 was illustrated in the operation of half sulphide grade, the cost of electric energy promptly moved the cost of motor 16 and gas source 20, if do not reduce the agitator energy supply, is about more than 35%.Yet if reduce this energy level, the energy consumption of every processing unit sulphide is about more than 21%.

[0026] if reduce sulphide grade, the efficient of oxidising process can reduce in the mode of describing in Fig. 3 at Fig. 1 so.What remember is in biological plant, reclaims if can reach the mineral of same percentage value, and other reduction of level does not also mean that the reduction of method conservation rate.

[0027] the enriched material tonnage reduces usually, causes the output in the equipment to reduce.When Fig. 4 represents that this equipment normally moves (point 48) with in 2/3rds levels of designed capacity and when reducing stirrer energy consumption operation (point 50) and the efficient when 2/3rds levels of designed capacity do not reduce stirrer energy consumption operation (point 52).Iff the power that reduces gas source 20, the reduction of enriched material feeding rate will make the energy of every processing unit sulphide increase by 24%.Yet if be optimized control by 30 pairs of motors 16 of treater and gas source 20, with control agitation energy and ventilation energy, the energy consumption increase of every processing unit sulphide is about 14%.

[0028] the present invention seeks the operation of the biological extracting stage of optimizing equipment.The aspect that relates to energy control can be by using various speed, common driving realization based on electric energy.Also may use coefficient of oxygen utilization mensuration or that infer and optimize whole technology or each reactor requirements with mathematical correlation and mathematical model.Aspect back one, must remember that the present invention is described with reference to single reactor or retort, but in fact, has used the series reaction jar.

[0029] therefore, the present invention allows with the raising whole efficiency that cuts down the consumption of energy accordingly.

[0030] can realize the reduction of energy consumption by energy input to influencing each other between the gas source to motor and energy input.With respect to the energy consumption of optimizing motor, optimized the aggregate energy of input then.

[0031] information that can automatically utilize this method and obtained or can pass to the control personnel to the information that is obtained is carried out suitable Artificial Control to realize controlled step by the control personnel then.

Claims

1. method of carrying out bioleaching process, wherein said method may further comprise the steps: the sulfide ore pulp is fed to reactor, in reactor, whitewash with gas, slurry stirs with electric mixer in reactor, impel the sulfide mineral heap that bio-oxidation takes place, and spray into the delivery rate of gas and the speed of giving the motor energize to reactor: the oxygen requirement of mensuration and the oxygen requirement of supposition according at least a following situation control.

2. the process of claim 1 wherein and said method comprising the steps of: form derived data according to the delivery rate that sprays into gas to reactor with from the reactor expellant gas, and according to the data computation oxygen requirement that derives from.

3. the process of claim 1 wherein that described oxygen requirement depends on the power of agitator of electric mixer, spray into the delivery rate of gas and the dissolved oxygen levels in the slurry to reactor.

4. the process of claim 1 wherein and said method comprising the steps of:, then reduce the feeding rate of described slurry feed to reactor if the sulfide grade of described slurry reduces.