CN101090983B - Leaching process in the presence of hydrochloric acid for the recovery of a value metal from an ore - Google Patents

Abstract

A process is described for leaching a value metal from an ore containing said value metal, the process including the steps of leaching the ore in the presence of hydrochloric acid so as to form a soluble metal-chloride salt in a leach solution; adding sulphur dioxide to the leach solution; recovering a metal-sulphate or metal-sulphite salt from the leach solution; and regenerating hydrochloric acid. The ore may be an oxidic base metal ore, such as a zinc oxide ore; a lateritic nickel ore, such as a saprolitic or limonitic ore; a sulphide ore or a titanium ore. The value metal is typically selected from the group consisting of Zn, Cu, Ti, Al, Cr, Ni, Co, Mn, Fe, Pb, Na, K, Ca, platinum group metals and gold. The metal in the metal-sulphate or sulphite salt may be the value metal, or may be a metal of less value than the value metal, such as magnesium. The regenerated hydrochloric acid is recycled within the leach process.

Description

Hydrochloric acid exists down and is used for from the leaching technology of ore recuperation precious metals

Background technology

The present invention relates to generate or the chloride brine water technology of the hydrochloric acid of regenerating, also relate to a kind of technology of the ore leaching metal from chloride soln.Described technology provides the hydrometallurgical processes route of a kind of not only economy but also environmental protection, and it is used for reclaiming precious metals from ore or concentrate.

Repeatedly proposed to use the medium of spissated relatively muriate bittern in the past as leaching base metal (base metals), a nearest example is its Outokumpu Hydrocopper technology of doing description and quote in numerous patents, for example WO 2003/35916, WO 2003/89675 etc.Known high strength chloride brine water is allowed faster leaching more completely than sulfate medium common, dilution relatively.But it generally is pretty troublesome utilizing this bittern to reclaim the dissolved precious metals, electrowinning technology that can not application standard.

In these years, use hydrochloric acid (muriate) medium leaching nickel laterite to become the research topic of a lot of institutes, especially the N.M.Rice (seeing Rice, 1989) with Leeds University is the pioneer of this area.The leaching kinetics that on typical silicate (serpentine) and oxide compound (limonite) ore, all can realize ideal, therefore illustrate that this system can be used to leach valuable material, for example obtains nickel in the multiple material from typical laterite rock stratum (horizon).Special concern be at high temperature, be generally and be higher than 80 ℃ temperature, the fast kinetics of the leaching in the 4mol hydrochloric acid soln (1 hour).Proposed the schema on the principle (Rice and Strong, 1974) subsequently, used hydrochloric acid leaching liquid to dissolve valuable cobalt and nickel, then respectively by solvent extraction with nickel is hydrolyzed into nickel hydroxide (using magnesium oxide as neutralizing agent) is removed.Impurity such as iron and magnesium is the main body of the hydrochloric acid of consume expensive.From solution, remove iron(ic) chloride by solvent extraction, and in the spray roasting step, handle the rhombohedral iron ore that makes formation stable, and regeneration hydrochloric acid, make its circulation return the leaching step.Similarly, in the spray roasting step to magnesium chloride handle make form magnesium oxide (as byproduct sell and/or as neutralizing agent) and the hydrochloric acid of regenerating (the leaching step is returned in recovery).

About in the world 70% soil class (land-based) Ni source is included in the laterite according to estimates.At present, only about 40% Ni that is produced extracts in laterite, and this numeral can increase to about 50% (numeral is from Dalvi et al, 2004) before 2012 according to estimates.Need new operational path from the laterite mineral deposit, to reclaim Ni and Co, can provide than prior art significantly reduced running cost, especially capital cost.And, consider supply, suppose about 4% (obviously several factors can be disturbed this numeral) of the annual growth of demand of Ni, market will need to produce 40-45 every year, and 000 ton of new Ni is with satisfy the demand (numeral is from Dalvi et al, 2004).Even when having comprised the new supply that comes that sulfide deposit from childhood obtains, main greenfield laterite project (the high pressure acidleach project of Goro and Ravensthorpe for example, the new smelting furnace of Koniambo, for example new sulfide hydrometallurgical process route of Voisey ' s Bay) supply still be lower than consumption.

Geology and mineralogy

The economic conditions of laterite technology extremely depend on the grade (grade) of used ore and form.The nickel laterite bed comprises two main rock stratum, that is, and and near limonite (hydrous iron oxide) material (low Ni and Mg, high Fe) on surface and following saprolite (saprolitic, hydrous magnesium silicate) material (high Ni and Mg, low Fe).These mineral deposits form by the efflorescence of parent rock, and conversely, the parent rock is the crystallization molten rock that is derived from the Fe-Mg-Si-O-mineral forms.The parent rock contains Ni (～0.2%) and Co, because it can replace Fe and Mg (similar valence state and ionic radius) in Fe and the Mg lattice silicate.In the serpentinization process, under high-temperature and high-pressure conditions, (there is water to exist, below the face of land), form elementary serpentine (primary serpentine) mineral, Mg by the parent rock ₃(Si ₂O ₅) (OH) ₄This cause Ni promote naturally grade (upgrade) (＜0.5%Ni).Serpentinization alteration process also forms the magnetite as concurrent product (co-product), and it is parent rock forming mineral (for example peridotites) main source of iron in addition in the efflorescence.When elementary serpentine (degree of proportional representation serpentinization) and relevant parent litho-relict mineral such as (particularly for example) peridotitess when standing to continue weathering laterization can take place, particularly in the torrid areas of humidity (being also referred to as the laterization process), or near the zone on the face of land.Compare with the parent rock, the laterization process has concentrated 3-30 doubly with Ni and Co.The laterization process is dynamic, and depth section is instantaneous substantially, and lowermost portion is represented the rock that changes recently, that is, when this section was passed in the surface water infiltration, surface water was (by dissolving CO ₂Make acidifying with organic acid) dissolving and leaching Ni, Mg, Si, Fe (is Fe ²⁺) and Al (in order to reduce mobility).Near the face of land, iron is by quick oxidation and precipitate into amorphous ferric hydroxide, co-adsorption Ni (being generally 1.5%Ni) and similar all Co:Fe in its structure ²⁺ _(s)+ 2H ₂O+O ₂+ (Ni, Co) ²⁺ _(aq)→ (Fe ³⁺, Ni, Co) O (OH) .nH ₂O _(s)+ O ₂+ H ₂O ^*(1)

(limonite)

^*This is a unbalanced reaction, shows the complicacy of occurring in nature precipitation process.Under oxidizing condition from such as the Fe-oxide compound of magnetite, maghemite etc. with such as dissolving Mg (the Fe)-silicate of peridotites and orthorhombic pyroxene etc. and leaching Fe ²⁺The solid of up-to-date formation (the right) also comprises the ironic hydroxide [Fe (OH) as intermediate phase probably ₃] precipitation.

As time goes on, this material improves its degree of crystallinity and at first forms pyrrhosiderite (main component of oxide deposit), and finally (from top to bottom) changes into the most stable natural form, that is, and and rhombohedral iron ore.Rhombohedral iron ore can not hold Ni and Co in its lattice under the environment of the oxidation Ni-of humidity laterite, and can lose grade formation upper epidermis (upper crust), is called ferricrete (this is the one deck that at first is removed when the laterite deposit mining).Important and be noted that Ni and particularly Co are also by Mn oxide/hydroxide mineral (main mineral ore or the top coat of forming on other mineral) absorption consumingly.In the Goro mineral deposit of New Caledonia with in the Moa of Cuba Bay mineral deposit is the example in mineral deposit, and this mineral deposit is made up of this class limonite of its depth section mostly.When dissociating quartz (coming from the parent rock) redeposition in a large number, form the limonite bed of a certain kind, again it is leached from Mg-silicate sturcture (serpentine, peridotites etc.), as the crystallite chalcedonic quartz.This general change owing to Eh and/or pH occurs in the laterite section.The frequent part recrystallization of this crystallite chalcedonic quartz becomes the more quartzy phase of crystallization, (example of this class ore is Ravensthorpe and the siliceous mineral deposit of Jacare meticulous extremely coarse free independent quartz particles to occur, that is, can physical property remove coarse quartzy part and promote grade).

Under not too severe weathering situation, under for example dried or nice and cool weather, or underground water wherein mobile restricted (impeded drainage), leaching speed can descend, and Mg preferentially leaches in serpentine and olivine crystal structure.This causes simultaneously in the lifting such as the grade of the mineralogical composition of other poor mobility such as Fe and Si, causes elementary serpentine and peridotites to change into montmorillonitic clay.Fe ²⁺Movability compare Mg ²⁺Therefore difference replaces Mg in the crystalline structure of the new montmorillonitic clay that forms.Therefore, these Mg, the Fe-clay becomes the nontronite that is rich in Fe by the sepiolite that is rich in Mg on forming.Clay seam (if existence) is present between limonite and the sapropel soil zone usually.Smectite clay mineral is fix N i (up to 1.5%Ni) in lattice also, and it replaces Fe in the interlayer position ²⁺And Mg ²⁺Ion.The quartz that requires to form montmorillonitic clay also can exist with crystallite chalcedonic quartz tuberculosis in clay.Murrin Murrin area contains the discontinuous montmorillonite band of determining very much (smecticzone) at its section.

No matter whether the montmorillonitic clay layer exists, remaining Ni, Mg, Fe and Si are brought into solution.Fall under water when underground, since itself and the reaction of unweathered basement rock, phreatic pH rising.In laterite-approaching position, basement rock interface, form loss and silicate hydrate magnesium mineral (being known as noumeite) that be rich in Ni (20% Ni).Ni causes the lifting of the grade of Ni in Mg-silicate at the horizontal redeposition of the alkaline pH lower than Mg, causes forming these so-called noumeites (being rich in the hydrated magnesium silicate of Ni).Noumeite is in the active area of tectonics, and for example New Caledonia is more remarkable, and in the zone of kraton landform, for example Brazil or western Australia are then not too remarkable.The Ni content of original parent rock is largely determining the Ni grade of gained laterite.Between basement rock or noumeite layer (if existence) and limonite or clay seam (if existence) is the transitional zone that is called the sapropel soil zone, the phyllosilicate that promptly contains mineral substance, it is made up of the variable Magnesium Silicate q-agent material of height, is derived from elementary serpentine and parent rock.Parent atmospheric disintegration of rocks without serpentinization also may cause the crystallite chalcedonic quartz occurring along the geologic framework such as easier infiltrations such as shear zone, tomography, mineral ore and fractures.Along with the time, Fe and especially Ni (being generally 2-3%Ni) preferably replace Mg and form secondary " alteration " serpentine.

For example:

Mg ₃(Si ₂O ₅)(OH) ₄(s)+0.3Ni ²⁺ _(aq)→(Mg _2.7，Ni _0.3)(Si ₂O ₅)(OH) _4(s)+0.3Mg ²⁺ _(aq) (2)

For reaction is moved right, the concentration of dissolved Ni only needs a little higher than its concentration in solid phase in the underground water of infiltration.

Ni preferentially replaces magnesium, i.e. the OH-key of tetrahedral site (so-called brucite layer) in the serpentine structure than the weak bond position.

At last, the weathering profile (on the degree of depth) of known because laterite ore bed is irregular, and because uneven exploitation, and concrete ore sample for example saprolite can contain other ores of variable ratio, for example limonite and/or clay.Mineralogy and relevant processing characteristics that gained ore charge so apparent altitude are variable.

Most in the world laterite Ni source is included in the limonite type ore, the degree that comprises at sapropel soil type ore then lower (Monhemius, 1987 and Elias, 2002).

Present practice

Once more, need know when processing has the ore of higher Ni grade that the economic benefit of any technology will be better thereupon.Therefore, if possible, should focus on ore dressing.Unfortunately, because Ni closely mixes with pyrrhosiderite and Magnesium Silicate q-agent mineralizer respectively, limonite and saprolitic ores all are difficult to ore dressing.Yet when having coarse barren material, still might carry out ore dressing to promote grade.If Ni content is low, can screen this roughage, for example coarse quartz grain, magnesite (MgCO ₃) and Magnesium Silicate q-agent etc.

Smelting process (Fig. 1)

Fig. 1 shows the principle flow chart that carries out the saprolite processing by the melting route.Ore contains the 20-50% free-water, at first dewaters by drying.Then ore is calcined and removed water of constitution, in stove, Fe and Ni are reduced into metallic state then with coke or coal.Mg, Si etc. be along with the slag phase, and allow to remove liquid molten Ni-Fe alloy like this.Need carry out refining and remove remaining S, C and Si: add lime and form the CaS slag, by atmospheric oxidation C is changed into CO gas simultaneously, Si is changed into oxide slag.If the generation Rhometal, because its importance in stainless steel is produced, very small amount of Fe is oxidized.The production route requirement of sulfonium is added into S in the kiln and forms sulfide with metal Ni and (unfortunately) Fe reaction under reductive condition.Melt this material then, and follow slag oxide compound and sulfide mutually and form the sulfonium phase.Finally, make most of Fe oxidation slagging phases to the converter bubbling air.

Feature:

-slag melting is to SiO ₂/ MgO and FeO sensitivity

-ore mutability needs blending (blended out) to keep feed target (exploitation and mixed ore increase expense);

-economic the border of a low-cost power ash project is supplied with grade (economical cutoff feedtrade) and is about 1.7%Ni, is about 2.1% as for green expensive project.Ni (Dalvi et al, 2004), established technology restriction resource occurs, and it can be used as the target ore;

-high fund and energy expenditure influence the smelting process route, and therefore its economy is very responsive for local cost of energy.

Though the recovery of-Ni good (～90%) might not have/have only a small amount of Co by product; At first because the Co content in saprolitic ores is generally very low, next is because of its recovery very poor (～50%), (Dalvi et al, 2004).

Caron technology (Fig. 2)

At first in rotary kiln with the ore drying, and reductibility ground baking (oil fuel is generally as reductive agent).Optionally Ni and Co are being reverted to metallic state (partial reduction of 10%Fe is arranged approximately) near 700 ℃.If the silicate content of feed increases (by handling more saprolitic ores), the recrystallization (it is difficult to reduce under 700 ℃) of forsterite (amorphous Mg-silicate) can take place, so fix N i, promptly it can not be leached.Similarly, higher reduction temperature causes increasing formation fire-resistant (being used for the leaching of aluminium carbonate ammonium) proneness mutually with excessive reduction, that is, it is summed up as the recovery of kinetics vs Ni and Co.After the cooling, the normal pressure leaching is carried out in alloy (air) in the aluminium carbonate ammonium solution (pH～10) under oxidizing condition.The Ni (Co) of leaching and Fe solution mutually in the very strong ammonia complex of formation.Ferrous ion is oxidized to positive iron state, and is hydrolyzed into colloidal iron hydroxide (Co tends to and the ironic hydroxide co-precipitation, and can not reclaim greatly).After liquid-solid separation, use H ₂S gas (Co is difficult for dissolving than Ni, but high Ni: the Co ratio causes part Ni precipitation), make some Ni and all Co precipitate into sulfide.Stripping (not containing Co) then, Ni solution forms the CO in alkaline carbonic acid nickel (solid phase) and the gas phase ₂And ammonia.Absorb the recyclable CO that utilizes again by water ₂With ammonia to generate ammonium hydrogen carbonate solution.The nickelous carbonate cake can be sold or by a kind of backend process wherein it is for further processing, and makes the Ni that reclaims in carbonate or the solution.Ni and Co can reclaim by solvent extraction, or subcarbonate can stir generation NiO (not being good pure products) in rotary kiln.Alternatively, cake can be dissolved in again and form nickel ammonium sulfate in the ammoniumsulphate soln, then it is used H ₂Gas is reduced into Ni metal (seeing Monhemius, 1987).

Feature:

Though-this technology goes for some saprolitic ores (more than high pressure acidleach taking technique),, promptly cause higher Ni loss) by the amount increase Mg of raising forsterite and the amount of silicate;

Though-main agents (ammonia and CO ₂) in technology, circulate, a large amount of loss (particularly because leaching Mg, the i.e. formation of magnesiumcarbonate ammonium) still appears; In order to make purer product relatively, also require to replenish reagent;

-total input energy greater than 60% is by the processes expend of front (drying of wet ore and the baking of reductibility), and rear end part (back-end) is got back to hydrometallurgical processes simultaneously, i.e. the extremely low technology of energy efficiency;

-because therefore the gelling properties of ferric hydroxide precipitate filters very poor;

The low alluvial of-pyrometallurgy (formation forsterite) and hydrometallurgy (co-precipitation of Co and because the leaching particulate obstruction that the precipitation of Fe causes) technology; Always reclaimed near 75%Ni and 50%Co.

Because the recovery of its low value metal, and the feed type of its target is low-grade feed (mainly being limonite ore), and follows high-energy and reagent cost, estimates not have green project to plan to use this technology (seeing Dalvi et al, 2004).

HPAL technology (Fig. 3)

On the metallurgy, be simple relatively in high pressure acidleach (HPAL) technology that begins to carry out the high-temperature acid decomposition step greater than 245 ℃.With in the lime and the mud of discharging, and the mud adverse current toppled over, remove impurity then, with sulfide (H ₂Or directly remove Ni and Co (Goro schema) S) or oxyhydroxide (lime) precipitation Ni and Co, by solvent extraction.Optional being further purified with separating comprises dissolving again (if producing precipitated solid) and the purifying by solvent extraction or selective precipitation.At last, reclaim metal, or produce Ni oxide compound (the muriate chemistry is relevant with SX or IX, and is irrelevant with leaching) by pyrohydrolysis by electrowinning or hydrogen reduction.

Feature:

-because this is limonite operational path (estimates limonite ore be the twice of saprolitic ores tonnage), so source target ratio to be used for fused big, but this technology consumes thing to main acid, i.e. Al (clay material) and particularly Mg (＜4%) performance sensitivity;

-corrosion is very serious, when particularly having muriate (salt solution).When using high-grade Ti alloy, can improve erosion resistance, but it is very expensive;

-because applying pressure equipment and construction material, so fund cost is very high;

-owing to use the consumption thing (Mg and Al) of acid and keep the needs of sour environment (because forming hydrosulfate), and need neutralization (lime), so reagent cost is very high.Usually, the acid that needs to add is 250-400 kg/t, the corresponding low Mg limonite ore in lower end;

-fouling is a problem of autoclave, and can cause stopping work, particularly for the feed of higher Mg and Al.

Researching and proposing of Dalvi et al (2004) is as follows: the economy of HPAL route is very responsive to the performance of feed grade, can in green project, use the feed grade that is limited to 1.3%Ni under estimating, offset or be positioned approaching cheap acid source (for example, sulfide smeltery operation) unless be lower than average acid consumption (with reference to .Ambatovy Project in Madagascar).

Fig. 4 illustrates the poor efficiency of HPAL technology on reagent uses.Suan main consumer is Mg as can be seen, except by handling low Mg (limonite type) the feed ore, does not have other effective meanss.In addition, be to keep chemical environment (at a certain temperature, the formation of compensation hydrosulfate) near half cost, but have actual participation leaching reaction.After the pressure leaching, need neutralization " extra " acid then.(pulp density) is high more for pulp density, and chemical environment is more little to the influence of cost on absolute value (cost/lb Ni).But because viscosity limitation, pulp density has maximum constraints.

Replace Sulfates technology

Because lower financing requirement and can handle the purpose of limonite and saprolite, there is clearly tendency attempt and propose feasible normal pressure leaching (ALP) technology industrial.Can typically under the remaining acid concentration of height, leach limonite ore, and the sour and d/d acid when the Fe hydrolysis with saprolitic ores (having higher neutralising capacity) neutralization remnants then.The combination of HPAL and ALP is called the acidleach of enhancing pressure and gets (EPAL) technology, and this technology has been developed and has been applied at present in the Ravensthorpe project of western Australia.Fig. 5 has illustrated the principle of ALP and EPAL.

The illustrated principle of Fig. 5 is from the patent of AMAX in the 1970's.AMAX technology has also been prepared stoving oven and has been made the partial reduction saprolitic ores, promptly increases its neutral reactivity, and recovery part Ni.With the process structure of Fig. 5 explanation, this operation can be recovered to (Monhemius, 1987) in the HPAL leaching technology with any not Ni (removing most of Mg) of leaching in resistates.

Feature: open circuit, ALP/EPAL technology:

The leaching of-normal pressure is characterised in that the slow motion mechanics, though it can greatly be compensated by low fund expenditure, promptly the residence time is relatively cheap (comparing with HPAL);

Even-normal pressure leaching system can remove Fe (by saprolite neutralization/hydrolysis) effectively, because excessive Mg leaches, a large amount of losses (still, this cost can part by being compensated from the additional energy of unnecessary combustion of sulfur gained and extra Ni income) of acid still can appear;

-to compare with HPAL, the EPAL method is introduced higher energy and higher fund cost;

-open circuit, normal pressure vitriol route need solve serious MgSO ₄Handling problems, particularly for the ENVIRONMENTAL LAW of increasingly stringent (especially obvious when handling high Mg feed ore).

In a word, the HPAL part can guarantee that high Ni and Co extraction generate stable Fe resistates simultaneously, so the EPAL route provides minimum technology risk.The AL part can be guaranteed the neutralization requirement of required minimum, has gathered in the crops additional Ni amount simultaneously.But main problem is high cost of capital and the problem of Mg.The open circuit that carries out whole AL technology in sulfate medium requires (high acidity) leaching condition of vigorous erosion to extract with the height of guaranteeing Ni and Co.The height neutralization requirement that this needs the saprolite material conversely causes causing the high loss of vitriol by the Mg in the solution, may stay in the residue as jarosite.Requirement on high reagent consumption (unless more cheap resource is arranged) and the environment can make that this route is infeasible.Therefore, proposed to attempt optional technology to take a whirl at and to handle problem about Mg.American Climax Inc (predecessor of AMAX company) has proposed such technology, uses non-evaporative crystallization with precipitation sulfuric acid monohydrate salt in 190-250 ℃ autoclave.Because the extra and expensive autoclave of this processing requirement, the Sulzer of Switzerland proposes SURAL technology (Sulzer Regenerative Acid Leach process), proposes evaporative crystallization to produce epsom salt (MgSO ₄.7H ₂O).This vitriol of thermolysis produces SO then ₂(change into sulfuric acid and loop back HPAL in the acid plant) and neutralizing agent, magnesium oxide (MgO), it is at technology internal recycle (seeing Monhemius, 1987).The nearest privately owned normal pressure leaching technology of Skye Resources that proposes, except elementary leaching step was normal pressure, this technology and SURAL technology were equal to substantially.In addition, what Skye process exploitation person claimed is the Mg vitriol of a low hydrated form, i.e. a hydration 2-3 water (with reference to Hatch Feasibility Study, 2005) behind evaporative crystallization.Fig. 6 shows the principle of Sural/Skye technology:

Feature: closed circuit, ALP technology, with reference to the Skye Process:

-replace the reagent supplementary cost by energy/fuel cost, its quality depends on the position;

-require big energy (demand of high evaporation) by evaporation crystallization Mg vitriol from all-fulfate solution, need to surpass the amount (significantly increasing) of other normal water balances along with the Mg grade increase of elementary feed ore.

The new technology that proposes in chloride media

Fig. 7 illustrates atmospheric chloride acidleach taking technique (hereinafter referred to as Jaguar technology, mean Canadian nickel exploitation and the Jaguar Nickel Inc. of mine development company, it has developed this privately owned technology).It is made up of the normal pressure leaching technology in hydrochloric acid soln, contains high MgCl ₂Environment.Its activity of claiming proton along with density of magnesium chloride in background solution increase and significantly improve.This saying is based on Bates et al (1970) and particularly Jansz (1983) about HCl-MgCl ₂-H ₂The work of O.Leaching can be 2 stages, and wherein ore at first leaches and makes Ni and Co enter solution, controlled then to make Fe do not entered subordinate phase.The another one advantage that hydrolysis Fe is claimed from bittern is that the low water activity in the aqueous salt brine tends to strengthen dehydration reaction.In theory, rhombohedral iron ore can at room temperature form, and (all-fulfate system) can also be autoclave, requires to operate under very high temperature.Reclaim after the precious metals, to keep water balance, the magnesium chloride bittern that obtains is recovered in the leaching process with solution evaporation.The steam of getting rid of is carried out thermal hydrolysis (seeing the reaction of Fig. 7) generate magnesium oxide (partially recycled) and HCl gas as inner neutralizing agent.Condensation HCl and it is recycled in the normal pressure leaching container then.

Be used to leach the bittern leaching system of laterite and at first proposed by Rice and Strong (1974) via the cardinal principle of the acid regeneration of thermal hydrolysis magnesium chloride, it proposes to use solvent extraction to remove FeCl from system ₃, form the hydrochloric acid of the stable rhombohedral iron ore and the equivalent of regenerating then by the spray roasting step.Jaguar technology is introduced and is said to be the method processing iron contamination that has more economic benefit.It is at high environment salinity (MgCI ₂Solution) operate under the condition, impel iron hydrolysis under the acidity of control, service temperature 80-105 ℃.But, before recognizing thermal hydrolysis or among from spissated magnesium chloride solution the water of evaporating surplus wasted big energy, rather than after the regeneration reagent, the difficulty on the Jaguar process economics also shows especially out.The Mg grade of leaching material is high more, and the water that is used for thermal hydrolysis on absolute value is many more, promptly handles the consumption (see figure 8) of every kilogram of ore.Final result is along with Mg feed grade improves, and it is not enough that the efficient of Jaguar technology on water balance becomes very soon; So, needs are added unnecessary water to the loop, when making the higher Mg of absorption to solution, be evaporated once more when it awaits thermal hydrolysis.Be similar to Jaguar technology, " recovering effect " in the water balance that causes by the Mg grade, although degree is low (in the case, avoid vitriol in the loop other part premature crystallization), and except the water that " additionally " adds can be handled multiple-effect evaporator/crystallizer relatively effectively, and the crystal water that Mg-vitriol is only arranged can influence (costliness) elevated temperature heat decomposition step, should " recovering effect " also may be present in the Skye technology.The hydrated state of the Mg-vitriol that produces is low more, and Mg feed grade is to the more little (see figure 8) of water influence of evaporation in the load high temperature reagent regeneration step.The steep more (see figure 8) of line, it is more little with the ability that is buffered in the water evaporation cost in the high temperature reagent regenerative process additionally to reclaim Ni (in the processing from the higher level saprolitic ores).

Very poor and the complicated (Steinbach﹠amp of the recovery of heat of thermal hydrolysis reactor; Baerhold, 2002 andAdham and Lee, 2002).Because hydrochloric acid is easy to be condensate in the waste heat boiler, therefore require exotic materials when energy exchange.Alternatively, if at first remove the step of hydrochloric acid, will lose the recovery calorific value.Another important factor is can not thermal hydrolysis such as impurity such as calcium chloride and sodium-chlor, and corresponding equivalent muriate is had to replace with expensive additional hydrochloric acid or magnesium chloride.The total efficiency of anticipation heat hydrolysis reaction will be significantly smaller than 100%.

Feature: use the closed circuit technology of thermal hydrolysis, with reference to Jaguar technology:

-thermal hydrolysis (～500 ℃) under low relatively temperature is feasible, but recovery of heat is complicated (a high fund expenditure) and relatively poor relatively;

-when handling the laterite ore of high Mg content, promptly mainly be that Jaguar technology is uneconomical when handling the technology of limonite ore;

-can not thermal hydrolysis such as impurity such as Ca and Na, equivalent muriate is had to replace with expensive additional hydrochloric acid or chlorination magnesium salts.

Jaguar technology can not absorb a large amount of Mg make its can not with the Sulfates normal pressure technology competition of wide spectrum such as for example Skye technology.Proposed chloride-based technology (Moyes et al, 2005) recently, attempted to avoid thermal hydrolysis, that is, and by make regeneration hydrochloric acid (seeing the chemical reaction among Fig. 9) with sulfuric acid precipitation vitriol.Its principle behind is round using cheap sulfuric acid to carry out precipitated crystal that chemistry orders about with the expensive hydrochloric acid of regenerating, rather than utilizes thermal hydrolysis.Intec technology is passed through CaCl ₂/ SO ₄Circulation is operated.

Except only exhaust vapour being carried out except that Fe and Ni/Co reclaimer operation with lime, this technology is similar to the logic of Jaguar technology.Mg with lime precipitation gained solution forms magnesium oxide (MgO) then.All these three unit operations mainly are to have replaced the positively charged ion muriate with the calcium chloride of equivalent.Then by adding the hydrochloric acid of the wastage in bulk or weight of regeneration of sulfuric acid in this loop, make calcium sulfate precipitation (low solubility).The hydrochloric acid that generates loops back the normal pressure leaching.Conversely can be by the thermolysis black sulfuric acid and the lime of calcium sulfate.But the simple thermodynamic model of this pyrolysis (utilizing HSC Chemistry) shows some complicacy (see figure 10)s.

Though the regeneration principle of sulfuric acid and lime seems feasible, vitriol needs elevated temperature heat to decompose, and promptly requires the high-energy input.This causes forming very fire-resistant and non-response type lime.In addition, in thermal decomposition process, generate the intermediate solid phase, make this technology complicated more.

Feature: the closed circuit technology (with reference to the Intec Process) of using Ca sulfate precipitation (by adding regeneration of sulfuric acid hydrochloric acid)

-claim the calcined lime (CaSO that formation adapts in this technology ₄- ¹/ ₂H ₂O) and magnesium oxide (MgO) byproduct.But problem always is to have on the purity of product of these byproducts;

-thermolysis black sulfuric acid and lime economically by calcium sulfate.Pyrolysis is undertaken by the intermediate product of complexity, and lime product may be a fireproof, and technology can require the high-energy input;

The Mg content of-feed ore is high more, just needs many more sulfuric acid and lime to replenish, and makes that therefore the technology of handling saprolite is uneconomical.

Therefore the applicant determines to need more effective more economical leaching technology to reclaim precious metals.Particularly, the applicant determine to need a kind of the generation or the method for regenerant salt strength of acid in chloride brine water extraction solution, need not to need to evaporate as thermal hydrolysis a large amount of water.All additional reagent all require relatively inexpensive, and choose the most of required additional reagent of regeneration in this technology wantonly.

Summary of the invention

According to first embodiment of the present invention, provide a kind of and be used for from the technology of the described precious metals of ore leaching that contains precious metals, this technology may further comprise the steps:

Make at leaching ore in the presence of the hydrochloric acid and in leaching solution, to form the soluble metal muriate;

Add sulfuric acid to leaching solution;

From leaching solution, reclaim metal sulfate; And

The hydrochloric acid of regenerating simultaneously.

Metal sulfate can have chemical formula: MeSO ₄.yH ₂O, wherein:

Me is a metal,

Y be 0 or more than, for example 0-3, more preferably 0-1.

The source metal of metal sulfate is mainly from ore.

Ore can mainly be metallic ore oxidation or siliceous, for example zinc oxide ore.

Ore can be a laterite-type nickel ore, for example saprolite or limonite.

Alternatively, ore can be sulfide, titanium or aluminum ore.

Metal sulfate can be separated out from leaching solution, or reclaims from leaching solution by evaporative crystallization.

Precious metals can be selected from by Zn, Cu, Ti, Al, Cr, Ni, Co, Mn, Fe, Pb, Na, K, Ca, the group that platinum metals and gold are formed.

Metal in metal sulfate can be a precious metals, and this technology can also comprise that decomposing metal sulphate reclaims the step of precious metals.

Alternatively, the metal in metal sulfate can be the low metal of its value ratio precious metals, for example magnesium.

Can handle metal sulfate to discharge sulfurous gas, sulphur trioxide or its mixture.

The metal-salt that can reclaim individually by adding sulfuric acid formation obtains precious metals.

The hydrochloric acid that reclaims can be super azeotropic acid.

Metal chloride solutions can be an alkali metal salt soln, and/or similarly, solution of metal sulfates can be the alkali metal sulphuric acid salts solution.

Regenerated hydrochloric acid can circulate in leaching technology.The hydrochloric acid that is used to leach ore can be the part of bittern, the saturated magnesium chloride solution of about 10-90% for example, the saturated liquor zinci chloridi of about 10-90%, or the saturated solution of other metal chlorides of about 10-90%.More specifically, aqueous salt brine can be the saturated magnesium chloride solution of about 25-40%, the saturated liquor zinci chloridi of about 25-40%, or the saturated solution of other metal chlorides of about 25-40%.Again more specifically, aqueous salt brine can be about 30% saturated magnesium chloride solution, about 30% saturated liquor zinci chloridi, or the saturated solution of other metal chlorides of about 30%.

Metal sulfate can be used to produce metal oxide.For example, can carry out thermolysis to metal sulfate and produce metal oxide and sulfurous gas, sulphur trioxide or its mixture.Metal oxide can be selected from magnesium oxide, zinc oxide, ferric oxide and aluminum oxide.Sulfurous gas, sulphur trioxide or its mixture can be used to produce sulfuric acid, and it can return leaching technology regeneration hydrochloric acid.

Can to the temperature between the boiling point of metal chloride leaching solution, from ore, leach precious metals in about room temperature.

Before forming metal sulfate, can from solution, optionally separate one or more precious metals, described metal is cobalt, nickel, platinum metals, gold and silver and/or copper for example.

The iron and/or other residual impurity that obtain from the ore dissolving can be passed through for example solvent extraction, thermal hydrolysis then; Or remove the solution from leaching by hydrolysis.

Sulfuric acid concentration is at least 30%, and for example about 98%.

According to second embodiment of the present invention, provide a kind of and be used for from the technology of the described precious metals of ore leaching that contains precious metals, this technology may further comprise the steps:

Make at leaching ore in the presence of the hydrochloric acid and in leaching solution, to form the soluble metal muriate;

Add sulfurous gas to leaching in the solution;

From ore recuperation metal sulfate or metal sulphite; And

The hydrochloric acid of regenerating simultaneously.

Metal sulfate or metal sulphite can have chemical formula: MeSO _x.yH ₂O, wherein:

Me is a metal,

X is 3 or 4; And

Y be 0 or more than, for example 0-3, more preferably 0-1.

The source metal of metal sulfate or metal sulphite mainly is an ore.

This technology may further include in leaching solution and adds the step that oxygenant is oxidized to ferrous ion iron ion.

Ore can mainly be metallic ore oxidation or siliceous, for example zinc oxide ore.

Ore can be a laterite-type nickel ore, for example saprolite or limonite.

Alternatively, ore can be sulfide, titanium or aluminum ore.

Metal sulfate or metal sulphite can be separated out from leaching solution, or reclaim from leaching solution by evaporative crystallization.

Precious metals can be selected from by Zn, Cu, Ti, Al, Cr, Ni, Co, Mn, Fe, Pb, Na, K, Ca, the group that platinum metals and gold are formed.

Can use the catalyzer accelerated reaction in this technology, appropriate catalyst is copper, graphite and the coal in the solution.

Metal in metal sulfate or metal sulphite can be a precious metals, and this technology can also comprise that decomposing metal sulphate or metal sulphite reclaim the step of precious metals.

Alternatively, the metal in metal sulfate or metal sulphite can be the low metal of its value ratio precious metals, for example magnesium.

Can handle metal sulfate or metal sulphite to discharge sulfurous gas, sulphur trioxide or its mixture.

The metal-salt that can reclaim individually by adding sulfurous gas formation obtains precious metals.

The hydrochloric acid that reclaims can be super azeotropic acid.

Before adding sulfurous gas, can from leaching liquid, remove magnesium, and with different metallic cations, for example calcium or plumbous replacement.Removing after the magnesium, can be intermediate sulphite or vitriol by the metal-salt that adds sulfurous gas formation.Intermediate sulphite or vitriol can be calcium sulfate, calcium sulfite, lead sulfate or plumbous sulfite.

Metal chloride solutions can be an alkali metal salt soln.

Metal sulfate or metal sulphite can be alkali metal sulfates or alkali metal sulfite.

Regenerated hydrochloric acid can circulate in leaching technology.

The hydrochloric acid that is used to leach ore can be the part of bittern, the saturated magnesium chloride solution of about 10-90% for example, the saturated liquor zinci chloridi of about 10-90%, or the saturated solution of other metal chlorides of about 10-90%.More specifically, aqueous salt brine can be the saturated magnesium chloride solution of about 25-40%, the saturated liquor zinci chloridi of about 25-40%, or the saturated solution of other metal chlorides of about 25-40%.Again more specifically, aqueous salt brine can be about 30% saturated magnesium chloride solution, about 30% saturated liquor zinci chloridi, or the saturated solution of other metal chlorides of about 30%.

Metal sulfate or metal sulphite can be used to produce metal oxide.For example, can carry out thermolysis generation metal oxide and sulfurous gas to metal sulfate or metal sulphite.Metal oxide can be selected from magnesium oxide, zinc oxide, ferric oxide and aluminum oxide.Sulfurous gas can be used to produce sulfuric acid, and sulfuric acid can return leaching technology regeneration hydrochloric acid.

Can carry out the thermolysis generation such as metal oxide and sulfurous gas, sulphur trioxide or its mixtures such as calcium oxide to intermediate vitriol or sulphite.Sulfurous gas, sulphur trioxide or its mixture can be used further to saltout vitriol or sulphite from leaching solution, and regeneration hydrochloric acid.

Can to the temperature between the boiling point of metal chloride leaching solution, from ore, leach precious metals in about room temperature.

Before forming metal sulfate or metal sulphite, can from solution, optionally separate one or more metals, described metal for example is cobalt, nickel, platinum metals, gold and silver and/or copper.

The iron and/or other residual impurity that obtain from the ore dissolving can be passed through for example solvent extraction, thermal hydrolysis then; Or partly or entirely remove the solution from leaching by hydrolysis.

Sulfuric acid concentration is at least 30%, and for example about 98%.

Description of drawings

Fig. 1: carry out the principle flow chart that saprolite is handled by melt route

Fig. 2: carry out the principle flow chart that main limonite is handled by Caron technology

Fig. 3: carry out the principle flow chart that limonite (and montmorillonite) is handled by HPAL technology

Fig. 4: the energy of HPAL technology and reagent Opex analyze

Fig. 5: normal pressure leaching (ALP) and HPAL-ALP (EPAL) method

Fig. 6: Sural/Skye principle: sal epsom crystallization and the regeneration of elementary reagent

Fig. 7: Jaguar technological principle: carry out elementary reagent regeneration by the magnesium chloride thermal hydrolysis

Fig. 8: compare (hypothesis) water evaporation load (load) between magnesium chloride solution thermal hydrolysis and crystallization sal epsom thermal synthesis (thermal composition)

Fig. 9: Intec technological principle: carry out elementary reagent regeneration by calcium sulfate precipitation

Figure 10: the calcium sulfate thermolysis, with reference to HSC phemistry model;

Figure 11: technological principle of the present invention: by sal epsom precipitation and thermolysis regeneration reagent

Figure 12: the sal epsom solubleness (with reference to AspenPlusmodel) that changes along with the change of content of magnesium chloride

Figure 13: the hydrogen ion activity of 0.5mol/kg HCl solution and the function of density of magnesium chloride and temperature

Figure 14: respectively at 0-1mol/kg HCl and 2.5mol/kg MgCl ₂, and 0-0.5mol/kgH ₂SO ₄With 2.5mol/kg MgSO ₄In the hydrogen ion volumetric molar concentration and the function of temperature

Figure 15: the thermolysis of sal epsom, with reference to HSC chemistry model

Figure 16: under differing temps from bittern sedimentary magnesium sulfate crystals

Figure 17: (base case) schema on the principle of technology of the present invention

Figure 18: the schema 1 of technology of the present invention

Figure 19: the schema 2 of technology of the present invention

Figure 20: test the nickel extract that obtains by saprolite

Figure 21: test the cobalt extract that obtains by saprolite

Figure 22: the extraction sectional view of all metals in the saprolite of high bittern test

Figure 23: test the nickel extract that obtains by limonite

Figure 24: test the cobalt extract that obtains by limonite

Figure 25: the extraction sectional view of all metals in the limonite of high bittern test

Figure 26: test the nickel extract that obtains by siliceous limonite

Figure 27: test the cobalt extract that obtains by siliceous limonite

Figure 28: the extraction sectional view of all metals in the siliceous limonite of high bittern test

Figure 29: MgCl ₂Influence to the nickel extraction

Figure 30: the typical crystalline SEM photo of formation

Figure 31: be inserted with the reactor of the syringe that is used to add reagent, it is with the oil heating

Figure 32: sulfide ore technology

Figure 33: muriate in comprehensive sulfide ore technology and vitriol flow circuits

Figure 34: small-sized non-oxide normal pressure leaching device

Figure 35: the leaching kinetics under the non-oxide leaching condition in HCl under 90 ℃ (+38-75 μ m)

Figure 36: the X-ray powder diffraction analysis of crystalline product

Preferred forms of the present invention

Technology of the present invention is introduced the use that a kind of new method is optimized reagent and energy.Elementary reagent, i.e. HCl can regenerate and the back leaching solution or replenish new reagent of need not to neutralize before crystallization.This method is more effective in high aqueous salt brine, and it has additional advantage: 1) make the crystalline product dehydration, promptly reduce heat and form required energy (reagent regeneration); 2) stable Fe hydrolysate (for example rhombohedral iron ore) is dewatered at normal temperatures; 3) owing to high proton activity has quick leaching kinetics; With 4) leach and reclaim important by product (for example Pb, Ag).

According to the present invention, a kind of being used for from the technology of one or more precious metals of solution leaching that contain hydrochloric acid has been described, wherein precious metals reclaims as solid sulfate salt or sulphite, recovers the hydrochloric acid in the solution simultaneously.

Leach precious metals from metallic material, it can be sulfide or unsulfided material.For example, material can be the base metal ore of oxidation, for example zinc oxide ore; Laterite-type nickel ore, for example saprolite or limonite; Sulfide ore, titanium ore or aluminum ore.Before forming solid sulfate salt or sulphite, precious metals at first forms the soluble metal muriate.

Precious metals generally is selected from by Zn, Cu, Ti, Al, Cr, Ni, Co, Mn, Fe, Pb, Na, K, Ca, the group that platinum metals and gold are formed.

The metal chloride salts solution can be an alkali metal salt soln, and/or similarly, solution of metal sulfates can be the alkali metal sulphuric acid salts solution.

Add sulfuric acid (general concentration is at least 30%, for example about 98%) or sulfurous gas to form solid metal vitriol or metal sulphite to the solution of the precious metals that contains leaching, metal sulfate or metal sulphite are recovered subsequently.Like this, with the more expensive reagent (hydrochloric acid) of relatively inexpensive reagent (sulfuric acid or sulfurous gas) regeneration, provide cost savings significantly.

Solid metal vitriol or metal sulphite generally have following chemical formula:

MeSO _x.yH ₂O，

Wherein Me is a metal,

X is 3 or 4; And

Y be 0 or more than, for example 0-3, more preferably 0-1.

The solution that contains hydrochloric acid is bittern (being chloride soln) normally, the saturated magnesium chloride solution of about 10-90% for example, the saturated liquor zinci chloridi of about 10-90%, or the saturated solution of other metal chlorides of about 10-90%.More specifically, aqueous salt brine can be the saturated magnesium chloride solution of about 25-40%, the saturated liquor zinci chloridi of about 25-40%, or the saturated solution of other metal chlorides of about 25-40%.More specifically, aqueous salt brine can be about 30% saturated magnesium chloride bittern, about 30% saturated zinc chloride bittern, or other metals or alkali metal chloride.Metal in the bittern or alkali metal chloride generally based on be present in leaching in the feed sour depleting substance and select, and usually its concentration is made selecting and makes the dissolubility difference of its muriate and vitriol bigger.

Form muriatic cationic metal and be preferably selected from the sour positively charged ion of waiting to leach in the ore of main consumption, described muriate forms the main component of bittern (leaching medium).

Selecting the concentration of metal chloride generally is for following purpose:

Leaching technology is done positive influence, for example, described in the Jaguar technology;

Metal is leached from ore and surpass the solubleness (alternatively, add entry prevent muriate run off to solid phase) of metal chloride under the leaching condition;

Make corresponding vitriol or sulphite be easy to precipitation---promptly, concentration of metal-be greater than the surely solubleness of vitriol or sulphite;

Influence the hydrated state of sedimentary vitriol or sulphite, therefore make may produce than obtain from neutral sulfatase or sulphite the low hydrated state of hydrated state; And

Be no more than the solubility limit in other cell process.Different cell process may require different service temperature (alternatively, can add water make be no more than solubility limit) in concrete cell process.

Select the starting point concentration of hydrochloric acid, make that a high proportion of precious metals of leaching is realized the demand that acid consumes simultaneously from ore.The pH that finds final leaching is 0.5 or lowlyer causes the extraction of precious metals to reach greater than 80%.But this is for particular ore, it should be appreciated by those skilled in the art that in the other materials beyond here testing to be issued to satisfied leaching effect in higher final pH value.

General sulfuric acid that in solution, adds capacity or sulfurous gas make with its vitriol or sulphite precipitation in the hydrochloric acid strength ratio that obtains, regenerated hydrochloric acid intensity is greater than azeotrope, and this salt strength of acid is measured by metal or alkali metal chloride solubleness.Aqueous salt brine has the background concentration of metal chloride, adds extra intensity to it in leaching process.Preferably adding sulfuric acid or sulfurous gas in solution can be significantly above making the strength of acid of bittern return to the required amount of initial value.In other words, background metal chloride concentration should not removed in the crystallization of corresponding vitriol or sulphite.Alternatively, when the muriate in the untreated part remained on background concentration, leaching liquid can break into portions, wherein had only portion to carry out vitriol or sulphite precipitation, in the case, can precipitate in the solubleness allowed band.

This technology comprises that also crystallisation step has the metal sulfate or the metal sulphite crystal of low combination water with generation.Alternatively, evaporative crystallization (therein or just over the needs of normal water balance) can be used to relax the load of above-mentioned chemicrystallization.Because background bittern makes this optional scheme feasible to the synergistic effect of salt precipitation threshold when water evaporates.And then, general general when carrying out crystallization at a lower temperature, the Ni co-precipitation takes place in the crystalline structure of magnesium salts.When carrying out chemicrystallization near the atmospheric boiling point of solution, the tendency of Ni cocrystallization reduces substantially.These salt can sell, and also can carry out thermolysis and produce the metal oxide that can sell and sulfurous gas, sulphur trioxide and composition thereof, and/or it can dissolving again in sulfate medium, carries out the electrowinning step then.

Before forming metal sulfate or sulphite, can from solution, optionally separate one or more precious metals, for example cobalt, nickel, platinum metals, gold and silver and/or copper.

The iron and/or other residual impurity that obtain from the ore dissolving can be passed through for example solvent extraction, thermal hydrolysis then; Or remove the solution from leaching by hydrolysis.

Metal in metal sulfate or sulphite can be a precious metals, and in the case, the step that this technology generally comprises decomposing metal sulphate reclaims precious metals.

Alternatively, the metal in metal sulfate or sulphite can be the low metal of its value ratio precious metals, and for example magnesium can reclaim the metal-salt that forms by adding sulfuric acid individually and obtain precious metals.

Can handle metal sulfate or sulphite and discharge sulfurous gas.

If the solubleness of metal sulfate or sulphite is much smaller than the corresponding chlorinated thing, this technology needn't the limit temperature scope.Yet, generally to the temperature between the boiling point of solution, leach, and generally under the temperature of dissolubility difference maximum, carry out the crystallization of vitriol or sulphite in room temperature.

Before adding sulfurous gas, can randomly from leaching liquid, remove magnesium, and replace, for example calcium, lead or barium with different metallic cations.Removing after the magnesium, is intermediate sulphite or vitriol by the metal-salt that adds sulfurous gas formation, for example is calcium sulfate, calcium sulfite, lead sulfate, plumbous sulfite, barium sulfate or barium sulfite.Can carry out the thermolysis generation such as metal oxide and sulfurous gas such as calcium oxide to intermediate vitriol or sulphite.Sulfurous gas can be used for once more from leaching solution saltout vitriol or sulphite, and regeneration hydrochloric acid.

The special aspect of described technology is:

Regenerant salt strength of acid in base metal muriate bittern;

The leaching technology that carries out in chloride media is kept by adding sulfur dioxide gas or sulfuric acid;

Form with suitable salt hydrate from muriate bittern reclaims such as metals such as zinc or magnesium, it can thermolysis, dissolving again in sulfate medium, and directly from solution or solid with vitriol or sulphite form electrowinning, or after thermolysis forms oxide compound, carry out.

The present invention further describes in detail by several embodiment.But such embodiment can not be used for limiting the spirit and scope of the present invention.

Non-sulfide ores

First embodiment of the present invention provide a kind of in elementary hydrochloric acid medium from such as laterite, the non-sulfide ores leaching magnesium of limonite oxide compound and/or siliceous saprolite and the technology of at least some valuable nickel and cobalt.Main leaching agent is the oxonium ion under the muriate background, as intrinsic contaminants magnesium chloride background particularly.

To use nickel laterite to describe the processing of unsulfided material in detail as the unsulfided examples of material below.It should be apparent to those skilled in the art that also can be with same art breading other unsulfided material, for example zinc silicate, bauxite etc.The example of laterite also is the example of a precious metals rather than the metal that uses in muriate bittern intensity regeneration step.Figure 17 shows the principle flow chart of this technology.

As mentioned above, the regeneration of hydrochloric acid and the recovery of magnesium with remove by evaporation more than water irrelevant because magnesium at first reclaims rather than directly obtains (as the situation in Jaguar technology) by precipitation from electrolysis of magnesium chloride solution.But as optional scheme, evaporative crystallization (therein or just over the needs of normal water balance) can be used to relax the load of above-mentioned chemicrystallization.Because background bittern makes this optional scheme become feasible to the synergistic effect of salt precipitation threshold when water evaporates.

Recover the strength of acid of used magnesium chloride bittern by adding sulfuric acid or sulfur dioxide gas, the sal epsom or the magnesium sulfite of the low hydrated state of precipitation generate hydrochloric acid simultaneously in solution thus.

In the leaching step of back, handle the laterite leach residue, make the extraction maximization of nickel and cobalt.

For vitriol, the experimental data of Linke and Seidell (1965) shows, kieserite (monohydrate acid magnesium) is the preferred crystalline product of under comparatively high temps (～100 ℃), and it will calcine formation magnesium oxide (its part can be used as the neutralizing agent of recovery) and the required energy of sulfurous gas further reduces.The reaction of this simplification can be write as:

MgCl ₂+H ₂SO ₄-＞MgSO ₄.H ₂O+HCl (3)

Magnesium chloride sulfuric acid kieserite hydrochloric acid

Or directly pass through SO ₂

This method produces the total chloride amount less than 0.01% crystalline product.When carrying out above-mentioned reaction when being pressed in comparatively high temps (or by add), find that the co-precipitation of Ni in the crystalline structure of kieserite can reduce to minimum near the atmospheric boiling point of solution.Therefore observe and use this technology, may generate that high purity is used to sell and/or as the magnesium oxide of neutralizing agent.Alternatively, if the nickel loss is unacceptable, can before the chemical process crystallization, remove nickel, for example ion-exchange of described chemical process, solvent extraction, gluing, precipitation etc.In addition, use relatively cheap and available reagent, as sulfuric acid or the relatively costly hydrochloric acid of sulfurous gas regeneration.

Positive iron in the bittern system-ferrous in the direct use of sulfurous gas precipitated sulfur hydrochlorate or sulphite, playing an important role.Do not have positive iron ion to exist, the ability of solution absorption sulfurous gas is very low in the solution that high bittern background is arranged, and therefore can not effectively absorb in system.But, because the reduction reaction of positive iron ion to ferrous ion can take place, exist positive iron ion make can be directly with gas absorption in solution.Finish reaction by the variation in the solution, cause preferentially salting out sal epsom or magnesium sulfite.

Figure 11 has illustrated the present invention's technology described herein, this technology around utilize sal epsom in the solution of magnesium chloride background with raising than low solubility.Adding sulfuric acid makes sulfate precipitation while reprocessing cycle return the hydrochloric acid of normal pressure leaching step to leaching mother liquor (PLS).Figure 12 represents the prediction sal epsom done with the variation of the increase of muriate background with the commercially available process simulation software that is called AspenPlus.

Sedimentary sal epsom thermolysis forms magnesium oxide (inner as neutralizing agent) and sulfur dioxide gas.Sulfur dioxide gas changes into sulfuric acid and loops back the sulfate precipitation step that chemistry drives in the acid plant.

Except the motion of temperature and water, bittern concentration is very important variable in whole flow process.On the contrary, only there is the motion of temperature and water to have degree of freedom such as Sulfates technologies such as Skye technologies.This makes that needing to add relatively large water avoids crystallization unnecessary in the loop, and must remove big water gaging (ore that every kg is processed) to reach the evaporative crystallization of desirable level." recovery " effect of this water is important further along with other raising of Mg feed level of ore.On the contrary, chemicrystallization step rather than evaporation technology are used in present invention, therefore the relation of the Mg content of water balance and feed ore are taken off and collude.And because the high bittern background in present technology is considered the water balance problem, being strict with has synergistic effect when water evaporates, and make has more sal epsom precipitation always.Compensate the poor efficiency in chemical precipitation (because unnecessary solubility behavior) thus, do not significantly improve the energy requirement of (surpassing the normal water balance) steam supply.Therefore, with pure, closed circuit, Sulfates technology, for example Skye technology is compared, and blended muriate-vitriol dielectrics systems has higher technological flexibility.

This technology is suppressed at vitriol solubleness in the loop by keep the perchloride background in the loop.Simultaneously, the perchloride background is guaranteed high proton activity and low water activity.Figure 13 is the diagram of block of the function representation proton activity of temperature and density of magnesium chloride.

This model is in order to be characterized in HCl-MgCl ₂-H ₂H in the O dielectrics systems ⁺Single ion(ic)activity and make especially.How Figure 13 explanation is adding such as MgCl ₂Improve H etc. background salt ⁺Single ion(ic)activity (this is an important parameters, though it is not a unique parameter, it can measure the quick degree that laterite is emitted Ni of destroying).At 65 ℃, among the 1M HCl, 10 times have been increased.Unfortunately, along with increasing effect, temperature significantly reduces.Therefore two kinds of reverse effects are arranged: people wish to leach at low temperatures to obtain high H ⁺Activity, but on the other hand, people wish that leaching is to overcome the energy barrier in solid-liquid interface under comparatively high temps.However, when leaching is carried out under 85 ℃, can obtain at pure HCl-H ₂The H of O system twice ⁺Activity, this is a particularly important, because can not realize the proton activity that this is identical in the all-fulfate system.

Figure 14 represents the comparison of two kinds of systems, and illustrates that clearly hydrochloric acid-magnesium chloride dielectric medium has obviously higher proton concentration than the sulfuric acid-sal epsom system of equivalent concentration.The major cause of this phenomenon is the difference of dielectric medium intermediate ion kind: H ⁺-Cl ^-A little less than, H ⁺-SO ₄ ^2-Strong and " capturing " a large amount of protons formation bisulfate ion complex compound of key, HSO ₄ ^-A little less than the tendency of formation hydrogen sulfate ion makes sulfuric acid relatively, particularly under the situation under higher magnesium sulfate concentration and the comparatively high temps.

Technology of the present invention is specially adapted to handle for example impurity such as Na and Ca, with all-chloride class technology, for example Jaguar technology difference.Ought to have enough vitriol to form the Na-jarosite in technology of the present invention, it is with the muriate of following its equivalent of regeneration:

6FeCl _3(aq)+4MgSO _4(aq)+2NaCl _(aq)+12H ₂O→Na ₂Fe ₆(SO ₄) ₄(OH) _12(s)+4MgCl _2(aq)+12HCl _(aq)(4)

In fact, preferably having enough vitriol can carry out above-mentioned reaction replace muriatic total losses from the loop.If desired, can add small amount of sodium chloride to the loop guarantees to have enough Na to be recycled to the step of removing Fe.When adding sulfuric acid in the chemicrystallization step, the calcium chloride in solution should precipitate and form insoluble calcium sulfate.Though calcium sulfate does not decompose with sal epsom, the elemental sulfur by the equivalent of burning can remedy its difference.Therefore, except the impurity in the treatment process loop effectively, can for example be respectively the loss that sodium-chlor and elemental sulfur remedy muriate and vitriol by adding cheap reagent.For other impurity, because competent SO is arranged ₂, therefore can be easy to handle Mn (SO ₂/ O ₂Oxidation forms MnO ₂), and need not to discharge.Consider that from environment and economic angle it is very important not having solution to discharge from the loop.

About the calcining of sedimentary magnesium products, analytical product is desirably every mole of magnesium in fluidized-bed reactor (900-1200 ℃) needs the 1.5-4 mole of water.This practice is at United States Patent (USP) 4,096, and 235 is open, quotes its full content in this.Precipitated product by crystallization control and being easy to the duration of contact of the aqueous solution makes monohydrate (produce optimize be used for pyrolysated hydrate) part rehydrated.The technology of the sulfurous gas black sulfuric acid that produces at calcining vitriol/sulphite is continued to use for a long time, and if very economical really, the method for sulfuric acid recirculation can be provided.

Use sal epsom/magnesium sulfite to carry out thermolysis and obtain magnesian main advantage and be to dewater, only be combination water promptly, thereby only relate to little energy (comparing) with the magnesium chloride solution heat hydrolysis of advising in the Jaguar technology.In this method, can produce very many magnesium oxide products with commercial value.

The thermolysis of sal epsom is simple relatively.HSC chemical model when Figure 15 is illustrated in carbon as the reductive agent thermolysis.Even under 800 ℃, kinetics of thermal decomposition should be very fast, because sedimentary sal epsom very tiny (＜10 μ m).Figure 16 explanation precipitates down at low temperature (65 ℃) and generates needle-like hexahydrate and very thin monohydrate particulate mixture.Under comparatively high temps (110 ℃), only form monohydrate, kieserite (MgSO from the bittern precipitation ₄-H ₂O).Therefore, the expectation of pyrolysated energy is lower than Skye technology, and this technology has two crystal water at least in sedimentary salt.Any magnesium chloride that adheres to fine particle should carry out thermal hydrolysis and form recuperable HCl gas.Experiment finds that the general composition of sedimentary vitriol is 17.1%Mg,＜0.05%Fe, 0.1%Ni,＜0.05%Co, the vitriol of 2%Cl and surplus and water.The Ni content of sedimentary salt is the function of temperature, and content reduces and increases along with Tc.

Can use cheap potentially fuel source, for example heavy oil (HFO) and particularly inferior grade matchmaker.Any sulphur in the coal can oxidation form SO ₂Thereby, reduce the needs that whole elemental sulfur replenishes.

As mentioned above, the major advantage of operating in the muriate system is bittern and dehydration solid phase equilibrated proneness.Except forming kieserite (monohydrate) or anhydrous salt when the crystallization, form rhombohedral iron ore in the time of can also under condition of normal pressure, carrying out the Fe hydrolysis.Not only from environment viewpoint selective hydrolysis product, and compare and improved precipitation and filtering property with more glue or hydrate precipitate in the all-fulfate system.Also form the low solid phase cake of humidity, therefore the valuable loss in the loop is reduced to minimum.

Another important factor is the tendency of coabsorption Ni and Co in the crystalline structure of ironic hydroxide and pyrrhosiderite, (only finds at occurring in nature) that wherein the tendency of these materials of rhombohedral iron ore coabsorption is very low.Can add the rhombohedral iron ore crystal seed by control supersaturation precipitation and when the Fe hydrolysis and from bittern preferential precipitation rhombohedral iron ore (seeing Riveros and Dutrizac, 1997).

Figure 17 represents the principle flow chart of the basic case of technology of the present invention.Circulation in non-pressure vessel makes hydrochloric acid will maximize the residence time to react and the neutralization in loop to be needed (the internal recycle load of the Mg that every milling of ores needs) minimize.Only and exhaust vapour with hydrolysis Fe, reclaim Ni and Co by precipitation of hydroxide then.After neutralization is that an independent evaporation step is to keep water balance.The equivalent hydrochloric acid that chemicrystallization step regeneration in the shunting of major cycle consumes and loses from the loop.Calcine sedimentary vitriol and produce SO ₂Gas and magnesium oxide.SO ₂Gas changes into sulfuric acid and is recycled in the crystallizer in the acid plant, simultaneously a part of magnesium oxide circulation is to satisfy inner neutral needs.Unnecessary magnesium oxide can be sold.

An important aspect of technology of the present invention is its Mg content relative insensitivity for the feed ore.From Fig. 8, directly can obtain.If generate a hydration cake, seldom with the not evaporation (thermolysis of sal epsom) relevant with regeneration step.This makes can handle high-grade saprolitic ores, and this operation has very high value owing to its high Ni metal value on the absolute value of processing cost.Below listed the explanation can satisfy all target capabilities standards in theory.

The target capabilities standard

Compare the financial need √ of reduction with melting with HPAL;

-do not need metallurgical unit operation of High Pressure Wet and warm pyrometallurgy unit operation in the requirement only;

Though-chloride media needs special etch-proof processing, all unit operations are to carry out under the pressure of occurring in nature;

The ability of comparing reduction with melting needs √;

If-in system, add reductive agent, can be lower than the thermolysis of carrying out anhydrous/low Magnesium sulfate heptahydrate under 800 ℃;

-will provide from the wasted energy value that the elevated temperature heat decomposition step obtains to adding of all hydrometallurgy loops by the waste heat boiler system and to pine for;

-can directly in the thermolysis stoving oven, burn as reductive agent and fuel with the inferior grade coal that contains sulphur;

The reagent of comparing reduction with HPAL needs √;

The thermolysis of-sal epsom makes vitriol (passing through the acid plant) regenerate and generates neutralizing agent (magnesium oxide);

-the needs that replenish sulphur are limited to the normal loss in closed circuit, and can be replenished by extra (cheapness) sulphur of burning;

-replenish muriatic needs and be limited to normal loss in closed circuit, and can be by cheap muriate NaCl for example, must be to replenishing;

-can solve (being respectively yellow modumite and calcium sulfate) by removing vitriol such as impurity such as Na and Ca, promptly do not need exhaust vapour;

Compare the recovery √ of Ni and Co with HPAL;

-have high proton activity, therefore be the leaching system (with the ore reacting phase ratio under the normal pressure in the all-fulfate system) that enlivens;

-even to compare kinetics slower with HPAL, and it can remedy by bigger normal pressure leaching amount, and promptly the residence time is relatively inexpensive;

Liquid-solid separation and residue stability √;

There is sedimentary Fe hydrolysate down in-muriate, shows precipitation and filtering feature preferably;

Environment √;

-can under the condition of normal pressure/pressurization a little, in the muriate system, form the Fe hydrolysate of dehydration, for example rhombohedral iron ore (ambient stable);

-thermolysis sal epsom is to satisfy the inner acid and the needs of neutralizing agent;

-closed circuit, promptly do not discharge refuse to environment;

From the ore object of widening, increase Ni income √;

-can associated treatment limonite and saprolitic ores for insensitive make of the Mg content of feed ore, obtain bigger relevant Ni income.

Figure 18 and Figure 19 show two principle flow charts that obtain by mass/energy balance.Schema 1 (Figure 18) is the base case flow process.Used bittern background of the present invention to suppress sal epsom solubleness.Load with the evaporative crystallization alleviation chemical precipitation step that is no more than normal water balance needs promptly replenishes because the formation of hydrosulfate causes the poor efficiency of chemicrystallization step.Schema 1 (Figure 18) makes variation and the needs of water evaporation of Mg in the feed ore take off and collude effectively.Figure 19 represents an optional schema, supposes owing to form hydrosulfate chemicrystallization to be carried out under high acid environment.The worst situation of this expression reagent regenerated.

1. mineral response test

Use mineral response test working routine test laterite sample.Selected 3 mineral samplers to make the effect of the high bittern background of further testing research and sulfurous gas.Under high solid concentration (30%), test, and add acid (sulfuric acid=2018kg/t, hydrochloric acid=1500kg/t; Two all promising 41.2kg H ⁺/ t).

Selection is from Jacar é saprolite, the iron-stone of Brazil and contain silicon ore and test.The grade of sample is as shown in table 1.

Table 1: the grade of specimen in use

Sample

Ni

Co

Fe

Mg

Al

Si

Cr

Mn

Jacar é saprolite

1.60％

0.07％

12.81％

17.43％

0.61％

17.06％

0.72％

0.24％

Jacar é contains iron ore

1.14％

0.17％

42.23％

0.63％

1.25％

10.00％

2.38％

0.85％

The siliceous ore deposit of Jacare

1.25％

0.22％

22.42％

2.35％

2.30％

20.92％

1.09％

0.92％

Each sample is carried out following one group of test:

1. hydrochloric acid leaching (1500kg/t)

2. sulfuric acid to leach (2018kg/t)

3. high bittern hydrochloric acid leaching (1500kg/t HCl; 2m MgCl ₂)

4. be with SO ₂High bittern hydrochloric acid leaching (1500kg/t HCl; 2m MgCl ₂20kg/t SO ₂)

In 21 glass reactors that have thermostatic control oil bath circulation oil jacket, test.All tests are carried out under 85 ℃, are begun by the 300g ore, make it break into 30% water slurry (solid/solid+water).Utilization is coated with the impeller of steel and the polypropylene baffle plate of insertion makes this slurries suspendible.Addition of acid is divided into 10 equivalent, and was the adding at interval with 1 hour.End up at interval at each and to get 40mL slurry samples (doing the analysis of extracting metals).In initial slurries, add Magnesium dichloride hexahydrate, add Magnesium Chloride Anhydrous and acid simultaneously to maintain the magnesium chloride level in the high bittern test.When needing, by the adding of Bronkhorst mass flowmeter control sulfurous gas.

A. saprolite result

Figure 20 and Figure 21 represent nickel and the cobalt extraction that the saprolite test realizes respectively.Obviously the extraction of two metals is all higher in chloride media, no matter it is owing to chlorion causes causing than peracid activity or owing to form the hydrosulfate complex compound in sulfate medium.Compare with the pure hydrochloric acid leaching, the bittern background has improved nearly 10% to extraction.Add the extraction not influence of sulfurous gas, but can improve the extraction of cobalt Ni.

Figure 22 illustrates the extraction section of all metals in high bittern test.Under low sour condition from saprolite selective extraction nickel, be manganese then, be magnesium more then.Selectivity reduces along with the addition that increases acid, becomes up to adding of acid to increase to 26H ⁺Behind/the t, section does not have noticeable change.

B.Jacar é contains the iron ore result

Figure 23 to Figure 25 represents the result of limonite test respectively.Observe the tendency (with reference to the situation of saprolite) of similar nickel extraction.But the muriate background is more favourable to limonite, and extraction has bigger separating with sulfuric acid to make hydrochloric acid.Observe once more that the bittern background has 10% improvement to extraction but sulfurous gas does not have effect.Add sulfurous gas to the bittern background and obtain higher cobalt extraction.Figure 25 explanation obtains low selectivity under high bittern background.The extraction section in sour add-on greater than 26kgH ⁺There is not considerable change behind the/t.

The siliceous limonite of c.Jacar é

Figure 26 to Figure 28 represents the extraction section of nickel and cobalt.Its tendency is similar to iron-stone.

From the ore response test, can sum up as drawing a conclusion:

-sulfuric acid of bittern system is changed over hydrochloric acid can be observed the remarkable extraction that improves nickel.Similar result is also observed in extraction at cobalt.

-adding sulfurous gas is only favourable to extracting cobalt.

-to extract nickel from the siliceous ore deposit of Jacar é relevant with the extraction of iron, magnesium and manganese, identical in limonite, Magnesium Silicate q-agent and the manganous hydroxide ratio cardinal principle in mutually respectively with nickel.

-to extract cobalt in the siliceous ore deposit of Jacar é only relevant with the extraction of manganese, not corresponding at various distribution proportions in mutually with cobalt.

2. crystallization test

The information that does not have magnesium salts performance of solubleness in acid chloride-vitriol or muriate-vitriol aqueous systems.When determining operational condition and in the integral body of various unit operations, need this information.Main parameter is:

-temperature

-acid concentration

-chloride concentration and

-vitriol/sulfite concentration.

At first select better simply two-phase vitriol system, promptly do not have gas phase to exist.The initial soln of preparation has the magnesium chloride of constant and the magnesium sulfate concentration of variable.Adding sulfuric acid up to observing under the temperature of precipitation.The Mg of analysed preparation solution ²⁺, Cl ^-, SO ₄ ^2-And free acid, therefrom calculate the ion product of magnesium and sulfate radical, analyze solid Mg simultaneously ²⁺, Cl ^-And SO ₄ ^2-

Crystal property

Comprehensive schema limits to some extent to the operational condition of crystallizer and the solid characteristic that is produced.Following crystal property is very important and need to quantize:

-particle size distribution: aerial fluidisation needs narrow particle size distribution and enough big mean sizes.Alternatively, product will thermolysis in rotary kiln.

-crystal water: need alap hydrated state.

-liquid inclusion: the loss of mother liquor need keep minimum.

-filterableness: also should consider filterableness and improve by satisfying above-mentioned requirements.

Be recognized that the crystalline character that the laboratory produces in batches can not be represented the production-scale flow reactor of tool.

As shown in figure 30, the crystal produced in batches of laboratory generally very thin (particle of 10 μ m is easy to reunite).Chemical analysis shows that the mol ratio of magnesium/sulfate radical is near 1 (～17%Mg+～67%SO ₄) and chloride content less than 2%.Actual crystal among Figure 30 be by under 110 ℃ to 6 mol/kgMgCl ₂Solution adds vitriol oil formation.These crystal are too little can not do monocrystalline analysis (minimum 50 μ m crystal), but chemical analysis is kieserite (MgSO with its body of X-ray powder diffraction (XRD) analysis confirmation mutually ₄.H ₂O).

3. closed circulation test

The closed circulation test is used for estimating leaching and the knot intergranular interacts, and this is the procedure of processing of two keys of this technology.Neutralization procedure also is used for the iron in the Control Circulation solution and the generation of nickel.Each round-robin is made of in proper order leaching, the crystalline that neutralizes then, and each step is all used the solution of preceding step gained.With this order cycle criterion to reach steady state.

The solubleness of sal epsom in leaching is enough to hold any extra magnesium with difference under crystalline solubleness is compared and enters this system.Unique outlet of magnesium is in crystallisation process.The difference of solubleness is further strengthened by the temperature of different crystallization (110 ℃) and leaching (85 ℃).

To solid density is that the Jacar é saprolite of 10% (solid/solid+water) carries out the closed circulation test.

The extraction of Ni surpasses 90% and by continuous adding sulfuric acid and remove sal epsom by crystallisation step and keep the hydrochloric acid background.The solution of removing (discharge) after the crystallization partly is enough to maintain the concentration of Fe and Ni in the initial cycle.But after three circulations, when carrying out the short run experiment, isorrheic keeping challenged in the initial cycle.Suffice to show that first the three times results of circulation in (table 2) elementary reagent (hydrochloric acid) can keep by adding sulfuric acid precipitation sal epsom.

Table 2: closed circulation test result:

Circulation

Leaching

Crystallization

The Ni extraction

The Mg extraction

The Fe extraction

Add sulfuric acid

Crystal/sulfuric acid

1

?96.0％

95.7％

92.5％

1000kg/t

?1.15kg/kg

?0.72mol/mol

?2

?94.5％

93.2％

91.9％

1000kg/t

?1.51kg/kg

?0.99mol/mol

?3

?95.5％

94.7％

92.5％

1000kg/t

?1.50kg/kg

?0.99mol/mol

The ore saprolite:

Fe：15％

Ni：1.5％

Mg：18％

Leaching solid density: 10%

Be also noted that in the process of from exhaust vapour, removing Fe that neutralizes and form some magnesium sulfate crystals.With the cake of less water flushing final residue the time, these crystal are very fast to be dissolved and enters circulate soln.

Table 3 is illustrated in the solid that forms respectively in the final round-robin crystallisation step of 85 ℃ and 105 ℃ two closed circulation tests carrying out.Both all produce high magnesium salts, and the mol ratio of magnesium/sulfate radical is all near 1.XRD result's (seeing Figure 29) shows that sedimentary salt is only by kieserite (MgSO under comparatively high temps ₄.H ₂O) constitute.

Table 3: the solid that forms in crystallizer is formed

Mg

Fe

Ni

Cl

SO 4

H 2O *

Mg∶SO4

?Mg∶H 2?O

?85℃

16.5％

0.30％

0.22％

0.54％

64.4％

18.0％

1∶0.99

?1∶1.5

?110℃

16.4％

0.27％

0.08％

1.94％

67.0％

14.3％

1∶1.03

?1∶1.2

^*Unaccounted weight hypothesis is a water.

4. directly replace the vitriolic test with sulfurous gas

Below method how to describe directly with the sulfurous gas hydrochloric acid of in blended muriate/vitriol system, regenerating, use gained solution leaches precious metals from oxide compound or sulfide ore.

At first, in acid recovery step, need Fe ³⁺The iron of state is as the carrier/sorbent material of sulfur dioxide gas.When the leaching ore, the iron of body phase can be with Fe ³⁺State enters solution, for example when oxide compound ores such as leaching Ni limonite.If but the iron of body phase is with Fe ²⁺State enters solution, needs oxygenant (for example oxygen) at first with Fe ²⁺Be oxidized to Fe ³⁺

2FeCl ₂+2HCl+ ¹/ ₂O ₂-＞2FeCl ₃+H ₂O(5)

Be acid recovery step then, wherein the absorption of sulfurous gas is accompanied by sulfuric acid is discharged in the solution.

2FeCl ₃+SO _2(g)+2H ₂O→2FeCl ₂+H ₂SO ₄+2HCl(6)

In blended muriate/vitriol system, the equivalent hydrochloric acid that utilizes the difference regeneration of the solubleness of major metal muriate and vitriol in leaching, to consume.When leaching magnesium from laterite oxide compound ore, react as follows:

MgCl ₂+H ₂SO ₄+H ₂O-＞MgSO ₄.H ₂O _(s)↓+?2HCl(7)

Therefore the entire reaction in acid recovery step becomes:

2FeCl ₃+MgCl ₂+SO _2(g)+3H ₂O→2FeCl ₂+MgSO ₄.H ₂O _(s)↓+4HCl(8)

Also can be write as similar reaction with other metal species, therefore provide a kind of and be used for replacing its consumption of equivalent at hydrochloric acid in the leaching step.Sedimentary salt (MgSO in the above-described embodiments ₄.H ₂O) can thermolysis regeneration equivalent sulfur dioxide gas, make whole technology self-sufficient.Alternatively, sulphur (or other cheap sulphur sources) can burn in air and produce sulfur dioxide gas and be directly used in above-mentioned technology, and need not earlier gas reforming to be become sulfuric acid in the factory of the expensive acid of system.

All above-mentioned reactions have all been carried out in applicant's laboratory.But along with the increase of acidity, it may be the result of a successive reaction, and reaction 6 speed is as slack-off as estimating.Commercial, such as the cupric ion in the solution, graphite or or even catalyzer such as coal can be used for accelerated reaction 6.

Nickeliferous laterite samples comes from the Jacar é mineral deposit of Brazil.Find that this material contains suitable magnesium, its expectation meeting consumes a large amount of acid when carrying out acidleach and get.Therefore, 80% saturated level prepares magnesium chloride bittern under 80 ℃.Add other bittern compositions according to mathematical routine predicted quality balance.Laterite samples is squeezed into medium, make the acidity of medium reach pH 0.5 by adding hydrochloric acid.Within 3 hour residence time, the nickel in the laterite and the extraction of magnesium also surpass 80%.The leaching mother liquor is sprayed with sulfur dioxide gas, make the magnesium that sedimentary magnesium is many at least as leach from laterite samples.Find that throw out is the crystalline monohydrate acid magnesium.Recover the strength of acid of leaching medium simultaneously, make and to leach the sample of back.

Calcining vitriol forms MgO, and it surpasses the needs of internal procedure, and some MgO are used for from leaching solution with two isolating hydroxide product precipitated iron, nickel and cobalts, and described hydroxide product is iron product and Ni/Co cake.Lose the iron product, the Ni/Co cake is main process products.

Table 4 explanation sulfur dioxide gas can be used for replacing sulfuric acid at crystallisation step in theory; The ferric ion of the capacity that provides and allow the enough reaction times.

Table 4: replace sulfuric acid with sulfurous gas

Reagent	Reaction times	Final acid (HCl)
			0% sulfur dioxide gas+100% sulfuric acid	2 hours	163g/l
25% sulfur dioxide gas+75% sulfuric acid	2.25 hour	159g/l
			50% sulfur dioxide gas+50% sulfuric acid	4.5 hour	157g/l

Be the summary that obtains from data below:

Elementary reagent (hydrochloric acid) can be by keeping in major cycle with vitriol oil sulfate precipitate magnesium, makes the extraction results unanimity of the Ni in elementary leaching step.

In crystallizer, the solubleness of sal epsom is lower than in leaching, particularly when when operating under high temperature and density of magnesium chloride is high in crystallizer the situation.

The crystal that forms when crystallization is monohydrate acid magnesium (kieserite), also has some nickel and muriate inclusion.The muriate inclusion may be because the solution embedding in the tiny throw out can reduce nickel inclusion (only being lower than the atmospheric boiling point of solution) by carry out crystallization under comparatively high temps simultaneously;

Sulfur dioxide gas can systematically be replaced equivalent sulfuric acid, provides enough ferric ions to absorb sulfur dioxide gas.

Sulfide ore

Below will second embodiment explanation according to the present invention the use of hydrochloric acid (muriate) medium in such as the oxidation of the sulfide sulfides concentrate of zinc or non-oxide leaching.Though from sulfide concentrate, reclaim the not novel (sulfate medium: S-C process for copper, Kawulka et al, 1978 of non-oxide technology of base metal itself; Chloride media: Molleman et al, 1998), but this area and do not know the technology of regenerating acid.Non-oxide leaching technology in high aqueous salt brine also is this area the unknown with comprehensive the combining of regeneration step of acid.

In elementary hydrochloric acid medium, from sulfide concentrate, leach such as valuable base metals such as zinc.Leaching the base metal that finally reclaims with salable form.Leaching kinetics is very fast, and for example the metal of copper is stayed solid phase (Cu easily _xS) in, if desired, can from tailings, reclaim by the oxidation leaching technology.Another advantage of operation under non-oxide condition is that elemental sulfur can reclaim (oil/petrochemical industry) by Claus technology conventional and used for a long time.

In primary return, main leaching agent is the oxonium ion in the muriate background, as endogenous salt, and especially base metal, for example zinc chloride.

Crystallisation step uses the low solubility product of base metal vitriol or sulphite, and for example those of the salt of zinc to suppress muriate bittern background, are removed the leaching valuable substance from solution.Vitriol or sulphite have low crystal water and are applicable to that thermolysis produces oxide compound (as inner neutralizing agent), this oxide compound can sell or be dissolved in the sulphuric acid soln with certain proportion again and (produces in electrowinning), directly uses its electrowinning metal then.

The recovery of base metals such as the regeneration of aforesaid hydrochloric acid and zinc is with remove excessive water by evaporation irrelevant, because metal is to reclaim from the crystallization cake of low water content and low crystal water.

The present invention relies on zinc solubleness different in vitriol and muriate system, and the latter almost is the former twice (seeing Linke and Seidell, 1965 disclosed experimental datas) in the time of 100 ℃.In addition, when in chloride media, operating, the contriver finds, when when adding vitriol or sulphite as the form of the recyclable reagent in centre with sulfur dioxide gas or sulfuric acid, can strengthen above-mentioned phenomenon and utilize it to reduce the solubleness of zinc in chloride media significantly, thereby form the also vitriol or the sulphite of depositing zinc.And then, the experimental result of gained shows that gunningite (Zinc sulfate monohydrate) is the preferred crystalline product of in than large-temperature range (general～60 ℃), and it will calcine formation ZnO (described ZnO can partly be used as the neutralizing agent that reclaims) and the required energy of regeneration sulfurous gas further reduces.The reaction of this simplification can be write as:

ZnCl ₂+H ₂SO ₄-＞ZnSO ₄.H ₂O+HCl

(5)

Zinc chloride sulfuric acid gunningite hydrochloric acid

Or directly pass through SO ₂

The applicant has produced total chloride content less than 0.01% crystallized product with this method, the potentiality of this technology are described, promptly produce sell high-purity ZnO (in proportion as inner neutralizing agent) of usefulness or ZnO is dissolved into again and (return electrowinning) in the sulphuric acid soln and direct electrowinning Zn metal from gained solution.In addition, with relatively cheap and available reagent, i.e. the relatively costly hydrochloric acid of sulfur dioxide gas or regeneration of sulfuric acid.About the calcining of sedimentary zinc sulfate product, it should be ideal analytical product in fluidized-bed reactor.It is rehydrated to be easy to make the duration of contact of the precipitated product by crystallization control and the suitable aqueous solution monohydrate (produce and preferably be used for the pyrolysated hydrate) to carry out part.If directly use sulfurous gas difficult technically, use the technology of the sulfurous gas black sulfuric acid that produces from calcining vitriol then to continue to use for a long time, and the method for precipitation gunningite is provided, proved that this method is feasible (experimentally).Perhaps, because sulfurous gas is the product of thermal decomposition steps, therefore do not need to replenish reagent.Use the major advantage of the zinc sulfate of low hydration to be in the step that is decomposed to form zinc oxide, compare, greatly reduce the energy that uses with the thermal hydrolysis of liquor zinci chloridi.

The leaching kinetics that can realize ideal in rough concentrate shows that this technology is fit to leach precious metals, for example zinc, silver and plumbous from source of sulphide.What is interesting is fast (＜1 hour) kinetics (Figure 35) of the leaching under 85 ℃ in 4 mole hydrochloride solution for it.

Figure 32 represents the principle flow chart of this technology, wherein uses the hydrochloric acid leaching medium to dissolve valuable zinc in non-oxide step from sulfide material, in acid recovery step zinc is removed with crystalline salt form then.Need not the leaching mother liquor is carried out neutralizing treatment with reclaim(ed) sulfuric acid zinc, zinc sulfate reclaims by adding sulfuric acid.Sedimentary vitriol is the monohydrate form, rather than hexahydrate (those skilled in the art can estimate).If vitriol will change into oxide compound, this is very favorable, because compare the very big energy of having saved with hexahydrate.By with in the zinc oxide calcining matter that reclaims and the hydrolysis treatment after the excess acid for example remove impurity such as iron.

Directly add sulfur dioxide gas by injection leaching mother liquor and also can reach analog result (replacement sulfuric acid).It can be more favourable than buying the sulfuric acid of making that roasting elemental sulfur or solid sulfate salt produce sulfurous gas.

Described technology is based on new reagent regeneration principle, i.e. circulation leaching agent and neutralizing agent in technology.

Preliminary mass/energy balance has shown that comparing this method with the routine processing of sulfide ore gets huge advantage on running cost.

Following factor is relevant especially:

-concentrate can be selected concentrate or preferred rough concentrate (recovery of higher total valuable substance):

-non-oxide the leaching of operation under any required HCl concentration, the total chloride that provides can be kept at the rest part in loop;

-Cu is with Cu _xThe S form is redeposition in the normal pressure leaching, promptly if desired, can reclaim from the gangue residue;

-Pb leaches from the loop with the chloride complex form, and may be with sulfate precipitation in crystallizer.In heat composition step, form PbO, be easy to then from the residue of ZnO re-leaching step with pure PbSO ₄Form reclaims;

-when adding H to chloride soln ₂SO ₄The time, utilize vitriol and muriatic different solubilities in crystallizer, to form ZnSO ₄.H ₂O:ZnCl ₂+ H ₂SO ₄+ H ₂O → ZnSO ₄.H ₂O+2HCl

The major advantage of carrying out this reaction is that background bittern can form dehydration salt (＜=1mol H thus in conjunction with free-water in essence ₂O/mol Zn), with the salt of hyperhydrated, for example ZnSO ₄.6H ₂O compares and requires few decomposition energy;

Verified directly use SO ₂(forming in thermal decomposition steps) is as elementary reagent precipitation ZnSO ₄.H ₂O is feasible, if the iron of abundant positive iron state exist solution mutually in to absorb SO ₂This requires to add oxide compound (for example airborne oxygen) before crystallization ferrous (obtaining from non-oxide leaching) is changed into positive iron;

-above-mentioned crystallization and thermal decomposition steps are stoichiometric balance, do not require to replenish H ₂SO ₄Or SO ₂(except the purpose of controlling in the real factory);

The part of-bittern is discharged (before crystallization) from master loop, to be limited in the generation of Fe in the primary return.With proportional ZnO (in thermal decomposition steps, obtaining) circulation with in and impurity discharge free acid in the solution, therefore before removing Fe, utilize zinc powder to make and valuable material (Ag, Ni, Co, Cd) gluing;

-in normal pressure or low pressure autoclave, carry out the Fe hydrolysis to form rhombohedral iron ore and/or pyrrhosiderite (may be akaganeite).Another advantage of operating in high aqueous salt brine is that it contains free-water seldom, makes anhydrous Fe oxide/hydroxide precipitation six rhombohedral iron ore under far below the temperature of conventional vitriol system thus;

-body phase ZnO (deduct to discharge and carry out neutral with a little) carries out the re-leaching step, wherein uses H ₂SO ₄With oxide dissolution in the anolyte of electrowinning.Once more, acid is stoichiometric balance, and need not supplemental acid or neutralizing agent (purposes that only is used for real factory's control);

-in whole loop, do not have/seldom need to discharge solution, because Na ₂SO ₄To generate to saturated and in loop the denseest some precipitation;

-owing to there is not/needs considerably less discharge, removing by multiple-effect evaporator of water realizes;

-Figure 33 illustrates that muriate and vitriol flow back to the general flow chart on road.

The metallurgical evaluation

Laboratory simulation is made up of four processing steps, i.e. the re-leaching of leaching, crystallization, thermolysis and ZnO calcinate.Arrange out the performance of column element down (by low detectability 10ppm restriction) by the loop: aluminium, calcium, cadmium, cobalt, chromium, copper, iron, magnesium, manganese, nickel, lead, silicon and zinc.

Test condition is simulated based on elementary mass/energy balance.Computer and test simulation one significantly be respectively computer simulation be on selected concentrate (cleaner concentrate) (～50%Zn) carry out, and laboratory simulation be on rough concentrate (rougher concentrate), carry out (～5%Zn).

Metallurgy evaluation in the primary stage of research focuses on the unit operation of non-oxide normal pressure leaching and crystallizer.Figure 34 has illustrated non-oxide normal pressure leaching device.

Collect vapor phase by ferric sulfate washer (scrubber), with all H that in leaching, forms ₂S changes into elemental sulfur.It is more effective than apply malleation in the leaching container that discovery is executed vacuum to washer, i.e. H ₂S leaks in the experimental situation.But by leaching the container injection air to guarantee from system, stably removing H ₂S, promptly driving a reaction moves right:

ZnS+2H ⁺

Zn ²⁺+H ₂S

Figure 35 explanation is gone up the typical case who carries out under the low solid density in the grade of selecting (size fraction) (removing fine particle) and is leached kinetic test.The kinetics of 4M HCl is shown as prospect especially.Because in the polarization of the surface of anode direction, promptly because O ₂The existence of (injection) has suppressed other two tests.Stopped injection air in solution subsequently.

Crystallization (ZnSO ₄.H ₂O) major advantage is that therefore leaching neutralization after need not is leached under the HCl concentration of wanting of can in officely what is the need for and carried out, and is promptly reached fast kinetics.Figure 36 represents the typical crystalline product that obtains from aqueous salt brine with the vitriol oil.The major portion of quality is gunningite [Zn (SO ₄) (H ₂O)], still the gypsum of height crystallization is being arranged XRD.With high density NaCl the time, also precipitate a small amount of changoite[Na ₂Zn (SO ₄) ₂.4H ₂O].

The influencing each other of crystallisation step, strength of solution maintains below their vitriol or the solubleness of sulphite for fear of other elements.This carries out gluing and/or neutral processing realization by current drainage for example being leached mother liquor.Part calcinate can be used for influencing neutralization.

The water balance of this technology is kept by evaporation, with control bittern intensity, and for example with the leaching feed, the various water inputs of compensation such as washing water.

The leaching sulfide ore

This technology further uses the example of zinc sulphide technology to make an explanation.

Use contains the flotation concentrate of zink sulphide, and it is by making from the ore in Gamsberg mineral deposit (South Africa).In 4N HCl, leach concentrate under 85 ℃, suppressing the zinc chloride background in the solution.Find to leach and in 15-30 minute, finish substantially.The background concentration of selective chlorination zinc and the ratio of concentrate/bittern are made the muriatic leaching mother liquor of 80% saturated zinc.Leaching liquid contacts with 98% sulfuric acid in stirring beaker, the zinc sulfate of the zinc equivalent of precipitation and leaching.Find that throw out is the crystalline sulfuric acid zinc of half hydration status.Choose wantonly this salt under suitable temperature, for example 750 ℃, become oxide compound with air calcination, to produce at least 20% gas phase SO ₂, be applicable to system vitriol works or directly utilization again in crystallization.

Crystallization

60 ℃ down preparation zinc, ferrous, the muriate of sodium and the resulting solution of vitriol are arranged, add sulfuric acid according to stoichiometry.These tests have dual purpose: at first determine the solubleness of main component in solution; Determine crystalline amount and purity then, this crystal can form by adding sulfuric acid.The result of these tests is summarised in the table 5

Table 5: solubleness and crystalline result

Test

Leaching agent

Crystal

?Zng/l

?Feg/l

?Na?g/l

?Clg/l

?SO 4g/l

?Zn

Fe

Na

Cl

SO 4

20050324D4

?288

?0

?0

?318

?167

?40％

0％

0％

5％

41％

20050324D5

?290

?0

?52

?407

?36

?41％

0％

1％

5％

45％

20050324D6

?98

?3.8

?61

?61

?230

?-

-

-

-

-

20050324D7

?320

?6.3

?23

?373

?94

?38％

2.5％

0.3％

4％

46％

Because the starting point concentration of Zn is low, in the 20050324D6 test, do not form crystal.These results show by the regenerate principle of elementary reagent of precipitated crystal mainly reliable in the Zn system.

The preparation of high strength of acid chloride brine water (peracid)

Muriate bittern can contact the hydrochloric acid bittern (being that gained salt strength of acid surpasses azeotrope) that produces super azeotropic concentration with sulfuric acid or sulfurous gas.In this technology, do not require complicated distillation technique or expensive reagent.The liquid that it provides the method for cheap and simple to produce high acidity is used for certain technology then, for example the characteristic dissolution process that often uses in the platinum metals practice in Refining.

The strength of acid that can reach is under azeotrope or surpass azeotrope, and it depends on muriatic selection.

The preparation of high strength of acid chloride brine water

Under 100 ℃, the dissolution degree of magnesium chloride is approximately the 42.3g/100g saturated solution.When adding H ₂SO ₄, extreme case is whole magnesium precipitates when becoming monohydrate, approximately forms 50.3g salt, stays 49.7g water and 32.4gHCl; Strength of acid is 39%.

The preparation of high strength of acid chloride brine water

Under 80 ℃, the dissolution degree of zinc chloride is approximately the 84.4g/100g saturated solution.When adding H ₂SO ₄, when 75% zinc precipitates into monohydrate, approximately form 71.7g salt, stay 28.3g water and 33.9g HCl; Strength of acid is 54%.

Consider by specific embodiment the present invention to be described in detail, those skill in the art will appreciate that do not exceeding in the spirit and scope of the present invention and can make various modification, improvement and other variations the present invention.Therefore expect that claim covers or comprises these modification, improvement and/or variation.

Reference paper

Rice，N.M.The?Hydrochloric?Acid?Route?for?Nickel?Laterites：A?Brief?History?of?anongoing?Project，Leeds?University?Mining?Association?Journal，pp.59-89，1989.

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Claims (46)

1. one kind is used for from containing the technology of the described metal of metal ores leaching, and this technology may further comprise the steps:

Make at leaching ore in the presence of the hydrochloric acid and in leaching solution, to form the soluble metal chloride salt;

In leaching solution, adding sulfurous gas in the presence of the positive iron ion with regeneration hydrochloric acid;

From ore recuperation metal sulfate or metal sulphite; With

The hydrochloric acid of regenerating simultaneously;

Wherein, described metal is selected from by Zn, Cu, Ti, Al, Cr, Ni, Co, Mn, Fe, Pb, Na, K, Ca, Ag, the group that platinum metals and gold are formed.

2. technology according to claim 1, wherein said metal sulfate or metal sulphite have chemical formula: MeSO _xYH ₂O, wherein:

Me is a metal;

X is 3 or 4; And

Y be 0 or more than.

3. technology according to claim 1, the source metal of wherein said metal sulfate or metal sulphite is mainly from ore.

4. technology according to claim 2, wherein y is 0-3.

5. technology according to claim 4, wherein y is 0.

6. technology according to claim 4, wherein y is 1.

7. technology according to claim 1 wherein adds oxygenant to leaching solution ferrous ion is oxidized to iron ion.

8. technology according to claim 1, wherein said ore are base metal ore oxidation or siliceous basically.

9. technology according to claim 8, wherein said ore is a zinc oxide ore.

10. technology according to claim 1, wherein said ore is a laterite-type nickel ore.

11. technology according to claim 10, wherein said laterite-type nickel ore are saprolite or limonite.

12. technology according to claim 1, wherein said ore is a sulfide ore.

13. technology according to claim 1, wherein said ore is a titanium ore.

14. technology according to claim 1, wherein said ore is an aluminum ore.

15. technology according to claim 1, wherein said metal sulfate or metal sulphite are separated out from leaching solution.

16. technology according to claim 1, wherein said metal sulfate or metal sulphite reclaim from leaching solution by evaporative crystallization.

17. technology according to claim 1, wherein the metal in metal sulfate or metal sulphite is a magnesium.

18. technology according to claim 1 is wherein handled metal sulfate or metal sulphite to discharge sulfurous gas or sulphur trioxide or its mixture.

19. technology according to claim 1 wherein reclaims metal individually from the metal-salt that forms by adding sulfurous gas.

20. technology according to claim 1 wherein before adding sulfurous gas, is removed magnesium from leaching liquid, and replaces with different metallic cations.

21. technology according to claim 20, wherein said metallic cation is a calcium.

22. technology according to claim 20, wherein said metallic cation are plumbous.

23. technology according to claim 20 is wherein removed after the magnesium, is intermediate sulphite or vitriol by the metal-salt that adds sulfurous gas formation.

24. technology according to claim 23, wherein said intermediate sulphite or vitriol are calcium sulfate or calcium sulfite.

25. technology according to claim 23, wherein said intermediate sulphite or vitriol are lead sulfate or plumbous sulfite.

26. technology according to claim 1, wherein said metal chloride salts solution is an alkali metal salt soln.

27. technology according to claim 1, wherein said metal sulfate or metal sulphite are alkali metal sulfates or alkali metal sulfite.

28. technology according to claim 1, wherein said regeneration hydrochloric acid circulates in leaching technology.

29. technology according to claim 1, the hydrochloric acid that wherein is used to leach ore is the part of aqueous salt brine.

30. technology according to claim 29, wherein said aqueous salt brine are the saturated magnesium chloride solutions of 10-90%, the saturated liquor zinci chloridi of 10-90%, or the saturated solution of other metal chlorides of 10-90%.

31. technology according to claim 29, wherein said aqueous salt brine are the saturated magnesium chloride solutions of 25-40%, the saturated liquor zinci chloridi of 25-40%, or the saturated solution of other metal chlorides of 25-40%.

32. technology according to claim 1, wherein said metal sulfate or metal sulphite are used to produce metal oxide.

33. technology according to claim 1, thereby wherein described metal sulfate or metal sulphite are carried out the mixture that thermolysis produces metal oxide and sulfurous gas, metal oxide and sulphur trioxide or metal oxide and sulfurous gas and sulphur trioxide.

34. technology according to claim 32, wherein said metal oxide is selected from magnesium oxide, zinc oxide, ferric oxide and aluminum oxide.

35. technology according to claim 33, wherein said sulfurous gas, sulphur trioxide or its mixture are used to produce sulfuric acid, and sulfuric acid returns leaching technology regeneration hydrochloric acid again.

36. technology according to claim 23, thereby wherein intermediate vitriol or sulphite are carried out thermolysis generation metal oxide and sulfurous gas, sulphur trioxide or its mixture.

37. technology according to claim 36, wherein said metal oxide is a calcium oxide.

38. technology according to claim 36, wherein sulfurous gas is reused in saltout from leaching solution vitriol or sulphite, and is used to the hydrochloric acid of regenerating.

39. technology according to claim 1 is wherein leached metal in room temperature from ore to the temperature between the boiling point of metal chloride leaching solution.

40. technology according to claim 1 wherein before forming metal sulfate or metal sulphite, is optionally isolated one or more metals that leach from ore from solution.

41. according to the described technology of claim 40, wherein said optionally isolating metal is cobalt, nickel, platinum metals, gold and silver and/or copper.

42. technology according to claim 1, wherein the iron that obtains from the ore dissolving and/or other residual impurity are partly or entirely removed from leaching solution.

43. according to the described technology of claim 42, wherein said iron and/or other residual impurity are removed through thermal hydrolysis then by solvent extraction.

44. according to the described technology of claim 42, wherein iron and/or other residual impurity are removed by hydrolysis.

45. technology according to claim 1 is wherein used the catalyzer accelerated reaction.

46. according to the described technology of claim 45, wherein said catalyzer is selected from the group of being made up of the copper in the solution, graphite and coal.

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