CN102643985B - Method for extracting valuable metals from high-iron bauxite with step-by-step acid leaching - Google Patents

Abstract

The invention belongs to the field of mineral processing, and specifically relates to a method for extracting valuable metals from high-iron bauxite with step-by-step acid leaching. The technical scheme of the invention is to extract multiple valuable metal elements in minerals with a step-by-step acid leaching method by taking high-iron bauxite as a raw material. The method comprises the following steps of: firstly, leaching the elements of scandium, gallium, iron and the like in the minerals at low temperature by use of low-concentration sulfuric acid; adding the aluminum-containing mineral phase into the first-step leached slag, and crystallizing the first-step leached liquid to obtain ferric sulfate; in the second-step leaching, extracting aluminum in the first-step leached slag under the pressure leaching condition by use of the first-step leached liquid after iron removal and acid supplement; crystallizing the second-step leached liquid to obtain the aluminum sulfate product, and returning the second-step leached liquid after the crystallization to the first-step leaching for circular use; and after multiple times of circular enrichment of the elements of scandium, gallium and the like in the leached liquid, separating by an extraction method to obtain the scandium and gallium products. In the invention, the comprehensive utilization, acid and water circulation and zero discharge of wastes of the valuable elements in high-iron bauxite are realized through a step-by-step extraction method.

Description

A kind of method of high-iron bauxite substep acid leaching extraction valuable metal

Technical field

The invention belongs to the mineral manufacture field, be specifically related to a kind of method of high-iron bauxite substep acid leaching extraction valuable metal.

Background technology

China is bauxite resource big country, end 2009, the proven reserve of China's bauxite have reached more than 2,300,000,000 tons, expected reserves is more than 5,000,000,000 tons, mainly concentrate on Shanxi, Guizhou, four provinces and regions in Henan and Guangxi, wherein the characteristics of Guangxi province bauxite resource are that iron level is high, and rare precious metals in the mineral, such as scandium, the content of gallium etc. is also much higher than other regional bauxite resource, correlative study shows: alumina content is 45% ~ 60% in the Guangxi province high-iron bauxite, iron oxide content is 6% ~ 40%, the content of scandium is 0.0047% ~ 0.012%, and the content of gallium is 0.008% ~ 0.014%, as uses traditional Bayer process to process such resource, not only can cause the serious waste of rare precious metals resource, also can a large amount of red mud solid waste of output.Along with the progressively raising of China to energy-saving and emission-reduction requirement in the Industrial processes, and novel material, new energy technology be to the year by year increase of the rare precious metals demands such as scandium and gallium, and the method for comprehensive utilization of valuable metal element has been subject to the extensive concern of industry member and academia in the high-iron bauxite.

At present, the method of comprehensive utilization of high-iron bauxite comprises that mainly choosing-smelting is united and pyrogenic process-wet method combined treatment process, publication number be CN1766128A patent disclosure a kind of method of from high-iron bauxite, extracting iron and aluminium, the method is to carry out sintering after being mixed in proportion after high-iron bauxite, Wingdale, the coal dust fragmentation, then carry out blast-furnace smelting, obtain cast iron product, obtain simultaneously calcium aluminate slag and CO ₂Furnace gas; After calcium aluminate slag leaches with the sodium carbonate solution dissolving, carry out red mud separating, washing, desiliconization, carbonating decomposition preparing hydrogen aluminum oxide, obtain aluminum oxide through roasting again; Publication number be CN101337683A patent disclosure a kind of combination production method for preparing multi-products take high-iron bauxite as raw material, the method is at first carried out pressure leaching with hydrochloric acid as leaching medium to high-iron bauxite, iron enters the muriate that forms iron in the hydrochloric acid with ionic species, aluminium is then stayed in the solid bauxite, thereby iron is separated with aluminium; Then hydrochloric acid leachate is carried out roasting, obtain iron oxide red and hydrogen chloride gas, hydrogen chloride gas body and function washing water absorb becomes recycle behind the hydrochloric acid, and the upper strata product is carried out melting, crystallographic orientation, and to prepare silicone content be cocrystallized Al-Si alloy below the 14wt%.

But aforesaid method mainly is the mode by sintering is smelted or pickling is extracted, to produce aluminum oxide and to realize that iron aluminium is separated into purpose, although also extracted element silicon, obtained the Eutectic Silicon in Al-Si Cast Alloys aluminium alloy, but the problem that the rare metal recovery of but all having ignored the high values such as the scandium in the high-iron bauxite, gallium utilizes has caused the serious wasting of resources.

Summary of the invention

For the problem that prior art exists, the invention provides a kind of method of high-iron bauxite substep acid leaching extraction valuable metal, purpose is to overcome the valuable element that exists in the prior art to make a low multiple use and the shortcomings such as the red mud quantity discharged is large.

The technical scheme of realization the object of the invention is carried out according to following steps:

(1) the high-iron bauxite fragmentation is finely ground to-74 ~-250 μ m, the adding mass concentration is 10% ~ 50% sulfuric acid, in solid-liquid than 1:(3 ~ 20) condition under be heated to 60 ~ 120 ℃, carry out the step Leaching reaction of 30 ~ 240min, obtain step leaching ore pulp, one step is leached ore pulp carry out solid-liquid separation, obtain a step leached mud and a step leach liquor, wherein the scandium in the high-iron bauxite, gallium and iron enter into a step leach liquor, aluminum oxide enters in the step leached mud, one step leach liquor is carried out crystallization obtain ferric sulfate, the reaction that a step leaching process occurs is as follows:

Sc ₂O ₃+3H ₂SO ₄=3H ₂O+Sc ₂(SO ₄) ₃

Ga ₂O ₃+3H ₂SO ₄=3H ₂O+Ga ₂(SO ₄) ₃

2FeOOH+3H ₂SO ₄=4H ₂O+?Fe ₂(SO ₄) ₃

After the crystallization one step leach liquor is used for the leaching of two steps through mending acid to h 2 so 4 concentration 30% ~ 80%;

(2) the step leach liquor through deironing and after mending acid is mixed with a step leached mud, in solid-liquid than 1:(5 ~ 20) condition under be heated to 100 ~ 220 ℃, carry out the two steps pressure leaching reaction of 30 ~ 240min, obtain two steps leaching ore pulp, it is carried out solid-liquid separation, obtain two step leach liquors and two step leached muds, two step leach liquors obtain Tai-Ace S 150 through crystallization, the composition of two step leached muds is the silicon-dioxide that contains residual acid, recycle in two leach liquor to a step in the step Leaching reactions after crystallization, the reaction that two step leaching process occur is as follows:

2AlOOH+3H ₂SO ₄=4H ₂O+?Al ₂(SO ₄) ₃

(3) described two step leach liquors are after 4 ~ 30 circulations, adopting the P507 mass concentration is that 1% ~ 10% P507 mixes organic phase as extraction agent with sulfonated kerosene, scandium in the extraction leach liquor, extraction conditions is: extraction phase is than O:A=(0.5 ~ 3): 1, acidity 0.2 ~ 2mol/L, extraction time 3 ~ 10min obtains containing the organic phase of scandium, use the NaOH of 1 ~ 3mol/L that the organic phase after extracting is carried out back extraction, obtain Sc (OH) ₃Product, described P507 are 2-ethylhexyl phosphoric acid single 2-ethyl polyhexamethylene, and it is as follows that leach liquor is proposed the reaction that occurs in scandium and the back extraction process:

Sc(HA ₂) ₃+3NaOH=Sc(OH) ₃+3Na(HA ₂)

(4) adopting HDEHP concentration is that HDEHP and the sulfonated kerosene of 0.02 ~ 0.5mol/L mixes organic phase as extraction agent, further extract the gallium in the leach liquor of carrying after resisting, extraction conditions is: extraction phase is than O:A=(0.5 ~ 2): 1, acidity 0.05mol/L ~ 2mol/L, extraction time 1 ~ 5min, described HEDHP is two (2-ethylhexyl phosphoric acids), and extractive reaction is:

Concentrated sulfuric acid solution back extraction to the use of the organic phase after the extraction 2 ~ 7mol/L obtains gallium sulfate solution.

Wherein, the ferric sulfate that a step leach liquor crystallization obtains in the step (1), the mode by pyrolysis prepares iron oxide red;

The Tai-Ace S 150 that two step leach liquors obtain through crystallization in the step (2) in 780 ~ 900 ℃ of pyrolysis temperatures, prepares γ-Al under the pyrolytical condition of pyrolysis time 5 ~ 60min ₂O ₃

Pyrolytic reaction:

Al ₂(SO ₄) ₃=Al ₂O ₃+SO ₃

In the step (2) two step leached mud uses in the lime and afterwards for the production of cement;

The SO that described Tai-Ace S 150 and ferric sulfate pyrolysis produce ₃Gas is directly used in the benefit acid of a step leach liquor after absorbing relieving haperacidity.

The one-tenth of described high-iron bauxite raw material is grouped into by mass percentage: Fe ₂O ₃10 ~ 40%, Al ₂O ₃35 ~ 70%, Sc0.001 ~ 0.005%, Ga 〉=0.003 ~ 0.010%, surplus is igloss and impurity.

Scandium hydroxide and gallium sulfate that the present invention is obtained carry out further calcination process, can also prepare high-purity Scium trioxide and gallium goods.

Compare with traditional high-iron bauxite comprehensive utilization technique, beneficial effect of the present invention is:

(1) the inventive method has effectively been extracted whole valuable elements in the high-iron bauxite, no matter is product ferric sulfate, Tai-Ace S 150, silicon-dioxide, scandium hydroxide and the gallium sulfate that directly obtains, or it is further processed iron oxide red, the γ-Al that obtains ₂O ₃, cement and high purity scandium gallium product, its value is to adopt product that conventional production methods obtains more than 3 times;

(2) adopt the inventive method, the acid of using in the production process and water all can recycles, without the discharging of waste water and spent acid;

(3) adopt the inventive method, without solid waste discharge, the acid leaching residue main component is the SiO that contains residual acid in the production process ₂, use in the lime and after can be directly used in manufacture of cement, be the high-iron bauxite ecological synthetic utilization method that meets environmental requirement.

Description of drawings

Fig. 1 is process flow diagram of the present invention.

Embodiment

The high-iron bauxite material composition that the present invention adopts forms by mass percentage: Fe ₂O ₃10 ~ 40%, Al ₂O ₃35 ~ 70%, Sc0.001 ~ 0.005%, Ga0.003 ~ 0.010%, surplus is igloss and impurity, among the embodiment only with Fe ₂O ₃12.46%, Al ₂O ₃57.57%, SiO ₂7.06%, Sc0.005%, Ga0.008%, surplus is that the high-iron bauxite of igloss and impurity is that example describes;

The leaching yield of scandium was 75% ~ 95% when a step leached in the embodiment of the invention, and the leaching yield of gallium is 70% ~ 95%, and the iron leaching rate is 90% ~ 99.5%, and the leaching yield of aluminium is that 0.5 ~ 5%, two leaching yields that go on foot aluminium when leaching are 93% ~ 99.5%.

Embodiment 1

The high-iron bauxite fragmentation is finely ground to particle diameter less than 250 μ m, functional quality concentration is 50% sulphuric acid soln, 120 ℃ of extraction temperatures, solid-liquid compares 1:3, extraction time is to carry out a step Leaching reaction under the condition of 240min, and the leaching yield of ferro element is 97.05%, obtains a step leach liquor and a step leached mud, one step leach liquor is carried out crystallization obtain ferric sulfate, obtain iron oxide red by pyrolysis;

After the crystallization one step leach liquor is sour to h 2 so 4 concentration 30% through mending, 170 ℃ of extraction temperatures, solid-liquid compares 1:20, under the leaching condition of extraction time 240min the aluminum oxide in the step leached mud being carried out for two steps leaches, obtain two step leach liquors and two step leached muds, the leaching yield of aluminum oxide is 99.48% in the two step leaching process, two step leached muds are the silicon-dioxide that contains residual acid, use lime rear for the production of cement to its neutralization, Tai-Ace S 150 in the two step leach liquors is after crystallization, 820 ℃ of pyrolysis temperatures, pyrolysis under the condition of pyrolysis time 15min obtains highly active γ-Al ₂O ₃Product, the step of two after crystallization leach liquor turns back to step leaching and recycles the SO that Tai-Ace S 150 and ferric sulfate pyrolysis produce ₃Gas is used for the benefit acid of a step leach liquor after absorbing relieving haperacidity;

Two step leach liquors are through 4 circulations, using the P507 mass concentration is that 1% P507 mixes organic phase as extraction agent with sulfonated kerosene, compare O:A=3:1 at extraction phase, acidity 2mol/L, scandium under the condition of extraction time 10min in the extraction leach liquor, and use the NaOH of 3mol/ that the organic phase after extracting is carried out back extraction, obtain high-purity Sc (OH) ₃Product, recovery of scandium efficient are 81.32%;

Use HDEHP concentration to mix organic phase as extraction agent as the HDEHP of 0.5mol/L and sulfonated kerosene, compare O:A=0.5:1 at extraction phase, acidity 2mol/L, gallium under the condition of extraction time 5min in the extraction leach liquor, and use the vitriol oil of 6mol/L that the organic phase after extracting is carried out back extraction, obtain the gallium sulfate product, the extraction yield of gallium element is 89.65%.

Embodiment 2

The high-iron bauxite fragmentation is finely ground to particle diameter less than 74 μ m, functional quality concentration is 30% sulphuric acid soln, 60 ℃ of extraction temperatures, solid-liquid compares 1:20, carry out a step Leaching reaction under the condition of extraction time 60min, the leaching yield of ferro element is 98.63%, obtains a step leach liquor and a step leached mud, one step leach liquor is carried out crystallization obtain ferric sulfate, obtain iron oxide red by pyrolysis;

One step leach liquor is sour to h 2 so 4 concentration 60% through mending, 190 ℃ of extraction temperatures, solid-liquid compares 1:10, under the leaching condition of extraction time 120min the aluminum oxide in the step leached mud being carried out for two steps leaches, obtain two step leach liquors and two step leached muds, the leaching yield of aluminum oxide is 99.45% in the two step leaching process, two step leached muds are the silicon-dioxide that contains residual acid, use lime rear for the production of cement to its neutralization, Tai-Ace S 150 in the two step leach liquors is after crystallization, 780 ℃ of pyrolysis temperatures, pyrolysis under the condition of pyrolysis time 60min obtains highly active γ-Al ₂O ₃Product, the step of two after crystallization leach liquor turns back to step leaching and recycles the SO that Tai-Ace S 150 and ferric sulfate pyrolysis produce ₃Gas is used for the benefit acid of a step leach liquor after absorbing relieving haperacidity;

Two step leach liquors are through 10 circulations, using the P507 mass concentration is that 10% P507 mixes organic phase as extraction agent with sulfonated kerosene, compare O:A=0.5:1 at extraction phase, acidity 0.2mol/L, scandium under the condition of extraction time 10min in the extraction leach liquor, and use the NaOH of 1mol/L that the organic phase after extracting is carried out back extraction, obtain high-purity Sc (OH) ₃Product, recovery of scandium efficient are 89.62%;

Use HDEHP concentration to mix organic phase as extraction agent as the HDEHP of 0.02mol/L and sulfonated kerosene, at extraction phase ratio: O:A=1:1, acidity 2mol/L, gallium under the condition of extraction time 5min in the extraction leach liquor, and the vitriol oil of use 3mol/L is to the organic phase back extraction, obtain the gallium sulfate product, the extraction yield of gallium element is 71.66%.

Embodiment 3

The high-iron bauxite fragmentation is finely ground to particle diameter less than 144 μ m, functional quality concentration is 10% sulphuric acid soln, 100 ℃ of extraction temperatures, solid-liquid compares 1:5, carry out a step Leaching reaction under the condition of extraction time 120min, the leaching yield of ferro element is 99.16%, obtains a step leach liquor and a step leached mud, one step leach liquor is carried out crystallization obtain ferric sulfate, obtain iron oxide red by pyrolysis;

One step leach liquor is sour to h 2 so 4 concentration 60% through mending, 200 ℃ of extraction temperatures, solid-liquid compares 1:5, under the condition of extraction time 240min the aluminum oxide in the step leached mud being carried out for two steps leaches, obtain two step leach liquors and two step leached muds, the leaching yield of aluminum oxide is 98.17% in the two step leaching process, two step leached muds are the silicon-dioxide that contains residual acid, use lime rear for the production of cement to its neutralization, Tai-Ace S 150 in the two step leach liquors is after crystallization, 900 ℃ of pyrolysis temperatures, pyrolysis under the condition of pyrolysis time 5min obtains highly active γ-Al ₂O ₃Product, the step of two after crystallization leach liquor turns back to step leaching and recycles the SO that Tai-Ace S 150 and ferric sulfate pyrolysis produce ₃Gas is used for the benefit acid of a step leach liquor after absorbing relieving haperacidity;

Two step leach liquors are through 10 circulations, using the P507 mass concentration is that 10% P507 mixes organic phase as extraction agent with sulfonated kerosene, compare O:A=1:1 at extraction phase, acidity 1mol/L, scandium under the condition of extraction time 5min in the extraction leach liquor, and use the NaOH of 2mol/L that the organic phase after extracting is carried out back extraction, obtain high-purity Sc (OH) ₃Product, recovery of scandium efficient are 92.32%;

Use HDEHP concentration to mix organic phase as extraction agent as the HDEHP of 0.5mol/L and sulfonated kerosene, at the extraction phase ratio: O:A=0.5:1, acidity 0.05mol/L, gallium under the condition of extraction time 1min in the extraction leach liquor, and use the vitriol oil of 7mol/Ld that organic phase is carried out back extraction, obtain the gallium sulfate product, the extraction yield of gallium element is 78.35%.

Embodiment 4

The high-iron bauxite fragmentation is finely ground to particle diameter less than 74 μ m, functional quality concentration is 60% sulphuric acid soln, 100 ℃ of extraction temperatures, solid-liquid compares 1:5, carry out a step Leaching reaction under the condition of extraction time 30min, the leaching yield of ferro element is 98.96%, obtains a step leach liquor and a step leached mud, one step leach liquor is carried out crystallization obtain ferric sulfate, obtain iron oxide red by pyrolysis;

Sour to h 2 so 4 concentration 60% through mending through a step leach liquor, 190 ℃ of extraction temperatures, solid-liquid compares 1:10, under the condition of extraction time 30min the aluminum oxide in the step leached mud being carried out for two steps leaches, obtain two step leach liquors and two step leached muds, the leaching yield of aluminum oxide is 97.25% in the two step leaching process, two step leached muds are the silicon-dioxide that contains residual acid, use lime rear for the production of cement to its neutralization, Tai-Ace S 150 in the two step leach liquors is after crystallization, 850 ℃ of pyrolysis temperatures, pyrolysis under the condition of pyrolysis time 30min obtains highly active γ-Al ₂O ₃Product, the step of two after crystallization leach liquor turns back to step leaching and recycles the SO that Tai-Ace S 150 and ferric sulfate pyrolysis produce ₃Gas is used for the benefit acid of a step leach liquor after absorbing relieving haperacidity;

Two step leach liquors are through 20 circulations, using the P507 mass concentration is that 8% P507 mixes organic phase as extraction agent with sulfonated kerosene, compare O:A=1:1 at extraction phase, acidity 2mol/L, scandium under the condition of extraction time 5min in the extraction leach liquor, and use the NaOH of 1mol/L that the organic phase after extracting is carried out back extraction, obtain high-purity Sc (OH) ₃Product, recovery of scandium efficient are 88.32%;

Use HDEHP concentration to mix organic phase as extraction agent as the HDEHP of 0.5mol/L and sulfonated kerosene, at the extraction phase ratio: O:A=1:1, acidity 2mol/L, gallium under the condition of extraction time 5min in the extraction leach liquor, and use the vitriol oil of 2mol/L that organic phase is carried out back extraction, obtain the gallium sulfate product, the extraction yield of gallium element is 86.37%.

Embodiment 5

The high-iron bauxite fragmentation is finely ground to particle diameter less than 74 μ m, functional quality concentration is 30% sulphuric acid soln, 120 ℃ of extraction temperatures, solid-liquid compares 1:10, carry out a step Leaching reaction under the condition of extraction time 60min, the leaching yield of ferro element is 99.45%, obtains a step leach liquor and a step leached mud, one step leach liquor is carried out crystallization obtain ferric sulfate, obtain iron oxide red by pyrolysis;

Sour to h 2 so 4 concentration 60% through mending through a step leach liquor, 100 ℃ of extraction temperatures, solid-liquid compares 1:20, under the condition of extraction time 60min the aluminum oxide in the step leached mud being carried out for two steps leaches, obtain two step leach liquors and two step leached muds, the leaching yield of aluminum oxide is 97.05% in the two step leaching process, two step leached muds are the silicon-dioxide that contains residual acid, use lime rear for the production of cement to its neutralization, Tai-Ace S 150 in the two step leach liquors is after crystallization, 850 ℃ of pyrolysis temperatures, pyrolysis under the condition of pyrolysis time 15min obtains highly active γ-Al ₂O ₃Product, the step of two after crystallization leach liquor turns back to a step leaching process and recycles the SO that Tai-Ace S 150 and ferric sulfate pyrolysis produce ₃Gas is used for the benefit acid of a step leach liquor after absorbing relieving haperacidity;

Two step leach liquors are through 30 circulations, using the P507 mass concentration is that 10% P507 mixes organic phase as extraction agent with sulfonated kerosene, compare O:A=1:1 at extraction phase, acidity 1mol/L, scandium under the condition of extraction time 10min in the extraction leach liquor, and use the NaOH of 1mol/L that the organic phase after extracting is carried out back extraction, obtain high-purity Sc (OH) ₃Product, recovery of scandium efficient are 86.05%;

Use HDEHP concentration to mix organic phase as extraction agent as the HDEHP of 0.5mol/L and sulfonated kerosene, at the extraction phase ratio: O:A=2:1, acidity 2mol/L, gallium under the condition of extraction time 5min in the extraction leach liquor, and use the vitriol oil of 5mol/L that organic phase is carried out back extraction, obtain the gallium sulfate product, the extraction yield of gallium element is 85.45%.

Claims (5)

1. the method for high-iron bauxite substep acid leaching extraction valuable metal is characterized in that carrying out according to following steps:

(1) the high-iron bauxite fragmentation is finely ground to-74 ~-250 μ m, the adding mass concentration is 10% ~ 50% sulfuric acid, in solid-liquid than 1:(3 ~ 20) condition under be heated to 60～120 ℃, carry out the step Leaching reaction of 30 ~ 240min, obtain step leaching ore pulp, one step is leached ore pulp carry out solid-liquid separation, obtain a step leached mud and a step leach liquor, wherein the scandium in the high-iron bauxite, gallium and iron enter into a step leach liquor, aluminum oxide enters in the step leached mud, one step leach liquor is carried out crystallization obtain ferric sulfate, the reaction that a step leaching process occurs is as follows:

Sc ₂O ₃+3H ₂SO ₄=3H ₂O+Sc ₂(SO ₄) ₃

Ga ₂O ₃+3H ₂SO ₄=3H ₂O+Ga ₂(SO ₄) ₃

2FeOOH+3H ₂SO ₄=4H ₂O+Fe ₂(SO ₄) ₃

After the crystallization one step leach liquor is used for the leaching of two steps through mending acid to h 2 so 4 concentration 30% ~ 80%;

(2) the step leach liquor through deironing and after mending acid is mixed with a step leached mud, in solid-liquid than 1:(5 ~ 20) condition under be heated to 100 ~ 220 ℃, carry out the two steps pressure leaching reaction of 30 ~ 240min, obtain two steps leaching ore pulp, it is carried out solid-liquid separation, obtain two step leach liquors and two step leached muds, two step leach liquors obtain Tai-Ace S 150 through crystallization, the composition of two step leached muds is the silicon-dioxide that contains residual acid, recycle in two leach liquor to a step in the step Leaching reactions after crystallization, the reaction that two step leaching process occur is as follows:

2AlOOH+3H ₂SO ₄=4H ₂O+Al ₂(SO ₄) ₃

(3) described two step leach liquors are after 4 ~ 30 circulations, adopting the P507 mass concentration is that 1% ~ 10% P507 mixes organic phase as extraction agent with sulfonated kerosene, scandium in the extraction leach liquor, extraction conditions is: extraction phase is than O:A=(0.5 ~ 3): 1, acidity 0.2 ~ 2mol/L, extraction time 3 ~ 10min obtains containing the organic phase of scandium, use the NaOH of 1 ~ 3mol/L that the organic phase after extracting is carried out back extraction, obtain Sc (OH) ₃Product, described P507 are 2-ethylhexyl phosphoric acid single 2-ethyl polyhexamethylene, and it is as follows that leach liquor is proposed the reaction that occurs in scandium and the back extraction process:

${\mathrm{Sc}}^{3+}+{\left(\mathrm{HA}\right)}_2\↔\mathrm{Sc}{\left({\mathrm{HA}}_2\right)}_3+{3H}^{+}$

Sc(HA ₂) ₃+3NaOH=Sc(OH) ₃+3Na(HA ₂)

(4) adopting HDEHP concentration is that HDEHP and the sulfonated kerosene of 0.02 ~ 0.5mol/L mixes organic phase as extraction agent, gallium in the leach liquor behind the further Sc extraction, extraction conditions is: extraction phase is than O:A=(0.5 ~ 2): 1, acidity 0.05mol/L ~ 2mol/L, extraction time 1 ~ 5min, described HEDHP is two (2-ethylhexyl phosphoric acids), and extractive reaction is:

${\mathrm{Ga}}^{3+}+{\left(\mathrm{HA}\right)}_2\↔\mathrm{Ga}{\left({\mathrm{HA}}_2\right)}_3+{3H}^{+}$

Concentrated sulfuric acid solution back extraction to the use of the organic phase after the extraction 2 ~ 7mol/L obtains gallium sulfate solution.

2. the method for a kind of high-iron bauxite substep acid leaching extraction valuable metal according to claim 1 is characterized in that the ferric sulfate that step leach liquor crystallization obtains in the described step (1), prepares iron oxide red by pyrolysis.

3. the method for a kind of high-iron bauxite substep acid leaching extraction valuable metal according to claim 1, it is characterized in that the Tai-Ace S 150 that two step leach liquors obtain through crystallization in the described step (2), in 780 ~ 900 ℃ of pyrolysis temperatures, prepare γ-Al under the pyrolytical condition of pyrolysis time 5 ~ 60min ₂O ₃, pyrolytic reaction is: Al ₂(SO ₄) ₃=Al ₂O ₃+ 3SO ₃Described two step leached muds use in the lime and afterwards for the production of cement.

4. according to claim 2 or the method for a kind of high-iron bauxite claimed in claim 3 substep acid leaching extraction valuable metal, it is characterized in that the SO that described Tai-Ace S 150 or ferric sulfate pyrolysis produce ₃Gas is directly used in the benefit acid of a step leach liquor after absorbing relieving haperacidity.

5. the method for a kind of high-iron bauxite substep acid leaching extraction valuable metal according to claim 1 is characterized in that the one-tenth of described high-iron bauxite raw material is grouped into by mass percentage: Fe ₂O ₃10 ~ 40%, Al ₂O ₃35 ~ 70%, Sc0.001 ~ 0.005%, Ga0.003 ~ 0.010%, surplus is igloss and impurity.

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