GEORGIEV CHAVDAR GEORGIEV (BG)
BELOMORSKI MITKO HRISTOV (BG)
GYUROV ATANAS STOYKOV (BG)
GEORGIEV CHAVDAR GEORGIEV (BG)
BELOMORSKI MITKO HRISTOV (BG)
GYUROV ATANAS STOYKOV (BG)
| DE19946326A1 | 2001-03-29 | |||
| CA2363969A1 | 2003-05-26 | |||
| US4515631A | 1985-05-07 | |||
| US3890139A | 1975-06-17 |
| Patent claims Claim 1: A method for recycling slag from production of copper containing iron silicate- fayalite, which is characterized by the circumstance that fayalite oxidizes in the air at oxidation temperatures of 700 to 1100 0C, and for 3 to 5 hours; hydroxide or carbonate of alkaline metal is added and the mixture is processed until a mixture of silicate and iron oxides is obtained; this product is mixed with water and then warmed up to a temperature of 100°C, at atmospheric pressure, or to a temperature from 150 to 2000C, at a pressure of 0,6 to 1 ,5 MPa, which results in the silicate going into water solution, the undissolved iron oxides separate by precipitation or filtration, and then are washed with water or water solution up to 0,25M of a mineral acid - hydrochloric or sulfuric acid. Claim 2: A method according a claim 1 which is characterized by the circumstance that some of the compounds is added to the oxidized fayalite: sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, the mixture is warmed up to temperatures of 400 to 1100 0C and is mixed intensively at isotermic conditions until the product consisting of a mixture of iron oxides and silicate or solution of silicon in the listed compounds is obtained. Claim 3: A method according a claim 1 which is characterized by the circumstance that the heated particles oxidized slag are mixed with some of the compounds: sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, the mixture is shacked intensively until the product consisting of a mixture of iron oxides and silicate or solution of silicon in the listed compounds is obtained. Claim4: A method according a claim 1 which is characterized by the circumstance that the oxidized slag is mixed with some of the compounds: sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide and water in quantities assuring pH of the solution up to 10, the mixture is heated at temperatures from 150 to 200°C at pressure 0.6-4 MPa until the product consisting of a mixture of iron oxides and silicate or solution of silicon in the listed compounds is obtained. |
Fields of the technique
The invention refers to a method without waste for recycling slag from production of copper till iron (ferrous) concentrate, silicate of alkaline metal or solution of silicon in hydroxide of alkaline metal which can be used for production of water glass (liquid glass). The method refers to recycling residue of flotation of copper ores as well to recycling slag from production of copper via pyrometallurgic method.
Preceding state of the technique
A large quantity of solid waste products (slag) containing mainly iron silicate — fayalite (2FeO-SiO 2 ), aluninium oxide, calcium oxide as well as lead, zinc, copper and molybdenum, arsenic and selenium in concentrations below one percentage. The warehouse of waste products creates serious ecological problems and requires significant expenses for maintenance of the depots.
The purpose of this invention is to create a technology for recycling of solid waste products from production of copper to useful products: iron concentrate and silicate of alkaline metal or solution of silicon in hydroxide of alkaline metal which can be used for product ion of water glass (liquid glass).
It is known that the fayalite (2FeO 1 SiO 2 ) is resistant to diluted acids and hydroxides. Concentrated acids and hydroxides dissolve slag but the consumption of reagent is not economical. On the other hand it is known that the alkaline metals (Na, K) form water-soluble silicates with silicon dioxide (silica) (SiO 2) . It is known also that the fayalite (2FeO-SiO 2 ) is transformed to a mechanical mixture of oxides (Fe 2 O 3 , Fe 3 O 4 and SiO 2 ) when oxidized.
Technical main point of the invention
We propose a method without waste for recycling slag from production of copper which includes four main steps:
1. Oxidation of the fayalite in slag up to a mixture of magnetite, hematite and quartz; 2. Treating the mixture of magnetite, hematite and quartz with hydroxides or carbonate of alkaline metal;
3. Treating of the obtained product with water at temperatures 90-250 0 C and at a pressure 0.1-4 MPa and obtaining of a solid residue of iron oxides, solution of silicon in hydroxide of alkaline metal and/or silicate of alkaline metal;
4. Separation of iron oxides from the solution with or without washing the solid residue with water or water solution up to 0.25 M of a mineral acid - HCl or H 2 SO 4 .
As e result of these four steps iron concentrate and silicate of alkaline metal and/or solution of silicon in hydroxide of alkaline metal are obtained which can be used for production of liquid glass.
The chemical and granulometric composition of this way produced iron concentrate are suitable for forming pellets and using for production of cast-iron or iron ferroalloys.
The oxidation of the fayalite is conducted in the air with or without adding oxygen in the gas atmosphere. The temperatures of oxidation are from 700 to HOO 0 C and continuation 3-5 hours when (at which conditions) the reactions occur:
2FeO ■ SiO 2 + 1/2 0 2 →Fe 2 0 3 + SiO 2 (1)
2FeO . SiO 2 + 1/3 O 2 →2β Fe 3 O 4 + SiO 2 (2).
The oxidation may be conducted in crucible, shaft or rotary furnace with or without mixing. The slag is in a powder form with sizes of grains from 10 to 30 μm that provides intensive fulfillment of the process. The bigger particles will be also oxidized intensively at the expense of the intensity of the process.
Some of the listed compounds are added in the oxidized particles: sodium carbonate Na 2 CO 3 , potassium carbonate K 2 CO 3 , sodium hydroxide, potassium hydroxide. The mixture is heated (warmed) up to temperatures from 400 to HOO 0 C and is mixed intensively at determinate time at isotermic conditions in order to occur the reactions:
M 2 CO 3 + X SiO 2 = M 2 O ^ x SiO 2 + CO 2 (3) 2M0H + X SiO 2 = M 2 O ' X SiO 2 + H 2 O (4), where M is Na - sodium or K - potassium.
Another option is to mix the particles slag heated at the time of oxidation with some of the listed compounds: sodium carbonate Na 2 CO 3 , potassium carbonate K 2 CO 3 , sodium hydroxide NaOH, potassium hydroxide KOH. The mixture is mixed intensively for determinate time in order to accomplish the reactions (3) and (4).
The produced product is a mixture of iron oxides Fe 2 O 3 , Fe 3 O 4 x SiO 2 or solution of silicon in the listed compounds. This product is mixed with water and then is heated (warmed) at an atmospheric pressure and a temperature up to 100 0 C or in autoclave at temperatures 150- 25O 0 C and pressure 0.6-4 MPa when the silicate turns into water solution. Undissolved iron oxides Fe 2 O 3 , Fe 3 O 4 (solid residue) are separated through precipitation or filtration after which they are washed with water or water solution up to 0.25M of mineral acid - HCl or H 2 SO 4 .
Another option is to mix oxidized slag containing mainly Fe 2 O 3 , Fe 3 O 4 and silicon dioxide SiO 2 with some of listed compounds: sodium carbonate Na 2 CO 3 , potassium carbonate K 2 CO 3 , sodium hydroxide NaOH, potassium hydroxide KOH and water in quantity providing pH of the solution more than 10. The mixture is heated in autoclave at temperatures 150-250 0 C and pressure 0.6-4 MPa when the reactions occur:
M 2 CO 3 + x SiO 2 + H 2 O = M 2 O • x SiO 2 + CO 2 + H 2 O (5)
2MOH + x SiO 2 + H 2 O = M 2 O • x SiO 2 + H 2 O (6).
Undissolved iron oxides Fe 2 O 3 , Fe 3 O 4 (solid residue) are separated from the solution through precipitation or filtration. The solid phase is washed with water or water solution up to 0.25M of mineral acid - HCl or H 2 SO 4 in order to dissolve the formed on the surface of the powder particles aluminosilicate hydrate. It is soluble in acid medium and it's removing leads to an enrichment the solid residue of iron. Liquid phase contains unused hydroxide of alkaline metal and may be used for a repeated washing of the final or the oxidized products.
In the result of the process the wastes from copper production are recycled to iron concentrate and silicate of alkaline metal and/or solution of silicon in hydroxide of alkaline metal which cam be used for production of liquid glass -M 2 O x SiO 2 , where M is Na or K.
Examples
Example I
100 g slag from copper production with composition in weight % was processed:
FeO MgO CaO MnO SiO 2 Al 2 O 3 Na 2 O K 2 O TiO 2
50.93 1.43 1.39 <0.01 31.26 6.93 3.02 1.74 0.22
The iron is in the form of fayalite 2FeO-SiO 2 . The slag is oxidized in air at temperature 1000 0 C for 4 hours. The composition of oxidized product is:
FeO MgO CaO MnO SiO 2 Al 2 O 3 Na 2 O K 2 O TiO 2
57.82 1.13 1.55 <0.01 31.90 4.00 6.68 2.59 0.15
The oxidized product is mixed with 3Og NaCO 3 and shacked continuously and kept at 1000 0 C for 3 h in order to accomplish a synthesis. The produced product, a mixture of iron oxides and sodium silicate and/or solution of silicon in sodium hydroxide, is mixed with water in ratio 1:3 and is heated up to 160 0 C and stirring continuously keeping the temperature for 6 hours. After the end of the process the solution is filtered and washed with water. The chemical composition of the residue is:
FeO MgO CaO MnO SiO 2 Al 2 O 3 Na 2 O K 2 O TiO 2
67.92 0.71 1.34 <0.01 23.62 3.28 1.98 0.78 0.12 Example II
100 g slag from copper production with composition in weight % was processed:
FeO MgO CaO MnO SiO 2 Al 2 O 3 Na 2 O K 2 O TiO 2
50.93 1.43 1.39 - 31.26 6.93 3.02 1.74 0.22
The iron is under form of fayalite 2FeO-SiO 2 . The slag is oxidized in air at temperature 1000 0 C for 4 hours. The composition of oxidized product is:
FeO MgO CaO MnO SiO 2 Al 2 O 3 Na 2 O K 2 O TiO 2
53.99 1.86 1.69 - 29.39 6.81 3.46 1.44 0.15
The oxidized product is mixed with 4Og NaOH and 400 ml water. Then it is put into an autoclave and heat up to 160 0 C at stirring continuously keeping the temperature for 6 hours. After the end of the process the solution is filtered. The solid residue is washed with water solution 0.25M of a mineral acid - HCl.
The chemical composition of the residue is:
FeO MgO CaO MnO SiO 2 Al 2 O 3 Na 2 O K 2 O TiO 2
75.02 - 0.49 - 21.49 2.57 <0.01 0.10 0.19
Example III
100 g slag from copper production with composition in weight % was processed:
FeO MgO CaO MnO SiO 2 Al 2 O 3 Na 2 O K 2 O TiO 2
50.93 1.43 1.39 - 31.26 6.93 3.02 1.74 0.22
The iron is under form of fayalite 2FeO.SiO 2 . The slag is oxidized in air at temperature 1000 0 C for 4 hours. The composition of oxidized product is:
FeO MgO CaO MnO SiO 2 Al 2 O 3 Na 2 O K 2 O TiO 2
53.99 1.86 1.69 - 29.39 6.81 3.46 1.44 0.15
The oxidized product is mixed with 2Og NaOH and 400 ml water. Then it is put into an autoclave and heat up to 160 0 C at stirring continuously keeping the temperature for 6 hours. After the end of the process the solution is filtered. The solid residue is washed with water solution 0.25M of a mineral acid - H 2 SO 4 .
The chemical composition of the residue is:
FeO MgO CaO MnO SiO 2 Al 2 O 3 Na 2 O K 2 O TiO 2
70.81 0.42 1.13 2.50 20.34 1.78 - - 0.23
Example IV
100 g slag from copper production with composition in weight % was processed: FeO MgO CaO SiO 2 Al 2 O 3 Na 2 O K 2 O TiO 2 MnO 50.93 1.43 1.39 31.26 6.93 3.02 1.74 0.22 <0.01
The iron is under form of fayalite 2FeO-SiO 2 . The slag is oxidized in air at temperature 800 0 C for 4 hours. The composition of oxidized product is:
FeO MgO CaO SiO 2 Al 2 O 3 Na 2 O K 2 O TiO 2 MnO
55.62 0.87 1.77 38.13 2.23 2.78 0.71 0.06 0.42
The oxidized product is mixed with 2Og NaOH and stirring continuously and kept at 1000 0 C for 3 h in order to accomplish a synthesis. The produced product, a mixture of iron oxides and sodium silicate and/or solution of silicon in sodium hydroxide, is mixed with water in ratio 1:3 and is heated up to 160 0 C in autoclave and stirring continuously for 6 hours. After the end of the process the solution is filtered and washed with water. The chemical composition of the residue is:
FeO MgO CaO SiO 2 Al 2 O 3 Na 2 O K 2 O TiO 2 MnO
63.20 1.15 1.81 28.85 2.27 1.92 0.66 <0.01 <0.01
Example V
100 g residue from test No2 with composition in weight % was processed:
FeO MgO CaO MnO SiO 2 Al 2 O 3 Na 2 O K 2 O TiO 2
75.02 - 0.49 - 21.49 2.57 <0.01 0.10 0.19
The residue is mixed with the solution from test Ns2 in ratio 1 :4 and then it is put into an autoclave and heat up to 160 0 C and stirring continuously keeping the temperature for 6 hours. After the end of the process the solution is filtered and the solid residue is washed with water solution 0.15M of a mineral acid - HCl.
The chemical composition of the residue is:
FeO MgO CaO MnO SiO 2 Al 2 O 3 Na 2 O K 2 O TiO 2
86.69 0.97 0.87 <0.01 6.163 3.04 1.92 <0.01 0.16