CN105483363A - Method for co-production of activated calcium silicate by adopting copper tailings to produce iron ore concentrate - Google Patents

Abstract

The invention discloses a method for co-producing active calcium silicate by producing iron concentrate from copper tailings, comprising the following steps: (1) mixing copper tailings with alkali for smelting, immersing in water and filtering after smelting to obtain filter residues I and Filtrate I; the filter residue I is washed and dried to obtain iron-rich concentrate; (2) adding slaked lime and a surface modifier to the filtrate I for in-situ modification to obtain filter residue II and filtrate II, and the filter residue II Active calcium silicate is obtained after washing and drying, and the filtrate II is returned to step (1) for recycling after evaporation and crystallization. The invention realizes the directional separation and enrichment of Fe and Si elements in copper tailings and the preparation of related high value-added products, and solves the problem of low resource utilization rate of copper tailings, high processing energy consumption, and secondary pollution easily caused by reaction auxiliary materials And other issues.

Description

A method for producing iron concentrate from copper tailings and co-producing active calcium silicate

technical field

The invention relates to the field of metallurgy, in particular to a method for producing iron concentrate from copper smelting tailings and co-producing active calcium silicate.

Background technique

Copper tailing slag is the tailing slag after the copper slag produced by smelting is crushed and screened, and the slag with a particle size of ≤12 mm is ball milled and then subjected to two flotations to extract copper. After the previous stage of treatment, the chemical composition of copper tailings is mainly fayalite, SiO ₂ and CaO, some Fe ₃ O ₄ , Fe ₂ O ₃ , Al ₂ O ₃ and a small amount of MgO, K ₂ O, Na ₂ O, etc., in addition, it also contains trace elements such as Mn, Zn, Cu, Ti, etc. The grade of iron in the slag is generally about 40%, which is much higher than the minable grade of iron ore (29.1%), and the silicon content in the slag is also as high as 20%, which is an ideal silicon source.

At present, except for a small part of copper tailings being used in the cement industry, most of the copper tailings are disposed of in piles. The accumulated copper tailings are easily blown by the wind to cause air pollution because of their small particles, and in the natural environment, the harmful heavy metals leached from copper tailings will pollute water bodies and soil, thereby affecting the production of agriculture, fishery and forestry, and causing economic losses. loss. In the cement concrete industry, copper tailings are mainly used as raw materials for firing cement clinker, as mineralizers, and as cement and concrete mixtures. Although these applications have achieved a certain economic value, the utilization of copper tailings is only limited to its physical properties, while the iron and silicon resources remaining in the slag have not been fully utilized, and the utilization rate of resources is extremely low. At the same time, the research on other aspects of copper tailings is also relatively limited. Some researchers have carried out high-temperature reduction treatment on copper tailings to further improve iron, but a large amount of coke powder and calcium oxide need to be added in the process, and the reduction temperature is as high as 1200-1300 ° C, which consumes a lot of energy and materials. At the same time, silicon in copper tailings Components are also not efficiently utilized. Some scholars also roast the tailings at a high temperature of about 1300 °C, use the iron components in the slag to convert the magnetite phase into selective enrichment, and then recover part of the iron through magnetic separation. However, this method also faces problems such as huge energy consumption and insufficient recovery of iron and silicon elements. The reason is that iron in copper tailings mainly consists of fayalite (2FeO·SiO ₂ ), magnetic iron oxide (Fe ₃ O ₄ ) The phase exists in the slag, and the proportion of weakly magnetic fayalite is relatively large, so the separation of ferrosilicon by magnetic separation cannot be realized. The fayalite phase has a dense structure and a high melting point (1209°C), so it is difficult to destroy it by the current technology, so that the silicon and iron phases are separated, and the utilization rate of resources is extremely low. Therefore, under the severe situation of resource shortage and environmental protection in our country, the development of comprehensive utilization technology of copper tailings is of great significance to promote circular economy and sustainable development.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a method for producing iron concentrate from copper tailings and co-producing active calcium silicate.

In order to solve the problems of the technologies described above, the technical solution proposed by the present invention is:

A method for coproducing active calcium silicate by producing iron concentrate from copper tailings, comprising the following steps:

(1) mixing copper tailings with alkali for smelting, immersing in water and filtering after smelting to obtain filter residue I and filtrate I; said filter residue I is washed and dried to obtain iron-rich concentrate;

(2) Adding slaked lime and a surface modifier to the filtrate I for in-situ modification to obtain filter residue II and filtrate II, the filter residue II is washed and dried to obtain active calcium silicate, and the filtrate II is evaporated and crystallized Back to step (1) for recycling. The active calcium silicate, also known as highly dispersed calcium silicate, has siloxyl and silanol functional groups on the surface, has strong reinforcing properties, and has good affinity and high dispersibility to rubber, thereby improving The mechanical strength of the product can significantly improve the performance and use value of the composite. The activation index represents the surface wettability of calcium silicate. Hydrated calcium silicate has a hypocritical hydrophilicity, while active calcium silicate is lipophilic. The larger the activation index, the better the lipophilicity. A layer of monomolecular film is formed on the surface of the active calcium silicate, and the dispersion degree of the split body is improved, so that the voids of the creosinate are reduced, and the oil absorption value is reduced. The lower the oil absorption value, the better the dispersion.

In the above-mentioned method for producing iron concentrate from copper tailings and co-producing active calcium silicate, preferably, in the step (2), the amount of the surface modifier added is 1% to 10% of the Si element mass in the filtrate I.

The above method for producing iron concentrate from copper tailings and co-producing active calcium silicate, preferably, in the step (1), the smelting time is 1.5 to 3.5 hours, the smelting temperature is 500 to 700°C, and the copper tailings and alkali The mass ratio is 1:1.0～3.0.

The above-mentioned method for producing iron concentrate from copper tailings and co-producing active calcium silicate, preferably, in the step (1), the leaching temperature is 20-80°C, the leaching time is 10-70min, and the solid-liquid mass ratio during leaching is 1:10-25.

Above-mentioned copper tailings production iron concentrate co-production active calcium silicate method, preferably, in described step (2), the add-on of slaked lime is calculated by calcium element, the silicon element in the filter residue 1 and calcium element mol ratio in the slaked lime It is 1:1.0～2.0.

In the above-mentioned method for producing iron concentrate from copper tailings and co-producing active calcium silicate, preferably, in the step (2), during the in-situ modification process, the reaction temperature is controlled to be 70-90° C., and the reaction time is 60-120 minutes.

In the above-mentioned method for producing iron concentrate with co-production of active calcium silicate from copper tailings, preferably, the copper tailings are solid wastes obtained by flotation depletion and extraction of copper during the copper smelting process, and the main elements in the copper tailings are Fe, Si, O.

In the above-mentioned method for producing iron concentrate from copper tailings and co-producing active calcium silicate, preferably, in the step (1), the alkali is sodium hydroxide.

Above-mentioned copper tailings production iron concentrate co-production active calcium silicate method, preferably, in described step (2), modifying agent is sodium hardate, and Ca (OH) in the slaked lime _The mass fraction is not less than 85%.

The invention proposes the method of using copper tailings as raw material to prepare iron concentrate by low-temperature alkaline smelting, water immersion and in-situ modification, and producing active calcium silicate to process copper tailings. In the smelting stage, since the addition of alkaline medium can effectively break the chemical bond between FeO and _SiO2 , and combine with _SiO2 to form silicate, which increases the activity of FeO and reduces the temperature of the reaction system; the smelted product only needs to pass through water The ferrosilicon element in it can be separated by leaching, avoiding the secondary pollution caused by the introduction of other leaching agents; the leachate (filtrate) is prepared by in-situ modified causticization reaction to prepare active calcium silicate, so that the active calcium silicate The preparation process and the modification process are carried out simultaneously, which shortens the reaction time and reduces the cost; the filtrate for preparing the active calcium silicate can be reused by alkali.

Compared with the prior art, the present invention has the advantages of:

(1) The process of the present invention realizes the directional separation and enrichment of Fe and Si elements in copper tailings, the enrichment and the preparation of related high value-added products, and solves the problem of low resource utilization rate of copper tailings, high energy consumption for processing, and the need for reaction auxiliary materials It is easy to cause secondary pollution and other problems.

(2) The present invention has the characteristics of high resource comprehensive utilization rate, low reaction energy consumption, short process flow, recyclable auxiliary materials, and high product added value: wherein the recovery rate of silicon is ≥ 85.5%, and the recovery rate of iron is higher than 97.7%. The highest iron grade of the iron-rich concentrate prepared by the invention reaches 62.29%, which meets the secondary standard of GB/T2593-2010, and the content of active ingredient CaO in the product active calcium silicate is as high as 50%, which meets the market standard.

(3) The technical process of the present invention does not generate solid waste, and the auxiliary materials in the process can be recycled, and the economic effect is remarkable. The water produced in the technical process of the invention can be recycled without waste water discharge.

Description of drawings

Fig. 1 is a process flow chart of the present invention for producing iron concentrate from copper tailings and co-producing active calcium silicate.

detailed description

In order to facilitate the understanding of the present invention, the following will describe the present invention more fully and in detail in combination with preferred embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

Unless otherwise defined, all technical terms used hereinafter have the same meanings as commonly understood by those skilled in the art. The terminology used herein is only for the purpose of describing specific embodiments, and is not intended to limit the protection scope of the present invention.

Unless otherwise specified, the various reagents and raw materials used in the present invention are commercially available products or products that can be prepared by known methods.

The raw copper tailings used in the following examples are solid wastes obtained by flotation depletion and copper extraction in the copper smelting process. The main elements are Fe, Si, and O. The chemical composition is shown in Table 1.

Table 1 Copper tailings chemical composition (%)

Fe o Si Zn Al Ca Na K Mg Pb Cu 40.74 26.42 20.68 2.86 3.09 1.61 0.87 0.87 0.68 0.71 0.24 Mo S Ti As mn sn P Cr Ni Zr Sr 0.17 0.26 0.29 0.27 0.06 0.06 0.05 0.03 0.02 0.01 0.01

Example 1:

A kind of copper tailings of the present invention produces iron concentrate and co-produces active calcium silicate method, and its technological process as shown in Figure 1, comprises the following steps:

(1) Grind copper tailings to below 200 mesh, weigh 100g copper tailings and 150g NaOH (slag-alkali mass ratio 1:1.5) and mix evenly, place in a muffle furnace and heat to 500°C, keep the temperature for 1.5 hours for smelting . The smelted product is air-cooled, ground, and then soaked in water for 20 minutes. The water soaking temperature is 40°C, and the solid-liquid mass ratio is 1:15. After the water soaking is completed, the solid-liquid separation is carried out. The obtained filter residue is washed to neutral and then dried to obtain iron-rich concentrate Products, the iron grade reaches 52.11%.

(2) Add sodium stearate of 5% Si element quality in the filtrate to the filtrate obtained in the step of solid-liquid separation and mix evenly, then add slaked lime (Ca(OH) ₂ with a mass fraction of 90 %) after being uniform, control the reaction temperature to be 75°C, and the reaction time is 90min. After the reaction is over, the filter residue obtained from solid-liquid separation is neutralized and then dispersed and washed, and dried to obtain the finished active calcium silicate; the filtrate is evaporated and crystallized to produce Get NaOH and return to step (1) for recycling. During the whole process, the recovery rates of iron and silicon reach 97.1% and 90.25% respectively, and the content of active ingredient CaO in the active calcium silicate reaches 51.6%.

Test the activity index of the active calcium silicate that this implementation obtains is 85%, and oil absorption value is 75ml/(100g); And when not adding modifying agent, the activity index of calcium silicate is 0%, and oil absorption value is 85ml/(100g) ).

Example 2:

A kind of copper tailings of the present invention produces iron concentrate and co-produces active calcium silicate method, and its technological process as shown in Figure 1, comprises the following steps:

(1) Grind the copper tailings to below 200 mesh, weigh 200g copper tailings and 400g NaOH (slag-alkali mass ratio 1:2) and mix evenly, place in a muffle furnace and heat to 550°C, keep the temperature for 2 hours for smelting . After the smelted product is air-cooled, it is ground and soaked in water for 40 minutes. The water immersion temperature is 50°C and the mass ratio of solid to liquid is 1:10. , the iron grade reaches 56.11%.

(2) in the filtrate that step (1) solid-liquid separation obtains, add the sodium stearate of Si element mass 8% in the filtrate after mixing uniformly, add slaked lime (Ca(OH) according to the silicon-calcium molar ratio ₁ :1.5 The quality of After the fraction is 85%), the reaction temperature is controlled to be 80°C, and the reaction time is 70min. After the reaction is over, the filter residue obtained by solid-liquid separation is neutralized and then dispersed and washed, dried to obtain the finished active calcium silicate, and the filtrate is evaporated The NaOH obtained after crystallization is returned to step (1) for recycling. In the whole process, the recovery rates of iron and silicon reach 98.1% and 87.69% respectively, and the content of active ingredient CaO in the active calcium silicate reaches 53.1%.

The activity index of the active calcium silicate obtained by testing the present embodiment is 87%, and the oil absorption value is 74ml/(100g); When no modifying agent is added, the activity index of calcium silicate is 0%, and the oil absorption value is 83ml/(100g) ).

Example 3:

A kind of copper tailings of the present invention produces iron concentrate and co-produces active calcium silicate method, and its technological process as shown in Figure 1, comprises the following steps:

(1) Grind the copper tailings to below 200 mesh, weigh 100g copper tailings and 250g NaOH (slag-alkali mass ratio 1:2.5) and mix evenly, place in a muffle furnace and heat to 600°C, keep the temperature for 2.5 hours for smelting . The smelted product is air-cooled, ground, and then soaked in water for 50 minutes. The water soaking temperature is 60°C, and the solid-liquid mass ratio is 1:25. After the water soaking is completed, the solid-liquid separation is carried out. The resulting filter residue is washed to neutral and then dried to obtain iron-rich concentrate. Products, the iron grade reaches 59.26%.

(2) In the filtrate that step (1) solid-liquid separation obtains, add the sodium stearate of Si element quality 10% in the filtrate after mixing uniformly, add slaked lime (Ca(OH) according to the silicon-calcium molar ratio 1: _2.0 The quality of After the fraction is 88%), the reaction temperature is controlled to be 90°C and the reaction time is 100min. After the reaction is over, the filter residue obtained by solid-liquid separation is neutralized and then dispersed and washed, and dried to obtain the finished active calcium silicate; the filtrate is evaporated The NaOH obtained after crystallization is returned to step (1) for recycling. In the whole process, the recovery rates of iron and silicon reach 98.2% and 91.5% respectively, and the content of active ingredient CaO in the active calcium silicate reaches 56.4%.

The activity index of the active calcium silicate obtained by testing the present embodiment is 83%, and the oil absorption value is 78ml/(100g); When no modifying agent is added, the activity index of the calcium silicate obtained is 0%, and the oil absorption value is 86ml / (100g).

Example 4:

A kind of copper tailings of the present invention produces iron concentrate and co-produces active calcium silicate method, its technological process as shown in Figure 1, comprises the following steps:

(1) Grind the copper tailings to below 200 mesh, weigh 100g copper tailings and 300g NaOH (slag-alkali mass ratio 1:3.0) and mix evenly, place in a muffle furnace and heat to 600°C, keep the temperature for 3 hours for smelting . The smelted product is air-cooled, ground and then immersed in water for 80 minutes. The temperature of water immersion is 70°C, and the mass ratio of solid to liquid is 1:20. Products, the iron grade reaches 62.29%.

(2) in the filtrate that step (1) solid-liquid separation obtains, add the sodium stearate of Si element quality 6% in the filtrate after mixing uniformly, add slaked lime (Ca(OH) according to the silicon-calcium molar ratio 1: _2.0 The quality of After the fraction is 92%), the reaction temperature is controlled to be 90°C and the reaction time is 80min. After the reaction is over, the filter residue obtained by solid-liquid separation is neutralized and then dispersed and washed, dried to obtain the finished active calcium silicate, and the filtrate is evaporated The NaOH obtained after crystallization is returned to step (1) for recycling. In the whole process, the recovery rates of iron and silicon reach 99.3% and 86.5% respectively, and the content of active ingredient CaO in the active calcium silicate reaches 53.4%.

The activity index of the active calcium silicate that the test present embodiment obtains is 84%, and oil absorption value is 74ml/(100g); When not adding modifying agent, product activity index is 0%, and oil absorption value is 88ml/(100g).

Claims (9)

1. copper tailings produces an iron ore concentrate coproduction active calcium silicate method, comprises the following steps:

(1) copper tailings is mixed with alkali carry out melting, water logging after melting completes, filtration, obtain filter residue I and filtrate I; Described filter residue I obtains rich iron ore concentrate through washing, drying;

(2) in described filtrate I, white lime is added and surface-modifying agent carries out in-situ modified, obtain filter residue II and filtrate II, described filter residue II obtains active calcium silicate after washing drying, and described filtrate II returns in step (1) and recycles after evaporative crystallization.

2. copper tailings as claimed in claim 1 produces iron ore concentrate coproduction active calcium silicate method, and it is characterized in that, in described step (2), the add-on of surface-modifying agent is 1% ~ 10% of Si element quality in filtrate I.

3. copper tailings as claimed in claim 1 produces iron ore concentrate coproduction active calcium silicate method, it is characterized in that, in described step (1), the time of melting is 1.5 ~ 3.5 hours, smelting temperature is 500 ~ 700 DEG C, and the mass ratio of copper tailings and alkali is 1:1.0 ~ 3.0.

4. copper tailings as claimed in claim 1 produces iron ore concentrate coproduction active calcium silicate method, and it is characterized in that, in described step (1), extraction temperature is 20 ~ 80 DEG C, and extraction time is 10 ~ 70min, and during leaching, solid-liquid mass ratio is 1:10 ~ 25.

5. copper tailings as claimed in claim 1 produces iron ore concentrate coproduction active calcium silicate method, it is characterized in that, in described step (2), the add-on of white lime is in calcium constituent, and in the element silicon in filter residue I and white lime, calcium constituent mol ratio is 1:1.0 ~ 2.0.

6. copper tailings as claimed in claim 1 produces iron ore concentrate coproduction active calcium silicate method, and it is characterized in that, in described step (2), controlling temperature of reaction in in-situ modified process is 70 ~ 90 DEG C, and the reaction times is 60 ~ 120min.

7. the copper tailings as described in any one of claim 1 ~ 6 produces iron ore concentrate coproduction active calcium silicate method, and it is characterized in that, described copper tailings is put forward the solid waste after copper through flotation dilution in Copper making process, and in copper tailings, principal element is Fe, Si, O.

8. the copper tailings as described in any one of claim 1 ~ 6 produces iron ore concentrate coproduction active calcium silicate method, and it is characterized in that, in described step (1), alkali is sodium hydroxide.

9. the copper tailings as described in any one of claim 1 ~ 6 produces iron ore concentrate coproduction active calcium silicate method, and it is characterized in that, in described step (2), properties-correcting agent is hard acid ester sodium, Ca (OH) in white lime ₂massfraction be not less than 85%.