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    Home > Chemicals Industry > China Chemical > The non-ferrous industry has broad prospects for acid recovery and comprehensive utilization

    The non-ferrous industry has broad prospects for acid recovery and comprehensive utilization

    • Last Update: 2022-06-25
    • Source: Internet
    • Author: User
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      As a basic industrial chemical raw material, sulfuric acid is widely used in various fields of the national economy.
    Statistics from the National Bureau of Statistics and related literature data show that my country's sulfuric acid consumption was 92.
    129 million tons in 2017, 96.
    859 million tons in 2018, and slightly dropped to 89.
    357 million tons in 2019.
    The main methods for producing sulfuric acid in my country are sulphur-burning sulphuric acid, non-ferrous smelting flue gas sulphuric acid and pyrite sulphuric acid production, accounting for 45.
    8%, 36.
    1% and 17.
    1% respectively, of which sulphur-burning sulphuric acid is the main method.
    Due to the large demand and the shortage of sulfur materials, my country needs to import tens of millions of tons of sulfur each year to meet the market demand for sulfuric acid.
    At the same time, a large amount of waste sulfuric acid is produced in industrial production.
    If industrial waste acid can be treated as a resource, it is not only beneficial to green development but also beneficial to the sustainable development of my country's sulfuric acid industry.


      The source of waste acid

      In the sulfuric acid consumption structure, although the fertilizer industry uses the largest amount, basically no waste acid is produced during the production process.
    my country's annual output of 10 million tons of waste acid is mainly the titanium dioxide industry, the steel industry and the non-ferrous smelting industry.
    Waste acid in the titanium dioxide industry is mainly derived from the production process of hydrolyzing metatitanic acid, and about 6 tons of waste sulfuric acid are produced for every ton of titanium dioxide produced.
    From 2016 to 2019, my country's titanium dioxide production capacity has stabilized, with an annual output of about 2.
    8 million tons and an annual output of about 16.
    8 million tons of waste acid.
    The main components are waste sulfuric acid and valuable metal ions such as titanium and iron.


      The waste acid in the iron and steel industry mainly comes from the surface pickling production process of sulfuric acid, and about 0.
    5 tons of waste sulfuric acid are produced for every ton of stainless steel produced.
    From 2017 to 2019, my country's stainless steel production capacity has basically stabilized at 28 million tons, and the annual output of waste sulfuric acid is about 14 million tons.
    The main components are waste sulfuric acid and valuable metal ions such as iron and chromium.


      In non-ferrous smelting flue gas scrubbing, the amount of scrubbing flue gas produced per ton of copper in the copper smelting process is about 0.
    2m3~0.
    3m3, and the concentration of waste acid is about 8%~15%.
    During the zinc smelting process, the amount of scrubbing flue gas is about 8%~15%.
    The amount of waste acid is about 0.
    3m3~0.
    5m3, and the amount of waste acid that is washed by ton of lead flue gas during the lead smelting process is about 0.
    6m3~1.
    0m3.
    Statistics from the China Nonferrous Metals Industry Association show that from 2017 to 2019, my country's total mineral copper, zinc and lead production capacity fluctuated slightly between 17 million and 20 million.
    In 2017, my country’s mineral copper, zinc, and lead production capacities were 6.
    59 million tons, 6.
    22 million tons, and 4.
    72 million tons, respectively, and the total mineral output was 17.
    53 million tons; in 2018, my country’s mineral copper, zinc, and lead production capacities were 6.
    34 million tons, respectively.
    5.
    68 million tons and 5.
    11 million tons, total mineral output is 17.
    13 million tons; in 2019, my country's mineral copper, zinc and lead production capacity were 7.
    43 million tons, 6.
    24 million tons and 5.
    8 million tons, respectively, and total mineral output was 19.
    47 million tons .
    According to conservative estimates of production capacity, the amount of waste acid from flue gas scrubbing in the non-ferrous industry is about 4.
    8 million to 10.
    2 million tons.
    The main components are sulfuric acid, hydrochloric acid, hydrofluoric acid, copper, lead, and zinc, and the acidity is about 2% to 10%.
    In the non-ferrous smelting production process, in the cathode copper electrolysis process, it is necessary to regularly remove the waste acid to reduce the impurity ion concentration to ensure the product quality.
    For every ton of valuable metals such as copper cathode, 0.
    6m3 of electrolytic waste acid needs to be removed regularly.
    According to statistics from the China Nonferrous Metals Industry Association, the total production capacity of mineral copper, zinc and lead in my country in the past three years has been 17-20 million, and the amount of smelting waste acid is about 10.
    2 million-12 million tons.
    Its main components are sulfuric acid and lead-zinc-copper.
    , The acidity is about 10%~20%.
    In the past three years, the annual output of waste acid was about 15 million to 22.
    2 million tons.
    Although all smelting waste acids in the non-ferrous industry have been harmlessly treated according to environmental protection requirements, the current comprehensive utilization level still needs to be improved.


      In summary, the amount of waste acid in my country's titanium dioxide industry, steel industry and smelting industry is large, with an annual output of about 50 million tons of waste acid.
    At the same time, because the waste acid in the smelting industry is dominated by a highly corrosive mixed acid system formed by sulfuric acid, hydrofluoric acid and hydrochloric acid, and is rich in other heavy metals, it is currently one of the most difficult waste acids to recover in the waste acid field.


      Current Status and Prospects of Waste Acid Recovery in Nonferrous Industry

      There are two main ways to dispose of waste acid.
    One is the traditional lime neutralization method, which is also the more commonly used method at present, that is, the use of lime, calcium carbide slag and slaked lime to neutralize the waste acid, and the neutralized liquid can be discharged through advanced treatment such as iron salt method.
    However, after the neutralization treatment, a large amount of sludge will be produced, and a large amount of heavy metal ions will remain in the waste liquid.
    The other is the recycling method of waste acid resources.
    Common treatment processes include sulfurization, sulfurization electrodialysis, sulfurization-electrodialysis-evaporation, and sulfurization-evaporative stripping.


      The composition of waste acid in the non-ferrous industry is complex, it is difficult to recycle, and the technical threshold is high.
    At the same time, in recent years, as China's environmental supervision policies have become stricter, the traditional lime neutralization treatment method does not meet the current environmental protection policy requirements, forcing the treatment of waste acid in the non-ferrous industry to move towards recycling.
    However, in general, due to technical thresholds, the recovery rate of waste acid in the industry is relatively small.
    In 2019, the amount of waste acid recovered in the non-ferrous industry was about 220,000 tons, and the recovery rate was less than 5%.
    Since the beginning of this year, the production capacity of copper, lead and zinc in the non-ferrous industry has basically stabilized, and the market supply and demand have basically been balanced.
    In the next 5 to 10 years, the annual output of waste acid will be basically the same at about 18 million tons.
    The non-ferrous industry has a bright future for acid recovery.


      As an important part of hazardous waste, waste acid from non-ferrous smelting has broad prospects for its recovery and resource utilization.
    Promoting the recycling of waste acid can not only avoid environmental pollution and reduce the use of primary resources, but also spawn new energy-saving and environmentally-friendly industries and form new economic growth points.
    With the continuous improvement of environmental protection policies and the improvement of the waste acid recycling mechanism, the amount of waste acid recycling in my country's non-ferrous industry will continue to increase, with a market size of tens of billions.



    Transfer from: China Nonferrous Metals News

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