Residual lyes from the manufacture of wood pulp, including lignin sulphonates, but excluding tall oil

CPC v2.1 Code: 3923

About residual lyes from the manufacture of wood pulp, including lignin sulphonates, but excluding tall oil

cpc code 3923 covers the residual lyes generated during the production of wood pulp. These lyes, which include lignin sulphonates, are an important byproduct of the pulp and paper industry. They find a variety of applications in other sectors, making this code a crucial link in the broader supply chain. Understanding the nature and uses of these residual lyes is essential for businesses involved in the import, export, or processing of wood-based products.

Production process

The production of residual lyes under cpc code 3923 is a byproduct of the kraft pulping process, which is the dominant method for manufacturing wood pulp. In this process, wood chips are cooked in a solution of sodium hydroxide and sodium sulfide, known as white liquor. This dissolves the lignin that binds the cellulose fibers, allowing the pulp to be separated. The resulting black liquor, which contains the dissolved lignin and other organic compounds, is then processed to recover the inorganic chemicals for reuse, while the residual lyes are collected as a valuable byproduct.

Production inputs

The primary inputs for the production of residual lyes under cpc code 3923 are the wood chips and chemicals used in the kraft pulping process. Hardwood and softwood species are the main sources of wood fiber, while the sodium hydroxide and sodium sulfide are the key chemical inputs. Additionally, the pulp and paper mills require specialized equipment such as digesters, evaporators, and recovery boilers to carry out the pulping and chemical recovery operations.

Production outputs

The main output of cpc code 3923 is the residual lyes, which contain a range of organic compounds, including lignin sulphonates. These lyes find applications in various industries, such as 3812 Tanning or dyeing extracts; tannins and their derivatives; dyes, pigments and other colouring matter; paints and varnishes; putty and other mastics; inks, where they are used as dispersants, emulsifiers, and binders. They are also utilized in 2011 Manufacture of basic chemicals, fertilizers and nitrogen compounds, plastics and synthetic rubber in primary forms, 2013 Manufacture of other inorganic basic chemicals, and 2014 Manufacture of other organic basic chemicals for the production of a wide range of chemical products.

Family tree for residual lyes from the manufacture of wood pulp, including lignin sulphonates, but excluding tall oil

    graph LR
    A["<a href='/classifications/cpc/v2-1/3'>3: Other transportable goods, except metal products, machinery and equipment</a>"]
A --> B["<a href='/classifications/cpc/v2-1/39'>39: Wastes or scraps</a>"]
B --> C["<a href='/classifications/cpc/v2-1/392'>392: Non-metal wastes or scraps</a>"]
C --> D["<a href='/classifications/cpc/v2-1/3923'>3923: Residual lyes from the manufacture of wood pulp, including lignin sulphonates, but excluding tall oil</a>"]

    C --> E["<a href='/classifications/cpc/v2-1/3921'>3921: Miscellaneous textile wastes</a>"]
C --> F["<a href='/classifications/cpc/v2-1/3922'>3922: Waste of leather, leather dust, powder and flour</a>"]
C --> G["<a href='/classifications/cpc/v2-1/3924'>3924: Waste and scrap of paper or paperboard</a>"]
C --> H["<a href='/classifications/cpc/v2-1/3925'>3925: Waste, parings and scrap of rubber (except hard rubber) and powders and granules obtained therefrom</a>"]
C --> I["<a href='/classifications/cpc/v2-1/3926'>3926: Used pneumatic tyres of rubber</a>"]
C --> J["<a href='/classifications/cpc/v2-1/3927'>3927: Waste, parings and scrap of plastics</a>"]
C --> K["<a href='/classifications/cpc/v2-1/3928'>3928: Sawdust and wood waste and scrap</a>"]
C --> L["<a href='/classifications/cpc/v2-1/3929'>3929: Other non-metal waste or scrap</a>"]

    D --> M["<a href='/classifications/cpc/v2-1/39230'>39230: Residual lyes from the manufacture of wood pulp, including lignin sulphonates, but excluding tall oil</a>"]


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class C level3
class D level4
class E level4
class F level4
class G level4
class H level4
class I level4
class J level4
class K level4
class L level4
class M level5

  class D highlight

  %% class A level1
  %% class B,C level2
  %% class D,E,F,G,H,I level2
  %% class J,K,L,M,N,O,P level3
  %% class D highlight