Plant - Yellow Dock
Plant - Yellow Dock
Mechotech designs and manufactures turnkey natural colour extraction plants for yellow dock. In the Mechotech catalogue, Plant - Yellow Dock is listed in the Brown Colour group alongside Bark - Oak Bark / Birch, Hulls - Walnut, Roots - Dandelion, Grinds - Coffee, Woody Stems - Ivy, Shoots - Golden Rod and Leaves - Tea / Sumac. According to Mechotech’s article on brown colour extraction from yellow dock roots, the plant is Rumex crispus, and the deep taproot yields yellow-brown to rich brown colour from two pigment families: yellow anthraquinones, which the article names as including emodin and chrysophanol, and tannins that add brown depth and dyeing power. Because the colour is not pH-indicating anthocyanin, it is described as comparatively stable across pH and tolerant of heat. The catalogue entry says ‘Plant’, while the article takes the root, so the plant part is confirmed with the client.
Mechotech’s Plant - Yellow Dock plant is configured around the raw material and the target colour extract. It is built in SS 316L with integrated solvent recovery, automation and full documentation, and is delivered as a commissioned turnkey system. The article describes a straightforward water route: the washed, chopped root is extracted with hot water at 70 to 95 degrees Celsius, with a mild alkaline adjustment able to raise anthraquinone solubility and deepen the tone, followed by pressing, filtration, a second leaching pass over the marc, vacuum concentration and spray drying, with standardisation on colour value and tannin content. The route and conditions for a given project are established during process development and pilot validation.
Technical Specifications
| Product | Plant - Yellow Dock Natural Colour Extraction Plant |
|---|---|
| Raw Material | Yellow dock roots (catalogue name: Plant - Yellow Dock) |
| Botanical Name | Rumex crispus (per Mechotech’s article) |
| Plant Part / Feed Form | Deep taproot, washed of soil, trimmed and chopped or crushed to expose the yellow inner tissue; fresh or dried (per the article); the catalogue says ‘Plant’, so the exact plant part and feed form are confirmed with the client |
| Colour Group | Brown Colour (see the Brown Colour page) |
| Colour-forming Components | Anthraquinones (the article names emodin, chrysophanol and related derivatives) for yellow to golden and orange-brown tones, and tannins for brown depth and dyeing power |
| Process Category | Natural Colour Extraction Plants |
| Extract Type | Natural colour extract (liquid concentrate or dried powder, per specification) |
| Extraction Method | Closed jacketed SS 316L hot-water extraction (the article gives 70 to 95 degrees Celsius), with repeated leaching of the marc; route confirmed during process development |
| Product-contact Material | SS 316L |
| Filtration System | Plate-and-frame filter press with cartridge polish filters |
| Concentration System | Falling-film / vacuum evaporator with solvent recovery where a solvent is used |
| Drying System | Spray or vacuum dryer, where a powder is required |
| Automation | PLC-based |
| Plant Capacity | Configured to requirement |
| Utility Requirements | Steam, chilled/cooling water, compressed air and power (project-specific) |
| Compliance | GMP hygienic design; full documentation for qualification |
| Final Product Form | Natural colour extract (brown colour group) |
Plant Capacities
| Plant Scale | Raw Material Throughput | Typical Use |
|---|---|---|
| Pilot | Configured to your feedstock and trial plan | Product development, parameter validation |
| Semi-Commercial | Configured between pilot and commercial scale | Scale-up trials, contract manufacturing |
| Commercial | Configured to raw-material supply and confirmed buyer volume | Commercial production |
Capacity is configured to raw-material supply, confirmed buyer volume and investment timeline; a pilot plant is recommended to validate parameters before scaling.
Manufacturing Process
Raw Material Preparation
The deep taproots are washed to remove soil, trimmed and chopped or crushed to expose the yellow, pigment-rich inner tissue; the article stresses thorough cleaning because the root is fibrous and soil-laden. The root is used fresh or dried.
Extraction
The prepared root is extracted with hot water in closed jacketed SS 316L vessels, typically at 70 to 95 degrees Celsius according to the article, which describes the anthraquinones and tannins as heat-stable. A mild alkaline adjustment can increase anthraquinone solubility and deepen the tone; the temperature, contact time and any adjustment are set during process development.
Filtration
The coloured liquor is pressed and drained from the spent root and filtered through a plate-and-frame filter press and cartridge polish filters to remove fibre and fine solids; the article describes a second pass over the marc to recover residual pigment.
Concentration & Solvent Recovery
The pooled extract is concentrated under vacuum to build strength in a falling-film / vacuum evaporator. The article notes that because the pigments tolerate heat, concentration and drying are undemanding.
Standardisation
The concentrate is standardised on colour value and tannin content, along with solids and cleanliness; the article says batches are blended and the finished concentrate standardised to a declared strength for reproducible results.
Drying & Quality Control
The standardised extract is supplied as a liquid dye concentrate or spray-dried into a stable powder, per specification, then released after assay, heavy-metal, microbial and moisture testing.
Major Plant Equipment
- Raw material cleaning, authentication and moisture testing
- Size-reduction system
- Closed jacketed SS 316L extraction vessels
- Solvent storage tanks
- Plate-and-frame filter press
- Cartridge polish filtration
- Falling-film / vacuum evaporator
- Solvent recovery unit and condensers
- Standardisation / blending vessel
- Spray or vacuum dryer
- CIP system
- Automation and instrumentation
Plant Output
Applications
- Natural textile dyeing of wool, silk and, with mordanting, cotton and linen in yellow, tan and brown tones (per the article)
- Craft and wood colourant, and leather colouring, where tannin content supports the role (per the article)
- Natural yellow-brown tint for cosmetics and personal care (per the article)
- Natural colour and dye ingredient supply
Key Features
SS 316L Construction
Electropolished SS 316L product-contact surfaces with CIP operation between batches.
Dual-Pigment Yellow-Brown
Anthraquinones supply the yellow and tannins the brown depth, so one extract spans soft yellow to rich brown depending on mordant, as the article describes.
Heat-Tolerant Pigments
The article notes the colour tolerates heat and holds its tone across a pH range, so extraction at elevated temperature and vacuum concentration are undemanding.
Standardised on Colour Value and Tannin
The finished concentrate is standardised on colour value and tannin content, with batches blended to a declared strength.
Scalable Batch Capacity
Plants are configured to requirement from pilot scale upward, with modular expansion.
Frequently Asked Questions
Does Mechotech supply the complete machinery for Plant - Yellow Dock?
What specification can the Plant - Yellow Dock plant achieve?
What production capacities are available for the Plant - Yellow Dock plant?
Which industries use the Plant - Yellow Dock plant?
Which part of yellow dock is processed?
What gives yellow dock root its colour?
Why is the page in the Brown Colour group when the root is yellow?
How do mordants change the shade?
Is yellow dock a cultivated crop?
Where does this page sit in the brown colour range?
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