Natural Colour Extraction Plants

Grey to Black Colour

Mechotech designs and manufactures turnkey natural colour extraction plants for the grey to black colour group. In the Mechotech catalogue this group lists Galls - Oak Galls, Leaves - Sumac, Hulls - Walnut, Roots - Iris, Dried Bean - Black Beans, Grains - Black Rice, Vegatables - Balck Carrot / Black Currant. The group spans two different colour mechanisms. Tannin-rich materials such as oak galls, sumac leaves and walnut hulls form grey-to-black iron-tannate colour when the extract is reacted with iron, while pigmented grains, beans and vegetables such as black rice and black beans carry anthocyanins.

Mechotech’s grey to black colour plant is configured around the raw material chosen from the group 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 raw material, solvent and extraction route are selected during process development and pilot validation.

Technical Specifications

Product	Grey to Black Colour Natural Colour Extraction Plant
Raw Material	Selected from the group: Galls - Oak Galls, Leaves - Sumac, Hulls - Walnut, Roots - Iris, Dried Bean - Black Beans, Grains - Black Rice, Vegatables - Balck Carrot / Black Currant
Plant Part / Feed Form	Varies by raw material (flowers, leaves, whole plant, skins, galls, hulls, roots, grains or vegetables); confirmed with the client for the chosen material
Colour Group	Grey to Black Colour
Extract Type	Natural colour extract (liquid concentrate or dried powder, per specification)
Extraction Method	Closed jacketed SS 316L extraction with food-grade solvent (alcohol / aqueous), multiple cycles at controlled temperature
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
Drying System	Spray or vacuum dryer
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 (grey to black 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 chosen raw material is authenticated, tested for moisture and cleaned, then milled, crushed or macerated to a uniform particle size to maximise solvent contact before extraction.

Extraction

The prepared raw material is extracted with food-grade solvent (alcohol / aqueous) in closed jacketed SS 316L extractors at controlled temperature over multiple cycles, with the solvent system chosen for the pigment class of the selected material.

Filtration

The extract (miscella) is clarified through a plate-and-frame filter press followed by cartridge polish filters.

Concentration & Solvent Recovery

The miscella is concentrated in a falling-film / vacuum evaporator, with solvent recovered through the condenser return system so that heat exposure of the pigment stays low.

Standardisation

The concentrate is assayed for colour strength and adjusted to the declared target specification before the final finishing step.

Drying & Quality Control

The standardised Grey to Black Colour extract is spray- or vacuum-dried where a powder is required, then released after the agreed assay, residual-solvent, heavy-metal, microbial and moisture tests.

Major Plant Equipment

Raw material cleaning and 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

Natural colour extract (grey to black colour group)

Applications

Natural colour and dye ingredient supply
Food and beverage colour applications (subject to approval of the specific colour in each market)
Cosmetic and personal-care colour applications
Nutraceutical and Ayurvedic / herbal formulations
Pharmaceutical standardised ingredient supply

Key Features

SS 316L Construction
Electropolished SS 316L product-contact surfaces with CIP operation between batches.
Closed-Loop Solvent Recovery
Integrated condenser-return recovery reuses solvent between batches and reduces solvent loss.
Multi-Material Flexibility
The same extraction, filtration and concentration line can be configured for the different raw materials in the group, with solvent and conditions set per material.
Standardised to Specification
In-process and batch-release assay are used to check the finished extract against its declared target specification.
Gentle Concentration
Vacuum concentration keeps heat exposure low for temperature-sensitive colour compounds.
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 Grey to Black Colour?

Yes. Mechotech supplies the complete turnkey plant for Grey to Black Colour — engineered, fabricated at our Hyderabad facility, installed and commissioned as a single integrated system. Final process parameters are established during process development and pilot validation.

What specification can the Grey to Black Colour plant achieve?

The plant is configured to the client’s target specification for Grey to Black Colour; the specification achieved is established during process development and pilot validation, and each batch is released with batch-release testing and certificate-of-analysis documentation.

What production capacities are available for the Grey to Black Colour plant?

Capacity for the Grey to Black Colour plant is configured to raw-material supply, confirmed buyer volume and investment timeline, starting at pilot scale; a pilot plant is recommended to validate parameters before scaling.

Which raw materials are in the Grey to Black Colour group?

The catalogue lists these raw materials in the group: Galls - Oak Galls; Leaves - Sumac; Hulls - Walnut; Roots - Iris; Dried Bean - Black Beans; Grains - Black Rice; Vegatables - Balck Carrot / Black Currant. Each has its own page with the plant part and process for that material.

How is a grey-to-black colour obtained from these materials?

Tannin-rich materials are extracted into water or alcohol and the tannin liquor is combined with iron salts and allowed to oxidise, building an iron-tannate colour whose shade, from grey to deep black, depends on the iron-to-tannin ratio, pH and oxidation. Pigmented grains and beans are extracted for their anthocyanins instead. See Grey to Black Colour Extraction from Oak Galls, from Sumac Leaves, from Walnut Hulls, Black Bean Colour Extraction and Black Rice Colour Extraction.

How is the raw material chosen?

The choice depends on the target shade, the pigment class, availability and the intended use. Mechotech screens the candidate materials during process development and confirms the choice on a pilot run before the plant is configured.

Which related colour pages does Mechotech list?

The catalogue hub is Natural Colour Extraction Plants. Other colour groups include Red Colour, Pink Colour, Yellow Colour, Blue to Bluish Purple Colour and Brown Colour.

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Grey to Black Colour