Scientific Article: Raw Material Extraction and Processing in the Deep-Sea and Energy Sector: Technological Strategies and Infrastructures

Introduction

The growing demand for high-tech metals such as lithium, nickel, cobalt, and manganese is a direct result of the global energy transition, digitalization, and electrification of transport. In this context, deep-sea mining, particularly the mining of manganese nodules, as well as the efficient transport and processing of rare raw materials, are becoming the focus of strategic considerations. This article analyzes the technical and infrastructural challenges and solutions in the following areas:

• On-site vs. off-site refining

• Deep-sea mining of manganese nodules

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• Lithium and hard material pipelines

• Hybrid pipeline technologies

• Comminution technologies for raw materials

1. On-Site vs. Off-Site Refining

1.1 On-Site Refining

On-site refining describes the direct processing of raw materials at the site of their extraction—for example, on a ship, a deep-sea station, or even an extraterrestrial outpost (e.g., on a moon or an asteroid). It is essential for:

• Volume reduction: Significant reduction in the mass that needs to be transported (e.g., 70–90% of the slag remains on site).

• Immediate value creation: Materials can be immediately processed as intermediate products.

• More efficient logistics: Less infrastructure required for return transport.

Technological requirements:

• Mobile high-temperature melting plants

• Electrometallurgical cells under seawater or vacuum-compatible conditions

• AI-controlled quality sensors for ore classification

• Corrosion-resistant materials against salt water, pressure, and temperature

1.2 Off-site refining

Off-site refining refers to traditional downstream processing in industrial facilities on land or in orbital stations. It is characterized by:

• Higher energy availability

• More complex chemical processes (e.g., ion exchange processes)

• Better waste recycling and environmental control

Disadvantages:

• High transportation costs

• Risk of raw material loss or piracy

• Delayed material availability

2. Deep-sea mining and manganese nodule mining

Manganese nodules are polymetallic nodules found on the deep sea floor (4,000–6,000 m depth) and contain manganese, nickel, copper, cobalt, and rare earth elements. Mining is considered energy- and logistics-intensive.

2.1 Challenges:

• Mechanical Stress: Extremely high ambient pressure (~600 bar)

• Environmental Risks: Destruction of biotopes, sediment clouds

• Legal Uncertainty: International Maritime Law Regimes (UNCLOS, ISA)

2.2 Extraction Technologies:

• Crawler Systems: Robotic platforms with vacuum or hydraulic grippers

• Suction Lift Systems: Tubers are transported vertically to the surface by water currents.

• Drilling and blasting methods: Only in consolidated subsoils.

3. Pipeline Technologies for Raw Material Transport

3.1 Lithium Pipelines

Lithium is transported in dissolved form (e.g., as lithium chloride), usually from brines or on-site refining.

• Corrosion-resistant pipes (titanium alloys, PTFE-coated)

• Temperature-controlled pipes to prevent crystallization

• Inline measurement sensors for ion concentrations

3.2 Hard Material Pipelines

Nodules, ores, or other solids must be transported in hydraulic suspension:

• Slurry pipelines with 20–40% solids content

• Internal coatingsagainst abrasion (ceramic, polyurethane)

• Lock valves and breaking mechanisms at inlet and outlet points

4. Hybrid Soft-Hard Pipelines

A pioneering concept is the combination of a liquid medium (e.g., lithium solution, salt water) and suspended solids.

Advantages:

• Combined transport of precursors

• Dynamic separation through flow velocity, centrifugal forces, or electromagnetic filters

• Adaptable to topography (e.g., subduction, deep-sea trenches)

Examples:

• Orbitals Production flows between asteroid mines and Lagrange stations

• Deep-sea-to-surface transport for intermediate storage on platforms

5. Comminution Mechanisms and Preprocessing

Efficient comminution is crucial for further processing, whether on-site or for pipeline feed.

5.1 Mechanical Comminution

• Jaw and impact crushers: For coarse lump comminution

• Ball mills and agitator mills: Fine grinding under water

• Autogenous comminution: Use of the plant's own lumps as grinding media

5.2 Thermal Pretreatment

• Pyrolysis process for pre-degassing nodules with organic inclusion matter

• Shock plasma comminution: Use with extraterrestrial ores

5.3 Chemical-physical disaggregation

• Leaching with weak acids, e.g. B. citric acid or sulfuric acid

• Ultrasonic desorption for the release of metal ions

Conclusion and Outlook

The combination of on-site processing, hybrid pipeline systems, and highly automated deep-sea technology opens up new horizons for securing raw materials in the future – both terrestrial and in space. The key challenge lies in balancing efficiency, environmental compatibility, and geopolitical stability. Innovative technologies such as intelligent hybrid pipelines, mobile refining systems, and adaptive crushing networks will become key components of the next industrial era. an era in which the deep sea and orbit are equally being developed industrially.

Literature and References:

• ISA (International Seabed Authority): Technical Study Series

• IEEE OCEANS Conference Proceedings

• Fraunhofer ISE: Studies on On-Site Lithium Extraction

• USGS: Manganese Nodule Resource Estimates

• JOGMEC (Japan Oil, Gas and Metals National Corporation): Deep Sea Mining Trials