增加值与产业关联：乘数取决于炼铁，而不仅是轧制

4.1 Three-quarters of the value of a tonne of rebar is iron

The economic value of long steel is created in steps: mining ore, making iron (by direct reduction or blast furnace), melting it into steel and casting billets, and rolling billets into products. International prices show where value accumulates. In September and October 2026, iron ore of 62% iron content sold for about US$97 to 98 per dry tonne delivered to China [G32][G34]; hot briquetted iron (HBI), a form of direct reduced iron, for US$385 to 395 per tonne delivered to Mediterranean buyers [W10]; heavy melting scrap for about US$403 per tonne delivered to Türkiye [G34]; billets for US$465 to 480 per tonne free on board from China and Russia; and rebar for US$620 to 630 per tonne free on board from Türkiye [G34].

On a common basis, delivered to Cameroon, a tonne of rebar worth about US$685 contains about 1.21 tonnes of metallic charge (scrap, DRI or HBI) worth about US$511 at October 2026 prices, or about 75% of the product value [G34][W10][F], derived. Melting adds only about US$47 per tonne of value at world prices when the iron units are bought in, and rolling about US$131 [G34][F], derived (Table 3.2). The step from ore to iron is where the large increment lies: a tonne of direct reduced iron sells for roughly four times the price of a tonne of 62% iron ore, although direct reduction requires higher-grade pelletised feed, natural gas and substantial capital [G32][W10]. For an economy, this arithmetic has a simple implication. A domestic industry that melts imported iron units or rolls imported billets retains about a quarter of the product value; one that makes its own iron from domestic ore and gas can retain most of it.

4.2 Today’s metal sector retains little of each FCFA of demand

The most recent economy-wide model for Cameroon is the social accounting matrix (SAM) for 2016 built by researchers at the European Commission’s Joint Research Centre from INS national accounts and household and labour surveys [W02]. Its multipliers measure how much output, value added and employment the whole economy generates when final demand for a commodity rises by one unit, taking into account that part of the demand is met by imports.

For basic metal products and articles of metal, the SAM gives an output multiplier of 1.09, a value-added multiplier of 0.58 and an employment multiplier of 0.54 jobs per million FCFA of final demand [W02]. These values sit near the bottom of the table. Construction work scores 2.26, 1.35 and 1.13; electricity 2.36 and 1.41 for output and value added; transport and storage 2.63 and 1.77 [W02]. Commodities that Cameroon almost entirely imports, such as machinery and electrical appliances (0.08) or transport equipment (0.07), score lowest of all [W02]. Non-metallic mineral products, which include cement made largely from imported clinker, score 0.91 [W02]; clinker imports rose by 20.5% to 3,107 thousand tonnes in 2025 [C05].

Source: El Meligi, Ferreira, Nechifor and Ferrari, Environmental sustainability and job creation: a SAM-based approach for Cameroon (European Commission JRC, 2023), Table 2 [W02].

The reason is structural. When a builder buys rebar rolled in Douala from Indonesian billets, most of the price leaves the country to pay for the billets, and only the rolling margin, the wages and the local services stay. The SAM captures this leakage. The 2016 matrix predates the expansion of domestic wire-rod rolling (Chapter 2), but that expansion replaced imports of wire rod with imports of billets, so the structure of the leakage has not fundamentally changed [C06].

The SAM multipliers are not a forecast for a new works. They describe the average structure of an existing sector. They do, however, show the baseline against which any claim of economic benefit should be measured, and they show that the problem is the import content of the iron, not a lack of rolling capacity.

4.3 In deep steel economies, each unit of steel value added supports several more

Multipliers estimated for mature steel economies show what becomes possible when supply chains are domestic. They are summarised in Table 4.1 and should be read as upper bounds for Cameroon.

European Union. The European steel association EUROFER estimates that the EU steel industry’s direct gross value added of about €39 billion supported €177 billion in total in 2024, a Type I value-added multiplier of 3.5 and a Type II multiplier of 4.5 [P02].

World. worldsteel and Oxford Economics estimated that each US dollar of value added in steelmaking supported a further US$2.50 of value added in the steel supply chain in 2017, and that steel supported or facilitated US$2.9 trillion of value added, 3.8% of world GDP, once steel-using sectors are included [P01].

United States. The Economic Policy Institute’s 2019 update of employment multipliers estimates that US$1 million of final demand for the products of iron and steel mills supports 0.81 direct jobs, 5.01 jobs at suppliers and 2.47 induced jobs [W01]. Chapter 5 discusses the job multipliers in detail.

Table 4.1 Value-added and output multiplier evidence for steel, and its applicability to Cameroon

Source: as cited; the last row is derived by Cameroon Steel (Chapter 9 and Annex A).

The gap between the first and the other rows is the economic case for domestic iron units. It is also a warning: a project that cites European or global multipliers for a works that melts imported scrap and HBI in Cameroon would overstate its effects several times over.

4.4 Backward linkages: power, gas, ports and iron units

A long-products works is one of the largest single customers an economy can host. Using Cameroon Steel’s reference configuration (RC-1), Table 4.2 sets out the planned or indicative quantities of the main inputs at each phase, and compares them with national benchmarks.

Power. At full capacity of 1 Mtpa, RC-1 would draw about 753 GWh a year, an average load of about 94 MW, equal to 9.3% of Cameroon’s 2025 electricity generation of 8,119.9 GWh and about 7.4% of the 2025 peak demand of 1,278 MW [F][E15], derived. Phase 1 alone would draw about 289 GWh (36 MW on average) [F]. These figures use the RC-1 planning value of 450 kWh per tonne of liquid steel in the furnace; with 30% DRI or HBI in the charge the upper planning value is about 490 kWh, which would add about 13 GWh a year in Phase 1 and 43 GWh at full capacity [F][T09], derived. The 225 kV line and substation that the Port Autonome de Kribi is building to serve the industrial zone are designed for 100 MW initially and 330 to 400 MW later [Z43]. A steelworks with a high load factor is an anchor customer: in 2025 the Kribi gas-fired plant delivered 559.7 GWh against a plan of 1,031.2 GWh, a capacity factor of about 30%, while 150 MW of industrial demand remained unmet because of transmission delays [E15][E16]. At 43.7 FCFA per kWh, the central power price of the series (Chapter 7), full-capacity consumption would be worth about 33 bn FCFA a year to the power sector, derived.

Gas. Phases 2 and 3 use gas-fired reheating furnaces for sections: about 0.26 PJ a year rising to 0.91 PJ at full capacity, equal to about 0.83 billion cubic feet, or 1.1% of Cameroon’s 2025 gas production of 75.5 billion cubic feet [F][E04], derived. A direct-reduction module for Cameroonian ore, which RC-1 reserves as an indicative step after 2034, would need about 9 billion cubic feet a year for 1 Mt of DRI, about 12% of 2025 production [F][E04], derived. Since the floating LNG vessel that took about 95% of 2025 output left in July 2026, domestic industrial demand is the main way to monetise Sanaga Sud gas [E04][E09].

Port and logistics. RC-1 implies about 0.35 Mt a year of inbound bulk and break-bulk cargo in Phase 1 (351,000 tonnes), about 0.60 Mt after Phase 2 and about 1.24 Mt at full capacity (1,239,000 tonnes), plus 0.3 to 1.0 Mt of outbound products [F]. Inbound cargo would equal 2.8% to 9.8% of Kribi port’s 2025 traffic of 12.7 Mt [E44], derived, and the works would generate 74 to 245 truck loads a day before any rail siding is built [F].

Iron units. Every tonne of finished product needs about 1.21 tonnes of metallic charge [F]. Domestic scrap collection is the first local source. The only quantified study of scrap arising in Cameroon, now dated, estimated 53,000 to 62,000 tonnes a year in 2006 [C42], and the existing mills already compete for it [C40]. RC-1 therefore plans on 30,000 tonnes a year of domestic scrap, within a range of 0 to 60,000 tonnes, at every phase; the rest of the charge is imported [F], assumed. The second source is Cameroonian ore. The 2023 Mining Code requires each mining convention to fix a share of production for local transformation, with a minimum of 15% (Article 40(4)) [W09]. Cameroon Steel’s sister company, Cameroon Mining Company, holds the Mbalam exploitation permit [X01]. Its convention is reported to oblige it to transform 15% of its production locally, and the same source presents Cameroon Steel as the national steel hub of that programme [O17]. Turning that obligation into iron units requires direct-reduction-grade concentrate, pelletising and gas, which are later-phase questions examined in other papers of this series.

Table 4.2 Backward linkages of a phased 1 Mtpa EAF long-products works (RC-1 planning balance)

Source: Cameroon Steel RC-1 reference configuration, planning balance, edition 10 October 2026 [F] (status: planned for Phase 1, indicative for later phases; derived from capacities and benchmarks); national benchmarks as cited. Average MW is annual energy divided by 8,000 operating hours.

4.5 Forward linkages: construction, fabrication and by-products

On the output side, long steel feeds a few large sectors. Construction, with 1,991 bn FCFA of value added in 2025 [C09], is the main user of rebar and wire products; the average cost of building in Cameroon was about 1.04 million FCFA per square metre in 2024 [C15]. Sections and beams feed fabrication of industrial buildings, warehouses, bridges, pylons and port structures, much of which is now imported as finished structures (HS 7308, US$58.0 million in 2023) [C06]. Wire rod feeds wire drawing, nails and mesh.

Forward linkages are where the quality of import substitution shows. Lane’s study of Korea found that downstream users of the targeted intermediates benefited, because the policy expanded supply and, over time, lowered the relative price of the inputs they bought [W04]. The opposite also holds: if domestic steel is sold above import parity, every builder and fabricator pays a tax that reduces their own competitiveness. The cost of protection estimated in Chapter 3 is a negative forward linkage. Availability of medium and heavy sections close to the user, with shorter lead times and smaller lot sizes than imports allow, is a positive one, provided prices are close to import parity.

Steelmaking also produces by-products with local uses. RC-1 projects 45 to 149 thousand tonnes a year of electric arc furnace slag, which, once processed, can be used as aggregate in road construction, and about 6 to 20 thousand tonnes of mill scale [F]. Using them locally avoids disposal and supplies a construction input.

Source: Cameroon Steel RC-1 reference configuration [F]; Mining Code, Article 40(4) [W09]; Mbalam convention as reported [O17].

4.6 Domestic iron units are the lever that raises the multiplier

The evidence of this chapter can be summarised in one comparison. Re-rolling imported billets, which is what Cameroon’s industry does today, retains about one-fifth to one-quarter of the value of a tonne of rebar in the domestic economy. Melting imported scrap and HBI retains a similar share, because the iron units are still bought abroad. Melting domestically collected scrap, and later direct reduced iron made from Cameroonian ore and gas, retains most of it, and adds the linkages to mining, gas production, rail and port that the SAM multipliers for transport, electricity and services show to be strong [W02]. Chapter 9 quantifies this comparison in foreign-exchange terms.

The policy implication is not that every phase must start with domestic iron. A phased works can begin with imported iron units, build skills, markets and logistics, and add domestic scrap collection and direct reduction as ore, gas and finance allow. But the economic case should be stated honestly at each phase: the early phases create jobs, skills and a regional supply of products not made locally; the large gains in value added and foreign exchange come with domestic iron.