今年论坛的议程里就藏着答案。11月8日，吉利汽车讲"ESG数字化赋能汽车循环经济"，中国汽车技术研究中心讲"新能源汽车用再生金属市场潜力"，UL美华认证讲"碳关税驱动下再生金属低碳认证体系与价值挖掘"。11月9日，再生金属分会发布《再生金属技术装备选型手册及案例（中英双语）》，圆桌议题是装备国产化、智能化改造与降本增效。

把这些题目并排放，会看到一个共同点：下游要的三样东西——碳足迹、再生比例、成分稳定性——没有一样是在贸易环节能解决的。它们的核算边界，落在熔炼、预处理和铸造这道工序上。也就是说，绿色采购这张审核表，最后是由熔炼炉来答卷的。

熔炼炉一年的运行成本里，天然气是最大的一块，它同时也是碳足迹表里最直接的一行。行业常见的气耗区间在65-75方/吨，上下差距不小。

把账算死：一条年产2万吨的线，气耗差10方/吨，一年就是20万方。按工业天然气4元/方（发布前复核当地气价），约80万元/年。这20万方天然气同时对应约430吨二氧化碳（按2.16 kgCO₂/m³ 的排放因子折算）——采购方在碳足迹表上看到的，就是这个数。省气，第一次不只是省钱，也是在降碳。

Natural gas is the single largest running cost of a melting furnace, and it is also the most direct line in a carbon footprint statement. Typical gas consumption across the industry falls in the 65-75 m³ per tonne range — a wide spread.

Do the arithmetic: on a 20,000 t/y line, a 10 m³/t difference means 200,000 m³ of gas a year. At RMB 4/m³ for industrial gas (verify the local price before publishing), that is roughly RMB 800,000 a year. Those 200,000 m³ also carry about 430 tonnes of CO₂ (using the 2.16 kgCO₂/m³ emission factor) — which is exactly the number a buyer reads off the footprint sheet. Saving gas is no longer only about cost; it is now also about carbon.

烧损和气耗是两笔账，不能混着算。气耗是燃料烧掉多少，烧损是金属变成了渣——铝氧化掉的那部分，是永远回不来的成品。

还是那条2万吨的线：烧损差1个百分点，一年就是200吨铝。按A00铝23,770元/吨，约475万元/年。这个量级，比气耗那笔账大一个数量级。

Burning loss and gas consumption are two separate accounts and must never be added together. Gas consumption is how much fuel is burned; burning loss is how much metal turned into dross — aluminium that has oxidized is finished product that will never come back.

On the same 20,000 t/y line, one percentage point of burning loss equals 200 tonnes of aluminium a year. At RMB 23,770/t for A00 aluminium , that is roughly RMB 4.75 million a year — an order of magnitude larger than the gas bill.

排放不是加分项，是入场券。GB 31574-2015 对再生铝的氮氧化物有明确限值，重点区域执行的是更严的一档。排烟温度也是一道隐性考核：排烟越热，说明热量没被炉子吃进去，跟着烟气直接走了。

这两个数在采购审核里常被当成附件，但它们决定你能不能进供应商名录——环保一旦不达标，前面两笔账算得再漂亮也没有意义。

Emissions are not a bonus; they are the entry ticket. GB 31574-2015 sets clear NOx limits for secondary aluminium, with the stricter tier applied in key regions. Exhaust gas temperature is a second, quieter test: the hotter the flue gas, the more heat left the furnace without doing any work.

Buyers often treat these two numbers as an annex to the audit — but they decide whether you make the approved vendor list at all. Fail them and the other two accounts, however good, no longer matter.

气耗这个数，最容易被"一天的数"美化。料有干有湿，炉子有热有凉，赶上顺的一天，谁的表都好看。所以谈设备时，真正要写进合同的不只是"多少方"，而是"怎么测、测几天、取不取平均"。

我们的做法是把验收口径写死：连续3天实测，取平均值。这既是双方对数的依据，也是客户日后做碳足迹申报、应对碳关税核查时拿得出手的台账。

A gas figure is easiest to flatter with "one good day". Scrap varies in moisture, the furnace varies in heat, and on a favourable day every meter looks good. So when negotiating equipment, what belongs in the contract is not only "how many cubic metres" but also "how it is measured, over how many days, and whether an average is taken".

Our practice is to fix the acceptance basis in writing: three consecutive days of measurement, averaged. That is the reference both sides settle on — and it is also the record a customer can produce later for carbon footprint reporting or carbon tariff verification.

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