Process for producing oxalic acid

A process for producing oxalic acid containing or having the following steps: i) utilizing a chemical reaction to produce an alkali metal formate and/or alkaline earth metal formate; ii) converting the alkali metal formate and/or alkaline earth metal formate to an alkali metal oxalate and/or alkaline earth metal oxalate in a thermal reaction, preferably utilizing hydrogen in the process; iii) converting the alkali metal oxalate and/or alkaline earth metal oxalate to oxalic acid and an alkali metal base and/or alkaline earth metal base utilizing an electrochemical process; and iv) recycling thealkali metal base and/or alkaline earth metal base from step (iii) to step (i). 种制备草酸的方法，其含有或具有以下步骤：i)利用化学反应制备碱金属甲酸盐和/或碱土金属甲酸盐；ii)在热反应中，优选在所述方法中利用氢气将所述碱金属甲酸盐和/或碱土金属甲酸盐转化为碱金属草酸盐和/或碱土金属草酸盐；iii)利用电化学方法将所述碱金属草酸盐和/或碱土金属草酸盐转化为草酸和碱金属碱和/或碱土金属碱；和iv)将所述碱金属碱和/或碱土金属碱从步骤(iii)再循环到步骤(i)。