烧结协同处置铬渣和含铁粉尘的基础和技术研究

铬渣的处置利用一直是世界性的难题。与此同时，钢铁厂产生的大量含铁含碳粉尘也未得到高效利用。目前，烧结法是处置这两种固废较常采用的方法，但烧结过程仍存在处理量小、六价铬还原解毒不完全等问题难以克服。为此，申请人提出烧结协同处置铬渣和含铁粉尘的新思路：首先将铬渣和粉尘制成复合球团，其他铁料、焦粉、熔剂等制成基体料，再将复合球团“植入”基体料层，布到烧结机上联合焙烧。本项目巧妙的利用联合焙烧过程中，复合球团内固体碳在高温条件下的还原作用使含铬化合物直接还原为金属铬或碳化铬，一步实现铬的彻底解毒。本项目通过揭示联合焙烧过程复合球团中铬、铁、碳等组分转化的热力学行为和相变规律，确定球团中含铬化合物直接还原为金属铬或碳化铬的外场条件，开发烧结法协同处置铬渣和含铁粉尘的新技术。本项目完成后，可为铬渣和含铁粉尘的清洁、高效利用提供新途径，为高炉冶炼含铬铁水提供新炉料。

The disposal of chromium slag has always been a worldwide problem. Similarly, a large amount of iron, carbon-bearing dusts are produced in the steel plants but not utilized effectively. The sintering-ironmaking process is always applied to utilize the two kinds of solid wastes, but there still exist some problems hard to overcome, such as incomplete detoxification of hexavalent chromium and low disposal efficiency. In order to solve these problems, a novel technical idea of “co-processing chromium slag and iron, carbon-bearing dusts by sintering process” is proposed. At first, the chromium slag and iron, carbon-bearing dusts are made into composite pellets (as pellet part), and the rest of iron ore fines, fluxes and fuels are granulated into coarse particles (as matrix part). Then, the pellet and matrix parts are mixed and put onto the sintering machine to roast. At high temperature, the chromium-bearing compounds are directly reduced to metallic chromium or chromium carbide by the carbon contained in the pellets during the sintering process, completing the detoxification of chromium slag by one step. In this project, the laws of phase transformation and thermodynamic behavior of Cr, C, Fe components in the composite pellets during the sintering are discovered, and the external field conditions for chromium-containing compounds being directly reduced to metallic chromium are clarified. The technical prototype of coprocessing chromium slag and iron, carbon-bearing dusts via sintering is built based on the above investigations. This project may provide a new method for effectively utilizing the chromium slag and iron, carbon-bearing dusts in a large scale, moreover, new burdens are produced for blast furnace ironmaking chromium-bearing hot metal by this new process.