Beneficiation of fine chromite slurry at Donskoy Mining and Beneficiation Plant JSC on concentration tables to produce hard chromite pellets

Processing industrial products and technogenic waste is an important task in the mining and metallurgical industry. In Kazakhstan, the processing of chrome ore from the Kempirsay group of deposits has produced more than 15 million tonnes of slurry tailings containing up to 30 wt% chrome oxide. The best results in the world for the processing of fine chromium raw materials are shown by Turkish enterprises with the use of the separation of slurries by size classes and beneficiation on concentration tables. The authors conducted researches for beneficiation of chrome slurry from Dubersay tailings pond (Kazakhstan) with the use of similar technological methods that enabled to obtain concentrates with chrome oxide content of 51 wt% and increasing the yield of beneficiated fine-graded chrome concentrates by 14% as compared with the existing beneficiation process. Strong chromium pellets with a crushing resistance of over 5000 N/pellet were produced from the rich chromium concentrates with the use of the ferrofluxing iron-calcium-silica binder technology by roasting the composition consisting of rich chromium concentrate, ferrous diatomite, and intermediate products and wastes of the chromium industry.

Chromium Concentrate Recovery from Solid Tannery Waste in a Thermal Process

Leather processing requires substantial inputs of energy, water and chemicals. Additionally, it generates significant amounts of liquid and solid waste, severely impacting the environment. Processing 1 Mg of raw hides yields up to 600–700 kg of waste, considerable amounts of which are solid tannery waste. Such waste contains chromium (Cr) compounds, which are commonly used as tanning agents. This paper reviews solid tannery waste treatment technologies, with emphasis on waste incineration in a specially designed experimental tunnel incinerator. Three different types of tannery waste were subjected to tests: trimmings, shavings and buffing dust. As the research revealed, the process can be applied to all types of solid tannery waste. Moreover, it enables the reuse of the heat of the process and results in a Cr concentrate in the process residues. The conducted analyses (carbon, hydrogen and nitrogen elemental analysis; inductively coupled plasma optical emission spectroscopy; powder X-ray diffraction) proved that there is no or little organic content in the obtained residual ash, which contains up to 53.1%(w/w) Cr in the form of Cr (III) oxide. Such material may be used as a Cr ore substitute in the chemical or metallurgical industries.

A New Method to Produce Ni–Cr Ferroalloy Used for Stainless Steel Production

A new electrosilicothermic method has been proposed in the present paper to produce Ni–Cr ferroalloy, which can be used for the production of 300 series stainless steel. Based on this new process, the Ni–Si ferroalloy is first produced as the intermediate alloy, and then the desiliconization process of Ni–Si ferroalloy melt with chromium concentrate is carried out to generate Ni–Cr ferroalloy. The silicon content in the Ni–Si ferroalloy produced in the submerged arc furnace should be more than 15 mass% (for the propose of reducing dephosphorization), in order to make sure the phosphorus content in the subsequently produced Ni–Cr ferroalloy is less than 0.03 mass%. A high utilization ratio of Si and a high recovery ratio of Cr can be obtained after the desiliconization reaction between Ni–Si ferroalloy and chromium concentrate in the electric arc furnace (EAF)–shaking ladle (SL) process.

The Influence of Indian Concentrate Chrome Ore on Top Quality Magnesite-Chrome Brick for RH Degasser

The top quality magnesity-chrome adding Indian concentrate chrome ore as investigated at this present. The samples adding 5%、10%、15%、20% Indian concentrate chrome ore respectively are prepared. The results shown that the thermal shock resistance of the brick is improved by adding right quantity of Chromium Concentrate and the brick which adding Chromium Concentrate have a better performance.