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This is an article in the field of mineral processing engineering. For the flotation of sulfide ores whose gangue mineral is serpentine, serpentine can deteriorate the flotation of sulfide ores due to its easy mudification. To solve this problem, 2-hydroxyphosphonoacetic acid (HPAA) was used for the first time in this paper to eliminate the negative effect of serpentine on chalcopyrite flotation. In this article, the effect of HPAA on chalcopyrite/serpentine flotation system and the mechanism of action were investigated by microflotation test, turbidity test, zeta potential test, adsorption amount test and XPS test. The tests showed that serpentine is positively charged and chalcopyrite is negatively charged. Due to the electrostatic attraction, serpentine slime will adsorb on the surface of chalcopyrite, thus inhibiting the flotation of chalcopyrite. After adding HPAA, the flotation recovery of chalcopyrite was increased from 47.85% to 92.44%. The mechanism was that HPAA chemisorbed with Mg2+ of serpentine, which significantly reduced the surface potential of serpentine and caused repulsive effect on mineral particles, thus recovering the floatability of chalcopyrite.

This is an essay in the field of mineral processing engineering. Through micro-flotation experiment, contact Angle test, Zeta potential test, Adsorption measurements and infrared spectrum analysis, the effects of alendronate sodium on the flotation behavior of fluorite and calcite were studied, and the adsorption mechanism of alendronate sodium on the surface of two kinds of minerals was investigated. Micro-flotation experiment results show that when only sodium oleate is added, fluorite and calcite have good floatability in the pH range of 7~12 and are difficult to separate. The floatability of fluorite and calcite is different when sodium alendronate is added, and the flotation separation of fluorite and calcite can be realized. The results of contact Angle test, Zeta potential test, adsorption capacity test and infrared spectrum analysis showed that the adsorption amount of sodium alendronate on fluorite surface was less, which had little effect on its surface wettability, while the adsorption amount on calcite surface was larger, which had a greater effect on its surface wettability. Two phosphate groups in sodium alendronate bind with calcium atoms on the surface of calcite, which hindered the adsorption of oleic acid molecules on the surface of calcite, thus inhibiting the calcite.

In this study, the innovative use of ethylenediamine tetramethylene phosphonic sodium (EDTMPS) as a calcite depressant in scheelite flotation was investigated by flotation experiments, and its selective depression mechanism was revealed by contact angle measurement, FTIR analysis, Zeta potential test and XPS analysis. The flotation experiment results showed that scheelite and calcite could be efficiently separated under the following conditions: pulp pH=9.5, NaOL concentration of 1.5×10−4 mol/L, EDTMPS concentration of 3.0×10−5 mol/L, a scheelite concentrate with WO3 grade of 65.49%, recovery of 83.29% and separation efficiency of 65.29% could be obtained from the artificially mixed minerals. The analysis results of mineral surface properties demonstrated that EDTMPS was strongly adsorbed onto the calcite surface through the reaction between the phosphonate group and the calcium ions, which hindered NaOL adsorption and increased the hydrophilicity of calcite. However, EDTMPS had weak adsorption strength on the scheelite surface, which didn’t affect further adsorption of NaOL, hence, the scheelite remained hydrophobic. Consequently, the selective adsorption of EDTMPS on the two minerals’ surfaces increased a difference in wettability and thus enabling them to be separated by flotation. Finally, the mechanism model of this flotation separation process was established.

As the main solid waste of the electrolytic aluminum industry, overhaul slag contains a large amount of hazardous substances, and how to treat it harmlessly and efficiently recover the valuable substances in it has become an urgent problem in the aluminum industry in recent years. This article analyzes and summarizes the composition and hazards of the overhaul slag and the current development status of domestic and international electrolytic aluminum overhaul slag disposal, and points out the development direction of hazardous waste disposal in China's electrolytic aluminum industry.

The flotation separation of magnesite from calcium-containing minerals has always been a difficult subject in minerals processing. This work studied the inhibition effects of carboxymethyl cellulose (CMC), sodium lignosulphonate, polyaspartic acid (PASP) and sodium silicate on flotation behaviors of magnesite, dolomite and calcite, providing guidance for the development of reagents in magnesite flotation. The micro-flotation results showed that among these four depressants, sodium silicate presented the strongest selectivity due to the highest recovery difference, and the flotation separation of magnesite from dolomite and calcite could be achieved by using sodium silicate as the depressant. Contact angle measurement indicated that the addition of sodium silicate caused the largest differences in surface wettability of the three minerals, which was in line with micro-flotation tests. Furthermore, zeta potential test, the Fourier transform infrared (FT-IR) spectroscopy and atomic force microscope (AFM) imaging were used to reveal the inhibition mechanism of sodium silicate. The results indicated that the dominated component SiO(OH)3− of sodium silicate could adsorb on minerals surfaces, and the adsorption of sodium silicate hardly affected the adsorption of NaOL on magnesite surface, but caused the reduction of NaOL adsorption on dolomite and calcite surfaces, thereby increasing the flotation selectivity.

Study on the mineral processing of a high sulfur lead-zinc ore in Yunnan Province were conducted. Grades of lead, zinc and silver were 2.98%, 2.79% and 114.95 g/t, respectively. Ore was ground to -0.074 mm 76.19% and under the condition of selective flotation process, the combined reagents ZnSO4 and Na2CO3 used as the depressant and HQ-Pb and HQ-Zn were used as a novel galena and sphalerite collector. From the results of closed circuit tests, the lead concentrate, containing 56.62% Pb and 1915.38 g/t Ag, was produced, at recovery of 82.36% Pb and 73.44% Ag. And zinc concentrate of 45.92% Zn and 171.38 g/t Ag, was obtained, at recovery of 82.29% Zn and 7.58% Ag.

Sulfuric acid was used as the leaching medium, and the leaching conditions, including acid concentration, liquid-solid ratio and temperature, were optimized by response surface methodology and Box-Behnken design (BBD). The results showed that the acid concentration was the most important factor, followed by temperature and liquid-solid ratio. Through response surface optimization, the optimal process conditions were determined as follows: acid concentration of 116.77 g/L, liquid-solid ratio of 8, and temperature of 170℃. Under these conditions, the arsenic extraction rate of copper converter reached 94.49%, indicating that the acid extraction experiment of lead converter arsenic ash could be successfully optimized by response surface methodology.