Recently, the ore base of the Republic of Kazakhstan has been characterized by involvement of rebellious and off-balance ores into processing. In this regard, much attention is paid to the methods of preliminary enrichment of mineral raw materials. The use of various methods of preliminary ore beneficiation allows removing a part of barren rock as well as harmful impurities from processing, thereby increasing quality of the feedstock, both in terms of metal content and material composition. The barren rock removal in the head of the process, as a rule, improves the mineral flotation conditions, reduces the consumption of reagents and operating costs for further processing, as well as allows involving the off-balance and rebellious ores into processing. This article presents the results of the heavy suspension gravity dressing of the Shalkiya deposit widely classified lumpy lead-zinc ore, and the study of grindability of both the original ore and gra vity dressing products according to the Bond procedure. When studying the lead-zinc ore gravity dressability, it has been found that the grade with size grade of 40–8 mm is optimal, and it has been determined that the optimal separation density required for the floating fraction precipitation is equal to 2730 kg/m3. As a result of gravity dressing, the material with a high content of waste minerals in the form of quartz, carbonates and coaly substances, with permissible minimum zinc and lead losses, is released to the floating fraction. According to the Bond procedure, the Wi Bond ball mill work index has been determined for original ore, sinking and floating fractions. It has been established that the barren rock removing in the head of an engineering process will allow to increase the content of non-ferrous metals in the sinking fraction relative to their content in the ore, to reduce power inputs for the sinking fraction grinding in comparison with the original ore grinding and, correspondingly, to increase the cost-performance of further ore processing. This work was supported by grant No. AP05133980.

The development of combined enrichment technologies becomes more significant due to the decreasing of the processed ores quality and involvement in the processing of poor, refractory ores. The difficulty in the flotation enrichment of mixed and oxidized polymetallic ores and intermediate products lies in the effective sulfidization of the surface of oxidized minerals. The sodium sulfide reagent used in flotation does not always provide complete sulfidization of the mineral surface. On the intermediate product of lead-zinc ores related to the phase composition of mixed ores, flotation studies were carried out on the original product and after preliminary sulfidization by the pyro-metallurgical method. It was found that in the pre-sulfidizied product, the extraction of zinc increased to 17.23 %, and lead to 10.07 %, compared with the original product without pre-treatment.

Lead-zinc ores of the Shalkiya deposit in Kazakhstan are classified as refractory, but, given their significant reserves, remain one of the main potential lead and zinc mining targets. Selective flotation is recommended for the industrial processing of these ores, which, however, fails to ensure high lead and zinc recovery into the concentrates. This paper presents gravity concentration studies for the ore of the Shalkiya deposit. Fractional analysis results for the particle size class of –40+8 mm were used to design and compile Henry–Reinhard washability curves, establish the separation density (2730 kg/m3) required to isolate the light fraction with the minimum possible content of lead and zinc, and calculate the gravity washability indices for all the size classes studied (0.7 to 0.71). It has been established that, when gravity concentration of the original crushed ore of the deposit is placed at the head of the process, tailings are released with a yield of up to 20 % and with the recoveries of up to 30 % for silica, up to 11 % for calcite, and up to 12 % for carbonaceous matter. It has also been found that the coarse crushed ore must be processed in dense media. One of the positive aspects of gravity concentration consists in the reduction of energy costs for grinding the heavy fraction, which has been experimentally proven in the article.This work was supported by grant no. AP 05133980 of the Ministry of Education and Science of the Republic of Kazakhstan.

The research results on gravity concentration of the Shalkiya deposit lead-zinc ore are presented. Using the float-and-sink analysis data, the Henry-Reinhard-type washability curves are calculated...

This article presents the results of the high-temperature hydrolysis process of FeCl2×4H2O and the study of iron oxide powder properties produced. It is observed that the process has a topochemical character and proceeds in a diffusion zone. Conditions sufficient for practically complete decomposition of FeCl2×4H2O are a temperature in the range of 803–903 K and a duration of 40 minutes. The powder, obtained as a result of high-temperature hydrolysis of FeCl2×4H2O, is represented by an ultradisperse powder of iron oxides of 10–100 nm in size (average — 20 nm), having a basically round shape. The results of microprobe, X-ray phase analyzes, magnetic susceptibility analysis, and Mössbauer spectroscopy have revealed that the product of hightemperature hydrolysis consists of a mixture of iron oxides consisting of magnetite and hematite.