RESEARCH OF THE DISTRIBUTION OF DISPERSE PARTICLES OF VALUABLE COMPONENTS IN THE SLUDGE OF THE SULFURIC ACID SHOP OF COPPER SMELTERS

ABSTRACT

The article analyzed lead-bismuth sludge, determined the distribution of dispersed particles in the composition of the initial product, and also assessed the manifestation of valuable components during the processing of lead-bismuth sludge by hydrometallurgical methods, in particular in the processes of filtration and selective precipitation. It was found that particle sizes of heavy non-ferrous metals range from 1 to 25 microns and, when filtered and selectively deposited during processing by leaching, they complicate the processes.

АННОТАЦИЯ

В статье проанализировано свинцово-висмутовых шламов, было определено распределение дисперсных частиц в составе исходного продукта, а также даны оценки проявление ценных компонентов при переработке свинцово-висмутовых шламов гидрометаллургическими методами, в частности в процессах фильтрации и селективного осаждения. Было выявлено, что размеры частицы тяжелых цветных металлов от 1 до 25 мкм и они при фильтрации и селективном осаждении при переработке выщелачиванием затрудняет протекании процессов.

Keywords: lead-bismuth sludge, size, content, metal, mineralogical analysis, X-ray analysis, hydrometallurgy, leaching, research, separation, solution, sediment.

Ключевые слова: свинцово-висмутовый шлам, размер, содержание, металл, минералогический анализ, рентгеноструктурный анализ, гидрометаллургия, выщелачивание, исследование, сепарация, раствор, осадок.

During the production of copper in the metallurgical workshop, gas is formed, which is sent to produce sulfuric acid. First, it enters the washing compartment, where it is cleaned. Purified gas is used to produce sulfuric acid, and impurities that fall into sludge are sent to the acid waste neutralization site, then enter a storage tank, from where they are removed and stored at factories. This leads to overstocking of non-ferrous metals, costs for their warehousing and storage, and deterioration of the environmental situation in the industrial zone of the plant. To solve this problem, a technological scheme has been developed for processing these stale lead-containing materials with acceptable technical and economic indicators, with the extraction of non-ferrous and precious metals from them. This work is devoted to determining the presence of minerals and valuable components in the composition of lead-bismuth sludge and presents an in-depth analysis of the initial product, showing the distribution of dispersed particles in order to establish optimal processing parameters and minimize the loss of fine particles with waste.

The object of study was lead-bismuth sludge from the sulfuric acid shop of the copper smelter of JSC AGMK.

As a result of the study, the following characteristics of lead-bismuth sludge were determined:

humidity on average is 9-11%, fluctuations from 5 to 15% are possible by season;

- initial fineness: from 0 to 20-30 mkm. During the process of accumulation in storm drains and drying in air, the sludge cakes into individual aggregates with a size ranging from 1 mm to 250 mm, the size of the fractions is uncontrollable and unpredictable;

- the main material is finely dispersed PbSO₄ in the form of sublimates in cooled gases.

- density of the main material PbSO₄ is about 5.2 g/cm³, in the natural form of sludge 1.9 g/cm³, compacted by vibration 2.1 g/cm³.

- The initial pH of the sludge at the site is 1.5-2.5 i.e. acidic medium H₂SO₄.

The results of semi-qualitative mineralogical analysis of lead-bismuth sludge are given in table. 1. As shown, the main minerals are: anglesite, cuprite, tenorite, gypsum and the like, zinc and iron sulfates. The total amount of lead sulfate is 48.2% according to the Rietveld method. A diffractogram of a sample of lead-bismuth sludge is shown in Fig. 1.

Table 1.

Semi-quality mineral content in lead-bismuth sludge sample

Figure 1. Powder diffraction pattern of the original lead-bismuth slurry

To determine the elemental, mineralogical composition and structure of the objects under study, the samples were studied using a JSM-IT200 scanning electron microscope.

After sampling to study the elemental composition and structure of the mineralogy of the lead-bismuth slurry, several images were taken using a digital electron microscope SEM (Fig. 2).

Figure 2. Multi-element map of a sample of the original lead-bismuth sludge at 2000x magnification

In Fig. 2, particles of lead, copper, and zinc are visible, associated with oxygen and with each other, and the main part of their surface is filled with iron oxides. As a result of the analysis, it was found that the structure of noble metals is more dense, that is, they reflect light brighter in part of the sample and they are more connected with oxygen and with each other. In a scanning electron microscope, heavy particles appear brighter, i.e. The brighter the particles, the heavier they are. Proof of this fact is that all heavy noble metals that have a high density are heavy, which means that the brighter SEM images are characterized by gold, silver, platinum and palladium. From the above we can conclude that the main surface of the sample consists of iron oxides.

Table 2.

Elemental composition of the total sample area of lead-bismuth sludge

The structures of lead-bismuth sludge were studied to determine the content of valuable components and their sizes.

Analyzing EMF images of lead-bismuth slurry, it is clear that iron, copper, zinc, palladium and silver are colored green, and lead, platinum, gold and bismuth are colored blue. The main impurity metals are calcium, silicates, aluminum and magnesium.

Thus, a comprehensive comparative analysis of the lead-bismuth sludge from the sulfuric acid shop of the copper smelter of JSC AGMK using an electron microscope showed that the particle sizes of heavy non-ferrous metals such as lead, copper and zinc are from 1 to 25 microns and they are filtered and selectively precipitated during processing by leaching complicates the process. Therefore, when researching recycling, it is necessary to creatively consider not only a theoretical point of view, but also practical experiments also give positive results.

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